Transcatheter Tricuspid Valve-in-Valve Intervention for Degenerative Bioprosthetic Tricuspid Valve Disease Fabien Praz, MD, Isaac George, MD, Susheel Kodali, MD, Konstantinos P. Koulogiannis, MD, Linda D. Gillam, MD, Mary Z. Bechis, MD, David Rubenson, MD, Wei Li, MD, and Alison Duncan, MRCP, PhD, New York, New York; Morristown, New Jersey; La Jolla, California; and London, United Kingdom
Isolated reoperative tricuspid valve replacement is one of the highest risk operations classified in the Society of Thoracic Surgeons registry, particularly in the setting of preexisting right ventricular dysfunction. Transcatheter tricuspid valve-in-valve implantation represents an attractive alternative to redo surgery in patients with tricuspid bioprosthetic valve degeneration who are considered high-risk or unsuitable surgical candidates. In this review article, the authors discuss the emergence of transcatheter tricuspid valve-in-valve therapy, preprocedural echocardiographic assessment of tricuspid bioprosthetic valve dysfunction, periprocedural imaging required for tricuspid valve-in-valve implantation, and postprocedural assessment of tricuspid transcatheter device function. (J Am Soc Echocardiogr 2017;-:---.) Keywords: Transcatheter, Tricuspid, Valve-in-valve, Degenerative bioprosthetic tricuspid valve
Transcatheter valve-in-valve (ViV) procedures are attractive alternatives to redo conventional surgery to treat dysfunctional aortic1 and mitral2 bioprostheses. Until recently, transcatheter tricuspid valve (TV) implantation within either an existing surgical bioprosthesis (tricuspid ViV implantation) or a previously repaired TV had been limited to small case series or case reports.3-12 However, with the recent publication of the global transcatheter tricuspid Valve-inValve International Database (VIVID) registry,13 and recognition that redo surgery for failing TV bioprosthesis carries increased morbidity and mortality, particularly when preexisting right ventricular (RV) dysfunction is present,14-17 it is likely that tricuspid ViV procedures will become an increasingly recognized alternative to redo surgical TV intervention. Moreover, novel transcatheter techniques to repair native regurgitant TVs are also emerging.18-21 Facilitation of successful transcatheter TV procedures requires comprehensive understanding of two-dimensional (2D) and realtime (RT) three-dimensional (3D) transthoracic echocardiographic and transesophageal echocardiographic (TEE) images of the normal and diseased TV, to permit early and accurate detection of TV disease, to direct the timing and assess the effectiveness of treatment, to guide transcatheter TV interventions, and to assess residual TV disease.
From the Structural Heart & Valve Center, New York Presbyterian/Columbia University Medical Center, New York, New York (F.P., I.G., S.K.); Morristown Medical Center, Morristown, New Jersey (K.P.K., L.D.G.); Division of Cardiovascular Diseases, Scripps Clinic, La Jolla, California (M.Z.B., D.R.); and Royal Brompton Hospital, London, United Kingdom (W.L., A.D.). Dr. Praz and Dr. Kodali are consultants for Edwards Lifesciences (Irvine, CA). Reprint requests: Alison Duncan, MRCP, PhD, Royal Brompton Hospital, Royal Brompton and Harefield NHS Foundation Trust, Sydney Street, London SW3 6NP, United Kingdom (E-mail: [email protected]). 0894-7317/$36.00 Copyright 2017 by the American Society of Echocardiography. All rights reserved. http://dx.doi.org/10.1016/j.echo.2017.06.014
ANATOMIC CONSIDERATIONS AND IMPLICATIONS FOR TV SURGERY The TV apparatus is composed of three leaflets (anterior, posterior, and septal) attached to the myocardium of the right ventricle either directly or by the means of chordae linked to a papillary muscle. Autopsy studies, however, report highly variable anatomy; in one study, the TV was found to be a single leaflet in 17% of cases, bicuspid in 72%, and tricuspid in only 17%, with the posterior leaflet being frequently either absent or incorporated into the anterior or septal leaflets.22 Other studies report absent septal papillary muscle23 or presence of accessory leaflets24 in a high proportion of human hearts. In tricuspid regurgitation (TR), anatomic distortion may be accentuated by multiple chordal attachments between the myocardium and valve leaflets, resulting in secondary leaflet tethering with RV dilatation. This process is aggravated by volume overload, which results not only in TV distortion but progressive deterioration in RV systolic function. As a result, severe TV disease has been associated with a threefold increase in all-cause mortality rate and a four- to fivefold increased incidence of cardiac events during long-term follow-up,25 while elective tricuspid annuloplasty for patients with functional TR undergoing elective left-sided heart surgery is associated with a reduction in cardiac-related mortality and improved echocardiographic outcomes.26 Because of the anatomic complexity of the TV and coexisting advanced RV disease, almost 30% of patients are deemed unsuitable for surgical TV repair at presentation and are instead offered TV replacement.27 Although robust comparative data are unavailable,28,29 implantation of a bioprosthesis is preferred in current practice.27 In addition, the increased bleeding risk associated with long-term oral anticoagulation and mechanical valve replacement can be avoided. A recently published meta-analysis of observational studies showed no differences between mechanical and biologic TV replacement in terms of survival and reoperation. However, the risk for valve thrombosis was significantly higher in patients with mechanical prostheses.30 For reasons still unclear, 1
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Abbreviations
2D = Two-dimensional 3D = Three-dimensional CW = Continuous-wave EOA = Effective orifice area IVC = Inferior vena cava LOE = Level of evidence LVOT = Left ventricular outflow tract
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the longevity of tricuspid bioprostheses seems shorter compared with that of bioprostheses exposed to the systemic circulation (aortic, mitral). This translates into a reoperation rate of about 20% for valve degeneration within 10 years and freedom from reintervention of only 53% at 15 years after surgical valve replacement.14,15,31
MSCT = Multislice computed tomography
PHT = Pressure half-time RT = Real-time RV = Right ventricular TEE = Transesophageal echocardiographic
EMERGENCE OF TRANSCATHETER TREATMENT ALTERNATIVES
Reoperation for valve degeneration is associated with mortality ranging from 17% to 37%,14-17 TR = Tricuspid regurgitation and isolated reoperative TV TS = Tricuspid stenosis replacement is one of the TTE = Transthoracic highest risk operations classified echocardiography in the Society of Thoracic Surgeons registry. Novel TV = Tricuspid valve transcatheter therapies are ViV = Valve-in-valve emerging for the treatment of TR,32 including transcatheter VIVID = Valve-in-Valve tricuspid ViV implantation for International Database patients with tricuspid bioVTI = Velocity-time integral prosthetic valve stenosis and/or transvalvular regurgitation deemed too high risk or unsuitable for reoperation. Notwithstanding, younger patients with Ebstein’s anomaly requiring multiple valve replacements because of somatic growth or bioprosthesis degeneration may also benefit from transcatheter intervention as a mechanism to extend the duration between repeat valve operations.33,34 Tricuspid ViV transcatheter treatment of degenerated tricuspid bioprostheses was first successfully performed using the Melody valve (Medtronic, Minneapolis, MN) in 2010 through a jugular venous route in a patient with previous TV replacement (27-mm Medtronic Mosaic valve) 8 years after treatment for TVendocarditis.3 Evolution of the access routes subsequently followed: in 2010, a 26mm Edwards SAPIEN transcatheter heart valve (Edwards Lifesciences, Irvine, CA) was implanted for the first time into a Medtronic Mosaic 27-mm bioprosthesis through a right atriotomy (off pump),4 and a fully percutaneous procedure using the jugular venous approach was described shortly later using a 23-mm SAPIEN valve5 in 2011. Upon commercial availability of the steerable RetroFlex delivery system, transfemoral venous implantation of a SAPIEN XT valve became technically possible, paving the way for a simplified and more convenient tricuspid ViV procedure.6 Subsequently, the safety, feasibility, and efficacy of the tricuspid bioprosthesis ViV procedure has been confirmed in multiple case reports and series.35 The largest series published to date, the tricuspid VIVID registry, reported on the outcomes of 152 patients.13 In this cohort, the age of the failing surgical bioprostheses was #5 years in as
Table 1 Doppler parameters of prosthetic TV function: current American Society of Echocardiography guidelines Consider TV stenosis* †
Peak velocity
>1.7 m/sec
Mean gradient†
$6 mm Hg
PHT
$230 msec
EOA and VTIPrTV/VTILVOT
‡
PrTV, Prosthetic TV. *Average more than five cycles to account for respiratory variation. † May also be increased with valvular regurgitation. Reprinted from Zoghbi et al.40 ‡ Although the current guidelines for the echocardiographic assessment of TV prostheses do not include cutoffs for EOA and VTIPrTV/VTILVOT, Blauwet et al.41 published data on a large series (N = 285) of a number of TV prosthesis models and sizes that include proposed cutoffs for these hemodynamic variables.
many as 30% of the patients, highlighting the accelerated degeneration observed in tricuspid bioprostheses. Overall, the study confirmed high procedural success (99%) as well as excellent safety, with only one procedural death and no acute conversion to open-heart surgery despite two valve embolizations that were managed percutaneously. Significant improvement of invasive transvalvular gradient and severity of TR were observed regardless of the type of valve implanted, which translated into sustained functional improvement in 76% of patients. Survival free from reintervention was 85% at 1 year. Valve thrombosis was suspected in 4 patients (3%), and 4 additional patients (3%) met the criteria for valve endocarditis. All-cause mortality was low, with a reported incidence of 3% at 30 days and a total of 22 deaths (15%) during a median follow-up period of 13 months.
TRANSTHORACIC ECHOCARDIOGRAPHIC ASSESSMENT OF DEGENERATIVE TV BIOPROSTHESIS Preprocedural transthoracic echocardiography (TTE) is an excellent first-line diagnostic tool in the assessment of tricuspid bioprosthetic valve function, as the anterior location of the TV permits favorable echocardiographic visualization and evaluation of prosthetic valve function. The primary goal of TTE is to evaluate the severity, mechanism, and anatomic substrate for prosthetic valve dysfunction, which may involve tricuspid stenosis (TS), TR, or a combination of TS and TR. Common causes of tricuspid bioprosthetic valve dysfunction include leaflet degeneration, leaflet thrombosis, endocarditis-related leaflet damage, and pannus formation. Paravalvular regurgitation is usually related to endocarditis or surgical suture tear. TTE should determine the presence or absence of thrombus, infective endocarditis, or paravalvular leak, as these are exclusion criteria for transcatheter tricuspid ViV. The specific role of TTE in determining the size of surgical and transcatheter valve devices is limited; operative notes, multislice computed tomography (MSCT), TEE imaging, and fluoroscopy are more reliable modalities for selecting transcatheter device size (see below). Comprehensive assessment of a patient with tricuspid bioprosthesis degeneration should include 2D and 3D imaging, as well as color flow, continuous-wave (CW), and pulsed-wave Doppler imaging. Multiple windows should be used: parasternal RV inflow and short-axis, apical four-chamber, and subcostal views.
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Figure 1 Transthoracic imaging of tricuspid bioprosthesis degeneration with TS. A 31-mm Medtronic Mosaic tricuspid bioprosthesis with leaflet thickening on 2D imaging (A) (Video 1), a dilated, noncollapsing IVC (B) (Video 2), turbulent diastolic forward flow (C) (Video 3), and increased (14 mm Hg) mean pressure gradient (D). PG, Pressure gradient; RA, right atrium; Vmax, mean maximum velocity; Vmean, mean velocity. On the occasion that acoustic shadowing limits evaluation in conventional views, alternative transthoracic echocardiographic windows such as short-axis subcostal or low parasternal may prove as useful as TEE imaging. In patients with adequate 2D images, simultaneous biplane imaging in orthogonal planes with complementary 3D images allows comprehensive evaluation of the prosthetic TV and its leaflets. However, low temporal and spatial resolutions36 are recognized limitations of 3D TTE of the TV. As with all prosthetic valves, the valve size of the tricuspid bioprosthesis should be recorded, if known, in all cases.
Tricuspid Bioprosthetic Valve Stenosis A combination of quantitative and qualitative assessments is used to determine the presence and severity of prosthetic TS (Table 1, Figure 1). Two-dimensional imaging of the TV bioprosthesis includes evaluation of valve seating, leaflet appearance, and leaflet mobility. The appearance of leaflet thickening, calcification, and/or hypomobility (Video 1, available at www.onlinejase.com), with right atrial enlargement and a dilated noncollapsing inferior vena cava (IVC; Video 2, available at www.onlinejase.com), may suggest the presence of TV stenosis. Normal color flow Doppler signal across the tricuspid
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Table 2 Echocardiographic and Doppler parameters used in grading severity of prosthetic TV regurgitation Parameter
Mild
Moderate
Severe
Valve structure
Usually normal
Abnormal or valve dehiscence
Abnormal or valve dehiscence
Jet area by color Doppler, central jets only (cm2)
10
Vena contracta width (cm)*
Not defined
Not defined, but 0.7
Jet density/contour by CW Doppler
Incomplete or faint, parabolic
Dense, variable contour
Dense with early peaking
Doppler systolic hepatic flow
Normal or blunted
Blunted
Holosystolic reversal
Right atrium, right ventricle, IVC
Normal†
Dilated
Markedly dilated
*For a valvular TR jet, extrapolated from native TR; unknown cutoffs for paravalvular TR. † If no other reason for dilatation. Reprinted from Zoghbi WA et al.40
bioprosthesis is typically laminar in appearance; turbulent and/or narrowed or eccentric color Doppler inflow suggests the presence of prosthetic TV stenosis (Video 3, available at www.onlinejase.com). CW Doppler across the prosthetic valve inflow measures transvalvular peak velocity and mean gradient and has been validated against catheter-derived data.37,38 To capture maximal transvalvular gradients, CW Doppler interrogation of prosthetic valve inflow should be performed from multiple echocardiographic windows, although the typical window to obtain the highest Doppler velocity is the apical four-chamber view, in which the flow direction is parallel to the transducer beam. The baseline should be shifted and the scale adjusted accordingly to allow optimal visualization and tracing of the spectral Doppler signal. CW Doppler measurements may vary with both heart rate and respiration, and a minimum of five cardiac cycles should be recorded and averaged to account for respirophasic variation of right-sided flow, even when the patient is in sinus rhythm.39,40 The average heart rate should also be noted because it can substantially affect the inflow gradient: diastole (time for atrial emptying) shortens with increasing heart rate, and a shorter diastole will of necessity result in a higher mean gradient. Doppler parameters such as peak E velocity, peak A velocity (in sinus rhythm), and velocity-time integral (VTI) across the valve can be measured to corroborate qualitative findings. Measurement of pressure half-time (PHT) and calculation of prosthetic valve effective orifice area (EOA) are additional parameters that can quantify prosthetic TV stenosis. The PHT is the time required for the maximal pressure gradient to decrease by half.39 Transvalvular gradient may be increased because of obstruction or regurgitation. In the context of increased transvalvular mean gradient, the PHT is a useful tool to differentiate between the two, as a prolonged PHT is suggestive of obstruction. Note that the PHT should not be used to calculate the EOA of TV prostheses but rather serve as a stand-alone measurement, because PHT-derived EOA calculation overestimates TV area compared with continuity equation–derived methods.41 The continuity equation is the preferred method for calculation of prosthetic TV valve EOA. This is typically performed by calculating the stroke volume across the left ventricular outflow tract (LVOT) and dividing it by the CW Doppler–derived prosthetic TV VTI. This calculation is accurate in the absence of significant aortic or TR. In the context of greater than mild aortic regurgitation (and if pulmonic valve
regurgitation is no more than mild), the RV outflow tract stroke volume may be used instead of LVOT stroke volume. If greater than mild TR is present, the continuity equation should not be used to assess EOA. According to American Society of Echocardiography guidelines, peak TV velocity > 1.7 m/sec, mean gradient > 6 mm Hg, and/or PHT > 230 msec suggest prosthetic TV obstruction40 (Table 1). In a large, more recent series of normal TV bioprostheses evaluated early after implantation, alternative thresholds for abnormal Doppler flow parameters have been proposed: transvalvular peak velocity > 2.1 m/sec, mean gradient > 8.8 mm Hg, and PHT > 193 msec.41 Tricuspid Bioprosthetic Valve Regurgitation As with TS, a combination of quantitative and qualitative assessments is used to determine the presence and severity of prosthetic TR (Table 2). TR may be either transvalvular or paravalvular in origin, and careful 2D assessment of the prosthetic TV from all available windows is necessary for complete evaluation. In the presence of clinically significant paravalvular regurgitation, percutaneous closure can be considered as a corrective strategy,42 whereas the extreme situation of ‘‘valve rocking,’’ suggestive of valve dehiscence, represents a contraindication to a ViV procedure. However, quantitation of paravalvular leaks is not established for TV prostheses. One might categorize severity by inferring from aortic valve literature and estimating the proportion of the annular circumference occupied by the leak,39 but this method has not been validated for TV prostheses. If transvalvular TR is present, transthoracic echocardiographic assessment should include qualitative assessment of TV leaflets (prolapse, flail), failure of leaflet coaptation (Video 4, available at www.onlinejase.com), and quantitative assessment of the regurgitant volume. Severe TR is usually associated with right atrial and RV dilatation, diastolic ventricular septal flattening, IVC dilatation, and hepatic vein systolic flow reversal (Figure 2). On color Doppler imaging, a large flow convergence (Video 5, available at www.onlinejase.com) and increased vena contracta width (>0.7 cm), effective regurgitant orifice area $ 40 mm2, and regurgitant volume $ 45 mL/beat all suggest severe TR, as does a dense CW Doppler tracing with a triangular, earlypeaking velocity, and increased transvalvular Doppler measurements (peak velocity and mean gradient).39,40 A VTI ratio between the TV
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Figure 2 Transthoracic imaging of tricuspid bioprosthesis degeneration with TR. A 33-mm Medtronic Mosaic tricuspid bioprosthesis with tricuspid leaflet prolapse (A) (Video 4), large forward flow convergence with eccentric TR on color Doppler imaging (B) (Video 5), dense CW Doppler tracing with a triangular, early-peaking velocity (C), and systolic flow reversal in the hepatic vein (D). PG, Pressure gradient; Vmax, maximum velocity. prosthesis (VTIPrTV; CW Doppler derived) and the LVOT (VTILVOT; pulsed-wave Doppler derived) of >3.3 in the context of increased transvalvular gradient and normal PHT may help confirm the presence of significant TR.40 Three-dimensional color Doppler imaging may be also helpful, but its role in quantifying the regurgitant volume has not been extensively evaluated.
PROCEDURAL IMAGE GUIDANCE WITH TEE IMAGING Imaging the TV The tricuspid annular plane is anterior, almost vertical, and orientated approximately 45 from the sagittal plane. To fully visualize the TV,
the American Society of Echocardiography advocates the use of multiple comprehensive TEE windows from multiple depths and plane angles.43,44 The midesophageal four-chamber view with simultaneous biplane imaging permits visualization of the septal and anterior TV leaflets (Figure 3A), where the anterior leaflet is usually adjacent to the aorta.45 However, in the midesophageal windows, the TV is in the far field and may be subject to beam widening and attenuation; further insertion of the TEE probe to the distal esophageal, shallow transgastric, and deep transgastric views approximates the TEE probe and the TV, bringing the TV into the near field and optimizing windows of the TV. At the distal esophageal view, the absence of left heart structures from the image allows comprehensive 3D assessment of TV function (Figure 3B); in the transgastric views, multiplane imaging
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Figure 3 Transesophageal multilevel imaging of the TV. (A) Midesophageal biplane imaging, showing the anterior TV leaflet (in blue, typically adjacent to the aorta) and septal leaflet (in yellow). (B) Low-esophageal biplane imaging, at the level of the coronary sinus (asterisk), visualizing the posterior (in green) and anterior TV leaflets. (C) Transgastric biplane imaging: the short-axis view provides en face simultaneous visualization of all three TV leaflets. (D) All the leaflet coaptation points can be imaged using simultaneous multiplane imaging mode in deep-gastric biplane view. (or rotating the probe 60 –90 ) produces simultaneous en face visualization of all three TV leaflets (Figure 3C) and is an ideal view for differentiating transvalvular TR from paravalvular TR and for diagnosing thrombus or vegetations on the leaflets; in the deep transgastric view, rightward anterior flexion45 (Figure 3D) permits optimal TV color flow and spectral Doppler evaluation of TR jets. It is important to rotate through multiple planes at each TEE level and use simultaneous orthogonal imaging to evaluate the TV comprehensively, to help with identifying leaflets, and to appreciate adjacent anatomy.
Anatomy, Orientation, and Nomenclature Standardized intraprocedural imaging RT 3D TEE TV orientation and nomenclature accurately guide the interventionalist to the target segment of the TV valve. This is essential in transcatheter TV repair for native TV disease18-21 but also important in tricuspid ViV procedures. In a standardized RT 3D TEE study of a failing TV bioprosthesis, the TV 3D volume image should be rotated so that the TV leaflets are visualized en face from the atrial side, with the interatrial septum placed inferiorly and the aortic valve to the left on the screen (Figure 4), so that the coronary sinus enters the right atrium close to the commissure between the septal and posterior leaflets.36 In this 3D surgical view, the leaflet opposite the aortic valve is the posterior leaflet, the leaflet adjacent to the aortic valve is the anterior leaflet, and the remaining leaflet is the septal leaflet. Movements
of the guidance catheter in the right atrium can thereafter be designated for clear orientation46 as toward the aortic valve (‘‘aortic direction’’), toward the posterior leaflet (‘‘posterior’’ direction), or toward the septal leaflet (‘‘septal’’ direction).
Selection of Transcatheter Valve Size In most tricuspid ViV cases, transcatheter valve sizing is based on the known size of the preexisting bioprosthesis. Because of the presence of the leaflets mounted inside the valve, the true internal diameter (which determines prosthesis anchoring) is typically 1 to 2 mm smaller than the diameter of the surgical valve size reported by the manufacturer. Because there are no dedicated surgical bioprostheses for the tricuspid position, a useful guide for sizing is the mitral ViV application.47 However, even when the surgical valve size is known, valve selection is not standardized, and the labeled dimensions (including external and internal diameter) may vary according to the manufacturer. Preprocedural planning should therefore include MSCT and TEE imaging in all patients.48 Balloon sizing using fluoroscopy can be considered at the beginning of the tricuspid ViV procedure but is used much less commonly than in aortic valve disease.49 The selected transcatheter device should have an external diameter that best matches the true internal diameter of the failing surgical
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Figure 4 Standardized RT 3D transesophageal image of a normal TV (A) with TV leaflets visualized en face from the atrial side (interatrial septum inferiorly, aortic valve left on the screen). The TV leaflet opposite the aortic valve is the posterior leaflet, the leaflet adjacent to the aortic valve is the anterior leaflet, and the remaining leaflet is the septal leaflet. Standardized (RT 3D) image of a TV bioprosthesis (B) and mitral bioprosthesis. Standardized (RT 3D) of a TV incomplete annuloplasty ring (C). bioprosthesis to ensure secure anchoring of the transcatheter device.50 Valve sizing should consider the amount of leaflet thickening, calcification and pannus formation that may further reduce the prosthesis internal diameter.51 Measurement of the TV bioprosthesis internal diameter is best performed by RT 3D imaging in multiple views, and oversizing by approximately 10% will ensure secure anchoring of the implant within the sewing ring and minimize intervalvular regurgitation. Undersizing risks device migration, while excessive oversizing may distort the transcatheter valve leaflets and affect hemodynamics and durability. The final decision regarding TV ViV device sizing therefore usually involves an integrated approach, taking into account the manufacturer’s guidance as well as the mean diameters determined by MSCT and RT 3D TEE imaging.
Management of Pacing Wires A transvalvular pacemaker or cardioverter defibrillator lead is present in about 18% of patients with surgical TVs52 and is, as a consequence, not infrequently encountered in tricuspid ViV candidates. Limited data suggest that jailing of the lead between the stent of the surgical valve and the frame of the transcatheter bioprosthesis might be safe, with low risk for lead dysfunction or relevant paravalvular leak.53,54 However, tricuspid ViV should not be performed in
patients with recently implanted transvalvular leads, because of the increased risk for lead dislodgement. Patients with implantable defibrillators may also be at risk for relevant paravalvular regurgitation because of the larger dimensions of the lead; in this situation, use of the SAPIEN 3 may be advantageous, as the outer cuff may promote improved sealing. Although not mandatory, rapid ventricular pacing during the ViV procedure can be facilitated through placement of a transarterial temporary pacing lead either in the left ventricle or in the coronary sinus, especially in patients with high pacemaker dependency. Alternatively, guidewire pacing may be attempted. In all cases, the position of the pacing leads should be confirmed with periprocedural TEE imaging.
Access Route Although transjugular access offers the most direct approach to the tricuspid annulus, advances in catheter steerability enables transfemoral valve delivery in almost two thirds of patients.13 When transfemoral access is being considered, the IVC–right atrium junction and angulation into the right atrium should be assessed in the mid and deep esophageal 2D TEE windows, as access to a failing TV bioprosthesis may be complicated by acute angulation from the IVC and the RV annulus.
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Figure 5 Tricuspid ViV in a patient with rheumatic heart disease. (A) Predilation of a stenotic 33-mm Carpentier-Edwards (CE) Perimount pericardial valve. The permanent extravalvular pacemaker lead does not interfere with the ViV procedure. (B) Placement of a 29-mm Edwards SAPIEN 3 valve and slow deployment under TEE control. (C) Position of the transcatheter valve overlapping the surgical bioprosthesis. During deployment, self-centering occurred. (D) Following concomitant TAVR for treatment of coexisting aortic stenosis, the intervention finally results in the replacement of three valves (asterisk, 23-mm Edwards SAPIEN 3 bioprosthesis in aortic position; double asterisk, 29-mm Edwards SAPIEN 3 valve in 33-mm CE surgical bioprosthesis; arrow, mechanical mitral valve with open leaflets). PA, Pulmonary artery. Advancement of the Transcatheter Valve System Once tricuspid bioprosthesis degeneration has been confirmed on RT 3D TEE imaging (Videos 6–8, available at www.onlinejase.com), the next stage is advancement of the transcatheter valve system. Regardless of access route, a stiff wire (such as an Amplatz Extra Stiff [Cook Medical, Bloomington, IN] with a small distal loop or a Confida [Medtronic] with a preshaped loop) is positioned either in the distal pulmonary artery or RV apex under RT 3D guidance, ensuring sufficient stability for traversing of the transcatheter heart valve from the right atrium into the right ventricle (Figure 5). Twodimensional (Figure 6E) and RT 3D (Figure 6F, Video 9, available at www.onlinejase.com) imaging should be used to monitor wire delivery and catheter positioning across the degenerative bioprosthesis: increasing the gain in the deep esophageal view of the TV will aid visualization of the TV leaflets, while decreasing the gain will aid visualizing the wire and catheter. Imaging the wire and catheter from the right ventricle (i.e., underneath the RV annulus) allows assessment of the correct trajectory and limits the possibility of RV puncture. Biplane imaging in the transgastric views readily confirms the depth and position of the wire and delivery catheter, particularly if the trajectory of the wire is in a different plane to the annulus. The position of the wire should be visible in the right atrium using RT 3D imaging. If the position is not acceptable, the wire should be removed. Crossing the TV bioprosthesis may be difficult in cases of TV leaflet calcification or pannus, and predilation has been reported in about 50% of these instances.13 In contrast, predilatation of the bioprosthesis should be avoided in cases of obvious severe TR to prevent risk for leaflet rupture or embolization. In contrast to the transcatheter Forma Repair System (Edwards Lifesciences), which is designed to provide a surface for native leaflet coaptation to reduce TR by occupying the regurgitant orifice area,18 tricuspid ViV device type choice is usually between the Melody valve
(stented bovine jugular vein graft) and the Edwards SAPIEN device13 (pericardial leaflets). The Melody valve has very thin, pliable leaflets and maybe less prone to thrombose than surgically implanted porcine prosthesis or pericardial SAPIEN devices. Although the Melody valve can be expanded over its nominal diameter (22 mm) when mounted on a 24- or even a 25-mm balloon, the Edwards SAPIEN XT or SAPIEN 3 valve may be more adapted to the large size of surgical tricuspid bioprostheses and is the preferred system for this particular indication. In bioprostheses exceeding a labeled diameter of 30 mm, prestenting of the surgical valve with a metallic stent (e.g., CP Stent) has been proposed.6 Maneuvering the transcatheter valve into position across the bioprosthesis often represents the most challenging aspect of the ViV intervention. The failing TV bioprosthesis may have fluoroscopic landmarks and anchoring zones for transcatheter valve deployment, so this stage of the procedure can be performed under fluoroscopic guidance. However, fluoroscopic markers are not always present,55 and continuous 2D and RT 3D TEE imaging is then mandatory in careful alignment and positioning of the transcatheter device (Figure 6G, Video 10, available at www.onlinejase.com) using the nomenclature described above. Significant back-and-forth or ‘‘push-pull’’ manipulation of the stiff wire while flexing the delivery system may be necessary. The delivery system should be oriented 90 to 180 opposite the normal orientation to facilitate flexion in the appropriate angulation (Figure 5). Orientation of the C-arm, typically into a right anterior oblique projection, perpendicular to the surgical valve stent, offers considerable navigation help and may ease valve crossing. Advances in echocardiographic technology with the new EchoNavigator system (Philips Healthcare, Best, the Netherlands) enable RT merging of echocardiographic and fluoroscopic images on the same display and may contribute to procedural success.50
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Figure 6 Intraprocedural transesophageal imaging. Severe tricuspid bioprosthesis degeneration should be demonstrated on RT 3D TEE imaging (flail leaflets) (A) (Video 6) and severe TR confirmed on fluoroscopy (B) (Video 7), color Doppler (C) (Video 8), and CW Doppler (D). Two-dimensional (E) and RT 3D TEE (F) imaging (Video 9) are used to monitor wire and delivery catheter positioning across the failed TV bioprosthesis and to assist in alignment and positioning of the transcatheter device (G) (Video 10). After ViV deployment, the position and circularity of the transcatheter device should be assessed, and symmetric leaflet mobility visualized (H) (Video 11). Tricuspid inflow gradients should be measured to exclude significant TS (I), and the presence or absence of transvalvular and paravalvular TR should be sought (J) (Video 12). PG, Pressure gradient; RA, right atrium.
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Figure 7 Paravalvular leak (PVL) after tricuspid ViV implantation. Color Doppler may demonstrate a PVL between the newly implanted transcatheter device and the failed tricuspid bioprosthesis (Video 13).
Figure 8 TS after tricuspid ViV implantation. Six weeks after tricuspid ViV, the transcatheter device leaflets had become thickened with reduced mobility (A) (Video 14, available at www.onlinejase.com). Color Doppler (Video 15, available at www.onlinejase.com) and CW Doppler (B) confirmed TS (mean gradient, 4 mm Hg). The patient had been noncompliant with oral anticoagulant therapy. PG, Pressure gradient.
Immediate Postimplantation Evaluation of ViV Function As with all ViV procedures, potential complications include device malpositioning, migration, and embolization; all should be excluded with periprocedural TEE imaging. A rigid bioprosthesis or a degenerative bioprosthesis with bulky leaflets may create a noncircular landing zone, resulting in underexpansion of the transcatheter device: the position and circularity of the transcatheter device should therefore be assessed, and symmetric leaflet mobility should be visualized (Figure 6H, Video 11, available at www.onlinejase.com). Postdilation is more frequent after placement of a Melody valve (40% vs 26% with the SAPIEN valve).13
TV inflow gradients should be assessed to exclude significant TS (Figure 6I), and the presence or absence of transvalvular and paravalvular TR should be sought (Figure 6J, Video 12, available at www.onlinejase.com). Because the implanted valve is usually large (>29 mm13), post-ViV patient-prosthesis mismatch is usually avoided. The right coronary artery and the coronary sinus run close to the atrioventricular groove, and Although both are likely to be protected by the rigid frame of the failing bioprosthesis, there may be distortion or rupture into the right coronary artery, with subsequent RV wall motion abnormalities and cardiac tamponade.
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Figure 10 Distribution of mean gradients across TV before and after transcatheter ViV implantation. Percentage of patients in the tricuspid VIVID registry with tricuspid inflow gradient as measured by CW Doppler before, immediately after, and at most recent follow-up of transcatheter valve implantation. Reprinted with permission from McElhinney et al.13 TVIV, Tricuspid valve-in-valve; FU, follow-up.
Figure 9 TR after tricuspid ViV implantation. On routine 6-month follow-up, ongoing right atrial dilatation was present (A), and there was no paravalvular leak (B), no significant TS, and mild transvalvular TR (C). PG, Pressure gradient; RA, right atrium; Vmax, maximum velocity. POSTPROCEDURAL ECHOCARDIOGRAPHIC ASSESSMENT OF TV FUNCTION AFTER VIV IMPLANTATION Transthoracic echocardiographic evaluation of tricuspid ViV function is not yet validated in clinical studies. Guidance is derived from American Society of Echocardiography guidelines for evaluating a surgically implanted prosthetic TV,39 expert recommendations derived from native valve evaluation with minor modifications, case report experience, and the tricuspid VIVID registry.3-13
Immediate Postimplantation Transthoracic Echocardiographic Assessment TTE within 24 hours postprocedure is recommended to reassess both valve function and the pericardial space for effusion. Comprehensive evaluation of the valve apparatus begins with assessing the valve position and stability, though fortunately valve embolization is rare,13 usually occurs during the implantation process, and is recognized intraprocedurally. The space between the surgical and
transcatheter valve should be interrogated by color flow Doppler to exclude paravalvular leak. Small paravalvular jets are common (Figure 7, Video 13, available at www.onlinejase.com) and often resolve over time with endothelialization,48 but larger paravalvular leaks may require repeat balloon dilation, percutaneous plug closure if anatomically suitable, or surgical repair. American College of Cardiology and American Heart Association guidelines suggest that percutaneous closure of paravalvular leaks is reasonable in symptomatic patients with New York Heart Association class III or IV heart failure who are high-risk surgical candidates (Class IIa, Level of Evidence [LOE]: B).56 Centers of expertise in percutaneous closures have reported success rates of 80% to 85%. Although rightsided pacemaker and defibrillator leads can theoretically interact with the valve structure and cause device instability or paravalvular leak, this has not been reported in the literature.54 Tricuspid ViV leaflet motion should be assessed by 2D TTE for leaflet excursion and restricted motion (Videos 14 and 15, available at www.onlinejase.com). The inflow gradient across the TV device should be interrogated by CW Doppler (Figure 8B): as described above, a mean transvalvular gradient of
Isolated reoperative tricuspid valve replacement is one of the highest risk operations classified in the Society of Thoracic Surgeons registry, particularly in the setting of preexisting right ventricular dysfunction. Transcatheter tricuspid valve-in-valve implantation represents an attractive alternative to redo surgery in patients with tricuspid bioprosthetic valve degeneration who are considered high-risk or unsuitable surgical candidates. In this review article, the authors discuss the emergence of transcatheter tricuspid valve-in-valve therapy, preprocedural echocardiographic assessment of tricuspid bioprosthetic valve dysfunction, periprocedural imaging required for tricuspid valve-in-valve implantation, and postprocedural assessment of tricuspid transcatheter device function. (J Am Soc Echocardiogr 2017;-:---.) Keywords: Transcatheter, Tricuspid, Valve-in-valve, Degenerative bioprosthetic tricuspid valve
Transcatheter valve-in-valve (ViV) procedures are attractive alternatives to redo conventional surgery to treat dysfunctional aortic1 and mitral2 bioprostheses. Until recently, transcatheter tricuspid valve (TV) implantation within either an existing surgical bioprosthesis (tricuspid ViV implantation) or a previously repaired TV had been limited to small case series or case reports.3-12 However, with the recent publication of the global transcatheter tricuspid Valve-inValve International Database (VIVID) registry,13 and recognition that redo surgery for failing TV bioprosthesis carries increased morbidity and mortality, particularly when preexisting right ventricular (RV) dysfunction is present,14-17 it is likely that tricuspid ViV procedures will become an increasingly recognized alternative to redo surgical TV intervention. Moreover, novel transcatheter techniques to repair native regurgitant TVs are also emerging.18-21 Facilitation of successful transcatheter TV procedures requires comprehensive understanding of two-dimensional (2D) and realtime (RT) three-dimensional (3D) transthoracic echocardiographic and transesophageal echocardiographic (TEE) images of the normal and diseased TV, to permit early and accurate detection of TV disease, to direct the timing and assess the effectiveness of treatment, to guide transcatheter TV interventions, and to assess residual TV disease.
From the Structural Heart & Valve Center, New York Presbyterian/Columbia University Medical Center, New York, New York (F.P., I.G., S.K.); Morristown Medical Center, Morristown, New Jersey (K.P.K., L.D.G.); Division of Cardiovascular Diseases, Scripps Clinic, La Jolla, California (M.Z.B., D.R.); and Royal Brompton Hospital, London, United Kingdom (W.L., A.D.). Dr. Praz and Dr. Kodali are consultants for Edwards Lifesciences (Irvine, CA). Reprint requests: Alison Duncan, MRCP, PhD, Royal Brompton Hospital, Royal Brompton and Harefield NHS Foundation Trust, Sydney Street, London SW3 6NP, United Kingdom (E-mail: [email protected]). 0894-7317/$36.00 Copyright 2017 by the American Society of Echocardiography. All rights reserved. http://dx.doi.org/10.1016/j.echo.2017.06.014
ANATOMIC CONSIDERATIONS AND IMPLICATIONS FOR TV SURGERY The TV apparatus is composed of three leaflets (anterior, posterior, and septal) attached to the myocardium of the right ventricle either directly or by the means of chordae linked to a papillary muscle. Autopsy studies, however, report highly variable anatomy; in one study, the TV was found to be a single leaflet in 17% of cases, bicuspid in 72%, and tricuspid in only 17%, with the posterior leaflet being frequently either absent or incorporated into the anterior or septal leaflets.22 Other studies report absent septal papillary muscle23 or presence of accessory leaflets24 in a high proportion of human hearts. In tricuspid regurgitation (TR), anatomic distortion may be accentuated by multiple chordal attachments between the myocardium and valve leaflets, resulting in secondary leaflet tethering with RV dilatation. This process is aggravated by volume overload, which results not only in TV distortion but progressive deterioration in RV systolic function. As a result, severe TV disease has been associated with a threefold increase in all-cause mortality rate and a four- to fivefold increased incidence of cardiac events during long-term follow-up,25 while elective tricuspid annuloplasty for patients with functional TR undergoing elective left-sided heart surgery is associated with a reduction in cardiac-related mortality and improved echocardiographic outcomes.26 Because of the anatomic complexity of the TV and coexisting advanced RV disease, almost 30% of patients are deemed unsuitable for surgical TV repair at presentation and are instead offered TV replacement.27 Although robust comparative data are unavailable,28,29 implantation of a bioprosthesis is preferred in current practice.27 In addition, the increased bleeding risk associated with long-term oral anticoagulation and mechanical valve replacement can be avoided. A recently published meta-analysis of observational studies showed no differences between mechanical and biologic TV replacement in terms of survival and reoperation. However, the risk for valve thrombosis was significantly higher in patients with mechanical prostheses.30 For reasons still unclear, 1
2 Praz et al
Abbreviations
2D = Two-dimensional 3D = Three-dimensional CW = Continuous-wave EOA = Effective orifice area IVC = Inferior vena cava LOE = Level of evidence LVOT = Left ventricular outflow tract
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the longevity of tricuspid bioprostheses seems shorter compared with that of bioprostheses exposed to the systemic circulation (aortic, mitral). This translates into a reoperation rate of about 20% for valve degeneration within 10 years and freedom from reintervention of only 53% at 15 years after surgical valve replacement.14,15,31
MSCT = Multislice computed tomography
PHT = Pressure half-time RT = Real-time RV = Right ventricular TEE = Transesophageal echocardiographic
EMERGENCE OF TRANSCATHETER TREATMENT ALTERNATIVES
Reoperation for valve degeneration is associated with mortality ranging from 17% to 37%,14-17 TR = Tricuspid regurgitation and isolated reoperative TV TS = Tricuspid stenosis replacement is one of the TTE = Transthoracic highest risk operations classified echocardiography in the Society of Thoracic Surgeons registry. Novel TV = Tricuspid valve transcatheter therapies are ViV = Valve-in-valve emerging for the treatment of TR,32 including transcatheter VIVID = Valve-in-Valve tricuspid ViV implantation for International Database patients with tricuspid bioVTI = Velocity-time integral prosthetic valve stenosis and/or transvalvular regurgitation deemed too high risk or unsuitable for reoperation. Notwithstanding, younger patients with Ebstein’s anomaly requiring multiple valve replacements because of somatic growth or bioprosthesis degeneration may also benefit from transcatheter intervention as a mechanism to extend the duration between repeat valve operations.33,34 Tricuspid ViV transcatheter treatment of degenerated tricuspid bioprostheses was first successfully performed using the Melody valve (Medtronic, Minneapolis, MN) in 2010 through a jugular venous route in a patient with previous TV replacement (27-mm Medtronic Mosaic valve) 8 years after treatment for TVendocarditis.3 Evolution of the access routes subsequently followed: in 2010, a 26mm Edwards SAPIEN transcatheter heart valve (Edwards Lifesciences, Irvine, CA) was implanted for the first time into a Medtronic Mosaic 27-mm bioprosthesis through a right atriotomy (off pump),4 and a fully percutaneous procedure using the jugular venous approach was described shortly later using a 23-mm SAPIEN valve5 in 2011. Upon commercial availability of the steerable RetroFlex delivery system, transfemoral venous implantation of a SAPIEN XT valve became technically possible, paving the way for a simplified and more convenient tricuspid ViV procedure.6 Subsequently, the safety, feasibility, and efficacy of the tricuspid bioprosthesis ViV procedure has been confirmed in multiple case reports and series.35 The largest series published to date, the tricuspid VIVID registry, reported on the outcomes of 152 patients.13 In this cohort, the age of the failing surgical bioprostheses was #5 years in as
Table 1 Doppler parameters of prosthetic TV function: current American Society of Echocardiography guidelines Consider TV stenosis* †
Peak velocity
>1.7 m/sec
Mean gradient†
$6 mm Hg
PHT
$230 msec
EOA and VTIPrTV/VTILVOT
‡
PrTV, Prosthetic TV. *Average more than five cycles to account for respiratory variation. † May also be increased with valvular regurgitation. Reprinted from Zoghbi et al.40 ‡ Although the current guidelines for the echocardiographic assessment of TV prostheses do not include cutoffs for EOA and VTIPrTV/VTILVOT, Blauwet et al.41 published data on a large series (N = 285) of a number of TV prosthesis models and sizes that include proposed cutoffs for these hemodynamic variables.
many as 30% of the patients, highlighting the accelerated degeneration observed in tricuspid bioprostheses. Overall, the study confirmed high procedural success (99%) as well as excellent safety, with only one procedural death and no acute conversion to open-heart surgery despite two valve embolizations that were managed percutaneously. Significant improvement of invasive transvalvular gradient and severity of TR were observed regardless of the type of valve implanted, which translated into sustained functional improvement in 76% of patients. Survival free from reintervention was 85% at 1 year. Valve thrombosis was suspected in 4 patients (3%), and 4 additional patients (3%) met the criteria for valve endocarditis. All-cause mortality was low, with a reported incidence of 3% at 30 days and a total of 22 deaths (15%) during a median follow-up period of 13 months.
TRANSTHORACIC ECHOCARDIOGRAPHIC ASSESSMENT OF DEGENERATIVE TV BIOPROSTHESIS Preprocedural transthoracic echocardiography (TTE) is an excellent first-line diagnostic tool in the assessment of tricuspid bioprosthetic valve function, as the anterior location of the TV permits favorable echocardiographic visualization and evaluation of prosthetic valve function. The primary goal of TTE is to evaluate the severity, mechanism, and anatomic substrate for prosthetic valve dysfunction, which may involve tricuspid stenosis (TS), TR, or a combination of TS and TR. Common causes of tricuspid bioprosthetic valve dysfunction include leaflet degeneration, leaflet thrombosis, endocarditis-related leaflet damage, and pannus formation. Paravalvular regurgitation is usually related to endocarditis or surgical suture tear. TTE should determine the presence or absence of thrombus, infective endocarditis, or paravalvular leak, as these are exclusion criteria for transcatheter tricuspid ViV. The specific role of TTE in determining the size of surgical and transcatheter valve devices is limited; operative notes, multislice computed tomography (MSCT), TEE imaging, and fluoroscopy are more reliable modalities for selecting transcatheter device size (see below). Comprehensive assessment of a patient with tricuspid bioprosthesis degeneration should include 2D and 3D imaging, as well as color flow, continuous-wave (CW), and pulsed-wave Doppler imaging. Multiple windows should be used: parasternal RV inflow and short-axis, apical four-chamber, and subcostal views.
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Figure 1 Transthoracic imaging of tricuspid bioprosthesis degeneration with TS. A 31-mm Medtronic Mosaic tricuspid bioprosthesis with leaflet thickening on 2D imaging (A) (Video 1), a dilated, noncollapsing IVC (B) (Video 2), turbulent diastolic forward flow (C) (Video 3), and increased (14 mm Hg) mean pressure gradient (D). PG, Pressure gradient; RA, right atrium; Vmax, mean maximum velocity; Vmean, mean velocity. On the occasion that acoustic shadowing limits evaluation in conventional views, alternative transthoracic echocardiographic windows such as short-axis subcostal or low parasternal may prove as useful as TEE imaging. In patients with adequate 2D images, simultaneous biplane imaging in orthogonal planes with complementary 3D images allows comprehensive evaluation of the prosthetic TV and its leaflets. However, low temporal and spatial resolutions36 are recognized limitations of 3D TTE of the TV. As with all prosthetic valves, the valve size of the tricuspid bioprosthesis should be recorded, if known, in all cases.
Tricuspid Bioprosthetic Valve Stenosis A combination of quantitative and qualitative assessments is used to determine the presence and severity of prosthetic TS (Table 1, Figure 1). Two-dimensional imaging of the TV bioprosthesis includes evaluation of valve seating, leaflet appearance, and leaflet mobility. The appearance of leaflet thickening, calcification, and/or hypomobility (Video 1, available at www.onlinejase.com), with right atrial enlargement and a dilated noncollapsing inferior vena cava (IVC; Video 2, available at www.onlinejase.com), may suggest the presence of TV stenosis. Normal color flow Doppler signal across the tricuspid
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Table 2 Echocardiographic and Doppler parameters used in grading severity of prosthetic TV regurgitation Parameter
Mild
Moderate
Severe
Valve structure
Usually normal
Abnormal or valve dehiscence
Abnormal or valve dehiscence
Jet area by color Doppler, central jets only (cm2)
10
Vena contracta width (cm)*
Not defined
Not defined, but 0.7
Jet density/contour by CW Doppler
Incomplete or faint, parabolic
Dense, variable contour
Dense with early peaking
Doppler systolic hepatic flow
Normal or blunted
Blunted
Holosystolic reversal
Right atrium, right ventricle, IVC
Normal†
Dilated
Markedly dilated
*For a valvular TR jet, extrapolated from native TR; unknown cutoffs for paravalvular TR. † If no other reason for dilatation. Reprinted from Zoghbi WA et al.40
bioprosthesis is typically laminar in appearance; turbulent and/or narrowed or eccentric color Doppler inflow suggests the presence of prosthetic TV stenosis (Video 3, available at www.onlinejase.com). CW Doppler across the prosthetic valve inflow measures transvalvular peak velocity and mean gradient and has been validated against catheter-derived data.37,38 To capture maximal transvalvular gradients, CW Doppler interrogation of prosthetic valve inflow should be performed from multiple echocardiographic windows, although the typical window to obtain the highest Doppler velocity is the apical four-chamber view, in which the flow direction is parallel to the transducer beam. The baseline should be shifted and the scale adjusted accordingly to allow optimal visualization and tracing of the spectral Doppler signal. CW Doppler measurements may vary with both heart rate and respiration, and a minimum of five cardiac cycles should be recorded and averaged to account for respirophasic variation of right-sided flow, even when the patient is in sinus rhythm.39,40 The average heart rate should also be noted because it can substantially affect the inflow gradient: diastole (time for atrial emptying) shortens with increasing heart rate, and a shorter diastole will of necessity result in a higher mean gradient. Doppler parameters such as peak E velocity, peak A velocity (in sinus rhythm), and velocity-time integral (VTI) across the valve can be measured to corroborate qualitative findings. Measurement of pressure half-time (PHT) and calculation of prosthetic valve effective orifice area (EOA) are additional parameters that can quantify prosthetic TV stenosis. The PHT is the time required for the maximal pressure gradient to decrease by half.39 Transvalvular gradient may be increased because of obstruction or regurgitation. In the context of increased transvalvular mean gradient, the PHT is a useful tool to differentiate between the two, as a prolonged PHT is suggestive of obstruction. Note that the PHT should not be used to calculate the EOA of TV prostheses but rather serve as a stand-alone measurement, because PHT-derived EOA calculation overestimates TV area compared with continuity equation–derived methods.41 The continuity equation is the preferred method for calculation of prosthetic TV valve EOA. This is typically performed by calculating the stroke volume across the left ventricular outflow tract (LVOT) and dividing it by the CW Doppler–derived prosthetic TV VTI. This calculation is accurate in the absence of significant aortic or TR. In the context of greater than mild aortic regurgitation (and if pulmonic valve
regurgitation is no more than mild), the RV outflow tract stroke volume may be used instead of LVOT stroke volume. If greater than mild TR is present, the continuity equation should not be used to assess EOA. According to American Society of Echocardiography guidelines, peak TV velocity > 1.7 m/sec, mean gradient > 6 mm Hg, and/or PHT > 230 msec suggest prosthetic TV obstruction40 (Table 1). In a large, more recent series of normal TV bioprostheses evaluated early after implantation, alternative thresholds for abnormal Doppler flow parameters have been proposed: transvalvular peak velocity > 2.1 m/sec, mean gradient > 8.8 mm Hg, and PHT > 193 msec.41 Tricuspid Bioprosthetic Valve Regurgitation As with TS, a combination of quantitative and qualitative assessments is used to determine the presence and severity of prosthetic TR (Table 2). TR may be either transvalvular or paravalvular in origin, and careful 2D assessment of the prosthetic TV from all available windows is necessary for complete evaluation. In the presence of clinically significant paravalvular regurgitation, percutaneous closure can be considered as a corrective strategy,42 whereas the extreme situation of ‘‘valve rocking,’’ suggestive of valve dehiscence, represents a contraindication to a ViV procedure. However, quantitation of paravalvular leaks is not established for TV prostheses. One might categorize severity by inferring from aortic valve literature and estimating the proportion of the annular circumference occupied by the leak,39 but this method has not been validated for TV prostheses. If transvalvular TR is present, transthoracic echocardiographic assessment should include qualitative assessment of TV leaflets (prolapse, flail), failure of leaflet coaptation (Video 4, available at www.onlinejase.com), and quantitative assessment of the regurgitant volume. Severe TR is usually associated with right atrial and RV dilatation, diastolic ventricular septal flattening, IVC dilatation, and hepatic vein systolic flow reversal (Figure 2). On color Doppler imaging, a large flow convergence (Video 5, available at www.onlinejase.com) and increased vena contracta width (>0.7 cm), effective regurgitant orifice area $ 40 mm2, and regurgitant volume $ 45 mL/beat all suggest severe TR, as does a dense CW Doppler tracing with a triangular, earlypeaking velocity, and increased transvalvular Doppler measurements (peak velocity and mean gradient).39,40 A VTI ratio between the TV
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Figure 2 Transthoracic imaging of tricuspid bioprosthesis degeneration with TR. A 33-mm Medtronic Mosaic tricuspid bioprosthesis with tricuspid leaflet prolapse (A) (Video 4), large forward flow convergence with eccentric TR on color Doppler imaging (B) (Video 5), dense CW Doppler tracing with a triangular, early-peaking velocity (C), and systolic flow reversal in the hepatic vein (D). PG, Pressure gradient; Vmax, maximum velocity. prosthesis (VTIPrTV; CW Doppler derived) and the LVOT (VTILVOT; pulsed-wave Doppler derived) of >3.3 in the context of increased transvalvular gradient and normal PHT may help confirm the presence of significant TR.40 Three-dimensional color Doppler imaging may be also helpful, but its role in quantifying the regurgitant volume has not been extensively evaluated.
PROCEDURAL IMAGE GUIDANCE WITH TEE IMAGING Imaging the TV The tricuspid annular plane is anterior, almost vertical, and orientated approximately 45 from the sagittal plane. To fully visualize the TV,
the American Society of Echocardiography advocates the use of multiple comprehensive TEE windows from multiple depths and plane angles.43,44 The midesophageal four-chamber view with simultaneous biplane imaging permits visualization of the septal and anterior TV leaflets (Figure 3A), where the anterior leaflet is usually adjacent to the aorta.45 However, in the midesophageal windows, the TV is in the far field and may be subject to beam widening and attenuation; further insertion of the TEE probe to the distal esophageal, shallow transgastric, and deep transgastric views approximates the TEE probe and the TV, bringing the TV into the near field and optimizing windows of the TV. At the distal esophageal view, the absence of left heart structures from the image allows comprehensive 3D assessment of TV function (Figure 3B); in the transgastric views, multiplane imaging
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Figure 3 Transesophageal multilevel imaging of the TV. (A) Midesophageal biplane imaging, showing the anterior TV leaflet (in blue, typically adjacent to the aorta) and septal leaflet (in yellow). (B) Low-esophageal biplane imaging, at the level of the coronary sinus (asterisk), visualizing the posterior (in green) and anterior TV leaflets. (C) Transgastric biplane imaging: the short-axis view provides en face simultaneous visualization of all three TV leaflets. (D) All the leaflet coaptation points can be imaged using simultaneous multiplane imaging mode in deep-gastric biplane view. (or rotating the probe 60 –90 ) produces simultaneous en face visualization of all three TV leaflets (Figure 3C) and is an ideal view for differentiating transvalvular TR from paravalvular TR and for diagnosing thrombus or vegetations on the leaflets; in the deep transgastric view, rightward anterior flexion45 (Figure 3D) permits optimal TV color flow and spectral Doppler evaluation of TR jets. It is important to rotate through multiple planes at each TEE level and use simultaneous orthogonal imaging to evaluate the TV comprehensively, to help with identifying leaflets, and to appreciate adjacent anatomy.
Anatomy, Orientation, and Nomenclature Standardized intraprocedural imaging RT 3D TEE TV orientation and nomenclature accurately guide the interventionalist to the target segment of the TV valve. This is essential in transcatheter TV repair for native TV disease18-21 but also important in tricuspid ViV procedures. In a standardized RT 3D TEE study of a failing TV bioprosthesis, the TV 3D volume image should be rotated so that the TV leaflets are visualized en face from the atrial side, with the interatrial septum placed inferiorly and the aortic valve to the left on the screen (Figure 4), so that the coronary sinus enters the right atrium close to the commissure between the septal and posterior leaflets.36 In this 3D surgical view, the leaflet opposite the aortic valve is the posterior leaflet, the leaflet adjacent to the aortic valve is the anterior leaflet, and the remaining leaflet is the septal leaflet. Movements
of the guidance catheter in the right atrium can thereafter be designated for clear orientation46 as toward the aortic valve (‘‘aortic direction’’), toward the posterior leaflet (‘‘posterior’’ direction), or toward the septal leaflet (‘‘septal’’ direction).
Selection of Transcatheter Valve Size In most tricuspid ViV cases, transcatheter valve sizing is based on the known size of the preexisting bioprosthesis. Because of the presence of the leaflets mounted inside the valve, the true internal diameter (which determines prosthesis anchoring) is typically 1 to 2 mm smaller than the diameter of the surgical valve size reported by the manufacturer. Because there are no dedicated surgical bioprostheses for the tricuspid position, a useful guide for sizing is the mitral ViV application.47 However, even when the surgical valve size is known, valve selection is not standardized, and the labeled dimensions (including external and internal diameter) may vary according to the manufacturer. Preprocedural planning should therefore include MSCT and TEE imaging in all patients.48 Balloon sizing using fluoroscopy can be considered at the beginning of the tricuspid ViV procedure but is used much less commonly than in aortic valve disease.49 The selected transcatheter device should have an external diameter that best matches the true internal diameter of the failing surgical
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Figure 4 Standardized RT 3D transesophageal image of a normal TV (A) with TV leaflets visualized en face from the atrial side (interatrial septum inferiorly, aortic valve left on the screen). The TV leaflet opposite the aortic valve is the posterior leaflet, the leaflet adjacent to the aortic valve is the anterior leaflet, and the remaining leaflet is the septal leaflet. Standardized (RT 3D) image of a TV bioprosthesis (B) and mitral bioprosthesis. Standardized (RT 3D) of a TV incomplete annuloplasty ring (C). bioprosthesis to ensure secure anchoring of the transcatheter device.50 Valve sizing should consider the amount of leaflet thickening, calcification and pannus formation that may further reduce the prosthesis internal diameter.51 Measurement of the TV bioprosthesis internal diameter is best performed by RT 3D imaging in multiple views, and oversizing by approximately 10% will ensure secure anchoring of the implant within the sewing ring and minimize intervalvular regurgitation. Undersizing risks device migration, while excessive oversizing may distort the transcatheter valve leaflets and affect hemodynamics and durability. The final decision regarding TV ViV device sizing therefore usually involves an integrated approach, taking into account the manufacturer’s guidance as well as the mean diameters determined by MSCT and RT 3D TEE imaging.
Management of Pacing Wires A transvalvular pacemaker or cardioverter defibrillator lead is present in about 18% of patients with surgical TVs52 and is, as a consequence, not infrequently encountered in tricuspid ViV candidates. Limited data suggest that jailing of the lead between the stent of the surgical valve and the frame of the transcatheter bioprosthesis might be safe, with low risk for lead dysfunction or relevant paravalvular leak.53,54 However, tricuspid ViV should not be performed in
patients with recently implanted transvalvular leads, because of the increased risk for lead dislodgement. Patients with implantable defibrillators may also be at risk for relevant paravalvular regurgitation because of the larger dimensions of the lead; in this situation, use of the SAPIEN 3 may be advantageous, as the outer cuff may promote improved sealing. Although not mandatory, rapid ventricular pacing during the ViV procedure can be facilitated through placement of a transarterial temporary pacing lead either in the left ventricle or in the coronary sinus, especially in patients with high pacemaker dependency. Alternatively, guidewire pacing may be attempted. In all cases, the position of the pacing leads should be confirmed with periprocedural TEE imaging.
Access Route Although transjugular access offers the most direct approach to the tricuspid annulus, advances in catheter steerability enables transfemoral valve delivery in almost two thirds of patients.13 When transfemoral access is being considered, the IVC–right atrium junction and angulation into the right atrium should be assessed in the mid and deep esophageal 2D TEE windows, as access to a failing TV bioprosthesis may be complicated by acute angulation from the IVC and the RV annulus.
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Figure 5 Tricuspid ViV in a patient with rheumatic heart disease. (A) Predilation of a stenotic 33-mm Carpentier-Edwards (CE) Perimount pericardial valve. The permanent extravalvular pacemaker lead does not interfere with the ViV procedure. (B) Placement of a 29-mm Edwards SAPIEN 3 valve and slow deployment under TEE control. (C) Position of the transcatheter valve overlapping the surgical bioprosthesis. During deployment, self-centering occurred. (D) Following concomitant TAVR for treatment of coexisting aortic stenosis, the intervention finally results in the replacement of three valves (asterisk, 23-mm Edwards SAPIEN 3 bioprosthesis in aortic position; double asterisk, 29-mm Edwards SAPIEN 3 valve in 33-mm CE surgical bioprosthesis; arrow, mechanical mitral valve with open leaflets). PA, Pulmonary artery. Advancement of the Transcatheter Valve System Once tricuspid bioprosthesis degeneration has been confirmed on RT 3D TEE imaging (Videos 6–8, available at www.onlinejase.com), the next stage is advancement of the transcatheter valve system. Regardless of access route, a stiff wire (such as an Amplatz Extra Stiff [Cook Medical, Bloomington, IN] with a small distal loop or a Confida [Medtronic] with a preshaped loop) is positioned either in the distal pulmonary artery or RV apex under RT 3D guidance, ensuring sufficient stability for traversing of the transcatheter heart valve from the right atrium into the right ventricle (Figure 5). Twodimensional (Figure 6E) and RT 3D (Figure 6F, Video 9, available at www.onlinejase.com) imaging should be used to monitor wire delivery and catheter positioning across the degenerative bioprosthesis: increasing the gain in the deep esophageal view of the TV will aid visualization of the TV leaflets, while decreasing the gain will aid visualizing the wire and catheter. Imaging the wire and catheter from the right ventricle (i.e., underneath the RV annulus) allows assessment of the correct trajectory and limits the possibility of RV puncture. Biplane imaging in the transgastric views readily confirms the depth and position of the wire and delivery catheter, particularly if the trajectory of the wire is in a different plane to the annulus. The position of the wire should be visible in the right atrium using RT 3D imaging. If the position is not acceptable, the wire should be removed. Crossing the TV bioprosthesis may be difficult in cases of TV leaflet calcification or pannus, and predilation has been reported in about 50% of these instances.13 In contrast, predilatation of the bioprosthesis should be avoided in cases of obvious severe TR to prevent risk for leaflet rupture or embolization. In contrast to the transcatheter Forma Repair System (Edwards Lifesciences), which is designed to provide a surface for native leaflet coaptation to reduce TR by occupying the regurgitant orifice area,18 tricuspid ViV device type choice is usually between the Melody valve
(stented bovine jugular vein graft) and the Edwards SAPIEN device13 (pericardial leaflets). The Melody valve has very thin, pliable leaflets and maybe less prone to thrombose than surgically implanted porcine prosthesis or pericardial SAPIEN devices. Although the Melody valve can be expanded over its nominal diameter (22 mm) when mounted on a 24- or even a 25-mm balloon, the Edwards SAPIEN XT or SAPIEN 3 valve may be more adapted to the large size of surgical tricuspid bioprostheses and is the preferred system for this particular indication. In bioprostheses exceeding a labeled diameter of 30 mm, prestenting of the surgical valve with a metallic stent (e.g., CP Stent) has been proposed.6 Maneuvering the transcatheter valve into position across the bioprosthesis often represents the most challenging aspect of the ViV intervention. The failing TV bioprosthesis may have fluoroscopic landmarks and anchoring zones for transcatheter valve deployment, so this stage of the procedure can be performed under fluoroscopic guidance. However, fluoroscopic markers are not always present,55 and continuous 2D and RT 3D TEE imaging is then mandatory in careful alignment and positioning of the transcatheter device (Figure 6G, Video 10, available at www.onlinejase.com) using the nomenclature described above. Significant back-and-forth or ‘‘push-pull’’ manipulation of the stiff wire while flexing the delivery system may be necessary. The delivery system should be oriented 90 to 180 opposite the normal orientation to facilitate flexion in the appropriate angulation (Figure 5). Orientation of the C-arm, typically into a right anterior oblique projection, perpendicular to the surgical valve stent, offers considerable navigation help and may ease valve crossing. Advances in echocardiographic technology with the new EchoNavigator system (Philips Healthcare, Best, the Netherlands) enable RT merging of echocardiographic and fluoroscopic images on the same display and may contribute to procedural success.50
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Figure 6 Intraprocedural transesophageal imaging. Severe tricuspid bioprosthesis degeneration should be demonstrated on RT 3D TEE imaging (flail leaflets) (A) (Video 6) and severe TR confirmed on fluoroscopy (B) (Video 7), color Doppler (C) (Video 8), and CW Doppler (D). Two-dimensional (E) and RT 3D TEE (F) imaging (Video 9) are used to monitor wire and delivery catheter positioning across the failed TV bioprosthesis and to assist in alignment and positioning of the transcatheter device (G) (Video 10). After ViV deployment, the position and circularity of the transcatheter device should be assessed, and symmetric leaflet mobility visualized (H) (Video 11). Tricuspid inflow gradients should be measured to exclude significant TS (I), and the presence or absence of transvalvular and paravalvular TR should be sought (J) (Video 12). PG, Pressure gradient; RA, right atrium.
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Journal of the American Society of Echocardiography - 2017
Figure 7 Paravalvular leak (PVL) after tricuspid ViV implantation. Color Doppler may demonstrate a PVL between the newly implanted transcatheter device and the failed tricuspid bioprosthesis (Video 13).
Figure 8 TS after tricuspid ViV implantation. Six weeks after tricuspid ViV, the transcatheter device leaflets had become thickened with reduced mobility (A) (Video 14, available at www.onlinejase.com). Color Doppler (Video 15, available at www.onlinejase.com) and CW Doppler (B) confirmed TS (mean gradient, 4 mm Hg). The patient had been noncompliant with oral anticoagulant therapy. PG, Pressure gradient.
Immediate Postimplantation Evaluation of ViV Function As with all ViV procedures, potential complications include device malpositioning, migration, and embolization; all should be excluded with periprocedural TEE imaging. A rigid bioprosthesis or a degenerative bioprosthesis with bulky leaflets may create a noncircular landing zone, resulting in underexpansion of the transcatheter device: the position and circularity of the transcatheter device should therefore be assessed, and symmetric leaflet mobility should be visualized (Figure 6H, Video 11, available at www.onlinejase.com). Postdilation is more frequent after placement of a Melody valve (40% vs 26% with the SAPIEN valve).13
TV inflow gradients should be assessed to exclude significant TS (Figure 6I), and the presence or absence of transvalvular and paravalvular TR should be sought (Figure 6J, Video 12, available at www.onlinejase.com). Because the implanted valve is usually large (>29 mm13), post-ViV patient-prosthesis mismatch is usually avoided. The right coronary artery and the coronary sinus run close to the atrioventricular groove, and Although both are likely to be protected by the rigid frame of the failing bioprosthesis, there may be distortion or rupture into the right coronary artery, with subsequent RV wall motion abnormalities and cardiac tamponade.
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Figure 10 Distribution of mean gradients across TV before and after transcatheter ViV implantation. Percentage of patients in the tricuspid VIVID registry with tricuspid inflow gradient as measured by CW Doppler before, immediately after, and at most recent follow-up of transcatheter valve implantation. Reprinted with permission from McElhinney et al.13 TVIV, Tricuspid valve-in-valve; FU, follow-up.
Figure 9 TR after tricuspid ViV implantation. On routine 6-month follow-up, ongoing right atrial dilatation was present (A), and there was no paravalvular leak (B), no significant TS, and mild transvalvular TR (C). PG, Pressure gradient; RA, right atrium; Vmax, maximum velocity. POSTPROCEDURAL ECHOCARDIOGRAPHIC ASSESSMENT OF TV FUNCTION AFTER VIV IMPLANTATION Transthoracic echocardiographic evaluation of tricuspid ViV function is not yet validated in clinical studies. Guidance is derived from American Society of Echocardiography guidelines for evaluating a surgically implanted prosthetic TV,39 expert recommendations derived from native valve evaluation with minor modifications, case report experience, and the tricuspid VIVID registry.3-13
Immediate Postimplantation Transthoracic Echocardiographic Assessment TTE within 24 hours postprocedure is recommended to reassess both valve function and the pericardial space for effusion. Comprehensive evaluation of the valve apparatus begins with assessing the valve position and stability, though fortunately valve embolization is rare,13 usually occurs during the implantation process, and is recognized intraprocedurally. The space between the surgical and
transcatheter valve should be interrogated by color flow Doppler to exclude paravalvular leak. Small paravalvular jets are common (Figure 7, Video 13, available at www.onlinejase.com) and often resolve over time with endothelialization,48 but larger paravalvular leaks may require repeat balloon dilation, percutaneous plug closure if anatomically suitable, or surgical repair. American College of Cardiology and American Heart Association guidelines suggest that percutaneous closure of paravalvular leaks is reasonable in symptomatic patients with New York Heart Association class III or IV heart failure who are high-risk surgical candidates (Class IIa, Level of Evidence [LOE]: B).56 Centers of expertise in percutaneous closures have reported success rates of 80% to 85%. Although rightsided pacemaker and defibrillator leads can theoretically interact with the valve structure and cause device instability or paravalvular leak, this has not been reported in the literature.54 Tricuspid ViV leaflet motion should be assessed by 2D TTE for leaflet excursion and restricted motion (Videos 14 and 15, available at www.onlinejase.com). The inflow gradient across the TV device should be interrogated by CW Doppler (Figure 8B): as described above, a mean transvalvular gradient of
