A simple way to treat mitral valve prolapse: chordal replacement using a new mitral leaflet retractor† Noriyuki Kashiyamaa, Takafumi Masaia,*, Masao Yoshitatsua, Takashi Yamauchia, Yukiko Ogasawaraa, Yuriko Matsunagaa and Yoshiki Sawab a b
Department of Cardiovascular Surgery, Sakurabashi Watanabe Hospital, Osaka, Japan Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
* Corresponding author. Department of Cardiovascular Surgery, Sakurabashi Watanabe Hospital, 2-4-32 Umeda, Kita-ku, Osaka 530-0001, Japan. Tel: +81-6-63418651; fax: +81-6-63410785; e-mail: [email protected] (T. Masai). Received 13 September 2013; received in revised form 8 December 2013; accepted 17 December 2013
Abstract OBJECTIVES: The most difficult aspect of chordal replacement during mitral valve repair is to determine the correct length of the new chordae. A simple technique of chordal replacement was developed employing the new mitral leaflet retractor that enables easy adjustment of the length of artificial chordae. METHODS: For prolapse of the anterior mitral leaflet (AML), the level of the normal opposing posterior leaflet can be used to determine the length of new chordae. We developed a double-headed leaflet retractor with which both mitral leaflets can be retracted simultaneously at the same level. This retractor makes it easy to tie the slippery Gore-Tex sutures for artificial chordae adjusting the length of the new chordae on AML to the level of the opposing normal posterior leaflet. We employed this retractor for the creation of artificial chordae in 55 consecutive patients with degenerative AML prolapse between 2005 and 2013. A ring annuloplasty was concomitantly performed to stabilize the reconstruction. RESULTS: We had no hospital death. Follow-up was 100% complete with a mean follow-up duration of 1181 ± 839 (range 50–2892) days. Reoperation-free survival at 5 years was 98.2%. Freedom from moderate-to-severe mitral regurgitation was 88.0% at 5 years. At follow-up, all non-reoperated survivors were in New York Heart Association Class I or II. CONCLUSIONS: We have reported the chordal replacement using the new double-headed mitral leaflet retractor. Our leaflet retractor is a convenient tool representing an easy creation of artificial chordae in mitral valve repair. Keywords: Anterior leaflet prolapse • Artificial chordae reconstruction • Mitral valve repair
INTRODUCTION
MATERIALS AND METHODS
Anterior leaflet prolapse, though less common than posterior prolapse, affects up to one-third of patients with mitral regurgitation (MR) [1]. Recently, reconstruction with artificial chordae for correction of anterior leaflet prolapse has been shown to be effective and safe, and associated with low operative mortality and low rates of valve-related complications at long-term follow-up examinations [2]. The widespread use of expanded polytetrafluoroethylene (e-PTFE) sutures has assisted chordal reconstruction; however, adjustment of the artificial chordae length remains difficult [3]. We developed a novel mitral leaflet retractor for easily adjusting that length to the same level as a normal posterior leaflet chordae, used as a reference. Here, we present this simple method of chordal reconstruction for anterior prolapse using a novel mitral leaflet retractor, and analyse early and mid-term results.
Patients
†Presented at the 27th Annual Meeting of the European Association for CardioThoracic Surgery, Vienna, Austria, 5–9 October 2013.
We retrospectively analysed 55 consecutive patients who underwent mitral valve repair for anterior mitral leaflet (AML) prolapse from August 2005 to May 2013. Surgical techniques included chordal reconstruction with e-PTFE using a mitral leaflet retractor for anterior prolapse and concomitant ring annuloplasty. In cases with bileaflet prolapse, a resection and suture technique was employed for posterior prolapse.
Mitral leaflet retractor We participated in the development of a specially designed doubleheaded retractor, for mitral leaflet retraction (Senko Medical Instrument Manufacturing Company, Tokyo, Japan), with which both mitral leaflets can be simultaneously retracted at the same level (Fig. 1). With this novel retractor, it is easy to adjust the length of the
© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
NEW IDEAS
NEW IDEAS – ADULT CARDIAC
Interactive CardioVascular and Thoracic Surgery 18 (2014) 701–705 doi:10.1093/icvts/ivu040 Advance Access publication 6 March 2014
702
N. Kashiyama et al. / Interactive CardioVascular and Thoracic Surgery
Figure 1: The mitral leaflet retractor (Senko Medical Instrument Manufacturing Company) was used to decide the length of artificial chordae, according to the opposite normal chordae of the posterior mitral leaflets.
atriotomy. After assessing the entire mitral apparatus, chordal reconstruction using e-PTFE sutures (CV-5) was performed to repair the prolapse of the AML. CV-5 sutures were passed through the papillary muscle and the free edge of the prolapsed anterior leaflet. Then, the mitral leaflet retractor was attached to the Hercules Arm and fixed on the sternal retractor. One head of the retractor was gently put into contact with the normal posterior leaflet, and the opposite prolapsed anterior leaflet was placed on the other head of the retractor. Finally, the suture was softly tied down (Fig. 1). An artificial ring was applied for supportive ring annuloplasty after measuring the intertrigonal distance and height of the anterior leaflet. In cases with bileaflet prolapse, the prolapsed posterior leaflet was repaired first using a conventional resection and suture technique, with a quadrangular resection of the redundant and prolapsed posterior leaflet performed. If the height of the posterior leaflet after quadrangular resection was >20 mm, the height of the remaining posterior leaflet was reduced by use of a sliding or folding leaflet technique to avoid systolic anterior motion of the AML. Finally, chordal reconstruction was performed in the same manner using the mitral leaflet retractor. Concomitant procedures, including tricuspid annuloplasty (n = 21, 38.2%), a modified maze procedure (n = 17, 30.9%), coronary artery bypass grafting (n = 4, 7.3%) and aortic valve replacement (n = 3, 5.5%), were also performed in some cases.
Echocardiography
new chordae on the AML to the level of the non-diseased reference chordae of the opposing normal posterior leaflet. In addition, the device can be attached to a Hercules Universal Stabilizer Arm (Estech, Inc., Danville, CA, USA) to ensure the tying of the e-PTFE suture knots counteracting its sliding tendency (Fig. 2).
Transthoracic preoperative echocardiography was performed in all patients, which allowed for the evaluation of the severity of MR in the long-axis parasternal view. Perioperative transoesophageal echocardiography was mandatory and used to evaluate valve competence according to the presence of colour Doppler residual regurgitation and the absence of systolic anterior motion. Transthoracic postoperative echocardiography was used to evaluate recurrence of mitral valve regurgitation.
Surgical procedures
Follow-up
After performing a median sternotomy and bicaval/aortic cannulation, the mitral valve was exposed through a right-sided left
Follow-up examinations were performed at the outpatient clinic and by phone interviews with local doctors. Postoperative
Figure 2: The mitral leaflet retractor can be attached to the Hercules Stabilizer Arm (Estech, Inc.).
N. Kashiyama et al. / Interactive CardioVascular and Thoracic Surgery
Statistical analysis Statistical analysis was performed using JMP 10.0.2 (SAS Institute, Cary, NC, USA). Descriptive statistics are shown as the mean ± standard deviation for continuous variables, and as frequencies and percentages for categorical variables, unless otherwise noted. Estimates of survival probability or freedom from a valve-related reoperation, as well as freedom from recurrence of MR, were done using the standard Kaplan–Meier method. The results are reported in accordance with accepted guidelines [4].
RESULTS Patients All 55 patients had moderate-to-severe MR due to AML prolapse, and their clinical profiles are summarized in Table 1. Twelve (21.8%) patients presented with bileaflet prolapse requiring concomitant posterior leaflet repair (Table 2).
Table 1: Preoperative clinical and echocardiographic profiles Patients characteristics Patients, n Males, n (%) Age, years (range) New York Heart Association Class I/II/III/IV, n (%) Comorbidity Hypertension, n (%) Hyperlipidaemia, n (%) Diabetes, n (%) Chronic obstructive lung disease, n (%) Chronic renal failure, n (%) Peripheral vascular disease, n (%) Neurological history, n (%) Atrial fibrillation, n (%) Previous cardiac surgery, n (%) Echocardiographic data LV end-diastolic dimension, mm LV end-systolic dimension, mm LV ejection fraction, % Left atrial dimension, mm Tricuspid regurgitation pressure gradient, mmHg Mitral regurgitation, 0/1+/2+/3+/4+, n (%) Tricuspid regurgitation, 0/1+/2+/3+/4+, n (%)
55 38 (69) 61 ± 15 (23–81) 12 (22)/31 (56)/10 (18)/2 (4) 24 (44) 11 (20) 6 (11) 0 (0) 4 (7) 0 (0) 7 (13) 21 (38) 3 (5) 54 ± 7 34 ± 6 66 ± 10 46 ± 10 28 ± 10 0 (0)/0 (0)/1 (2)/20 (36)/ 34 (62) 11 (20)/21 (38)/14 (25)/ 7 (13)/2 (4)
LV: left ventricle.
Procedure Mitral valve repair was feasible in all patients, while additional AML repairs, including a paracommissural edge-to-edge procedure, were performed in 17 (30.9%) patients. Anterior leaflet triangular resection was not performed. Mitral annuloplasty was performed in all patients using a complete ring or a band as follows: a Carpentier–Edwards Physio ring (Edwards Lifescience, Irvine, CA, USA) was used in 36 (65.5%) patients, a Carpentier– Edwards Physio ring II (Edwards Lifescience) in 16 (29.1%), a Cosgrove–Edwards annuloplasty band (Edwards Lifescience) in 2 (3.6%) and a Rigid Saddle Ring (St. Jude Medical, Inc., St. Paul, MN, USA) in 1 (1.8%). The mean size of the annuloplasty rings was 27.5 ± 2.3 mm. Cardiopulmonary bypass and aortic cross-clamp times were 171.4 ± 56.8 and 119.5 ± 42.5 min, respectively. By intraoperative saline injection test, readjustment of artificial chordae was required in 10 patients. Intraoperative echocardiographic findings revealed residual Grade 2 MR in 3 patients with bileaflet prolapse or extended anterior leaflet lesion (5.5%), which required second pump runs. Systolic anterior motion was noted in 1 (1.8%) patient and was managed successfully with short-acting beta-blockers and volume expansion. At discharge, we had no residual or recurrent more-than-moderate MR, excluding the patient who required reoperation due to recurrent severe MR by detachment of artificial ring (Table 3).
Mortality There was no in-hospital mortality. The overall mortality rate was 1.9, 9.6 and 9.6% (n = 3) at 1, 3 and 5 years, respectively, after surgery. Two of the 3 deaths occurred late after surgery. Two were
Table 2:
Operative data
Total number of artificial chordae, chordal no. Numbers of artificial chordae 1/2/3/4/5, n (%) APM to A1, A2, A3, chordal no. (%) PPM to A1, A2, A3, chordal no. (%) Ring type Physio ring, n (%) Physio ring II, n (%) Cosgrove band, n (%) Semirigid saddle ring, n (%) Ring size 24, 26, 28, 30, 32, n (%) Additional procedure Paracommissural edge-to-edge, n (%) Concomitant procedure Coronary artery bypass grafting, n (%) Tricuspid annuloplasty, n (%) Modified maze procedure, n (%) Aortic valve replacement, n (%) Operation time, min Cardiopulmonary bypass time, min Aortic cross-clamp time, min Second pump run, n (%) Mitral valve replacement conversion, n (%)
97 23 (42)/19 (35)/12 (22)/0 (0)/1 (2) 8 (8), 32 (33), 3 (3) 0 (0), 23 (24), 31 (32) 36 (65) 16 (29) 2 (4) 1 (2) 8 (15), 20 (36), 15 (27), 8 (15), 5 (9) 17 (31) 4 (7) 21 (38) 17 (31) 3 (6) 307 ± 82 171 ± 56 120 ± 43 3 (6) 0 (0)
APM: anterolateral papillary muscle; PPM: posteromedial papillary muscle.
NEW IDEAS
follow-up examinations were scheduled at 1, 3 and 6 months, and annually thereafter, during which clinical status and echocardiographic data were recorded. Postoperative events were compiled and analysed according to the guidelines for reporting morbidity and mortality after cardiac valvular operations [4]. Only the latest echocardiographic data were considered for the present study.
703
704
N. Kashiyama et al. / Interactive CardioVascular and Thoracic Surgery
Table 3: Echocardiography at discharge LV end-diastolic dimension, mm LV end-systolic dimension, mm LV ejection fraction, % Left atrial dimension, mm Tricuspid regurgitation pressure gradient, mmHg Mitral regurgitation, 0/1+/2+/3+/4+, n (%) Tricuspid regurgitation, 0/1+/2+/3+/4+, n (%)
47 ± 6 32 ± 7 59 ± 11 39 ± 8 19 ± 8 43 (87)/7 (13)/4 (7)/1 (2)/0 (0) 33 (60)/12 (22)/9 (16)/1 (2)/0 (0)
LC: left ventricular.
due to sepsis (231 and 1024 days postoperatively), and the other died of an unknown cause (1088 days postoperatively).
Reoperation Freedom from reoperation was 98.2% at 5 years. One patient (1.8%) required a mitral valve reoperation for recurrent MR on postoperative day 85 because of detachment of the artificial annuloplasty ring, and mitral valve replacement with a bioprosthesis was performed. No patient developed mitral valve endocarditis during the follow-up period.
Clinical and echocardiographic follow-up Clinical and echocardiographic follow-up examinations were completed in all patients, and the mean follow-up duration was 1181 ± 839 (range 50–2892) days. At the latest follow-up examination, all non-reoperated patients (n = 54) were in New York Heart Association Class I or II. Of those, 37 (67.3%) had no or trivial MR, 13 (23.6%) had mild MR and 5 (9.1%) had moderate MR. Causes of the MR recurrences were progression of valve degeneration, development of valve tethering by ischaemic heart disease, limited motion of anterior leaflet by artificial chordae and detachment of artificial annuloplasty ring. The rate of freedom from recurrent moderate MR was 88.0% at 5 years.
DISCUSSION Determination of the proper length of the neochordae is a major concern, and various modalities have been proposed to establish that length, which can be categorized as anatomical and functional [5]. Anatomical means of length determination are common. von Oppell and Mohr [6] as well as others have described a simple method of determining neochordal length, in which a calliper is used intraoperatively to measure the distance between the papillary muscle tip and the annular plane. However, this technique presumes that the pathology has not affected the adjacent native chordae. Furthermore, the chordae are examined in an empty heart resting state. Calafiore [7] described a method that combines preoperative echocardiographic data and intraoperative measurements to determine the correct neochordae length, although it is difficult to obtain good preoperative echocardiographic images in all cases.
Furthermore, because the necessary neochordae length is dependent on the suture site in the papillary muscle or prolapsed leaflet, preoperative measurements based on echocardiography are not always correct. Several functional methods for the determination of neochordae length have also been reported. Kasegawa et al. [8] proposed the use of a small tourniquet to progressively adjust the length of the chordae, while David et al. distended the ventricle with saline in order to observe where the free margin of the leaflets should coapt [2]. In this report, we present a new method for the determination of neochordae length using our novel mitral leaflet retractor. With this technique, it is not necessary to obtain proper echocardiography findings, as the precise distance between the tip of the papillary muscle and the annular plane can be determined preoperatively and intraoperatively. When the retractor is attached to the stabilizer arm, easy and reliable suture ligation with an e-PTFE thread is possible, as the sliding characteristic of the device makes it difficult to tie the knots without the aid of an assistant. In the present method, the opposite normal chordae of the posterior mitral leaflets is used as a reference to adjust the length of the artificial chordae. This concept for repair is similar to that reported by Matsumoto et al. [9] and Sarsam [10] in terms of referring to the opposing leaflet, though our method is considered to have advantages of speed and simplicity. Mid-term results following chordal replacement with the mitral leaflet retractor are similar to those obtained with other methods. Even though the method for determining the length of the artificial chordae may affect the success of the operation, the main mechanism of recurrent regurgitation after MV repair is progressive degeneration, as reported by Shimokawa et al. [11]. Thus, we think that additional procedures such as triangular resection for redundant anterior leaflets or prophylactic replacement of artificial chordae to the sites that are suspected to progress degeneration earlier may be required for further improvement of long-term results following chordal replacement.
LIMITATIONS The main limitation of the current study is its retrospective and non-randomized design. We did not routinely perform quantitative echocardiography for these cases. Therefore, the severity of MR may have been over- or underestimated in some echocardiograms, considering the limitations of the colour Doppler jet method.
CONCLUSIONS The present method offers a simple and reproducible solution for correction of anterior leaflet prolapse. Our novel mitral leaflet retractor can used to reliably determine the length of the artificial chordae. However, long-term results must be evaluated and compared with those of other surgical strategies. Conflict of interest: none declared.
REFERENCES [1] Grossi EA, Galloway AC, LeBoutillier M III, Steinberg B, Baumann FG, Delianides J et al. Anterior leaflet procedures during mitral valve repair do not adversely influence long-term outcome. J Am Coll Cardiol 1995;25: 134–6.
[2] David TE, Armstrong S, Ivanov J. Chordal replacement with polytetrafluoroethylene sutures for mitral valve repair: a 25-year experience. J Thorac Cardiovasc Surg 2013;145:1563–9. [3] Ibrahima M, Rao C, Athanasiou T. Artificial chordae for degenerative mitral valve disease: critical analysis of current techniques. Interact CardioVasc Thorac Surg 2012;15:1019–32. [4] Akins CW, Miller DC, Turina MI, Kouchoukos NT, Blackstone EH, Grunkemeier GL et al. Guidelines for reporting mortality and morbidity after cardiac valve interventions. J Thorac Cardiovasc Surg 2008;135:732–8. [5] Zussa C. Different applications of ePTFE valve chordae: surgical technique. J Heart Valve Dis 1996;5:356–61. [6] von Oppell UO, Mohr FW. Chordal replacement for both minimally invasive and conventional mitral valve surgery using premeasured Gore-Tex loops. Ann Thorac Surg 2000;70:2166–8. [7] Calafiore AM. Choice of artificial chordae length according to echocardiographic criteria. Ann Thorac Surg 2006;81:375–7. [8] Kasegawa H, Kamata S, Hirasa S, Kobayashi N, Mannouji E, Ida T et al. Simple method for determining proper length of artificial chordae in mitral valve repair. Ann Thorac Surg 1989;97:98–103. [9] Matsumoto T, Kado H, Masuda M, Shiokawa Y, Fukae K, Morita S et al. Clinical results of mitral valve repair by reconstructing artificial chordae tendineae in children. J Thorac Cardiovasc Surg 1999;118:94–8. [10] Sarsam MA. Simplified technique for determining the length of artificial chordae in mitral valve repair. Ann Thorac Surg 2002;73:1659–60. [11] Shimokawa T, Kasegawa H, Katayama Y, Matsuyama S, Manabe S, Tabata M et al. Mechanisms of recurrent regurgitation after valve repair for prolapsed mitral valve disease. Ann Thorac Surg 2011;91:1433–9.
APPENDIX. CONFERENCE DISCUSSION Dr O. Jegaden (Lyon, France): It is true, as you mentioned, that the concept of artificial chordae is becoming more and more adopted by the surgical community, but the adjustment of their length remains controversial and tricky, and sometimes I have the feeling or the impression that each surgeon has his own technique. In this field it is important to have standardization of the technique, and the clever tool that you suggest and that you have presented could pave the way in this direction. Your technique is very attractive and seems to be effective and reproducible according to the good results that you have demonstrated, with a very low rate of recurrence of mitral regurgitation at mid-term and long-term. I have several questions, mainly regarding the technique itself. Firstly, in your series you have used this technique only to correct anterior leaflet prolapse. Do
705
you think that it could also be used to correct posterior leaflet prolapse? In the case of prolapse of both leaflets, you have mentioned that you correct the posterior with the resection technique and the anterior with the chordae. Do you think that your tools could open the way to easily correct prolapse of both leaflets with artificial chordae? The third question is regarding the tying of the chordae. Dr A.P. Kappetein (Rotterdam, Netherlands): Perhaps the English language is difficult for him, so answer the first question. Dr Kashiyama: The first question is whether our leaflet retractor can be adapted to posterior leaflet prolapse or not. The answer is yes. But when you use this retractor, the most important thing is whether the reference point can be obtained or not. So when the opposing anterior leaflet is normal, of course you can adapt this retractor to posterior leaflet prolapse. However, in bileaflet prolapse, it is often difficult to detect the reference point. That is why in such a case, in order to obtain the reference point, we should repair the posterior leaflet prolapse first by the resection suture, and then we can use the repaired posterior leaflet as a reference point and achieve chordal replacement for the anterior leaflet. We know it is one of the limitations of this retractor, but there are no problems when you resect it. Dr Jegaden: Only one more question. It is regarding the surface of coaptation. With your technique, particularly if you tie the artificial chordae above the annuloplasty, I have the feeling that you could easily increase the surface of coaptation, and we know that is the main point in improving the long-term results. Do you have some data to support the fact that your technique allows increase of the surface of coaptation? Dr Kashiyama: Good question. I don’t know why you think that you can obtain better coaptation by performing chordal replacement after annuloplasty. When I think simply, we can match the height of the anterior and posterior leaflet by chordal replacement with this retractor and we can obtain better coaptation by the annuloplasty. So I don’t think the sequence of chordal replacement and annuloplasty would be important. Of course, if you want to perform annuloplasty initially, it would be possible. However, we think it is easier to rehang artificial chordae to papillary muscle before annuloplasty when the length of artificial chordae is too long or too short. Dr Jegaden: And the last question is, is this tool available for minimally invasive techniques, I mean with a long handle. Dr Kashiyama: The last question is whether this retractor can be adapted to minimally invasive mitral surgery. Actually we have never used this retractor in minimally invasive mitral surgery. When we can develop this retractor with a long handle to reach the deep surgical field, it may be useful to employ this device in this approach. However, actually the longer handle makes it harder to precisely adjust the head of the retractor. So it is challenging, but I will try in the near future.
NEW IDEAS
N. Kashiyama et al. / Interactive CardioVascular and Thoracic Surgery
Department of Cardiovascular Surgery, Sakurabashi Watanabe Hospital, Osaka, Japan Department of Cardiovascular Surgery, Osaka University Graduate School of Medicine, Osaka, Japan
* Corresponding author. Department of Cardiovascular Surgery, Sakurabashi Watanabe Hospital, 2-4-32 Umeda, Kita-ku, Osaka 530-0001, Japan. Tel: +81-6-63418651; fax: +81-6-63410785; e-mail: [email protected] (T. Masai). Received 13 September 2013; received in revised form 8 December 2013; accepted 17 December 2013
Abstract OBJECTIVES: The most difficult aspect of chordal replacement during mitral valve repair is to determine the correct length of the new chordae. A simple technique of chordal replacement was developed employing the new mitral leaflet retractor that enables easy adjustment of the length of artificial chordae. METHODS: For prolapse of the anterior mitral leaflet (AML), the level of the normal opposing posterior leaflet can be used to determine the length of new chordae. We developed a double-headed leaflet retractor with which both mitral leaflets can be retracted simultaneously at the same level. This retractor makes it easy to tie the slippery Gore-Tex sutures for artificial chordae adjusting the length of the new chordae on AML to the level of the opposing normal posterior leaflet. We employed this retractor for the creation of artificial chordae in 55 consecutive patients with degenerative AML prolapse between 2005 and 2013. A ring annuloplasty was concomitantly performed to stabilize the reconstruction. RESULTS: We had no hospital death. Follow-up was 100% complete with a mean follow-up duration of 1181 ± 839 (range 50–2892) days. Reoperation-free survival at 5 years was 98.2%. Freedom from moderate-to-severe mitral regurgitation was 88.0% at 5 years. At follow-up, all non-reoperated survivors were in New York Heart Association Class I or II. CONCLUSIONS: We have reported the chordal replacement using the new double-headed mitral leaflet retractor. Our leaflet retractor is a convenient tool representing an easy creation of artificial chordae in mitral valve repair. Keywords: Anterior leaflet prolapse • Artificial chordae reconstruction • Mitral valve repair
INTRODUCTION
MATERIALS AND METHODS
Anterior leaflet prolapse, though less common than posterior prolapse, affects up to one-third of patients with mitral regurgitation (MR) [1]. Recently, reconstruction with artificial chordae for correction of anterior leaflet prolapse has been shown to be effective and safe, and associated with low operative mortality and low rates of valve-related complications at long-term follow-up examinations [2]. The widespread use of expanded polytetrafluoroethylene (e-PTFE) sutures has assisted chordal reconstruction; however, adjustment of the artificial chordae length remains difficult [3]. We developed a novel mitral leaflet retractor for easily adjusting that length to the same level as a normal posterior leaflet chordae, used as a reference. Here, we present this simple method of chordal reconstruction for anterior prolapse using a novel mitral leaflet retractor, and analyse early and mid-term results.
Patients
†Presented at the 27th Annual Meeting of the European Association for CardioThoracic Surgery, Vienna, Austria, 5–9 October 2013.
We retrospectively analysed 55 consecutive patients who underwent mitral valve repair for anterior mitral leaflet (AML) prolapse from August 2005 to May 2013. Surgical techniques included chordal reconstruction with e-PTFE using a mitral leaflet retractor for anterior prolapse and concomitant ring annuloplasty. In cases with bileaflet prolapse, a resection and suture technique was employed for posterior prolapse.
Mitral leaflet retractor We participated in the development of a specially designed doubleheaded retractor, for mitral leaflet retraction (Senko Medical Instrument Manufacturing Company, Tokyo, Japan), with which both mitral leaflets can be simultaneously retracted at the same level (Fig. 1). With this novel retractor, it is easy to adjust the length of the
© The Author 2014. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.
NEW IDEAS
NEW IDEAS – ADULT CARDIAC
Interactive CardioVascular and Thoracic Surgery 18 (2014) 701–705 doi:10.1093/icvts/ivu040 Advance Access publication 6 March 2014
702
N. Kashiyama et al. / Interactive CardioVascular and Thoracic Surgery
Figure 1: The mitral leaflet retractor (Senko Medical Instrument Manufacturing Company) was used to decide the length of artificial chordae, according to the opposite normal chordae of the posterior mitral leaflets.
atriotomy. After assessing the entire mitral apparatus, chordal reconstruction using e-PTFE sutures (CV-5) was performed to repair the prolapse of the AML. CV-5 sutures were passed through the papillary muscle and the free edge of the prolapsed anterior leaflet. Then, the mitral leaflet retractor was attached to the Hercules Arm and fixed on the sternal retractor. One head of the retractor was gently put into contact with the normal posterior leaflet, and the opposite prolapsed anterior leaflet was placed on the other head of the retractor. Finally, the suture was softly tied down (Fig. 1). An artificial ring was applied for supportive ring annuloplasty after measuring the intertrigonal distance and height of the anterior leaflet. In cases with bileaflet prolapse, the prolapsed posterior leaflet was repaired first using a conventional resection and suture technique, with a quadrangular resection of the redundant and prolapsed posterior leaflet performed. If the height of the posterior leaflet after quadrangular resection was >20 mm, the height of the remaining posterior leaflet was reduced by use of a sliding or folding leaflet technique to avoid systolic anterior motion of the AML. Finally, chordal reconstruction was performed in the same manner using the mitral leaflet retractor. Concomitant procedures, including tricuspid annuloplasty (n = 21, 38.2%), a modified maze procedure (n = 17, 30.9%), coronary artery bypass grafting (n = 4, 7.3%) and aortic valve replacement (n = 3, 5.5%), were also performed in some cases.
Echocardiography
new chordae on the AML to the level of the non-diseased reference chordae of the opposing normal posterior leaflet. In addition, the device can be attached to a Hercules Universal Stabilizer Arm (Estech, Inc., Danville, CA, USA) to ensure the tying of the e-PTFE suture knots counteracting its sliding tendency (Fig. 2).
Transthoracic preoperative echocardiography was performed in all patients, which allowed for the evaluation of the severity of MR in the long-axis parasternal view. Perioperative transoesophageal echocardiography was mandatory and used to evaluate valve competence according to the presence of colour Doppler residual regurgitation and the absence of systolic anterior motion. Transthoracic postoperative echocardiography was used to evaluate recurrence of mitral valve regurgitation.
Surgical procedures
Follow-up
After performing a median sternotomy and bicaval/aortic cannulation, the mitral valve was exposed through a right-sided left
Follow-up examinations were performed at the outpatient clinic and by phone interviews with local doctors. Postoperative
Figure 2: The mitral leaflet retractor can be attached to the Hercules Stabilizer Arm (Estech, Inc.).
N. Kashiyama et al. / Interactive CardioVascular and Thoracic Surgery
Statistical analysis Statistical analysis was performed using JMP 10.0.2 (SAS Institute, Cary, NC, USA). Descriptive statistics are shown as the mean ± standard deviation for continuous variables, and as frequencies and percentages for categorical variables, unless otherwise noted. Estimates of survival probability or freedom from a valve-related reoperation, as well as freedom from recurrence of MR, were done using the standard Kaplan–Meier method. The results are reported in accordance with accepted guidelines [4].
RESULTS Patients All 55 patients had moderate-to-severe MR due to AML prolapse, and their clinical profiles are summarized in Table 1. Twelve (21.8%) patients presented with bileaflet prolapse requiring concomitant posterior leaflet repair (Table 2).
Table 1: Preoperative clinical and echocardiographic profiles Patients characteristics Patients, n Males, n (%) Age, years (range) New York Heart Association Class I/II/III/IV, n (%) Comorbidity Hypertension, n (%) Hyperlipidaemia, n (%) Diabetes, n (%) Chronic obstructive lung disease, n (%) Chronic renal failure, n (%) Peripheral vascular disease, n (%) Neurological history, n (%) Atrial fibrillation, n (%) Previous cardiac surgery, n (%) Echocardiographic data LV end-diastolic dimension, mm LV end-systolic dimension, mm LV ejection fraction, % Left atrial dimension, mm Tricuspid regurgitation pressure gradient, mmHg Mitral regurgitation, 0/1+/2+/3+/4+, n (%) Tricuspid regurgitation, 0/1+/2+/3+/4+, n (%)
55 38 (69) 61 ± 15 (23–81) 12 (22)/31 (56)/10 (18)/2 (4) 24 (44) 11 (20) 6 (11) 0 (0) 4 (7) 0 (0) 7 (13) 21 (38) 3 (5) 54 ± 7 34 ± 6 66 ± 10 46 ± 10 28 ± 10 0 (0)/0 (0)/1 (2)/20 (36)/ 34 (62) 11 (20)/21 (38)/14 (25)/ 7 (13)/2 (4)
LV: left ventricle.
Procedure Mitral valve repair was feasible in all patients, while additional AML repairs, including a paracommissural edge-to-edge procedure, were performed in 17 (30.9%) patients. Anterior leaflet triangular resection was not performed. Mitral annuloplasty was performed in all patients using a complete ring or a band as follows: a Carpentier–Edwards Physio ring (Edwards Lifescience, Irvine, CA, USA) was used in 36 (65.5%) patients, a Carpentier– Edwards Physio ring II (Edwards Lifescience) in 16 (29.1%), a Cosgrove–Edwards annuloplasty band (Edwards Lifescience) in 2 (3.6%) and a Rigid Saddle Ring (St. Jude Medical, Inc., St. Paul, MN, USA) in 1 (1.8%). The mean size of the annuloplasty rings was 27.5 ± 2.3 mm. Cardiopulmonary bypass and aortic cross-clamp times were 171.4 ± 56.8 and 119.5 ± 42.5 min, respectively. By intraoperative saline injection test, readjustment of artificial chordae was required in 10 patients. Intraoperative echocardiographic findings revealed residual Grade 2 MR in 3 patients with bileaflet prolapse or extended anterior leaflet lesion (5.5%), which required second pump runs. Systolic anterior motion was noted in 1 (1.8%) patient and was managed successfully with short-acting beta-blockers and volume expansion. At discharge, we had no residual or recurrent more-than-moderate MR, excluding the patient who required reoperation due to recurrent severe MR by detachment of artificial ring (Table 3).
Mortality There was no in-hospital mortality. The overall mortality rate was 1.9, 9.6 and 9.6% (n = 3) at 1, 3 and 5 years, respectively, after surgery. Two of the 3 deaths occurred late after surgery. Two were
Table 2:
Operative data
Total number of artificial chordae, chordal no. Numbers of artificial chordae 1/2/3/4/5, n (%) APM to A1, A2, A3, chordal no. (%) PPM to A1, A2, A3, chordal no. (%) Ring type Physio ring, n (%) Physio ring II, n (%) Cosgrove band, n (%) Semirigid saddle ring, n (%) Ring size 24, 26, 28, 30, 32, n (%) Additional procedure Paracommissural edge-to-edge, n (%) Concomitant procedure Coronary artery bypass grafting, n (%) Tricuspid annuloplasty, n (%) Modified maze procedure, n (%) Aortic valve replacement, n (%) Operation time, min Cardiopulmonary bypass time, min Aortic cross-clamp time, min Second pump run, n (%) Mitral valve replacement conversion, n (%)
97 23 (42)/19 (35)/12 (22)/0 (0)/1 (2) 8 (8), 32 (33), 3 (3) 0 (0), 23 (24), 31 (32) 36 (65) 16 (29) 2 (4) 1 (2) 8 (15), 20 (36), 15 (27), 8 (15), 5 (9) 17 (31) 4 (7) 21 (38) 17 (31) 3 (6) 307 ± 82 171 ± 56 120 ± 43 3 (6) 0 (0)
APM: anterolateral papillary muscle; PPM: posteromedial papillary muscle.
NEW IDEAS
follow-up examinations were scheduled at 1, 3 and 6 months, and annually thereafter, during which clinical status and echocardiographic data were recorded. Postoperative events were compiled and analysed according to the guidelines for reporting morbidity and mortality after cardiac valvular operations [4]. Only the latest echocardiographic data were considered for the present study.
703
704
N. Kashiyama et al. / Interactive CardioVascular and Thoracic Surgery
Table 3: Echocardiography at discharge LV end-diastolic dimension, mm LV end-systolic dimension, mm LV ejection fraction, % Left atrial dimension, mm Tricuspid regurgitation pressure gradient, mmHg Mitral regurgitation, 0/1+/2+/3+/4+, n (%) Tricuspid regurgitation, 0/1+/2+/3+/4+, n (%)
47 ± 6 32 ± 7 59 ± 11 39 ± 8 19 ± 8 43 (87)/7 (13)/4 (7)/1 (2)/0 (0) 33 (60)/12 (22)/9 (16)/1 (2)/0 (0)
LC: left ventricular.
due to sepsis (231 and 1024 days postoperatively), and the other died of an unknown cause (1088 days postoperatively).
Reoperation Freedom from reoperation was 98.2% at 5 years. One patient (1.8%) required a mitral valve reoperation for recurrent MR on postoperative day 85 because of detachment of the artificial annuloplasty ring, and mitral valve replacement with a bioprosthesis was performed. No patient developed mitral valve endocarditis during the follow-up period.
Clinical and echocardiographic follow-up Clinical and echocardiographic follow-up examinations were completed in all patients, and the mean follow-up duration was 1181 ± 839 (range 50–2892) days. At the latest follow-up examination, all non-reoperated patients (n = 54) were in New York Heart Association Class I or II. Of those, 37 (67.3%) had no or trivial MR, 13 (23.6%) had mild MR and 5 (9.1%) had moderate MR. Causes of the MR recurrences were progression of valve degeneration, development of valve tethering by ischaemic heart disease, limited motion of anterior leaflet by artificial chordae and detachment of artificial annuloplasty ring. The rate of freedom from recurrent moderate MR was 88.0% at 5 years.
DISCUSSION Determination of the proper length of the neochordae is a major concern, and various modalities have been proposed to establish that length, which can be categorized as anatomical and functional [5]. Anatomical means of length determination are common. von Oppell and Mohr [6] as well as others have described a simple method of determining neochordal length, in which a calliper is used intraoperatively to measure the distance between the papillary muscle tip and the annular plane. However, this technique presumes that the pathology has not affected the adjacent native chordae. Furthermore, the chordae are examined in an empty heart resting state. Calafiore [7] described a method that combines preoperative echocardiographic data and intraoperative measurements to determine the correct neochordae length, although it is difficult to obtain good preoperative echocardiographic images in all cases.
Furthermore, because the necessary neochordae length is dependent on the suture site in the papillary muscle or prolapsed leaflet, preoperative measurements based on echocardiography are not always correct. Several functional methods for the determination of neochordae length have also been reported. Kasegawa et al. [8] proposed the use of a small tourniquet to progressively adjust the length of the chordae, while David et al. distended the ventricle with saline in order to observe where the free margin of the leaflets should coapt [2]. In this report, we present a new method for the determination of neochordae length using our novel mitral leaflet retractor. With this technique, it is not necessary to obtain proper echocardiography findings, as the precise distance between the tip of the papillary muscle and the annular plane can be determined preoperatively and intraoperatively. When the retractor is attached to the stabilizer arm, easy and reliable suture ligation with an e-PTFE thread is possible, as the sliding characteristic of the device makes it difficult to tie the knots without the aid of an assistant. In the present method, the opposite normal chordae of the posterior mitral leaflets is used as a reference to adjust the length of the artificial chordae. This concept for repair is similar to that reported by Matsumoto et al. [9] and Sarsam [10] in terms of referring to the opposing leaflet, though our method is considered to have advantages of speed and simplicity. Mid-term results following chordal replacement with the mitral leaflet retractor are similar to those obtained with other methods. Even though the method for determining the length of the artificial chordae may affect the success of the operation, the main mechanism of recurrent regurgitation after MV repair is progressive degeneration, as reported by Shimokawa et al. [11]. Thus, we think that additional procedures such as triangular resection for redundant anterior leaflets or prophylactic replacement of artificial chordae to the sites that are suspected to progress degeneration earlier may be required for further improvement of long-term results following chordal replacement.
LIMITATIONS The main limitation of the current study is its retrospective and non-randomized design. We did not routinely perform quantitative echocardiography for these cases. Therefore, the severity of MR may have been over- or underestimated in some echocardiograms, considering the limitations of the colour Doppler jet method.
CONCLUSIONS The present method offers a simple and reproducible solution for correction of anterior leaflet prolapse. Our novel mitral leaflet retractor can used to reliably determine the length of the artificial chordae. However, long-term results must be evaluated and compared with those of other surgical strategies. Conflict of interest: none declared.
REFERENCES [1] Grossi EA, Galloway AC, LeBoutillier M III, Steinberg B, Baumann FG, Delianides J et al. Anterior leaflet procedures during mitral valve repair do not adversely influence long-term outcome. J Am Coll Cardiol 1995;25: 134–6.
[2] David TE, Armstrong S, Ivanov J. Chordal replacement with polytetrafluoroethylene sutures for mitral valve repair: a 25-year experience. J Thorac Cardiovasc Surg 2013;145:1563–9. [3] Ibrahima M, Rao C, Athanasiou T. Artificial chordae for degenerative mitral valve disease: critical analysis of current techniques. Interact CardioVasc Thorac Surg 2012;15:1019–32. [4] Akins CW, Miller DC, Turina MI, Kouchoukos NT, Blackstone EH, Grunkemeier GL et al. Guidelines for reporting mortality and morbidity after cardiac valve interventions. J Thorac Cardiovasc Surg 2008;135:732–8. [5] Zussa C. Different applications of ePTFE valve chordae: surgical technique. J Heart Valve Dis 1996;5:356–61. [6] von Oppell UO, Mohr FW. Chordal replacement for both minimally invasive and conventional mitral valve surgery using premeasured Gore-Tex loops. Ann Thorac Surg 2000;70:2166–8. [7] Calafiore AM. Choice of artificial chordae length according to echocardiographic criteria. Ann Thorac Surg 2006;81:375–7. [8] Kasegawa H, Kamata S, Hirasa S, Kobayashi N, Mannouji E, Ida T et al. Simple method for determining proper length of artificial chordae in mitral valve repair. Ann Thorac Surg 1989;97:98–103. [9] Matsumoto T, Kado H, Masuda M, Shiokawa Y, Fukae K, Morita S et al. Clinical results of mitral valve repair by reconstructing artificial chordae tendineae in children. J Thorac Cardiovasc Surg 1999;118:94–8. [10] Sarsam MA. Simplified technique for determining the length of artificial chordae in mitral valve repair. Ann Thorac Surg 2002;73:1659–60. [11] Shimokawa T, Kasegawa H, Katayama Y, Matsuyama S, Manabe S, Tabata M et al. Mechanisms of recurrent regurgitation after valve repair for prolapsed mitral valve disease. Ann Thorac Surg 2011;91:1433–9.
APPENDIX. CONFERENCE DISCUSSION Dr O. Jegaden (Lyon, France): It is true, as you mentioned, that the concept of artificial chordae is becoming more and more adopted by the surgical community, but the adjustment of their length remains controversial and tricky, and sometimes I have the feeling or the impression that each surgeon has his own technique. In this field it is important to have standardization of the technique, and the clever tool that you suggest and that you have presented could pave the way in this direction. Your technique is very attractive and seems to be effective and reproducible according to the good results that you have demonstrated, with a very low rate of recurrence of mitral regurgitation at mid-term and long-term. I have several questions, mainly regarding the technique itself. Firstly, in your series you have used this technique only to correct anterior leaflet prolapse. Do
705
you think that it could also be used to correct posterior leaflet prolapse? In the case of prolapse of both leaflets, you have mentioned that you correct the posterior with the resection technique and the anterior with the chordae. Do you think that your tools could open the way to easily correct prolapse of both leaflets with artificial chordae? The third question is regarding the tying of the chordae. Dr A.P. Kappetein (Rotterdam, Netherlands): Perhaps the English language is difficult for him, so answer the first question. Dr Kashiyama: The first question is whether our leaflet retractor can be adapted to posterior leaflet prolapse or not. The answer is yes. But when you use this retractor, the most important thing is whether the reference point can be obtained or not. So when the opposing anterior leaflet is normal, of course you can adapt this retractor to posterior leaflet prolapse. However, in bileaflet prolapse, it is often difficult to detect the reference point. That is why in such a case, in order to obtain the reference point, we should repair the posterior leaflet prolapse first by the resection suture, and then we can use the repaired posterior leaflet as a reference point and achieve chordal replacement for the anterior leaflet. We know it is one of the limitations of this retractor, but there are no problems when you resect it. Dr Jegaden: Only one more question. It is regarding the surface of coaptation. With your technique, particularly if you tie the artificial chordae above the annuloplasty, I have the feeling that you could easily increase the surface of coaptation, and we know that is the main point in improving the long-term results. Do you have some data to support the fact that your technique allows increase of the surface of coaptation? Dr Kashiyama: Good question. I don’t know why you think that you can obtain better coaptation by performing chordal replacement after annuloplasty. When I think simply, we can match the height of the anterior and posterior leaflet by chordal replacement with this retractor and we can obtain better coaptation by the annuloplasty. So I don’t think the sequence of chordal replacement and annuloplasty would be important. Of course, if you want to perform annuloplasty initially, it would be possible. However, we think it is easier to rehang artificial chordae to papillary muscle before annuloplasty when the length of artificial chordae is too long or too short. Dr Jegaden: And the last question is, is this tool available for minimally invasive techniques, I mean with a long handle. Dr Kashiyama: The last question is whether this retractor can be adapted to minimally invasive mitral surgery. Actually we have never used this retractor in minimally invasive mitral surgery. When we can develop this retractor with a long handle to reach the deep surgical field, it may be useful to employ this device in this approach. However, actually the longer handle makes it harder to precisely adjust the head of the retractor. So it is challenging, but I will try in the near future.
NEW IDEAS
N. Kashiyama et al. / Interactive CardioVascular and Thoracic Surgery
