New approaches to cardiovascular surgery.

New Approaches to Cardiovascular Surgery Robert C. Neely, MD, Marzia Leacche, MD, Christopher R. Byrne, Anthony V. Norman, and John G. Byrne, MD Abstract: Modern treatment of cardiovascular disease requires a patient-centered approach. With several technological advances, the options for treatment must be carefully weighed and novel approaches tested for safety and efficacy. In this article, we outline some of the new approaches available to cardiothoracic surgeons for the treatment of cardiovascular diseases, including off-pump coronary artery bypass grafting, transcatheter valve replacement, and hybrid and robotic technology. We discuss current evidence and controversies and highlight the challenges that we face in training surgeons in an environment of ever-evolving surgical techniques. (Curr Probl Cardiol 2014;39:427–466.)

Introduction here is a rich history of innovation in the treatment of cardiovascular disease, and medicine’s newest technologies are used in modern cardiac surgical practice. Recent decades have seen an unprecedented application of new approaches to heart disease, from hybrid coronary revascularization (HCR) techniques and percutaneous valve implantations to robotic technology and mechanical assist devices. In the current environment of strict quality control and public reporting of clinical outcomes, the use of novel techniques is often met with resistance. Yet maintaining a safe and effective clinical practice is not mutually exclusive with implementing new approaches. In this article, we outline some of the

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The authors have no conflicts of interest to disclose. Curr Probl Cardiol 2014;39:427–466. 0146-2806/$ – see front matter http://dx.doi.org/10.1016/j.cpcardiol.2014.07.006

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new surgical approaches to cardiovascular pathologies with an emphasis on the currently available evidence to ensure best practice. No review of evolving technologies would be complete without discussing the effect new techniques have on surgical training. As technologies evolve, so must our approaches in training the next generation of cardiac surgeons. With an ever-growing array of procedures to be learned within a system enforcing work-hour limits, educators are redesigning the model for surgical training programs and employing advanced simulation modules to ensure proficiency. The cardiothoracic surgeons of tomorrow will have a very different practice from surgeons who trained even a decade ago, and this article addresses some of the essential technical and practical elements of this evolution.

Modern Surgical Approaches to Cardiovascular Disease Off-Pump Coronary Artery Revascularization Coronary artery bypass grafting surgery (CABG) is traditionally performed on cardiopulmonary bypass (CPB) and remains the standard intervention for coronary artery disease requiring surgical revascularization. The bypass circuit is not without drawbacks, such as the activation of complement cascades, the release of proinflammatory cytokines, and the upregulation of inflammatory mediators that may affect postoperative morbidity.1 Moreover, the act of aortic cannulation places patients at risk for aortic injury and adverse neurologic sequelae. In an attempt to decrease CPB-related morbidity, off-pump CABG (OPCAB) was developed and has gained some favor among cardiac surgeons.2 Though controversies regarding superiority and learning curves remain, the safety and efficacy of OPCAB are well established. Currently, on-pump CABG remains the time tested, reproducible approach and OPCAB the newer technique performed in a minority of centers by experienced surgeons.3 Technique. The primary challenge during OPCAB is balancing patient hemodynamics with optimal cardiac positioning. Although CBP allows myocardial decompression and elective cardiac arrest for maximal coronary exposure without compromising systemic perfusion, manipulating the beating heart during OPCAB distorts venous return and may prohibitively decrease cardiac output. Initial lifting maneuvers assess the heart’s tolerance for positioning, and careful attention must be paid to central venous and mean arterial pressures at this time, and throughout the procedure. These limitations are less important for anterior anastomoses but may preclude adequate visualization of the lateral or posterior wall 428


targets. To overcome these barriers, patients are supported with inotropes and typically infused with relatively larger volumes of fluid supplemented by patient positioning (head down) to ensure adequate preload.1 Clear communication between surgical and anesthesia teams is essential. Several heart positioning devices have been designed to facilitate a reliable exposure, including devices to stabilize the myocardium around the target vessel (Fig 1). Target vessels must be isolated and blood flow controlled to allow sufficient visualization for sewing. Intracoronary shunts are used to circumvent the transient occlusion of the coronary allowing distal coronary perfusion (Fig 1).4,5 Patient Selection. As experience increases, surgeons who perform OPCAB often liberalize the criteria for patients who may benefit from OPCAB.6 Early experience with off-pump revascularization typically focuses on younger patients with anterior targets and preserved ejection fractions to gain technical proficiency. Paradoxically, proponents of OPCAB believe that the patients who are most likely to benefit are older (470 years) and possess significant comorbidities such as chronic obstructive pulmonary disease, renal dysfunction, or a history of cerebrovascular events.7 Contraindications for OPCAB include hemodynamic instability and difficult targets such as intramyocardial vessels. Relative contraindications should be weighed against surgeon’s experience (Table 1). As individual experience increases, so does the surgeon’s ability to take on more challenging operations. An OPCAB for multiple posterior and lateral coronary targets in the setting of cardiomegaly is a poor candidate for surgeons with little off-pump experience, but may be a reasonable candidate for more seasoned off-pump surgeons. Clinical Outcomes. The major proposed advantages of OPCAB are related to the avoidance of CPB, namely decreased neurocognitive and renal impairment as well as bleeding complications and transfusion requirements. To date, however, there are few large trials demonstrating significant benefit compared with on-pump CABG. The CABG off- or on-pump revascularization study (CORONARY) is the largest multicenter, prospective, randomized trial and has reported 30-day and 1-year outcomes of 4752 patients.8,9 OPCAB was associated with a lower rate of blood product transfusion and reoperations for bleeding at 30 days, but fewer grafts were performed and no significant difference was found in the primary composite outcome of death, myocardial infarction, stroke, and new-onset renal failure requiring dialysis. No difference in this same Curr Probl Cardiol, December 2014

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FIG 1. OPCAB technology in use. (Left) The Medtronic Octopus4 tissue stabilizer with Starfish2 heart positioner isolates and exposes the left anterior descending (LAD) coronary artery. (Middle) An intraluminal shunt is shown inserted and positioned across the LAD arteriotomy. (Right) The Medtronic Starfish2 heart positioner lifts the heart and exposes the posterior vessels, whereas the Octopus 4 tissue stabilizer immobilizes a segment of the posterior descending artery. (Reprinted with permission from Wolters Kluwer Health and Verma et al.1) (Color version of figure is available online.)

TABLE1. Contraindications to OPCAB Absolute contraindications

Relative contraindications

Hemodynamic instability Poor quality target vessels Intramyocardial vessels Diffusely diseased vessels Calcified coronary vessels

Cardiomegaly or congestive heart failure Critical left main disease Small distal targets Recent or current acute MI Cardiogenic shock Poor left ventricular function (LVEF o 35%)

LVEF, left ventricular ejection fraction; MI, myocardial infarction. Reprinted with permission from Wolters Kluwer Health and Verma et al.1

primary composite outcome was seen at 1-year follow-up nor was there a benefit seen in quality of life or neurocognitive function assessments.9 A principle criticism of OPCAB is the concern of incomplete revascularization.10-13 In the randomized on/off bypass (ROOBY) study of 2203 patients from the Veterans Affairs medical centers, OPCAB was associated with fewer grafts performed, lower patency rates at 1 year, and higher rate of incomplete revascularization. Unlike the CORONARY trial, which was limited to highly experienced surgeons, the OPCABGs in the randomized on/off bypass trial were performed by surgeons with a wide range of experience and included trainees.11 The level of training in studies notwithstanding, concerns regarding rates of revascularization persist,10 and long-term follow-up has yielded inconsistent results.14,15 Dr Schaff: Coronary artery bypass operations were originally performed without the use of extracorporeal circulation, but surgeons quickly realized that more precise anastomoses could be performed on a quiet, bloodless field provided by cardiopulmonary support and cardioplegic arrest. Over a decade ago, interest in off-pump surgery was revived by renewed interest in minimally invasive procedures, and the development of tools for stabilization of the anastomotic site, and control of and coronary blood flow led to more widespread application for off-pump revascularization of patients with multivessel disease via sternotomy. The theoretical benefits of avoiding CPB may be advantageous in selected patients, especially those with extensive atherosclerosis of the ascending aorta and, perhaps, patients with impaired renal function. The practical problem with off-pump surgery is that revascularization is generally less complete compared with that achieved by coronary artery bypass procedures using extracorporeal circulation. Emerging evidence suggests that late results of off-pump coronary artery bypass, survival, and need for repeat intervention are inferior to outcomes of patients having revascularization using standard methods (Kim JB, Yun SC, Lim JW, Hwang SK, Jung SH, Song H, Chung CH, Lee JW, Choo SJ. Long-term survival following coronary artery bypass grafting: off-pump versus on-pump strategies. J Am Coll Cardiol. 2014;63:2280-2288). Indeed, use of off-pump surgery for coronary revascularization in the United States appears to be Curr Probl Cardiol, December 2014

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declining. In the Society for Thoracic Surgeons database, coronary revascularization was performed off pump in 17.8% of patients in 2012 and 16.6% of patients in 2013.

Postoperative atrial fibrillation (POAF) remains a common and challenging problem in cardiothoracic surgery. Some evidence supports a decreased incidence of POAF in patients who have undergone off-pump compared with on-pump CABG, and a higher rate of conversion to sinus rhythm in those patients who develop POAF (OPCAB 94.7% vs ONCAB 82.2%, P = 0.006).16 However, this outcome has not been systematically evaluated in larger trials. Many cardiothoracic surgeons debate the patency and reproducibility of OPCAB.17 As with any procedure, the treatment approach must be patient centered and within the comfort level of the operating surgeon. Indeed, the application of OPCAB may evolve as the popularity of HCR increases (see section Hybrid Surgery). At present, it is generally agreed that the level of success for OPCAB procedures is associated with surgeon’s experience,18 but as long-term outcomes from the CORONARY trial are shared, the next question may be how to best train surgeons in this complex operation.

Percutaneous Valve Interventions Aortic Valve. The transcatheter approach for aortic valvular pathology was first described by Cribier et al19 in 1985 with the successful application of balloon aortic valvuloplasty for aortic stenosis. This technique, however, failed to provide significant and lasting effect compared with surgical aortic valve replacement20 and, consequently, many patients deemed too high risk for surgery were left without a better therapeutic option. In 2002, Cribier et al21 once again reported a first, this time the successful implantation of a percutaneously delivered bioprosthetic aortic valve. Since then, more than 60,000 valves have been implanted worldwide with growing evidence to support transcatheter aortic valve replacement (TAVR) in certain patient populations.22,23 The Placement of AoRtic TraNscathetER Valves (PARTNER) trial demonstrated that the transcatheter approach was safe and effective for patients with symptomatic aortic stenosis who are deemed prohibitive risk for aortic valve replacement by full sternotomy,24 such as patients with severe aortic calcifications, multiple prior sternotomies, severe pulmonary disease, or advanced age. Technique. An extensive preoperative workup is required to determine eligibility. Transcatheter approaches are commonly performed in 432


interventional suites, but dedicated hybrid operating rooms may provide better support for transapical and transaortic techniques. Moreover, supporting staff and operating room personnel trained in transcatheter techniques may prove to offer the safest overall working environment as the technology becomes widespread. In current practice, the catheter is advanced retrograde, via femoral arterial or transaortic routes, or antegrate, via a transapical route. Transfemoral retrograde approach—Direct femoral artery exposure may be required. Access is gained and, with fluoroscopy, a catheter is passed retrograde across the arterial vasculature, which limits its usefulness with tortuous or severely calcified femoral or aortic vessels. After deployment, the arteriotomy must be closed with a percutaneous closure device or via direct suturing if a femoral cut down is required. Alternatively, retrograde approaches via transaxillary (sheath inserted through a side graft sewn to axillary or subclavian arteries) or transaortic approaches (via partial upper sternotomy) have been described.25 Transapical antegrade approach—A left anterior minithoracotomy is performed to expose the apex of the heart. Once the apex of the left ventricle (LV) is observed on transesophageal echocardiography (TEE), pledgeted sutures are placed into the myocardium. A modified Seldinger technique is used to gain wire access. The wire is then passed antegrade across the aortic valve under fluoroscopy. As with the femoral approach, the sheath and device are passed over the wire. This technique is commonly used for patients with severe femoral, carotid, and aortic disease.

There are 2 currently Food and Drug Administration–approved valves: (1) the SAPIEN device (Edwards Lifesciences Corporation, Irvine, CA) and (2) the Medtronic CoreValve device (Medtronic Inc, Minneapolis, MN) (Fig 2). The SAPIEN valve is a trileaflet bovine pericardium valve that requires expansion with a balloon. The CoreValve is a trileaflet porcine pericardium valve with a nickel-titanium frame that is selfexpanding. A balloon aortic valvuloplasty is commonly performed before valve deployment (Fig 3). Transvenous pacing capabilities, typically obtained through the femoral or internal jugular vein into the right ventricle, and continuous arterial blood pressure monitoring are essential components of this step. After valvuloplasty, severe aortic insufficiency may be present and hemodynamics should be carefully monitored. As is Curr Probl Cardiol, December 2014

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FIG 3. Balloon aortic valvuloplasty is commonly performed before valve deployment. An angiogram is performed to confirm proper positioning of the balloon, and during a short period of rapid ventricular pacing, the balloon is inflated. This frequently causes aortic insufficiency, and therefore, intense monitoring is required during this period. (Reprinted with permission from CTSNet [www.ctsnet.org].)

the case throughout the procedure, clear communication is essential to ensure readiness among team members and the safety of the patient. Both devices are deployed through percutaneous sheaths and performed on the beating heart. Rapid ventricular pacing may increase the accuracy of valve deployment by minimizing motion of the aortic annulus and temporarily suspending LV cardiac output. Concomitant TEE by an echocardiographer experienced with the operation is a helpful adjunct to fluoroscopy and digital subtraction angiography to confirm proper valve sizing and positioning before deployment, as well as confirm positioning and check for paravalvular leaks (PVLs) after deployment (Fig 4). Patient Selection. In the era of strict Food and Drug Administration approvals and evolving insurance health care coverage, the emergence of new technologies is subject to rigorous evaluation and oversight. In this way, patient selection for transcatheter valve interventions is closely tied FIG 2. (A) The SAPIEN device by Edwards Lifesciences, a balloon-expandable metal stent with a trileaflet bovine pericardium valve and (B) the Medtronic CoreValve device, a self-expanding prosthesis with a nickel-titanium frame and a trileaflet porcine pericardium valve. (Reprinted with permission from [A] Edwards Lifesciences, inc and [B] Medtronic, inc.) (Color version of figure is available online.) Curr Probl Cardiol, December 2014

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FIG 4. A completion angiogram is performed after the transapical deployment of the valve. The implanted aortic valve is shown. The completion angiogram should not only confirm that the aortic root, ascending aorta, and the coronary ostia are intact, but also confirm that the mitral valve apparatus has not been disrupted by the transapical approach. (Reprinted with permission from CTSNet [www.ctsnet.org].)

with national coverage discussions to allow suitable Medicare beneficiaries appropriate TAVR evaluation (Table 2). Surgical AVR remains the standard of care for patients with severe aortic stenosis, but patients considered high risk or prohibitive risk may be considered for transcatheter interventions.22 A dedicated, multidisciplinary heart team versed in TAVR candidate selection and treatment should evaluate patients. Recently, the Society of Catheterization and Angiographic Intervention, American Association for Thoracic Surgery, the American College of Cardiology (ACC), and the Society of Thoracic Surgeons (STS) released joint guidelines for operator and institutional requirements for transcatheter valve programs, specifically addressing minimum case requirements among participating cardiologists and cardiac surgeons. Ongoing institutional quality assurance assessments for certification were also outlined (Table 3). The ACC and American Heart Association (AHA) have also recently released updated guidelines for the management of valvular heart disease. Consistent with recommendations for operator and institutional requirements, these guidelines highlight the importance of Centers of Excellence 436


TABLE 2. Highlights of the national coverage determination for TAVR TAVR is covered for the treatment of symptomatic aortic valve stenosis when furnished according to an FDA-approved indication and when all of the following conditions are met: The procedure has received FDA premarket approval for that system's FDA-approved indication Two cardiac surgeons have evaluated the patient's suitability for open AVR surgery The patient is under the care of a heart team: a cohesive, multidisciplinary team of medical professionals TAVR must be furnished in a hospital with the appropriate infrastructure that includes: On-site heart valve surgery program Cardiac catheterization laboratory or hybrid operating room or catheterization lab equipped with a fixed radiographic imaging system Qualifications to begin a TAVR program for heart teams without TAVR experience: The heart team must include Intervention Program: 1000 catheterizations/400 PCIs per year Operators: 100 structural procedures lifetime or 30 left-sided structural procedures per year (60% should be BAV) Surgery Program: 50 total AVRs per year, of which at least 10 are high risk (STS Z 6%) Operators: 100 AVR career, of which at least 10 are high risk (STS Z 6%) or 25 AVRs per year or 50 AVRs in 2 y (at least 20 in the last year before initiating TAVR) The heart team's interventional cardiologist(s) and cardiac surgeon(s) must jointly participate in the intraoperative technical aspects of TAVR. The heart team and hospital are participating in a prospective, national, audited registry. TAVR is covered for uses that are not expressly listed as an FDA-approved indication when performed within a clinical study. TAVR is not covered for patients in whom existing comorbidities would preclude the expected benefit from correction of the aortic stenosis. FDA, Food and Drug Administration. Reprinted with permission from Elsevier and Mack et al.22

for valvular heart disease26 and propose important preoperative risk assessment algorithms. Preoperative assessment should aim to identify symptoms of severe aortic stenosis such as chest pain, dyspnea on exertion, or syncope. Transthoracic echocardiography is the standard tool to grade severity of stenosis. Severe aortic stenosis is defined as an aortic valve area of less than 0.8 cm2 with either a peak velocity of at least 4.0 m/s or mean valve gradient of at least 40 mm Hg. In addition to echocardiographic data, complete workup and evaluation includes an assessment of comorbidities, functional status, life expectancy, and estimation of STS risk score.22 Two cardiac surgeons and a multidisciplinary heart team determine operative risk and patients must fall into 1 of 2 categories based on ACC-AHA 2014 guidelines:


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High-risk—STS predicted risk of mortality (PROM) 48% or Z2 indices of frailty (see later) or 42 organ systems compromised or possible procedure-specific impediment. Prohibitive risk—Predicted risk with surgery or major comorbidity 450% at 1 year or 43 organ systems compromised or severe procedure-specific impediments.26 Dr Schaff: Experts in valve disease differentiate criteria for severity of aortic valve stenosis in patients who are asymptomatic from those patients who are symptomatic. Asymptomatic severe aortic stenosis is defined not by valve area, but by a Doppler echocardiographic peak velocity of 4 m/s or 40 mm Hg or higher. In symptomatic patients with aortic valve disease, severe stenosis is confirmed by demonstration of a velocity of 4 m/s or an area of 1.0 cm2 or less (Otto CM, Nishimura RA. New ACC/AHA valve guidelines: aligning definitions of aortic stenosis severity with treatment recommendations. Heart. 2014 15;100:902-904). Severe aortic valve stenosis may also be present in patients with lower gradients when there is low cardiac output (low stroke volume).

Procedure-specific impediments may be prior chest radiation, dangerous location of prior bypass conduits, or severely atherosclerotic aorta. The guidelines have incorporated frailty measures to recognize the increasing age and range of functional status seen in TAVR referrals.

TABLE 3. Recommendations for operator and institutional requirements for TAVR Intervention Program: 1000 catheterizations/400 PCIs per year Operators: 100 structural procedures lifetime or 30 left-sided structural procedures per year (60% should be BAV) Surgery Program: 50 total AVRs per year, of which at least 10 are high risk (STS score Z6%) Operators: 100 AVRs, of which at least 10 are high risk (STS Z 6%) or 25 AVRs per year or 50 AVRs in 2 y (at least 20 in the last year before initiating TAVR) Outcomes for continued certification for both new and existing TAVR programs applies to “inoperable” (PARTNER Cohort B) TAVR patients 30-d All-cause mortality o15% 30-d All-cause neurologic events, including transient ischemic attack, 15% Major vascular complication o15% 490% Institutional follow-up 60% 1-y Survival rate for nonoperable patients All cases must be submitted to a single national database BAV, balloon aortic valvuloplasty. Reprinted with permission from Elsevier and Mack et al.22

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No frailty—able to perform 1 activity of daily living and perform a 5-m walk in o6 seconds.

Mild degree of frailty—unable to perform 1 activity of daily living and perform a 5-m walk in o6 seconds.

Moderate-to-severe degree of frailty—unable to perform 42 activities of daily living.26

Dr Schaff: Experienced clinicians have always incorporated assessment of frailty into evaluation and planning of treatment for patients. This is especially important in elderly patients with aortic valve stenosis who may have other serious comorbid illnesses. Criteria to quantify frailty may become increasingly useful in evaluating patients for transcatheter valve therapy, but it is also important to distinguish between frailty and futility in elderly patients with limited reserve and limited life expectancy.

Once a patient is considered a suitable candidate for TAVR, the decision to perform an antegrade or retrograde approach requires routine assessment of ascending aortic and ileofemoral arterial anatomies and size with multidetector computed tomography scan. Ileofemoral arteries that are tortuous, severely calcified, or smaller than the sheath size may preclude a transfemoral approach. Extensive aortic atherosclerotic disease or multiple prior sternotomies prohibit the transaortic technique through a hemisternotomy. Transaxillary and transapical approaches are alternatives typically reserved for patients unsuitable for other techniques, and studies comparing their outcomes have shown inconsistent results.22,27 Dr Schaff: Transcatheter insertion of an aortic valve prosthesis is one of the most exciting recent developments in management of patients with aortic valve disease. Current prostheses were developed mainly for treatment of aortic valve stenosis, but new designs and implementation will undoubtedly be utilized in patients with aortic regurgitation in the future. Also, these valves (and also the Melody transcatheter pulmonary valve prosthesis) have been used off-label to treat degenerating stented bioprostheses in the aortic position as well as the mitral and tricuspid positions.

Clinical Outcomes. All-cause mortality outcomes of the PARTNER trial revealed that transfemoral aortic valve replacement was superior to “standard therapy,” which included aortic balloon valvuloplasty in 85% of the patients (cohort B) and transcatheter (transfemoral or transapical) AVR was noninferior to surgical AVR at 1 year (cohort A). Numerous Curr Probl Cardiol, December 2014

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follow-up studies and subgroup analyses have been performed. Additional observed benefits of TAVR include decreased blood product transfusion, shorter hospital length of stay, and fewer major bleeding complications compared with surgical AVR.28 Dr Schaff: In current practice, transcatheter valves are considerably more expensive (5-6 fold increase in acquisition cost) than standard valves, and this may be a consideration for patients who are candidates for either procedure. For patients who are not candidates for standard surgical aortic valve replacement, transcatheter valves may be cost effective if treatment of aortic valve stenosis decreases cost of longitudinal care for congestive heart failure related to valve disease.

In a recent randomized trial from multiple institutions in the United States, the CoreValve demonstrated higher 1-year survival compared with surgical AVR in patients considered increased surgical risk. The 1-year mortality with TAVR (using the CoreValve) was 14.2% vs 19.1% with surgical AVR.29 Unlike the PARTNER trial, which used a mean STS PROM of Z10% for study inclusion, the STS PROM was a mean of 7.4% in this study by Adams et al.29 An important finding was that decreased stroke was seen in the TAVR group at 1 year (20.4% vs 27.3%, P ¼ 0.03).29 Most studies report that cerebrovascular events are more common with transcatheter techniques than surgical AVR at 30 days and 2 years (3.8% vs 2.1% and 7.7% vs 4.9%, respectively),25 though anticoagulation and antiplatelet therapy are not standardized. In a recent post hoc analysis of the PARTNER trial, Lindman et al30 found that patients with diabetes had a survival benefit at 1 year, as well as less renal failure requiring dialysis, and no increased risk of stroke with TAVR compared with surgical AVR. Further studies may identify additional subgroups that benefit from TAVR. Another concern after TAVR is heart block, which results from structural displacement of existing calcium deposits and may also be related to direct pressure on the conduction system from the newly implanted valve.23 In the French national transcatheter aortic valve implantation registry (FRANCE 2) of more than 3000 patients, new pacemaker requirements were significantly more frequent in Medtronic CoreValve vs Edwards SAPIEN valve (24.2% vs 11.5%).23 Preoperative assessment should include a thorough examination of baseline rhythm characteristics and patients with preexisting conduction abnormalities should be considered higher risk for new heart block and pacemaker requirements after TAVR. 440


A higher rate of PVL has been seen with TAVR compared with surgical AVR.29 Imperfect sizing and an irregular annular ring may place patients at risk for PVL after TAVR, and intraoperative TEE can help to identify size and location of regurgitation after valve deployment. If regurgitation is due to incomplete expansion of the bioprosthetic frame, postdeployment balloon dilatation may reduce PVL in up to 70% of cases, but this maneuver is associated with higher incidence of cerebrovascular events and some patient’s will have ongoing regurgitation.31 In a 2-year follow-up of the PARTNER trial, the absence of PVLs was associated with lower mortality. A tendency to undersize valves may be partly to blame, which could improve with the use of more accurate sizing using 3-dimensional TEE technology.32 Transcatheter placement of self-expanding prostheses such as the Amplatzer Septal Occluder (St. Jude Medical Inc, St. Paul, MN) have been described and shown to reduce the grade of regurgitation,33,34 though experience is limited and long-term outcomes unknown. Persistent PVL remains a problem after TAVR and is associated with substantial morbidity and mortality.32,35,36 The 10-year global experience has demonstrated that TAVR is a safe and beneficial alternative in selected patients and further investigations into intermediate-risk patients are ongoing. The Transcatheter Valve Therapy national registry, which supplements other registries such as the German Aortic Valve Registry, tracks transcatheter programs and patients and will help measure outcomes in the years to come so that the long-term durability of transcatheter valves can be compared with surgically placed valves. Dr Schaff: Transcatheter valve insertion may influence initial selection of prostheses because a degenerating bioprosthesis can be treated with a valve-in-valve transcatheter approach (Dvir D, et al. J Am Med Assoc. 2014;312:162-170). This is possible if the initial prosthesis has a sufficiently large orifice area to allow insertion of an adequately sized second valve without creating prosthetic obstruction. It is unclear whether this strategy, initial bioprosthesis followed by transcatheter valve-and-valve management of bioprosthesis degeneration, will achieve similar, better, or worse outcomes than initial implantation of a mechanical valve that requires chronic anticoagulation with Coumadin.

Mitral Valve. Surgical mitral valve repair remains the standard approach for severe, functional mitral valve regurgitation, though transcatheter techniques have been developed. The endovascular valve edge-to-edge repair study (EVEREST) investigated a percutaneous technique to address Curr Probl Cardiol, December 2014

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FIG 5. MitraClip (Abbott Vascular, Santa Clara, CA). (A) Loaded on catheter and (B) after deployment, resulting in a double-orifice mitral valve. (Reprinted with permission from [A] Feldman et al37 and [B] Oxford University Press and Frazen O, Baldus S, Rudolph V, et al. Acute outcomes of MitraClip therapy for mitral regurgitation in high-surgical-risk patients: emphasis on adverse valve morphology and severe left ventricular dysfunction. Eur Heart J. 2010;31:1373-1381.) (Color version of figure is available online.)

severe mitral regurgitation. Safety and feasibility were established in 27 patients with moderate-to-severe magnetic resonance (MR) with a LV ejection fraction o60%. The MitraClip, loaded on a catheter and deployed from a transeptal approach (Abbott Vascular, Santa Clara, CA) fastens the central mitral leaflets together to create a double orifice37 (Fig 5). The EVEREST II trial compared surgical treatment for moderate-tosevere mitral regurgitation vs percutaneous repair and found that major adverse events at 30 days were higher in the surgical group. This difference may have been disproportionately caused by the rates of packed red blood cell transfusions in the surgical group.37,38 LaPar et al39 compared their series of surgical mitral valve repairs with the surgical arm of the EVEREST II trial and demonstrated substantially lower transfusion rates, attenuating the conclusions drawn from EVEREST II 30-day outcomes. The 1-year outcomes from EVEREST II revealed higher composite efficacy end point of freedom from death, surgical mitral valve intervention, or Z3þ MR in surgical patients (73%) vs transcatheter MitraClip patients (57%) (P ¼ 0.007). Other studies of the MitraClip revealed shortterm symptomatic improvement but higher rates of recurrent MR at 1 year.40,41 Based on recent 4-year results from EVEREST II, it appears that most of the differences in residual MR requiring surgical intervention are confined to the first year, after which similar rates of MR severity were seen in percutaneous and surgical repair groups. Though surgical repair was associated with improved LV dimensions, this did not translate into a difference in long-term mortality.38 Much like early work in TAVR technology, current research for mitral valve interventions is focusing on high-risk patients. The clinical outcomes assessment of the MitraClip Percutaneous therapy for high surgical risk patients (NCT01626079) and a randomized study of the MitraClip Device in heart failure patients with clinically significant functional mitral regurgitation (NCT01772108) trials are investigating high surgical risk patients with low ejection fraction and New York Heart Association Class III or IV.42 The current AHA-ACC guidelines reserve transcatheter mitral repair for chronic, primary (nonfunctional) MR in patients with severe symptoms and New York Heart Association Class III or IV heart failure.26 Percutaneous mitral annuloplasty has also been described and includes approaches through the coronary sinus or retrograde across the aortic valve and into the LV. The Mitralign system (Mitralign, Inc, Tewksbury, MA) and Accucinch (Guided Delivery Systems, Inc, Santa Clara, CA)43,44 are examples of this novel but understudied technique. Additional studies are required to compare percutaneous techniques for mitral regurgitation. Although transcatheter interventions remain uncommon, minimally Curr Probl Cardiol, December 2014

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invasive surgery for mitral pathology has become the preferred approach for many surgeons. Transcatheter techniques must be measured against not only medical therapy, but also these growing surgical alternatives to full sternotomy.

Hybrid Surgery Hybrid surgery refers to the integration of traditional surgical and catheter-based therapies to maximize the therapeutic advantage of each modality.45 Though “hybrid” approaches have been employed for years with the combination of percutaneous coronary intervention (PCI) and CABG, the coordination of a planned, stepwise, or concomitant use of these modalities has grown with the recent development of hybrid operating rooms (Fig 6). Table 4 outlines several proposed definitions pertaining to HCR. With the advent of drug-eluting stents (DES) and the welldemonstrated advantages of the left internal mammary conduit, ideal coronary revascularization strategies may be a combination of the 2 techniques.46,47 As suggested by proponents of OPCAB, hybrid approaches that minimize CPB may provide advantages for the elderly or patients with severe comorbidities. If treatment is focused by specialty, it is possible that the traditional separation of percutaneous techniques applied by cardiologists and surgical interventions by cardiac surgeons may preclude the benefits of treatment synergy. Coordinating efforts in a hybrid operating room bridges the gap between specialties. In addition to coronary revascularization, interventions for valvular, carotid, and aortic pathologies have also used a combination of percutaneous and minimally invasive surgical strategies. The possibilities for combined therapies are growing. Coronary Revascularization. Current evidence supports the continued use of CABG with CPB for patients with multivessel disease, diabetes, proximal left anterior descending (LAD) lesions, or 2-vessel disease with a decreased ejection fraction.48–50 However, DES are superior to saphenous vein graft for select coronary arteries.51 To date, most major studies have compared PCI vs CABG but few studies have compared a combination of therapies. Technique. There is no established best HCR strategy. All hybrid approaches are inherently “staged,” as interventions can be performed as “1 stop” or over multiple trips to the operating room separated by hours, 444


Curr Probl Cardiol, December 2014 FIG 6. Hybrid operating room. (Courtesy of Maquet Medical Systems, USA.) (Color version of figure is available online.)

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TABLE 4. Currently used definitions for hybrid coronary revascularization Guideline or registry

Definition

2011 ACCF-AHA-SCAI guidelines for PCI and 2011 ACCF-AHA guidelines for CABG

The planned combination of LITA-LAD artery grafting and PCI of Z1 non-LAD coronary arteries. Hybrid coronary revascularization may be performed in a hybrid suite in a single operative setting or as a staged procedure (PCI and CABG performed in 2 different operative suites, separated by hours to 2 d, but typically during the same hospital stay). Planned, intentional combination of CABG, with a catheter-based intervention to other coronary arteries during the same hospital stay. Procedures can be performed consecutively in a hybrid operating room or sequentially on separate occasions in the conventional surgical and PCI environments. A hybrid procedure is defined as a procedure that combines surgical and transcatheter interventional approaches: (1) planned, concurrent is performed in same setting; (2) planned, staged is performed in the same hospital admission; and (3) unplanned is performed after incomplete revascularization or graft closure during the same hospital admission. Hybrid therapy occurs when both surgical and percutaneous coronary revascularization are planned, with different lesions treated with the different techniques. Minimal invasive LITA-to-LAD and PCI of non-LAD lesions. Procedures can be performed either in the same operating suite or during the same hospitalization.

2010 ESC-EACTS guidelines on myocardial revascularization

STS Adult Cardiac Registry National Database (version 2.73)

NCDR Cath PCI Registry (version 4.4)

Clinicaltrials.gov (definitions by registered studies)

ACCF, American College of Cardiology Foundation; SCAI, Society for Cardiovascular Angiography and Interventions; LITA, left internal thoracic artery; ESC, European Society of Cardiology; EACTS, European Association for Cario-Thoracic Surgery; NCDR, National Cardiovascular Data Registry. Reprinted with permission from Elsevier and Harskamp RE, Bonatti JO, Zhao DX, et al. Standardizing definitions for hybrid coronary revascularization. J Thorac Cardiovasc Surg. 2014;147:556-560.

days, or weeks. This flexibility allows for recovery, medical optimization, and tailoring of anticoagulation or antiplatelet regimens as determined by operating teams. The most commonly encountered HCR strategies combine surgical CABG, typically a left internal mammary artery (LIMA) LAD anastomosis performed via full sternotomy or a minimally invasive

446


technique, and PCI to non-LAD coronary arteries. To achieve this, several techniques have been described:

Open LIMA ⫾ right internal mammary artery harvest through traditional sternotomy with on-pump CABG or OPCABG, combined with PCI for select coronary artery branches. Minimally invasive direct coronary artery bypass grafting is performed through an anterior thoracotomy incision with or without concomitant PCI.52 A thoracotomy lateral to the midclavicular line has also been described.53 Robotic LIMA harvest may be combined with the limited thoracotomy technique (Fig 7A). Thoracoscopic endoscopic atraumatic coronary artery bypass uses a thoracoscopic port access to harvest the LIMA followed by LIMALAD anastomosis on the beating heart via minithoracotomy. Totally endoscopic coronary arteries bypass graft anastomoses are performed through port access with or without the aid of peripheral cannulas for CPB (Fig 7B).

A quintessential advantage of HCR is the ability to perform completion angiography. At the time of PCI, or before chest closure if no PCI is planned, conduits can be evaluated for patency and issues with kinking or stenosis addressed immediately. Intraoperative graft failure rates have been reported from 2%5%,54,55 but angiography may also detect issues before they become a problem (Fig 8). In a series of 366 consecutive patients undergoing CABG or combined CABG-PCI, Zhao et al56 reported a 12% graft defect rate prompting unplanned PCI or graft adjustment or revision. Intraoperative coronary angiography is not readily available in most operating rooms, which prevents the widespread adoption of completion angiography evaluation. However, with the rising interest in hybrid operating rooms, the use of completion angiography is likely to increase. Patient Selection. Selecting appropriate candidates for HCR can be challenging. Patients with multivessel disease and diabetes deserve special attention given the known limitations of PCI in these groups. These patients have higher restenosis rates with DES, and worse long-term outcomes compared with CABG as demonstrated in the Synergy Between PCI With Taxus and Cardiac Surgery and Future Revascularization Evaluation in Patients With Diabetes Mellitus: Optimal Management of Multivessel Disease trials.49,57,58 Patients must also be able to adhere to Curr Probl Cardiol, December 2014

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FIG 7. (A) Robotic harvesting of left internal mammary artery and (B) totally endoscopic coronary artery bypass (TECAB) port placement. (Reprinted with permission from Elsevier and Gao C, Yang M, Wu Y, et al. Hybrid coronary revascularization by endoscopic robotic coronary artery bypass grafting on beating heart and stent placement. Ann Thorac Surg. 2008:737-741) (Color version of figure is available online.)

strict antiplatelet therapy regimens after stent placement. Best candidates have proximal LAD artery disease that will benefit from a LIMA conduit and 1-2 non-LAD territory vessels amenable to PCI. A dedicated heart team comprising cardiologists and cardiac surgeons at an experienced 448


Curr Probl Cardiol, December 2014 FIG 8. Completion angiography after coronary artery bypass grafting surgery showing a chest tube compressing the saphenous vein graft (SVG) to the posterior descending artery graft (PDA) (yellow arrow) before (A) and after (B) repositioning of chest tube. (Reprinted with permission from Elsevier and Zhao et al.57) (Color version of figure is available online.)

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center should assess each patient’s specific comorbidities and coronary anatomy to determine the best revascularization strategy. Clinical Outcomes. Long-term outcomes of HCR techniques have not been widely reported, but good evidence supports its short-term safety and efficacy.59 Acceptable graft and stent patency rates have been demonstrated60,61 and some suggest that major adverse cardiac and cerebrovascular events are comparable between HCR and CABG.62,63 Though long-term follow-up and larger studies are needed to reproduce results and identify the patients who will best benefit from a hybrid approach, this combination therapy may ultimately find the balance between catheter and traditional surgical-based techniques. Dr Schaff: HCR aims to combine the known advantages of internal mammary artery bypass of the LAD coronary artery with percutaneous treatment of other coronary lesions. In some centers, this strategy is popular as it involves both interventional cardiologists and surgeons in the treatment of individual patients. However, studies suggest that there is a greater need for repeat revascularization with the hybrid technique with minimal differences in procedural morbidity compared with standard coronary artery bypass (Harskamp RE, Bagai A, Halkos ME, Rao SV, Bachinsky WB, Patel MR, de Winter RJ, Peterson ED, Alexander JH, Lopes RD. Clinical outcomes after hybrid coronary revascularization versus coronary artery bypass surgery: a meta-analysis of 1,190 patients. Am Heart J. 2014;167:585-592). When full sternotomy is used with CPB for hybrid procedures, it is reasonable to ask: Why not simply use additional arterial grafts rather than intracoronary stenting of the right and/or circumflex systems?

Combined Valve, CABG, or PCI. In certain high-risk patients, it is preferred to separate coronary and valvular interventions. Hybrid operating theaters increase treatment options for patients with combined pathologies or a challenging clinical status. In the setting of acute myocardial ischemia, PCI can help stabilize a patient for subsequent valvular intervention. If valvular pathology necessitates urgent or emergent intervention but reoperative sternotomy is deemed prohibitive, access to mitral valve pathology, for example, can be gained via right minithoracotomy with staged or concomitant PCI.64,65 There is evidence to support improved short-term outcomes including decreased ventilation time, stroke, and death with hybrid valve or PCI compared with CABG or valve,66 though increased bleeding complications and transfusion requirements have been reported.64 Santana et al67 recently published long-term follow-up on a series of 222 patients undergoing combined PCI and valve with 4 patients (2.1%), requiring subsequent target vessel revascularization and 1- and 450


4.5-year survival of 91.9% and 88.3%, respectively. Variability in antiplatelet strategies, availability of hybrid technology, and timing for PCI interventions differ greatly between practitioners and institutions, making large series difficult to compare.68,69 As with other new approaches to cardiovascular disease, preoperative planning requires coordination between cardiologists and cardiac surgeons to determine an individualized treatment strategy; further work must be directed toward larger scale systematic comparisons between PCI/valve and CABG/valve. Aortic Aneurysm Repair. Aortic surgery is associated with high morbidity and mortality. The introduction of endovascular stent grafts has revolutionized the treatment of aortic disease. Ascending aorta and arch work remain the purview of surgeons, but incorporating endovascular approaches into operative planning expands the therapeutic repertoire, possibly decreasing the morbidity and mortality of more extensive surgery. Combination aortic arch repair and staged endovascular interventions have been well described. Saccular arch aneurysms, for instance, can be treated by performing a total arch repair with brachiocephalic bypass and concomitant aortic arch stent graft placement.64 Open debranching of the great vessels creates proximal and distal landing zones amenable to endovascular stent deployment.70,71 Aneurysms located in either the ascending aorta or the arch can be addressed with cerebral perfusion strategies at moderate or deep hypothermia depending on circumstances and surgeon preference. When pathology is limited to the descending thoracic and abdominal aortas, an endovascular approach alone is both sufficient and the preferred approach.70,72 Occasionally, complex thoracic, abdominal, or thoracoabdominal aneurysms involve the visceral or renal arteries and require surgical revascularization. In such patients, a combined endovascular and open surgical approach may be considered. In a large multicenter study from France, Rosset et al reported experience with 76 hybrid endovascular and surgical approaches for complex aneurysms and found a high incidence of postoperative death (34.2%) and bowel ischemia (17.1%). The authors concluded that previous reports from selected patients may overestimate the safety of this approach, and that hybrid approaches for complex aneurysms should be reserved for the highest risk patients.73 As patient selection is refined and experience with combined approaches for aortic pathology grows, the hybrid operating room provides the best venue, allowing for choreographed interventions and a safe environment to address complications.


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Robotic Surgery The first robotic mitral valve repair was performed by Alain Carpentier in 1996. He was also the first one to employ the da Vinci Surgical System in 1998, which remains the most common robotic technology in cardiac surgery to date (Fig 9). The first robotic mitral repair in North America was performed by Walter Chitwood in 2000.74 Outcomes of robotic surgery have reported decreased patient pain, improved cosmesis, quicker recoveries, and possibly decreased transfusion requirements.74 In addition to mitral pathology, robotic surgery has played a role in minimally invasive mammary dissections and anastomoses for coronary revascularization. Despite these successes, robotic procedures have not yet been fully integrated into routine care of the cardiac surgery patient owing to difficult learning curves and high costs. Dr Schaff: Minimal access surgery for mitral valve repair whether performed through a small anterolateral thoracotomy or through ports with robotic assistance is used in many centers in the United States and Europe. Surgeons who are experienced with these methods achieve generally similar results as regards repair rates and durability of valvuloplasty. It is important, however, for surgeons in training and those beginning their practice to become proficient in open repair methods before attempting valve repair with more limited exposure. There may be small, measurable benefits to minimal access mitral surgery with regard to early recovery and return to work, but the one clear advantage is cosmetic for those patients who wish to avoid sternal incision.

Some surgeons point to the loss of tactile sensation with robotic technology, which they feel may decrease safety and accuracy (Fig 10). Contraindications to robotic cardiac surgery include extensive pleural adhesions, poor pulmonary function, severe pulmonary hypertension, poor ventricular function, aortic regurgitation, and pectus excavatum.74,75 Robotic surgery for mitral disease should be performed by experienced open mitral valve surgeons and a highly trained team.74,76,77 In a propensity-matched series of 759 patients with posterior leaflet degenerative disease undergoing repair via full sternotomy, minianterolateral thoracotomy, or robotic approaches, Mihaljevic et al78 reported longer bypass and cross clamp times in the robotic group but similar repair quality (95% incidence of residual MR mild or less), and shorter hospital length of stay. Robotic approaches for mitral valve disease can be combined with cryomaze techniques for atrial fibrillation with excellent results.79 Qualityof-life measures have shown favorable outcomes with robotic mitral valve repairs at 1 and 2 years postoperatively including better self-reported physical and mental health.80 452


Curr Probl Cardiol, December 2014 FIG 9. The da Vinci robotic system. (Reprinted with permission from Intuitive Surgical, Inc.) (Color version of figure is available online.)

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FIG 10. Robotic mitral repair. (A) P1 is the most anterior or lateral posterior leaflet scallop and P2 is the redundant midscallop that is being resected. Ant. Leaflet, anterior mitral leaflet. (B) P1, P2, and P3 of the posterior leaflet are shown. P2 will be resected. P3 has been elevated radially from the mitral annulus and will be displaced toward P2 for the sliding plasty. *left fibrous trigone; AC, anterior commissure; PC, posterior commissure. (Reprinted with permission from Elsevier and Chitwood WR. Current status of endoscopic and robotic mitral valve surgery. Ann Thorac Surg. 2005;79:s2248-s2253.)

In coronary disease, it has been suggested that one of the common reasons for conversion from robotic surgery to traditional full sternotomy is owing to difficulty with coronary anastomoses. Other reasons include dissection of the LIMA, incorrect vessel grafting, ventricular fibrillation, cardiac arrest, equipment malfunction, and adhesions.75 In their series of 500 454


totally endoscopic coronary arteries bypass operations, Bonaros et al81 identified a 10% conversion from robotic to full sternotomy with a LIMA injury rate of 5%, though reportedly half of the operations were performed by surgeons with less than 20 cases of robotic experience. A variety of techniques can be employed for robotic coronary revascularization (harvesting techniques, beating heart, arrested heart, etc), thus making comparisons difficult. In terms of hospital management, most analyses suggest the cost of performing these procedures is higher than traditional methods and this undoubtedly affects the adoption of this technology across centers.77,82 Nevertheless, applications of robotic procedures continue to expand, including a recent study reporting combination mitral and tricuspid valve interventions with good early outcomes.83 Robotic surgery should be performed in experienced centers and outcomes should be critically evaluated. Training programs must be developed as this technology establishes an appropriate niche in the care of patients with coronary and valvular disease.

Challenges in Modern Cardiothoracic Surgery Training Work Hours Patient safety, resident sleep deprivation, and other factors led to the mandate of an 80-hour workweek by the Accreditation Council for Graduate Medical Education in July 2003.84,85 Work-hour restrictions have prompted significant adjustments in workflow coverage at teaching institutions, as well as an overhaul of resident education in general, with unclear consequences on surgical training. Currently, physicians in training are required to work shifts and report weekly hours with increasing oversight and punitive consequences for transgressions. From a surgical education standpoint, less time in the hospital decreases the number of cases that residents can cover, resulting in fewer opportunities to gain experience.86 Though studies on patient safety as well as resident and attending satisfaction surveys have inconsistently reported improvement with the new system, some form of hour regulations seems here to stay.87,88 The more relevant issue at hand is how to train aspiring cardiac surgeons in less time within the era of increasing data per patient and growing complexity of surgical techniques.

Integrated Training Programs Recently, in recognition of this trend toward specialization, as well as the decreased applications to cardiothoracic surgery fellowships among graduating general surgery residents, streamlined cardiothoracic surgery training programs Curr Probl Cardiol, December 2014

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have been established. These “integrated” programs are residencies dedicated to cardiothoracic surgery training beginning after medical school. Through earlier exposure and education in cardiovascular disease, residents develop knowledge and skills directly relevant to a career in cardiothoracic surgery. Early reports by these programs have shown renewed interest among medical students yielding a highly qualified applicant pool (Table 5).89 Yet this transition has not been without detractors, and some fear the shift away from traditional training will eliminate the necessary skill set gained in general surgery, thereby leaving gaps in surgical expertise.90 However, similar transitions toward specialization are seen in other surgical fields, including vascular; orthopedics; urology; and ear, nose, and throat surgery. TABLE 5. Comparison of integrated cardiothoracic applicants with traditional fellowship applicants Traditional fellowship (n ¼ 27)

Integrated residency (n ¼ 116)

P value

33 ⫾ 3 6 (22) 20 (74) 27 (100) 18 (67) 17 (63) 0 7 (26) 0

29 ⫾ 4 19 (16) 62 (53) 67 (58) 65 (56) 52 (45) 7 (6) 23 (20) 11 (9)

o0.0001 0.57 0.05 o0.001 0.39 0.13 0.01 0.60 o0.001

Research None Published research National research grant National research prize Publications, no.

1 (4) 2 (7) 7 (26) 5 (19) 6⫾5

14 (12) 19 (16) 17 (15) 20 (17) 4⫾7

0.30 0.37 0.16 40.99 0.20

Experience Years of previous training General surgery Thoracic surgery Worked as attending physician

4 1.1 4 (15)

1 0.6 12 (10)

o0.001 0.42 0.50

USMLE step 1 score 4230 4250

10 (37) 1 (4)

44 (38) 12 (10)

40.99 0.46

Variables Demographics Age, y Female US citizen Completed medical school US undergraduate US medical school ΑΩΑ (of those with chapter) Advanced degree 6-y Program at home institution

AΩA, alpha omega alpha; USMLE, United States Medical Licensing Exam. Reprinted with permission from Elsevier and Chikwe J, Brewer Z, Goldstone AB, Adams DH. Integrated thoracic residency program applicants: the best and the brightest? Ann Thorac Surg. 2011;92:1586-1591.

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Integrated residents perform dedicated rotations in echocardiography, as well as general and interventional cardiology, whereas traditional fellows must obtain this knowledge informally over time. With this revolution in cardiothoracic surgery training bringing younger trainees into the operating room, there is also concern that a generational difference may hinder the necessary transfer of skills.91 If this new approach to training is to be a success, a truly integrative culture must be established at all levels through innovative teaching methods. This is especially true amidst current technological advances and the rapid expansion of surgical techniques available to treat cardiovascular disease.

Simulation Training An important area of interest among educators in surgery is the use of simulation. Simulations have been shown to enhance technical abilities across specialities.92 In cardiac surgery, this has been demonstrated in mitral ring replacements with specific attention to suture spacing, tissue handling, and bite depth.93 This training is applicable for all levels of skill because it can be used to practice a complex procedure or smaller components, and we know that task proficiency is directly related to the number of hours performing a given task.94,95 There are instances, however, where hospitals lack the volume sufficient for training residents in all types of procedures. Simulation training should be considered a supplemental tool for training residents as they move forward through their training.93 Robotic surgery exemplifies this intersection of advancing technology, complex procedures, and the challenge of training young surgeons. In addition to cardiac surgery, the da Vinci Surgical System has been used in general, urologic, and gynecologic surgery.96 Studies in general surgery have demonstrated improved accuracy in robotic and laparoscopic operations after dedicated robotic and laparoscopic training simulation courses.97 With the success seen in other surgical fields requiring laparoscopic technical proficiency through simulation, a similar competency-based educational curriculum is likely in the future for cardiothoracic training programs.98 A recent example of evolving educational approaches was demonstrated by a group of experienced cardiothoracic surgeons who undertook simulation training in a variety of cardiac and thoracic techniques. According to the participants, specific simulation models—including aortic cannulation, aortic valve replacement, video assisted thoracoscopic surgery, mitral valve repair, and others—differed in “realism” or applicability, but each served a worthwhile practice in basic technique.99 This Curr Probl Cardiol, December 2014

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FIG 11. Thoracic Surgery Directors Association hosts annual “boot camp” for trainees in cardiothoracic surgery. (Photo courtesy of the Thoracic Surgery Directors Association.) (Color version of figure is available online.)

approach has been extended to trainees as well. An annual “boot camp” is held for cardiothoracic surgery residents by the Thoracic Surgery Directors Association focusing on introducing new trainees to basic techniques in a safe and supervised environment (Fig 11). With regulated work hours and the growing complexity of surgical techniques, such simulation in surgery is necessary for trainees and likely to increase in the future. Dr Schaff: An often overlooked challenge in training cardiothoracic surgical residents is the complexity of current practice compared with earlier eras when cardiac procedures included relatively simple operations that were useful in training residents, such as closure of secundum atrial septal defects and patent foramen ovale and single- or double-vessel coronary artery bypass operations. As was described previously, many centers routinely use minimal access approaches for mitral valve surgery, including techniques 458


that reduce exposure and increase difficulty in guiding residents through valve repair or replacement. Simulation laboratories can be very helpful for introduction to basic techniques, but there is no substitute for adequate hands-on clinical experience to the wide variety of pathology encountered in cardiac surgical practice.

Conclusions Current treatments for cardiovascular disease require a patient-centered approach by specialized health care providers. With the latest technology at our fingertips, options for therapeutic interventions must be balanced with costs and benefits to the individual patient and pathology. This process demands a thorough investigation of the myriad new approaches to cardiovascular disease to uncover best practices. As in the cases of transcatheter valve interventions and HCR, we must pursue novel techniques safely in an environment of critical yet constructive evaluation to establish ever higher standards of care. To meet this end, we must create a culture of alignment across specialties that extends to educational reform. Young surgeons should be exposed to innovative techniques within restructured training systems to meet the demands of modern technological advancement. Although new approaches to cardiovascular disease are evolving, and it remains unclear what the future holds, it is certain that treating cardiovascular disease will remain an ever-growing and exciting field rich in innovation. Dr Schaff: Dr Neely and associates have provided a thoughtful overview of some of the more current and interesting aspects of surgical treatment of cardiovascular disease. In addition to the discussions of off-pump coronary surgery, percutaneous valves, and robotic approaches, readers should be aware of the progress that has occurred in mechanical circulatory support, including LV assist devices and extracorporeal membrane oxygenation (ECMO). This area of cardiac surgery continues to evolve rapidly with new devices and new applications of technology. LV assist devices were once considered an extreme measure and applicable only to candidates for heart transplantation. In the United States, more than 150 centers implant support devices, and from 2006 through 2013 more than 10,000 patients had device implantation for treatment of advanced hear failure. Use of ventricular assist devices as destination therapy rather than planned bridge to transplant has increased from 14.7% in 2006-2007 to 41.6% in 2011-2013, and this trend will likely continue with increasing numbers of patients who have end-stage heart disease coupled with limited supply of donor hearts. ECMO is now widely used for postcardiotomy support and stabilization of patients with severe, reversible lung injury. ECMO is also now used to bridge patients waiting for lung transplant who have severe respiratory failure necessitating mechanical ventilation. Previously these patients were removed from consideration of transplant as their clinical condition deteriorated; but Curr Probl Cardiol, December 2014

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ECMO can support such patients without the need for mechanical ventilation and, in some cases, allow ambulation and exercise to improve outcome of subsequent lung transplant.

Acknowledgments: Thanks to Allison Hassett for her help in preparing

this manuscript.

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