Clinical Experience With HeartWare Left Ventricular Assist Device in Patients With End-Stage Heart Failure

Transcription

1 ADULT CARDIAC Clinical Experience With HeartWare Left Ventricular Assist Device in Patients With End-Stage Heart Failure Aron Frederik Popov, MD, Morteza Tavakkoli Hosseini, MD, Bartlomiej Zych, MD, Prashant Mohite, MD, Rachel Hards, BS, Heike Krueger, BS, Toufan Bahrami, MD, Mohamed Amrani, MD, PhD, and Andre Ruediger Simon, MD, PhD Department of Cardiothoracic Surgery and Transplantation, Harefield Hospital, Harefield, United Kingdom Background. The gold standard treatment for endstage heart failure is cardiac transplantation. Because of the increasing number of heart failure patients and the limited supply of donor hearts, a ventricular assist device (VAD) is used as a bridge to transplantation, recovery, or decision. Newer generation VADs have lower risk of fatal adverse events and are also smaller in size. We present our experience with the intrapericardial HeartWare VAD (HeartWare, Framingham, MA) and its clinical outcome. Methods. The clinical outcome of HeartWare VAD implantations for end-stage heart failure patients performed at Harefield Hospital from March 2007 to June 2011 was studied. The study design was a retrospective review of the prospectively collected data. Results. Thirty-four patients with a mean age of years were included in this study. Twenty-nine patients were male (85%). The mean duration of mechanical support was days. Five patients (15%) were successfully bridged to heart transplantation. The overall mortality was 24% (8 patients). There were 1 case of mechanical device failure (2%) and 3 cases of device failure due to thrombus formation (8%). Postoperative complications included 5 reoperations for bleeding (15%), 12 acute renal failures (36%), 7 respiratory failures (21%), 2 hepatic dysfunctions (6%), 3 neurologic dysfunctions (9%), 7 right-side heart failures (21%), and 5 driveline infections (15%). Conclusions. Although cardiac transplantation remains the gold standard for treatment of end-stage heart failure patients, the HeartWare VAD can be used as a safe alternative with a satisfactory clinical outcome. (Ann Thorac Surg 2012;93:810 5) 2012 by The Society of Thoracic Surgeons Cardiac transplantation is the gold standard therapeutic option for end-stage heart failure. However, the limited supply of donor hearts imposes a big limitation to this option. A ventricular assist device (VAD) can be used as an alternative for mechanical circulatory support, and VADs play a very important role in the management of heart failure patients. They have been used for the last 20 years as a bridge to transplantation, recovery, or decision [1, 2]. The newer generations of VADs are smaller and have lower risk for fatal adverse events. Also, mechanical circulatory support has been shown to be superior in comparison with medical optimization in heart failure patients [1, 3, 4]. The miniaturized centrifugal HeartWare VAD (HeartWare, Framingham, MA), is one of the new additions to the VAD family [5]. It can be implanted intrapericardially, and there is no need for abdominal surgery or pump pocket formation, hence avoiding the related complications [6]. Initial clinical experience with the HW has shown that the design of the VAD enables a quick Accepted for publication Nov 30, Address correspondence to Dr Popov, Department of Cardiothoracic Transplantation and Mechanical Support, Royal Brompton and Harefield Hospital, Harefield Hospital, Middlesex, London UB9 6JH, United Kingdom; a.popov@rbht.nhs.uk. and less invasive implantation with a satisfactory longterm survival [7]. Moreover, a recent multicenter trial showed that this device is safe and effective, and it can improve the patient s quality of life during mechanical circulatory support [8]. We present our institutional experience with the intrapericardial HW and its clinical outcome. Material and Methods Study Population All HW implantations due to end-stage heart failure refractory to medical treatment, performed at Harefield Hospital from March 2007 to June 2011 were included in this study. Data were collected prospectively as part of Harefield Hospital VAD surgery database collection. The Harefield Hospital database includes detailed information about patient demographics, preoperative risk factors, operative details, postoperative hospital course, morbidity, and mortality. This data collection is part of the national VAD surgery data collection and outcome evaluation in the United Kingdom. This study was categorized as a Service Evaluation by the Ethical Committee and required no need for ethical approval. The study design was a retrospective review of the prospectively collected data by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc doi: /j.athoracsur

2 Ann Thorac Surg POPOV ET AL 2012;93:810 5 EXPERIENCE WITH HEARTWARE VAD Thirty-four patients were included in this study. 2 patients of this study were also included in the multicenter trial by Wieselthaler and colleagues [7]. The etiology of heart failure was dilated cardiomyopathy in 25 cases (73%), ischemic cardiomyopathy in 8 cases (23%), and hypertrophic cardiomyopathy in 1 case (3%). Mean age of the study population was years (range, 19 to 62 years), and 29 patients were male (85%). Six patients (17%) had a history of a previous cardiac operation through median sternotomy coronary artery bypass grafting in 2 cases (6%), Dor procedure in 1 case (3%), aortic valve replacement in 1 case (3%), closure of patent foramen ovale in 1 case (3%), and correction of congenital heart abnormality in 1 case (3%). Preoperative demographics, risk factors, and laboratory investigations are shown in Tables 1 and 2. Definition of Events Hemolysis was defined as two consecutive samples with plasma-free hemoglobin of more than 40 mg/dl. Cardiac arrhythmia was defined as any cardiac arrhythmias that resulted in a hemodynamic compromise after HW implantation. Renal failure was defined as postoperative low urine output and rising creatinine and blood urea nitrogen that required hemodialysis or hemofiltration. Respiratory failure was defined as any impairment of respiratory function requiring reintubation or tracheostomy and mechanical ventilator support after the operation. Liver dysfunction was defined as a postoperative minimum fourfold rise of baseline values in any two of the following: total bilirubin, serum aspartate transaminase, and serum alanine transaminase. Neurologic dysfunction was defined as any postoperative neurologic dysfunction. Bleeding was defined as excessive blood loss requiring surgical reexploration. Right-side heart failure was defined as poor postoperative right-side heart function resulting in hemodynamic compromises and requiring medical or surgical treatment. Anticoagulation Protocol After a minimum of 12 hours after implant, when the chest tube drainage has fallen to less than 50 ml per hour together and the coagulation profile has returned to normal or near normal levels, heparin was administered intravenously as an infusion to maintain activated partial thromboplastin time between 50 s and 70 s. Also, aspirin, 75 mg daily, was immediately started after extubation. Once the patient was extubated, tolerating oral medications, and chest drains were removed, warfarin was administered to maintain the international normalized ratio between 1.7 and 2.5. Follow-Up No patient was lost during follow-up. Mean follow-up time was 331 days (range, 10 to 1,556 days). Follow-up included clinical evaluation and transthoracic echocardiographic assessment. The postoperative echocardiography at follow-up was performed in all patients as a routine procedure at 1, 3, 6, and 9 months after the operation. Echocardiography data included left ventric- Table 1. Baseline Clinical Characteristics of 34 Patients 48 Hours Before Left Ventricular Assist Device Implantation Characteristics 811 Value Age, years Male 29 Body mass index, kg/m Diabetes mellitus 7 (21) Current smoker 1 (3) Former smoker, 6 months 10 (30) Hypertension 3 (9) Cardiac resynchronization therapy 23 (69) Implantable cardioverter-defibrillator 26 (78) Moderate-severe RV dysfunction 3 (9) Heart failure etiology Hypertrophic cardiomyopathy 1 (3) Ischemic cardiomyopathy 8 (24) Dilated cardiomyopathy 25 (78) Preimplant comorbidity Previous acute myocardial infarction 7 (21) Coronary angioplasty 2 (6) Previous sternotomy 7 (21) Intraaortic balloon pump 1 (3) Inotropic support 31 (93) Renal replacement therapy 1 (3) Medication ACE inhibitors 10 (30) Angiotensin-receptor antagonist 7 (21) Beta-blockers 26 (78) Amiodarone 18 (54) Aldosterone antagonist 17 (51) Loop diuretics 29 (87) Warfarin 8 (24) Antiplatelet drug 1 (3) Hemodynamics Heart rate, beats/min Sinus rhythm 19 (51) Paced 13 (39) Arrhythmia 2 (6) Mean arterial pressure, mm Hg 77 9 Central venous pressure, mm Hg 17 8 Mean pulmonary pressure, mm Hg 36 7 Pulmonary capillary wedge pressure, mm Hg 27 6 Cardiac output, L/min SvO 2,% 57 3 Echocardiography data preoperative LVDD, mm LVSD, mm Fractional shortening, % 13 6 Mitral regurgitation Mild 20 (60) Moderate 8 (24) Severe 6 (18) Data are presented as mean SD or n (%) unless otherwise indicated. ACE angiotensin-converting enzyme; LVDD left ventricular diastolic diameter; LVSD left ventricular systolic diameter; SvO 2 mixed venous oxygen saturation. ADULT CARDIAC

3 ADULT CARDIAC 812 POPOV ET AL Ann Thorac Surg EXPERIENCE WITH HEARTWARE VAD 2012;93:810 5 Table 2. Laboratory Investigations Measurement Before Implantation Postoperative Day 7 Blood urea nitrogen, mmol/l 10 4 (5 23) 9 5 (3 24) Blood urea nitrogen, maximum 13 6 (4 29) 14 5 (5 24) Serum creatinine, mol/l (38 200) (30 290) Serum creatinine maximum, mol/l (73 200) (69 352) Serum sodium, mmol/l ( ) ( ) Serum potassium, mmol/l ( ) ( ) Total bilirubin, mg/dl (8 84) (9 340) Alanine aminotransferase, IU/L (8 968) (11 211) Hemoglobin, g/dl 12 2 (10 15) ( ) White blood count, ml, 1, (5 27) 15 8 (6 44) Platelets, 1,000/mL ( ) (54 394) C-reactive protein (1 107) (35 262) International normalized ratio ( ) ( ) Data are presented as mean SD (range). ular end-systolic diameter, left ventricular end-diastolic diameter at baseline VAD pump speed of 2,800 rpm, and also left ventricular fractional shorting. Statistical Analysis Statistical analysis was performed using commercial statistic software (Statistica 5.1; StatSoft, Tulsa, OK). The data were shown as mean SD. Preoperative left ventricular parameters were compared with the postoperative left ventricular parameters using analysis of variance. All p values of less than 0.05 were considered statistically significance. Patient survival was estimated using Kaplan-Meier analysis, taking time zero as the date of HW implantation and late death as the endpoint. Results Perioperative Outcome There was no perioperative mortality after HW implantation. Four cases had a simultaneous temporary right ventricular assist device implantation in addition to their HW implantation due to right-side heart failure. Another 4 cases had a combined procedure with HW implantation (tricuspid valve repair, aortic valve replacement, closure of atrial septal defect, closure of patent foramen ovale). The operation was performed through median sternotomy with cardiopulmonary bypass. The mean cardiopulmonary bypass time was minutes (range, 0 to 180 minutes). Four patients underwent minimally invasive HW implantation through bilateral anterior minithoracotomy incisions. The minimally invasive operations were performed with cardiopulmonary bypass support in 2 cases and without it in 2 cases. Early Postoperative Outcome Postoperative hemolysis occurred in 1 case. The patient was supported for a total of 540 days with HW and was successfully bridged to heart transplantation. The patient died of refractory liver failure 3 months after heart transplantation. Cardiac arrhythmias occurred in 3 cases, and all were treated successfully. Twelve patients (36%) had postoperative acute renal failure and required hemofiltration; 10 patients had a complete recovery, but chronic renal failure developed in 2 patients and they needed permanent dialysis. Respiratory failure occurred in 7 patients (21%), and 6 of them underwent a tracheotomy procedure for long-term respiratory support. There were 2 cases of liver dysfunction (6%): the one developed immediately after HW implantation, and the other occurred after successful bridging to transplantation. Both patients died of liver failure. Three patients (9%) had a non device-related postoperative neurologic event due to intracranial hemorrhage in 1 case and embolic events in 2 cases. All patients fully recovered with no residual neurologic symptoms. Five patients (15%) were reexplored for bleeding. A hematothorax developed after minimally invasive HW implantation in a patient and required thoracotomy to control the bleeding. Right-side heart failure occurred in 7 cases (21%), requiring a temporary CentriMag (Levitronix, Zurich, Switzerland) right ventricular assist device (RVAD) implantation at the time of the HW implantation in 4 cases (12%). After right-side heart recovery, the RVAD was successfully weaned in 3 cases, and 1 patient died of multiorgan failure. Midterm Outcome and Duration of Support The overall mortality rate was 24% (8 patients) in this study. The majority of the deaths occurred within 30 days of HW implantation, while the patients were still in hospital. Two patients died of non device-related multiorgan failure and liver failure after successful bridging to transplantation. In 1 patient, myocardial function was recovered after device implantation, and hence the device was explanted. The actuarial survival after HW implantation, including recovery, transplanted, and ongoing support is shown in Figure 1. The overall cumulative survival at 700 days was 56%. All patients were supported for a total of 9,132 patientdays with mean duration of days (range, 8 to

4 Ann Thorac Surg POPOV ET AL 2012;93:810 5 EXPERIENCE WITH HEARTWARE VAD Fig 1. Actuarial survival after HeartWare left ventricular assist device implantation, including recovery, transplant, and ongoing support. 1,369 days). The mechanical support to transplantation was achieved in 5 patients (15%). For patients who were successfully bridged to transplantation, the mean duration of mechanical support was days. Of the entire cohort, 5 patients (15%) had driveline infection that was treated with antibiotics or surgical debridement, or both. One patient had a mechanical device failure, and 3 patients required pump exchange due to pump thrombus formation. The details are summarized in Table 3. Echocardiographic Outcome Postoperative left ventricular systolic and diastolic diameters at 1, 3, 6, and 9 months were significantly reduced compared with preoperative values (p 0.01). There was no significant difference between postoperative left ventricular diameters at 1, 3, 6, and 9 months. No significant difference was noticed between preoperative and postoperative values of fractional shortening. Echocardiographic details are shown in Figure 2. Comment Although heart transplantation remains the gold standard treatment for end-stage heart failure, owing to the shortage of donor organs, VADs are playing an increasingly important role in the management of heart failure patients. These devices have proved to be an excellent treatment option for patients with end-stage heart failure and for those awaiting cardiac transplantation. They significantly improve the survival and the quality of life [1, 4]. The HW LVAD is a miniaturized centrifugal blood pump that could be placed intrapericardially, thereby avoiding abdominal surgery and pump pocket formation. It has proved to provide satisfactory long-term survival with excellent quality of life and a low rate of adverse events [7, 8]. Our report describes a single-center experience, at Harefield Hospital, with HW implantation in 34 patients with end-stage heart failure. The results of our series confirm that the HW is a reliable device for bridging patients to heart transplantation. All adverse events recorded in this study are commonly encountered with other implantable VADs, and the incidence rates are consistent with those reported previously [7, 8]. Postoperative mortality rate was 17%, exclusive of the 2 patients who died after having orthotopic heart transplantation. The overall mortality rate was 24%, and overall cumulative survival at 700 days was 56%, inclusive of the 2 deaths after heart transplantation. The majority of the deaths were within 30 days after HW implantation, and were mostly due to multiorgan failure. The success rate of the bridge to transplantation was 15%. Our mean HW support time was 261 days, and the mean time to transplantation was 532 days. Because of a general shortage of heart donors, size mismatch, and relatively small population in the United Kingdom, in our clinical experience, patients stayed significantly longer on HW support before proceeding to heart transplantation. However, HW support could be considered as an Table 3. Perioperative and Midterm Outcome for 34 Patients After Implantation of LVAD (Inclusive Ongoing Support) Outcome Value Concomitant procedure TVR 1 (3) AVR 1 (3) ASD 1 (3) PFO closure 1 (3) RVAD implantation 4 (12) Cardiopulmonary bypass time, minutes (0 180) Early postoperative period Hemolysis 1 (3) Cardiac arrhythmias 3 (9) Renal dysfunction 12 (36) Respiratory failure 7 (21) Liver failure 2 (6) Stroke 3 (9) Reopening due to bleeding 5 (15) Right-side heart failure 7 (21) Tracheotomy 6 (18) Intensive care stay, days (1 49) Postoperative hospital stay, days (11 169) Midterm outcome Recovery 1 (3) Transplanted 5 (15) LVAD duration to transplantation, days LVAD duration, days Drive line infection 5 (15) Device failure 1 (3) Pump exchange 3 (9) Death 8 (24) 813 Data are presented as mean SD or n (%) unless otherwise indicated. ASD atrial septal defect; AVR aortic valve replacement; LVAD left ventricular assist device; PFO patent foramen ovale; RVAD right ventricular assist device; TVR tricuspid valve repair. ADULT CARDIAC

5 ADULT CARDIAC 814 POPOV ET AL Ann Thorac Surg EXPERIENCE WITH HEARTWARE VAD 2012;93:810 5 Fig 2. Preoperative and postoperative echocardiographic left ventricular end-diastolic diameter (LVEDD [diamonds]), left ventricular end-systolic diameter (LVESD [squares]), and fractional shortening (FS [triangles]). alternative and practical long-term solution to transplantation. Multiorgan failure is a well-known cause of death after VAD implantation, and right-side heart failure plays an important role in this process [9]. In our clinical experience, 4 patients required mechanical RVADs; of these, only 1 patient died of multiorgan failure. Our clinical experience supports the theory that early RVAD implantation in selected patients improves the clinical outcome [10]. Postoperative bleeding, neurologic dysfunction, respiratory failure, liver dysfunction, and device failure rates were the same in comparison with the multicenter trials [7, 8], but the renal dysfunction rate (36%) was higher in our institute. Permanent renal failure developed in 5% of our patients, and they required long-term renal replacement therapy. However, that could be reflective of the poor preoperative hemodynamics, renal impairment, and severity of the illness. In our study, preoperative creatinine ( mol/l) was significantly increased, which indicates preoperative renal impairment. A recent study with the HeartMate 2 LVAD also showed that preoperative LVAD patients already having mild to moderate renal impairment have a higher risk of postoperative renal failure [11]. The recovery rate from postoperative renal dysfunction in our institute is comparable to that of other studies [12]. We encountered only one mechanical device failure at the beginning of our clinical experience, necessitating optimization of manufacturing process. After optimization of manufacturing process, no more cases of mechanical device failure were noticed. The mechanical device failure rate was 2%, and it is partly in accordance with the success rate of other VAD devices [3]. The higher device failure rate could be reflective of the shorter experience time and a smaller study population. Three cases of pump thrombosis were reported. Heparin infusion was started as a standardized institutional treatment protocol. Two of these cases required pump exchange despite anticoagulation therapy. The device thrombosis and exchange rates are consistent with other commonly used LVADs [3]. Based on the company report, early in the trial, a series of HW pumps developed unexplained thrombi. After a review of the clinical and technical data, it was determined that manufacturing variability of the thrust bearings resulted in an area of reduced flow that could have been more prone to thrombus formation. In 2 of our cases of pump thrombosis, the thrombus formed within the HW was resistant to anticoagulation and thrombolytic therapy, necessitating device replacement. Later on, this problem was resolved by the company by optimizing the manufacturing process, and no further events have occurred in more than 450 additional implants. Driveline infection is a serious complication after LVAD implantation that can lead to a life-threatening situation. In our cohort, we observed 5 patients (15%) with driveline infections; however, this observation was comparable with other continuous-flow rotary LVADs [3]. According to our protocol, they were treated with long-term intravenous antibiotic therapy, driveline immobilization, debridement, or a combination thereof. Our echocardiography data show that the HW LVAD is capable of significantly decompressing the left ventricle in the short and long term after device implantation. This finding confirms that the miniaturized nature of the pump does not affect its function. Several limitations of this study merit attention. The primary limitations to this study are its retrospective design and the analysis of patients from a single institution who underwent a HW LVAD implantation. Moreover, as the first single-center study of HW implantation, our cohort is relatively small and is not randomized; thus, there is a referral bias that may limit generalizability. Unfortunately, despite the successful introduction of many new and innovative implantable devices, the longterm outcome of heart failure patients remains poor. These patients represent a technical challenge and should be treated by very experienced surgeons, transplant cardiologists, and anesthetists in specialized institutions. In summary, the HeartWare LVAD could be considered as a safe and effective device that is easy to implant, even through limited access without sternotomy [13], and is capable of improving the quality of life during mechanical support of patients with end-stage heart failure. References 1. Goldstein DJ, Oz MC, Rose EA. Implantable left ventricular assist devices. N Engl J Med 1998;339: Rose EA, Gelijns AC, Moskowitz AJ, et al. Randomized Evaluation of Mechanical Assistance for the Treatment of Congestive Heart Failure (REMATCH) study group. Longterm use of a left ventricular assist device for end-stage heart failure. N Engl J Med 2001;345: Pagani FD, Miller LW, Russell SD, et al. Extended mechanical circulatory support with a continuous-flow rotary left ventricular assist device. J Am Coll Cardiol 2009;54: Slaughter MS, Rogers JG, Milano CA, et al. Advanced heart failure treated with continuous-flow left ventricular assist device. N Engl J Med 2009;361:

6 Ann Thorac Surg POPOV ET AL 2012;93:810 5 EXPERIENCE WITH HEARTWARE VAD 5. LaRose JA, Tamez D, Ashenuga M, Reyes C. Design concepts and principle of operation of the HeartWare ventricular assist device. ASAIO J 2010;56: Bhama JK, Rayappa S, Zaldonis D, et al. Impact of abdominal complications on outcome after mechanical circulatory support. Ann Thorac Surg 2010;89: Wieselthaler GM, O Driscoll G, Jansz P, Khaghani A, Strueber M, for the HVAD Clinical Investigators. Initial clinical experience with a novel left ventricular assist device with a magnetically levitated rotor in a multi-institutional trial. J Heart Lung Transplant 2010;29: Strueber M, O Driscoll G, Jansz P, Khaghani A, Levy WC, Wieselthaler GM, for the HeartWare Investigators. Multicenter evaluation of an intrapericardial left ventricular assist system. J Am Coll Cardiol 2011;57: Baumwol J, Macdonald PS, Keogh AM, et al. Right heart failure and failure to thrive after left ventricular assist 815 device: clinical predictors and outcomes. J Heart Lung Transplant 2011;30: Berman M, Parameshwar J, Jenkins DP, et al. Thoratec implantable ventricular assist device: the Papworth experience. J Thorac Cardiovasc Surg 2010;139: Sandner SE, Zimpfer D, Zrunek P, et al. Renal function after implantation of continuous versus pulsatile flow left ventricular assist devices. J Heart Lung Transplant 2008;27: Demirozu ZT, Etheridge WB, Radovancevic R, Frazier OH. Results of HeartMate II left ventricular assist device implantation on renal function in patients requiring post-implant renal replacement therapy. J Heart Lung Transplant 2011;30: Popov AF, Tavakkoli Hosseini M, Zych B, Simon AR, Bahrami T. HeartWare left ventricular assist device implantation through bilateral anterior thoracotomy. Ann Thorac Surg 2012;93: ADULT CARDIAC INVITED COMMENTARY Technologic advances in ventricular assist devices (VADs) have improved outcomes for patients with advanced heart failure. In this issue of The Annals, Popov and colleagues [1] report their experience using the next generation of implantable blood pump. While multicenter clinical trials are essential in demonstrating efficacy and limitations of new treatments, post approval single-center reports may provide a more real world estimate of outcomes and adverse events. It is difficult to compare these results with the multicenter clinical trial because of the relatively small numbers reported in this study. However, this experienced and highly successful VAD center clearly demonstrates that implantable mechanical circulatory support continues to require substantial utilization of hospital resources. The HeartWare (HeartWare International, Inc, Framingham, MA) device is the first continuous flow intrapericardial pump that requires no abdominal incision for implantation. Complications from the abdominal pocket were common with the larger pulsatile pumps such as the HeartMate XVE (Thoratec Corporation, Pleasanton, CA) and Novacor (World Heart, Inc, Oakland, CA). The smaller HeartMate II (Thoratec) also relies upon a subdiaphragmatic implantation but the abdominal incision and pump pocket size are small, and complications related to its positioning are infrequent. The comparative advantages of HeartWare s intrapericardial implantation may be less pronounced. The most notable potential benefit of the HeartWare device is its hydrodynamic rotor suspension and bearingless design. This improves blood-handling characteristics and could reduce hemolytic and thrombotic complications from prolonged mechanical support. Additional implantations and the ongoing ENDURANCE (Evaluate the HeartWare Ventricular Assist System) trial may demonstrate an important clinical advantage of this device. The authors suggest that with improvements in VAD technology, mechanical circulatory support may be a viable alternative to transplantation. At the present time, this remains far from reality. While short-term survival is excellent, there are no reports demonstrating comparable long-term survival or quality of life. The VAD patients continue to be affected by right ventricular dysfunction, gastrointestinal bleeding, stroke, driveline infections, aortic valve insufficiency, and need for chronic anticoagulation. Until substantial advances mitigate these limitations, transplantation will remain the gold standard treatment for end-stage heart failure in eligible patients. Nonetheless, we welcome these incremental improvements in device technology and expect an expanding role for VADs both as bridge treatment and in the transplant noneligible or destination population. Jonathan W. Haft, MD Surgery University of Michigan 1500 E Medical Center Dr Ann Arbor, MI haft@umich.edu Reference 1. Popov AF, Hosseini MT, Zych B, et al. Clinical experience with HeartWare left ventricular assist device in patients with end-stage heart failure. Ann Thorac Surg 2012;93: by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc doi: /j.athoracsur