Left Ventricular Assist Device Explantation Research Articles

Prior Sternotomy and Ventricular Assist Device Implantation Do Not Adversely Impact Survival or Allograft Function After Heart Transplantation

Orthotopic heart transplantation (OHT) remains the gold standard for end-stage heart failure. However, donor availability is severely limited. With a median wait time of 6.6 months and more than 12% of patients waiting 5 or more years, the decision is often made to implant a left ventricular assist device (LVAD) asa bridge to transplantation for medical stabilization. Furthermore, the number of patients who have had at least one prior sternotomy while awaiting transplantation is increasing. Previous studies have indicated reoperative sternotomy as a risk factor for compromised survival. Concerns are specifically focused on perioperative, short-term, and long-term outcomes after LVAD explantation or redo sternotomy before OHT because of increasing operative complexity. We hypothesize that despite the greater technical difficulty caused by LVAD explantation or redo sternotomy, outcomes would not be compromised. We retrospectively analyzed patients who underwent OHT at the University of Pennsylvania during a 5-year period (2008-2013; n= 253). All patients who underwent a bridge to transplantation LVAD (n= 72) or prior sternotomy (n= 65) were compared with those undergoing OHT with a virgin chest (n= 116). Preoperative, intraoperative, and postoperative variables were analyzed. Short- and long-term survival were studied (minimum follow-up, 6 months). Comorbidities were similar among the groups. There was no difference in donor allograft ischemic time (p= 0.6). However, cardiopulmonary bypass time was longer in both bridge to transplantation and prior sternotomy cohorts (p < 0.00001). The blood transfusion requirement was higher in bridge to transplantation (12.5 ± 13.7 units; p= 0.0007) and prior sternotomy groups (11.7 ± 12.9 units; p= 0.02) as compared with the virgin chest cohort (7.1 ± 10.7 units). For bridge to transplantation, both time to extubation (1.0 ± 1.6 versus 0.9 ± 1.0 days; p= 0.03) and intensive care unit length of stay (7.0 ± 7.0 versus 6.0 ± 7.0 days; p= 0.06) were longer compared with the virgin chest cohort. The same was true for prior sternotomy (extubation time, 1.9 ± 4.4 days; p= 0.005; intensive care unit length of stay, 8.0 ± 12.0 days; p= 0.06). There was no difference in hospital length of stay (p= 0.2). Overall, there was no difference in short- or long-term survival. Implantation of an LVAD as a bridge to transplantation or prior sternotomy does not adversely impact allograft function, hospital length of stay, or long-term outcomes after OHT. The decision to manage a patient medically while awaiting transplantation versus an LVAD bridge strategy should not be limited by concerns of subsequent poor outcomes after transplantation.

Attenuation of the unfolded protein response and endoplasmic reticulum stress after mechanical unloading in dilated cardiomyopathy.

Abnormal intracellular calcium (Ca(2+)) handling can trigger endoplasmic reticulum (ER) stress, leading to activation of the unfolded protein response (UPR) in an attempt to prevent cell death. Mechanical unloading with a left ventricular assist device (LVAD) relieves pressure-volume overload and promotes reverse remodeling of the failing myocardium. We hypothesized that mechanical unloading would alter the UPR in patients with advanced heart failure (HF). UPR was analyzed in paired myocardial tissue from 10 patients with dilated cardiomyopathy obtained during LVAD implantation and explantation. Samples from healthy hearts served as controls. Markers of UPR [binding immunoglobulin protein (BiP), phosphorylated (P-) eukaryotic initiation factor (eIF2α), and X-box binding protein (XBP1)] were significantly increased in HF, whereas LVAD support significantly decreased BiP, P-eIF2α, and XBP1s levels. Apoptosis as reflected by C/EBP homologous protein and DNA damage were also significantly reduced after LVAD support. Improvement in left ventricular dimensions positively correlated with P-eIF2α/eIF2α and apoptosis level recovery. Furthermore, significant dysregulation of calcium-handling proteins [P-ryanodine receptor, Ca(2+) storing protein calsequestrin, Na(+)-Ca(2+) exchanger, sarcoendoplasmic reticulum Ca(2+)-ATPase (SERCA2a), ER chaperone protein calreticulin] was normalized after LVAD support. Reduced ER Ca(2+) content as a causative mechanism for UPR was confirmed using AC16 cells treated with a calcium ionophore (A23187) and SERCA2a inhibitor (thapsigargin). UPR activation and apoptosis are reduced after mechanical unloading, which may be mediated by the improvement of Ca(2+) handling in patients with advanced HF. These changes may impact the potential for myocardial recovery.

(532) - At Left Ventricular Assist Device (LVAD) Implantation, Morphologic Differences Are Observed Between Patients With Improved Cardiac Function Allowing LVAD Removal and Patients With Prolonged LVAD Support as a Bridge to Transplantation

To evaluate differences in morphologic parameters of ventricular remodeling in tissue samples and echocardiograms obtained at left ventricular (LV) assist device (LVAD) implantation in patients who later had sufficient clinical improvement to undergo device explantation versus those who required prolonged continuous-flow (CF) LVAD support and subsequent orthotopic heart transplantation (OHT). We evaluated 25 CF-LVAD patients, 10 of whom had improved cardiac function allowing device removal and 15 of whom underwent long-term device support (>24 months) and subsequent OHT. In all cases, myocardial tissue samples were collected from the LV core obtained at device implantation. Computerized morphometry was used to evaluate fibrosis and hypertrophy, including the cytoplasmic and nuclear diameter. Echocardiographic and hemodynamic parameters at the time of LVAD implantation were correlated with the histopathologic findings. Ten patients (7 men, 3 women; age 30±10 years) had their LVAD (HeartMateII) explanted due to cardiac functional improvement. Fifteen patients (11 men, 4 women; age 46±15 years) underwent OHT after 33±8 months (range: 26-50 months) of CF-LVAD support (HeartMate II, 13 cases; HeartWare, 2 cases). Four patients had ischemic cardiomyopathy, and 11 had nonischemic disease. At LVAD implantation, the LV core from the explant group showed a smaller myocyte diameter (24.55±4.63 vs. 37.09±10.22µ; P=0.0003), a smaller nuclear diameter (12.21±1.72 vs. 15.65±3.88µ; P=0.003), and less fibrosis (10.24±4.03% vs. 17.5±10.36%; P=0.014) than were observed in the transplant group. The left ventricular end-diastolic diameter (LVEDD) was smaller in the explant group than in the transplant group (6.37±0.63 vs. 7.18±1.11 cm; P=0.017). Patients with clinical improvement allowing LVAD explantation had less hypertrophy, less fibrosis, and a smaller LVEDD at the time of LVAD implantation than did patients who required prolonged LVAD support and subsequent OHT. These findings suggest that less extensive morphologic ventricular remodeling changes at LVAD implantation may help determine which subset of patients may have a potential for myocardial reconditioning.

(105) - Influence of Liver Dysfunction in Patients Undergoing Heart Transplantation With Left Ventricular Assist Device Explantation: Comparative Analysis Using the MELD Excluding INR (MELD-XI) Scoring System

Purpose: Cardiac allograft vasculopathy (CAV) is a major factor limiting survival after heart transplant. CAV may present as small vessel or microvascular disease, which is correlated with reduced coronary flow reserve (CFR). CFR is commonly performed through intracoronary flow wire. Recently, rubidium positron emission tomography (PET) scanning has become a reliable test to demonstrate CFR. We reviewed patients with low CFR (CFR< 2) and assessed them for cardiac dysfunction as defined by decreased left ventricular ejection fraction (LVEF), increased left ventricular end diastolic volume index (LVEDVI) and left ventricular enlargement. Methods: We assessed 36 patients transplanted between 1994 and 2013 and who underwent routine rubidium PET scanning between 2011 and 2014 at their annual visit. Patients with established coronary disease were excluded. CFR was determined by rubidium PET scanning. Additional concomitant information of LVEF at rest and post stress, LVEDVI at rest and post-stress, and left ventricular enlargement was recorded. Results: 9 patients had a low CFR. The low CFR group had significantly decreased LVEF post-stress and a trend towards decreased LVEF at rest. The low CFR group also had significantly higher LVEDVI at rest and post-stress. A significantly larger percentage of patients had left ventricular enlargement in the low CFR group (see table). Conclusion: Low CFR is associated with cardiac dysfunction which may be due to small vessel coronary disease in the absence of epicardial CAV. Rubidium PET may have a role in determining small vessel disease in heart transplant patients.

Minimally invasive ventricular assist device surgery.

The use of mechanical circulatory support to treat patients with congestive heart failure has grown enormously, recently surpassing the number of annual heart transplants worldwide. The current generation of left ventricular assist devices (LVADs), as compared with older devices, is characterized by improved technologies and reduced size. The result is that minimally invasive surgery is now possible for the implantation, explantation, and exchange of LVADs. Minimally invasive procedures improve surgical outcome; for example, they lower the rates of operative complications (such as bleeding or wound infection). The miniaturization of LVADs will continue, so that minimally invasive techniques will be used for most implantations in the future. In this article, we summarize and describe minimally invasive state-of-the-art implantation techniques, with a focus on the most common LVAD systems in adults.

Building a bridge to save a failing ventricle: radiologic evaluation of short- and long-term cardiac assist devices.

Heart failure is recognized with increasing frequency worldwide and often progresses to an advanced refractory state. Although the reference standard for treatment of advanced heart failure remains cardiac transplantation, the increasing shortage of donor organs and the unsuitability of many patients for transplantation surgery has led to a search for alternative therapies. One such therapy is mechanical circulatory support, which helps relieve the load on the ventricle and thereby allows it to recover function. In addition, there is increasing evidence supporting the use of mechanical devices as a bridge to recovery in patients with acute refractory heart failure. In this article, the imaging evaluation of various commonly used short- and long-term cardiac assist devices is discussed, and their relevant mechanisms of action and physiology are described. Imaging, particularly computed tomography (CT), plays a crucial role in preoperative evaluation for assessment of candidacy for implantation of a left ventricular assist device (LVAD) or total artificial heart (TAH). Also, echocardiography and CT are indispensable in assessment of complications associated with cardiac devices. Complications commonly associated with short-term assist devices include bleeding and malpositioning, whereas long-term devices such as LVADs may be associated with infection, pump thrombosis, and cannula malfunction, as well as bleeding. CT is also commonly performed for preoperative planning before LVAD or TAH explantation, replacement of a device or one of its components, and cardiac transplantation. Online supplemental material is available for this article.

Abstract 13291: Left Ventricular Assist Device Support is Associated with Sustained Cardiac CamKII Activation and Increased MEF2

Background: Ca2+/calmodulin-dependent protein kinase (CaMK)II has been implicated in impaired myocardial Ca2+ signaling and may play an important role in the development of heart failure (HF). The objective of this study was to characterize CAMKII signaling in patients with HF before and after prolonged left ventricular assist device (LVAD) support. Methods: LV apex tissue pairs were collected in patients with dilated cardiomyopathy (n=10) at LVAD implantation and explantation. Normal cardiac tissue was used as control (n=4). Total protein, as well as cytoplasmic and nuclear fractions, were analyzed by Western Blot analysis. Results: The duration of LVAD support ranged from 48 to 595 days (mean = 271±54) with no patient exhibiting myocardial recovery. Total CamKIIδ levels in failing hearts were significantly higher than normal hearts and increased after LVAD, mainly due to an increase in cytoplasmic CaMKIIδC, which regulates Ca2+ handling (Table 1). Nuclear CaMKIIδB, which regulates Ca2+ gene transcription, did not change. Calmodulin remained increased in the nuclear and cytoplasmic fractions after LVAD. CaMKII autonomous, non-CaM-dependent activity, reflected by phosphorylation in Thr207, was increased pre- and post LVAD in cytoplasmic CaMKIIδC. The CaMKII-dependent myocyte enhancer factor 2 (MEF2) was increased pre- and significantly further post LVAD in the nucleus while decreased in the cytoplasm, suggesting translocation into the nucleus after LVAD support. Class IIa HDACs 4 and 5 interact with MEF2, resulting in repression of MEF2-dependent genes. Phosphorylated levels of HDAC4 and HDAC5 were increased pre- and post LVAD, which would result in activated MEF2. Conclusions: This study shows for the first time an increase of the hypertrophic factor MEF2 associated with persistent activation of CamKIIδC after prolonged LVAD support, which may have implications for cardiac remodeling during mechanical support.

Hemodynamic changes during left ventricular assist device-off test correlate with the degree of cardiac fibrosis and predict the outcome after device explantation.

Myocardial recovery occurs in a small cohort of patients receiving left ventricular assist device (LVAD) support, but identification of candidates for device removal remains challenging. We hypothesized that hemodynamic evaluation using echocardiography and right heart catheter during temporary suspension of LVAD support (LVAD-off test) can assess cardiac recovery to predict successful device removal. To prove this hypothesis, we reviewed 44 patients who underwent LVAD-off test from January 2000 to March 2011 at Osaka University Hospital. Twenty-two of them underwent LVAD explant, 9 showed sustaining recovery (successful explant, SE-group); whereas 13 had a recurrent heart failure (failed explant, FE-group). The other 22 patients remained LVAD dependent (nonrecovery, NR-group). Echocardiography showed significant lower ejection fraction (LVEF) in NR-group than in SE- and FE-group after termination of LVAD support, but there was no difference between SE- and FE-group. On the other hand, elevation in pulmonary capillary wedge pressure (ΔPCWP) was significantly smaller in SE-group than in FE- and NR-groups. The degree of cardiac fibrosis significantly increased in FE- and NR-group during the LVAD support, while it did not increase in SE-group. The degree of cardiac fibrosis at the time of LVAD explantation correlated significantly with PCWP at LVAD halt and ΔPCWP, and it had significant impact on the outcome after LVAD weaning. In conclusion, the data obtained during LVAD-off test using echocardiography and right heart catheter significantly correlated with the degree of cardiac fibrosis at the time of LVAD explantation. LVAD-off test is a useful method to predict the successful LVAD explantation.

Mechanical circulatory support improves diabetic control in patients with advanced heart failure.

Left ventricular assist devices (LVADs) are increasingly being used as life-saving therapy for end-stage advanced heart failure. Diabetes is prevalent in advanced heart failure patients. In this study, we sought to investigate the effects of mechanical circulatory support on diabetic parameters with LVAD implantation. In this retrospective study, data on 244 LVAD recipients between 2006 and 2013 were reviewed. Patients without history of diabetes, death within the first 3 months after LVAD implantation, heart transplantation after LVAD, or LVAD explantation were excluded from the study. Baseline demographic, laboratory, and echocardiographic information prior to LVAD placement and 6-month follow-up were obtained. Laboratory values indicative of diabetic control were found to improve significantly at 6 months post-LVAD implantation (glycated haemoglobin, 7.2 vs. 6.1%, P < 0.0001; serum fasting glucose, 141 vs. 122 mg/dL, P = 0.003; mean daily insulin dose, 30 vs. 24 IU/day, P = 0.02). Additionally, the use of oral hypoglycaemic medication was successfully discontinued in six patients at 6 months post-LVAD implantation. Long-term LVAD therapy is associated with improvement in diabetic control which is probabvly due to improvements in cardiac output and normalization of biochemical derangements resulting from diabetes.

Ventricular reconditioning and pump explantation in patients supported by continuous-flow left ventricular assist devices

The potential for myocardial reconditioning and device explantation after long-term continuous-flow left ventricular assist device (LVAD) support presents an opportunity to delay or avoid transplantation in select patients. Thirty of 657 patients with end-stage heart failure supported with continuous-flow LVADs were assessed for device explantation. Each patient underwent an individualized process of weaning focused on principles of ventricular unloading, gradual reconditioning, and transition to medical therapy. After varying reconditioning periods, 27 patients (16 men, 11 women; age, 39 ± 12 years) underwent LVAD explant, and 3 patients (2 men, 1 woman; age, 22 ± 6 years) were evaluated for explantation but could not be weaned. The duration of LVAD support was 533 ± 424 days (range, 42-1,937 days) for the explant cohort and 1,097 ± 424 days (range, 643-1,483) for the non-explant cohort. The LV end-diastolic dimension, LV ejection fraction, systolic pulmonary artery pressure, cardiac output, and cardiac index in the explant cohort were significantly improved at explantation (all, p < 0.05). Two late deaths occurred after LVAD explantation despite satisfactory native cardiac function, and 1 patient required resumption of LVAD support 2.7 years after device removal. The remaining explant patients remain in New York Heart Association classes I to II with medical management alone (mean survival post-explant, 1,172 ± 948 days). The 3 candidates who could not be weaned ultimately underwent transplantation. The potential for recovery of native LV function after long-term continuous-flow LVAD support should encourage a more aggressive approach to ventricular reconditioning with the goal of device explantation and a return to medical management, particularly in young patients with dilated cardiomyopathy.

VAD as Bridge to Recovery in Anthracycline-Induced Cardiomyopathy and HHV6 Myocarditis

This report describes an 8-year-old child with acute anthracycline-induced cardiomyopathy triggered by human herpesvirus 6 and the subsequent implantation of an intracorporeal continuous-flow left ventricular assist device (LVAD) and the process to discharge the child from the hospital. After barely 3 months on mechanical support, the device was explanted after thorough examination. Experiences regarding LVAD removal are limited, and no guidelines for echocardiographic and hemodynamic criteria for LVAD removal in children have been published thus far. We present our institutional algorithm for device selection, surveillance in an ambulatory setting, and testing for myocardial recovery, as well as our criteria for LVAD explantation in children.

Midterm outcome of implantable left ventricular assist devices as a bridge to transplantation: Single-center experience in Japan

BackgroundTwo implantable continuous-flow left ventricular assist devices (LVADs), DuraHeart (Terumo Heart, Ann Arbor, MI, USA) and EVAHEART (Sun Medical, Nagano, Japan), were approved in Japan in April 2011. We analyzed the midterm outcome of patients implanted with these implantable LVADs at the University of Tokyo Hospital. Methods and resultsA total of 31 patients who underwent implantation of LVADs (10 DuraHeart, 21 EVAHEART) as a bridge to transplantation at our institution between April 2011 and August 2013 were retrospectively reviewed. All patients were followed up through December 2013. Seven patients underwent conversions from NIPRO paracorporeal LVAD (Nipro, Osaka, Japan) to an implantable LVAD. The mean observation period was 483±239 days (41.0 patient years). Eight patients were transplanted and one patient showed functional recovery with subsequent LVAD explantation. Four patients died due to cerebrovascular accident, empyema, or device malfunction due to pump thrombosis after cerebral bleeding. Kaplan–Meier analysis revealed 6-, 12-, and 24-month survival rates of 93%, 86%, and 86%, respectively. The rates of freedom from cerebrovascular accidents and device-related infections at 1 year after LVAD implantation were 65% and 36%, respectively. Twenty-nine patients were discharged home after LVAD implantation. During the period of this study, there were 59 readmissions (53 urgent, 6 elective) among 22 patients (76%). The overall and urgent readmission rates were 1.66 and 1.49 per patient year, respectively. The common reason for readmission was device-related infection (31%), followed by cerebrovascular accidents (17%). The total out-of-hospital time after the primary discharge was 90%. ConclusionsOur midterm survival rate after LVAD implantation is satisfactory. However, patients undergoing LVAD support were often readmitted with adverse events.

Institutional volume of heart transplantation with left ventricular assist device explantation influences graft survival

There are increasing numbers of patients undergoing orthotopic heart transplantation (OHT) with left ventricular assist device (LVAD) explantation (LVAD explant-OHT). We hypothesized that LVAD explant-OHT is a more challenging surgical procedure compared to OHT without LVAD explantation and that institutional LVAD explant-OHT procedural volume would be associated with post-transplant graft survival. We sought to assess the impact of institutional volume of LVAD explant-OHT on post-transplant graft survival. This is a retrospective analysis of the Scientific Registry of Transplant Recipients for adult OHTs with long-term LVAD explantation. LVAD explant-OHT volume was characterized on the basis of the center's year-specific total OHT volume (OHTvol) and year-specific LVAD explant-OHT volume quartile (LVADvolQ). The effect of LVADvolQ on graft survival (death or re-transplantation) was analyzed. From 2004 to 2011, 2,681 patients underwent OHT with LVAD explantation (740 with HeartMate XVE, 1,877 with HeartMate II and 64 with HeartWare devices). LVAD explant-OHT at centers falling in the lowest LVADvolQ was associated with reduced post-transplant graft survival (p = 0.022). After adjusting for annualized OHTvol (HR = 0.998, 95% CI 0.993 to 1.003, p = 0.515 and pulsatile XVE (HR = 0.842, 95% CI 0.688 to 1.032, p = 0.098), multivariate analysis confirmed a significantly (approximately 37%) increased risk of post-transplant graft failure among explant-OHT procedures occurring at centers in the lowest volume quartile (HR = 1.371, 95% CI 1.030 to 1.825, p = 0.030). Graft survival is decreased when performed at centers falling in the lowest quartile of LVAD explant-OHT for a given year. This volume-survival relationship should be considered in the context of limited donor organ availability and the rapidly growing number of LVAD centers.

Comparative cost-effectiveness of the HeartWare versus HeartMate II left ventricular assist devices used in the United Kingdom National Health Service bridge-to-transplant program for patients with heart failure

Patients with advanced heart failure may receive a left ventricular assist device (LVAD) as part of a bridge-to-transplant (BTT) strategy. The United Kingdom National Health Service (UK NHS) has financed a BTT program in which the predominant LVADs used have been the HeartMate II (HM II; Thoratec, Pleasanton, CA) and HeartWare (HW; HeartWare International, Inc. Framingham, MA). We aimed to compare the cost-effectiveness of the use of these within the NHS program. Individual patient data from the UK NHS Blood and Transplant Data Base were analyzed with Kaplan-Meier and competing outcomes methodologies. Outcomes were time to death, time to heart transplant (HT), and cumulative incidences of HT, death on LVAD support, and LVAD explantation. A semi-Markov multistate economic model was built to assess cost-effectiveness. The perspective was from the NHS, discount rates were 3.5%. Outcomes were quality-adjusted life-years (QALYs) and incremental cost (2011 prices in GB£) per QALY (ICER) for HW vs HM II. Survival was better with HW support than with HM II. Cumulative incidence of HT was low for both groups (11% at ~2 years). HW patients accrued 4.99 lifetime QALYs costing £258,913 ($410,970), HM II patients accrued 3.84 QALYs costing £231,871 ($368,048); deterministic and probabilistic ICERs for HW vs HM II were £23,530 ($37,349) and £20,799 ($33,014), respectively. Patients In the UK BTT program who received the HW LVAD had a better clinical outcome than those who received the HM II, and the HW was more cost-effective. This result needs to be reassessed in a randomized controlled trial comparing the 2 devices.

Safety and efficacy of prothrombin complex concentrates for the treatment of coagulopathy after cardiac surgery

Coagulopathy is an important cause of bleeding after complex cardiac surgery. The conventional treatment for coagulopathy is transfusion, which is associated with adverse outcomes. We report our initial experience with the prothrombin complex concentrate FEIBA (factor VIII inhibitor bypassing activity) for the rescue treatment of coagulopathy and life-threatening bleeding after cardiac surgery. Twenty-five patients who underwent cardiac surgery with coagulopathy and life-threatening bleeding refractory to conventional treatment received FEIBA as rescue therapy at our institution. This cohort represents approximately 2% of patients undergoing cardiac surgery in our university-based practice during the study. The patients were at high risk for postoperative coagulopathy with nearly all patients having at least 2 risk factors for this. Aortic root replacement (Bentall or valve-sparing procedure) and heart transplant with or without left ventricular assist device explant were the most common procedures. The mean FEIBA dose was 2154 units. The need for fresh frozen plasma and platelet transfusion decreased significantly after FEIBA administration (P=.0001 and P<.0001). The mean internationalized normalized ratio decreased from 1.58to 1.13 (P<.0001). Clinical outcomes were excellent. No patient returned to the operating room for reexploration. There was no hospital mortality and all patients were discharged home. One patient who had a central line and transvenous pacemaker developed an upper extremity deep vein thrombosis. Our initial experience with FEIBA administration for the rescue treatment of postoperative coagulopathy and life-threatening bleeding has been favorable. Further studies are indicated to confirm its efficacy and safety and determine specific clinical indications for its use in patients undergoing cardiac surgery.

Successful bridge to recovery using two-stage HeartWare LVAD explantation approach after embolic stroke

A two-stage explantation of a left ventricular assist device (LVAD) was performed on 47 year old afro-american gentlemen with non-ischemic dilated cardiomyopathy (DCM) who was successfully bridged to recovery. After he suffered a stroke caused by a VAD thrombosis with embolisation, the VAD outflow graft was first ligated using minimally-invasive approach. Two months later, the device was explanted and a manufactured titanium plug was placed into the sewing ring. This stepwise procedure might be beneficial in cases of high thromboembolic risk and in patients who suffered a thromboembolic event previously.

Minimally Invasive Left Ventricular Assist Device Explantation After Cardiac Recovery: Surgical Technical Considerations

The new generation of left ventricular assist devices (LVADs) has enabled minimally invasive surgical procedures for implantation. Herein we present two alternative approaches for minimally invasive LVAD explantation following cardiac recovery, avoiding a sternotomy and improving patient safety.

Implantable Cardioverter-Defibrillators Are Not Associated with Survival in Patients with a Left Ventricular Assist Device

The use of ICDs for the primary prevention of sudden cardiac death is well established in the heart failure (HF) population. Most patients with advanced HF who receive a left ventricular assist device (LVAD) have an ICD. However, the survival benefit of an ICD has not been shown in this population. To determine the association of ICDs with overall survival in patients with LVADs. All patients receiving a continuous-flow LVAD at our center since 2005 were included. Charts were retrospectively reviewed to identify baseline characteristics and outcomes. Fisher's Exact test and the Mann-Whitney U test were used to compare categorical and continuous variables, respectively. The Cox proportional hazards model was used to compare survival between patients with and without an ICD. Patients were censored at the time of transplantation, LVAD explantation or exchange for biventricular support. Logistic regression was used to determine the predictive value of baseline VT on post-LVAD VT. The study included 215 patients, with 84% receiving a LVAD for destination therapy (DT). 28 patients (13%) did not have an ICD during LVAD support. Median follow-up was 506 days [interquartile range 196-1015]. As compared to patients with an ICD, patients without an ICD were younger (56 ± 13 years vs. 61 ± 13 years), more likely to present in acute cardiogenic shock (21% vs. 7%) and less likely to have atrial fibrillation (11% vs. 38%) or chronic kidney disease (32% vs. 63%). The incidence of bloodstream infection (BSI) was similar between the two groups (36% vs. 25%; p=0.26). There was no difference in age-adjusted survival (HR 0.91; 95% CI 0.46-1.80; P=0.78) or survival free from BSI (HR 0.82; 95% CI 0.42-1.62; P=0.82) between the two groups. ICD shocks for VT were delivered in 24 patients (13% of patients with ICD). Baseline VT was a strong univariate predictor of post-LVAD VT (OR 2.8; 95% CI 1.3-6.4; P=.011). Inappropriate ICD shocks for either sinus tachycardia or atrial arrhythmias were received by seven patients (4% of patients with ICD). Seven patients developed ICD infections and six underwent ICD explantation at an average of 345 ± 323 days following LVAD implantation. In our single-center analysis of a predominantly DT LVAD population with up to four years of follow-up, the presence of an ICD did not affect survival. Additionally, ICDs were not associated with an increased risk of bloodstream infections. Appropriate ICD shocks are relatively uncommon in the LVAD population.

Minimally invasive access for off-pump HeartWare left ventricular assist device explantation

The implantation of a left ventricular assist device as a bridge to transplantation is a well-established treatment of end-stage heart failure in selected patients. Device-related infection is a well-known complication that may require the removal of the device. We describe a minimally invasive explantation approach with complete removal of all components of a HeartWare left ventricular assist device in a patient with persistent infection related to the device.

Heart transplantation vs long-term mechanical assist devices: clinical equipoise?

Heart transplantation became a clinical entity in 1967, but reached clinical viability in the early 1980s. Since the first heart transplant the donor’s age has increased, as has the recipient’s. The length of stay for the initial hospitalization has decreased. The time to the first rejection episode has increased. Long-term survival has also improved [1]. The current generation of mechanical assist devices was born in the early 1990s, if we exclude the experience with an artificial heart in 1982. Their clinical usage has steadily increased since the REMATCH trial was published in 2001 [2]. The criteria for destination therapy continue to evolve as we learn more about patient selection and management. For this editorial, let us exclude total artificial hearts, as the experience is limited. There are certain patients who cannot benefit from placement of a left ventricular assist device (LVAD) alone. These are patients with pronounced right ventricular failure, as well as patients with protracted arrhythmias. Those with a restrictive cardiomyopathy do not have a large enough left ventricular chamber to receive an LVAD. Hypertrophic cardiomyopathy patients have too-thick a left ventricle to receive a functioning LVAD. Finally, what about patients who have received various palliative procedures for a single ventricle? Heart transplantation is the appropriate procedure for them [3]. At the University of Minnesota, there have been patients who required temporary biventricular support as a bridge to an implantable LVAD. They underwent eventual LVAD explant and heart transplantation, but then required temporary right ventricular assist support. How long will insurance companies pay for this much surgery? How many patients will recover from this much time in the hospital? All of these operations increase the patient’s exposure to blood products. This increases the number of patients who are sensitized. Sensitized patients increase the challenges of suppressing rejection and infection after heart transplantation. The patient with multiple cardiac operations as well as multiple cardiac catheterizations may develop complications from these treatments such as heparin-induced thrombocytopenia. All programmes are becoming more experienced in dealing with this problem. Plasmapheresis or bivalirudin offer solutions, but it is better to avoid the condition entirely. With obese patients, there is a patient-heart mismatch that contributes to the development of heart failure. Dealing with the obesity epidemic in terms of prevention would cut down on the number of patients requiring a heart transplant or LVAD. There are patients with significant fixed pulmonary hypertension or recent malignancy who are not candidates for heart transplantation. A transpulmonary gradient of ≥15 would mean that the patient should be considered for LVAD over heart transplantation. A patient with a malignancy within the past 5 years should also be considered a candidate for LVAD over heart transplantation. Any evidence of ongoing infection makes the patient a poor candidate for either procedure. The very-sensitized patient is also one who should be considered for a destination LVAD. According to the most recent report of the Registry of the International Society for Heart and Lung Transplantation, the median survival of 96 273 adult and paediatric heart recipients is 10 years [4]. Those who survive 1 year have a 63% chance of living 10 years and a 27% chance of living 20 years. Recipients of ventricular assist devices are significantly fewer in number and post-procedure years. Dr Kirklin presented the Interagency Registry of Mechanically Assisted Circulatory Support (INTERMACS) data on patients who received a continuous-flow LVAD as destination therapy [5]. The patients who were not in cardiogenic shock at the time of implantation were the most favourable group for good outcomes. These patients had survival of 88 and 80% at 1 and 2 years, respectively. The mortality rate for these patients was 10% per year. After heart transplantation, it is 6% per year. Moreno et al. [6] used a probabilistic Markov model to estimate the cost-effectiveness of the HeartMate II LVAD (Thoratec, Pleasanton, CA, USA). They found that the HeartMate II had a mean cost per quality-adjusted life-year of $414 275. The cost of the device alone was $150 720. Medical management of patients awaiting transplant has improved since the REMATCH trial. At least in the UK, the HeartMate II LVAD is not judged to be costeffective as a bridge to transplantation. According to OPTUM health, in the USA a heart transplant hospitalization costs $550 000. The hospitalization for a patient receiving an LVAD is $400 000, beginning on the day that the LVAD is implanted. Length of stay depends on how sick the patient is at the time of transplant or implant. Clinical equipoise suggests that there is true uncertainty about which of two potential clinical treatments is appropriate for a