Post-cardiac transplant survival after support with a continuous-flow left ventricular assist device: impact of duration of left ventricular assist device support and other variables

Special Considerations for Advanced Heart Failure Surgeries: Durable Left Ventricular Devices and Heart Transplantation

Heart transplantation and durable left ventricular assist devices (LVADs) represent two definitive therapies for end-stage heart failure in the modern era. Despite technological advances, both treatment modalities continue to experience unique risks that impact surgical and perioperative decision-making. Here, we review special populations and factors that impact risk in LVAD and heart transplant surgery and examine critical decisions in the management of these patients. As both heart transplantation and the use of durable LVADs as destination therapy continue to increase, these considerations will be of increasing relevance in managing advanced heart failure and improving outcomes.

Sleeve gastrectomy facilitates weight loss and permits cardiac transplantation in patients with severe obesity and a left ventricular assist device (LVAD)

INTRODUCTION

Patients suffering from advanced heart failure may undergo left ventricular assist device (LVAD) placement as a bridge to cardiac transplantation. However, those with a BMI above 35 kg/m2 are generally not considered eligible for transplant due to their elevated cardiac risk. We review our experience with bariatric surgery in this high-risk population to assess its safety and efficacy in reducing BMI to permit cardiac transplantation.

METHODS

We retrospectively reviewed all patients on durable LVAD support who underwent sleeve gastrectomy (SG) at Mount Sinai Hospital between August 2018 and December 2022. Electronic medical records were reviewed to analyze patient demographics, surgical details, and outcomes regarding weight loss and heart transplantation.

RESULTS

We identified twelve LVAD patients who underwent SG. Three were performed laparoscopically and 9 via robotic approach. Four patients (33.3%) underwent an orthotopic heart transplant (OHTx). Half of these patients were female. For patients who underwent OHTx, mean age at LVAD placement was 41.0 (R30.6-52.2), at SG was 43.9 (R32.7-55.0) and at OHTx was 45.3 years (R33.3-56.8). Mean BMI increased from 38.8 at LVAD placement to 42.5 prior to SG. Mean time from SG to OHTx was 17.9 months (R6-7-27.5) during which BMI decreased to mean 32.8 at the time of OHTx. At most recent follow-up, mean BMI was 31.9. All patients were anticoagulated prior to surgery; one required return to the operating room on post-operative day 1 after SG for bleeding and one was re-admitted on post-operative day 7 for hematochezia treated conservatively.

CONCLUSION

SG is a safe and effective operation in patients with severe obesity and heart failure requiring an LVAD. 66.7% of our cohort achieved target BMI < 35 and 33.3% underwent heart transplantation. Longer term follow-up is needed to clarify full bridge-to-transplant rate and long-term survival outcomes.

Optimal timing of heart transplantation in patients with an implantable left ventricular assist device

Heart transplantation (HTPL) has been established as the gold-standard surgical treatment for end-stage heart failure. However, the use of a left ventricular assist device (LVAD) as a bridge to HTPL has been increasing due to the limited availability of HTPL donors. Currently, more than half of HTPL patients have a durable LVAD. Advances in LVAD technology have provided many benefits for patients on the waiting list for HTPL. Despite their advantages, LVADs also have limitations such as loss of pulsatility, thromboembolism, bleeding, and infection. In this narrative review, the benefits and shortcomings of LVADs as a bridge to HTPL are summarized, and the available literature evaluating the optimal timing of HTPL after LVAD implantation is reviewed. Because only a few studies have been published on this issue in the current era of third-generation LVADs, future studies are needed to draw a definite conclusion.

Key questions about aortic insufficiency in patients with durable left ventricular assist devices

The development of the latest generation of durable left ventricular assist devices (LVAD) drastically decreased adverse events such as pump thrombosis or disabling strokes. However, time-related complications such as aortic insufficiency (AI) continue to impair outcomes following durable LVAD implantation, especially in the context of long-term therapy. Up to one-quarter of patients with durable LVAD develop moderate or severe AI at 1 year and its incidence increases with the duration of support. The continuous regurgitant flow within the left ventricle can compromise left ventricular unloading, increase filling pressures, decrease forward flow and can thus lead to organ hypoperfusion and heart failure. This review aims to give an overview of the epidemiology, pathophysiology, and clinical consequences of AI in patients with durable LVAD.

Residual Pulmonary Vascular Resistance Increase Under Left Ventricular Assist Device Support Predicts Long-Term Cardiac Function After Heart Transplantation

Aims

We compared hemodynamics and clinical events after heart transplantation (HTx) in patients stratified by the severity of residual pulmonary vascular resistance (PVR) after left ventricular assist device (LVAD) implantation for bridge to transplantation.

Methods

We retrospectively analyzed patients who had undergone HTx at the University of Tokyo Hospital. We defined the high PVR group as patients with PVR of >3 Wood Units (WU) as measured by right heart catheterization performed 1 month after LVAD implantation.

Results

We included 85 consecutive HTx recipients, 20 of whom were classified in the high PVR group and 65 in the low PVR group. The difference in PVR between the two groups became apparent at 2 years after HTx (the high PVR group: 1.77 ± 0.41 WU, the low PVR group: 1.24 ± 0.59 WU, p = 0.0009). The differences in mean pulmonary artery pressure (mPAP), mean right arterial pressure (mRAP), and mean pulmonary capillary wedge pressure (mPCWP) tended to increase from the first year after HTx, and were all significantly higher in the high PVR group at 3 years after HTx (mPAP: 22.7 ± 9.0 mm Hg vs. 15.4 ± 4.3 mm Hg, p = 0.0009, mRAP: 7.2 ± 3.6 mm Hg vs. 4.1 ± 2.1 mm Hg, p = 0.0042, and mPCWP: 13.4 ± 4.5 mm Hg, 8.8 ± 3.3 mm Hg, p = 0.0040). In addition, pulmonary artery pulsatility index was significantly lower in the high PVR group than in the low PVR group at 3 years after HTx (2.51 ± 1.00 vs. 5.21 ± 3.23, p = 0.0033). The composite event including hospitalization for heart failure, diuretic use, and elevated intracardiac pressure (mRAP ≥ 12 mm Hg or mPCWP ≥ 18 mm Hg) between the two groups was significantly more common in the high PVR group. Residual high PVR was still an important predictor (hazard ratio 6.5, 95% confidence interval 2.0–21.6, and p = 0.0023) after multivariate Cox regression analysis.

Conclusion

Our study demonstrates that patients with residual high PVR under LVAD implantation showed the increase of right and left atrial pressure in the chronic phase after HTx.

HVAD versus heartmate III bridge to heart transplantation: Waitlist and posttransplant outcomes

BACKGROUND

This study compared outcomes of patients bridged with either the Heartware HVAD or Heartmate 3 (HM3) device to orthotopic heart transplantation (OHT).

METHODS

The United Network of Organ Sharing registry was queried to perform two separate analyses of adult, isolated OHT candidates bridged with HVAD or HM3. First, waitlist outcomes were compared among patients waitlisted 1/1/2015-3/20/2020. Second, posttransplant survival was compared among those transplanted 1/1/2015-3/20/2020.

RESULTS

Two thousand two hundred fifty-five candidates were waitlisted within the study period, 1587 (70.4%) bridged with HVAD and 668 (29.6%) with HM3. At 1 year from waitlisting, cumulative incidence of OHT higher in the HVAD cohort (p < .001). During the same time period, 2643 patients underwent OHT, 2154 (81.5%) with prior HVAD and 489 (18.5%) with HM3. Yearly proportions of patients bridged with HM3 increased across the study period and decreased for HVAD (p < .001). HM3-bridged recipients had shorter waitlist times, longer graft cold ischemic times, and experienced a higher rate of posttransplant dialysis requirement. Unadjusted and risk-adjusted posttransplant mortality rates were similar between both groups.

CONCLUSIONS

Posttransplant survival is equivalent regardless of device type used for bridging. However, HM3 patients had lower likelihood of reaching transplantation, which may be a reflection of the recent heart allocation policy changes.

Impact of Ventricular Assist Device-Specific Infections on Post-Heart Transplant Infections: A Retrospective Single-Center Study

BACKGROUND

Patients with a ventricular assist device (VAD) who are awaiting heart transplant (HTx) are susceptible to infections. Such infections, especially at the site of the VAD, may increase the risk of severe post-transplant infections and mortality. Information on the characteristics of VAD-specific infections and outcomes in HTx recipients after prolonged periods of LVAD therapy is scarce.

PURPOSE

We aimed to assess the impact of active VAD-specific infections on the incidence of early post-transplant infections and patient survival.

METHODS

We conducted a retrospective review of adult HTx cases at our center between April 2011 and October 2020. Informed consent was waived due to study design. A total of 86 patients were included in this study, among whom 94.2% (n = 81) were bridged with a VAD, and the median VAD support period was 1089 days.

RESULTS

Patients with active VAD-specific infections were significantly more likely to develop severe acute mediastinitis [odds ratio (OR) 14.8, 95% confidence interval (CI) 4.83-45.4, P < .01]. Active VAD infections were significantly related to increased length of intensive care unit stay (22.1 days vs 13.0 days, P = .016) and longer mechanical ventilation periods (324.7 hours vs 113.2 hours, P = .03). The 30-day survival rates for patients with and without post-transplant infections were 100% and 97.1%, respectively.

CONCLUSION

Compared to other risk factors, the presence of active VAD-specific infections increases the risk of early post-heart transplant infections and morbidity, without affecting mortality.

Decreased frequency of transplantation and lower post-transplant survival free of re-transplantation in LVAD patients with the new heart transplant allocation system

PURPOSE

To evaluate the effect of the new heart transplant (HT) allocation system in left ventricular assist device (LVAD) supported patients listed as bridge to transplantation (BTT).

METHODS

Adult patients who were listed for HT between October 18, 2016 and October 17, 2019, and were supported with an LVAD, enrolled in the UNOS database were included in this study. Patients were classified in the old or new system if they were listed or transplanted before or after October 18, 2018, respectively.

RESULTS

A total of 3261 LVAD patients were listed for transplant. Of these, 2257 were classified in the old and 1004 in the new system. The cumulative incidence of death or removal from the transplant list due to worsening clinical status at 360-days after listing was lower in the new system (4% vs. 7%, P = .011). LVAD Patients listed in the new system had a lower frequency of transplantation within 360-days of listing (52% vs. 61%, P < .001). A total of 1843 LVAD patients were transplanted, 1004 patients in the old system and 839 patients in the new system. The post-transplant survival at 360 days was similar between old and new systems (92.3% vs. 90%, P = .08). However, LVAD patients transplanted in the new system had lower frequency of the combined endpoint, freedom of death or re-transplantation at 360 days (92.2% vs. 89.6%, P = .046).

CONCLUSION

The new HT allocation system has affected the LVAD-BTT population significantly. On the waitlist, LVAD patients have a decreased cumulative frequency of transplantation and a concomitant decrease in death or delisting due to worsening status. In the new system, LVAD patients have a decreased survival free of re-transplantation at 360 days post-transplant.

Impact of pretransplant left ventricular assist device support duration on outcome after heart transplantation

 

OBJECTIVES

Heart transplantation after left ventricular assist device (LVAD) implantation remains challenging. It is still unclear whether its support duration impacts the outcome after transplantation.

METHODS

All patients undergoing heart transplantation between 2010 and 2021 at a single department after previous left ventricular assistance were retrospectively reviewed and divided into 4 different study groups with regard to the duration of LVAD support to examine the impact on the postoperative morbidity and mortality.

RESULTS

A total of n = 198 patients were included and assigned to the 4 study groups (group 1: <90 days, n = 14; group 2: 90 days to 1 year, n = 31; group 3: 1–2 years, n = 29; group 4: >2 years, n = 24). Although there were no differences between the 4 groups concerning relevant mismatch between the recipients and donors, the incidence of primary graft dysfunction was numerically increased in patients with the shortest support duration, and also those patients with >1 year of support (group 1: 35.7%, group 2: 25.8%, group 3: 41.4%, group 4: 37.5%, P = 0.63). The incidence of acute graft rejection was by trend increased in patients of group 1 (group 1: 28.6%, group 2: 3.3%, group 3: 7.1%, group 4: 12.5%, P = 0.06). Duration of LVAD support did not impact on perioperative adverse events (infections, P = 0.79; acute kidney injury, P = 0.85; neurological events, P = 0.74; thoracic bleeding, P = 0.61), neither on postoperative survival (1-year survival: group 1: 78.6%, group 2: 66.7%, group 3: 80.0%, group 4: 72.7%, P = 0.74).

CONCLUSION

We cannot identify a significant impact of the duration of pretransplant LVAD support on postoperative outcome; therefore, we cannot recommend a certain timeframe for transplantation of LVAD patients.

Ten-Year Survival With a Continuous-Flow Left Ventricular Assist Device and Aortic Valve Closure

We report the long-term survival of a 46-year-old man supported with a HeartMate II continuous-flow left ventricular assist device after complex repair of a bicuspid aortic valve, anomalous left main coronary artery, and dilated aorta. He has been maintained on an anticoagulation regimen of warfarin and low-dose aspirin without problems for 10 years, during which he has worked continuously and productively. Device flow has been kept at 10,000 rpm. Possible contributors to this long-term success include proper alignment of the device inflow cannula, pericardial patch closure of the left ventricular outflow tract, and, notably, the remarkable freedom from mechanical failure of the continuous-flow left ventricular assist device. Whether the higher flow rate produced by the pericardial patch closure contributes to pump longevity is unknown and merits further investigation.

National Trends in Heart Donor Usage Rates: Are We Efficiently Transplanting More Hearts?

Background

It is unclear whether the recent increase in the number of heart transplants performed annually in the United States is only because of higher availability of donors and if it affected recipients’ survival.

Methods and Results

We examined characteristics of donors and recipients from 2008 to 2012 (n=11 654) and 2013 to 2017 (n=14 556) and compared them with 2003 to 2007 (n=10 869). Cox models examined 30‐day and 1‐year risk of recipients’ death post transplant. From 2013 to 2017, there was an increase in the number of transplanted hearts and number of donor offers but an overall decline in the ratio of hearts transplanted to available donors. Donors between 2013 and 2017 were older, heavier, more hypertensive, diabetic, and likely to have abused illicit drugs compared with previous years. Drug overdose and hepatitis C positive donors were additional contributors to donor risk in recent years. In Cox models, risk of death post transplant between 2013 and 2017 was 15% lower at 30 days (hazard ratio [HR] 0.85; 95% CI, 0.74–0.98) and 21% lower at 1 year (HR, 0.79; 95% CI, 0.73–0.87) and between 2008 and 2012 was 9% lower at 30 days (HR, 0.91; 95% CI, 0.79–1.05) and 14% lower at 1 year (HR, 0.86; 95% CI, 0.79–0.94) compared with 2003 to 2007.

Conclusions

Despite a substantial increase in heart donor offers in recent years, the ratio of transplants performed to available donors has decreased. Even though hearts from donors who are older, more hypertensive, and have diabetes mellitus are being used, overall recipient survival continues to improve. Broader acceptance of drug overdose and hepatitis C positive donors may increase the number and percentage of heart transplants further without jeopardizing short‐term outcomes.

Clinical effectiveness of therapy with continuous-flow left ventricular assist devices in nonischemic versus ischemic cardiomyopathy: a systematic review and meta-analysis

Background

Clinicians may be less inclined to consider long-term left ventricular assist device (LVAD) therapy in end-stage heart failure (ESHF) as a result of non-ischemic cardiomyopathy (NICM) versus ischemic cardiomyopathy (ICM) owing to potentially greater right ventricular involvement in the former; however, it is unknown whether the cause of heart failure has a clinically meaningful effect on outcomes following LVAD implantation. In this systematic review, we aimed to determine whether ischemic versus nonischemic etiology has any impact on patient-relevant outcomes.

Methods

We searched MEDLINE, Embase, PubMed and the Cochrane Library for studies published in English between Jan. 1, 2000, and Nov. 22, 2018, that examined survival and transplantation rates following LVAD implantation in patients with NICM or ICM. Randomized clinical trials, cohort studies, case–control studies, cross-sectional studies and case series with a sample size of at least 8 patients were eligible for inclusion. To be included in the meta-analysis, outcomes had to include at least death reported at 30 days or 1 year after LVAD implantation. Quality of included studies was assessed by 2 independent reviewers using the Newcastle–Ottawa Quality Assessment Scale for Cohort Studies. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) quality-assessment tool was used to assess outcomes (30-d survival, 1-yr survival and cardiac transplantation following LVAD therapy) across studies.

Results

From a total of 2843 citations identified, 7 studies met all inclusion criteria. Studies were generally of good quality, but reporting of patient demographic characteristics, outcomes and complications was heterogeneous. We found no significant difference in 30-day or 1-year survival or in cardiac transplantation rates after device implantation between the NICM and ICM groups. Patients in the 2 groups had similar outcomes up to 1 year with LVAD therapy.

Conclusion

Early outcomes of LVAD therapy do not appear to be affected by heart failure etiology. Ongoing investigation is required to determine the long-term outcomes of LVAD therapy in ICM and NICM.

Systematic review registration: PROSPERO register, record ID 76483.

CARDIAC TRANSPLANT -A SINGLE CENTRE RETROSPECTIVE OBSERVATION

Background and Aim: Advances in pharmacological and nonpharmacological management of heart failure shifted the paradigm to transplantation of heart. Currently so many centers are doing heart transplant as the availability of donors and recipients are increasing day by day. The goal of this study is to share our experience in all our heart transplantation procedures. Ours is a tertiary care government multi super Speciality hospital. In our institute we have been doing cardiac surgeries for six years and heart transplants for past three years. In this discussion we share our experience about how we did all the procedures in our center . Method: After getting approval from institutional research committee we analyzed 8 transplants done in our center. The preoperative optimization, monitoring tools, anesthetic technique and post-operative complications and management are discussed . Apart from routine monitors we have used BIS, Cerebral oximetry and cardiac output monitors. Result: Of the eight cases, six are doing well including a (pediatric) 10-year-old recipient. Of the remaining two, one patient died on 3rd Post-Operative Day due to acute kidney injury and the other was death due to acute rejection. Conclusion: The key points we have learnt from our experience are careful selection and preparation of the donor, adequate preload with optimal inotropic support during weaning, minimizing increase in pulmonary vascular resistance and good pain relief are key aspects for successful outcome.

Cardiac allograft rejection in the current era of continuous flow left ventricular assist devices

OBJECTIVE

Left ventricular assist device (LVAD) implantation has been shown to increase allosensitization before orthotopic heart transplantation, but the influence of LVAD support on posttransplant rejection is controversial. This study examines the postoperative incidence of acute cellular rejection (ACR) in patients bridged with continuous flow LVAD (CF-LVAD) relative to primary transplant (Primary Tx).

METHODS

All patients who underwent orthotopic heart transplantation at our institution between July 2006 and March 2019 were retrospectively reviewed (n = 395). Patients were classified into Primary Tx (n = 145) and CF-LVAD (n = 207) groups. Propensity score matching on 13 covariates implemented a 0.1 caliper logistic model with nearest neighbor 1:1 matching. Development of moderate to severe (ie, 2R/3R) rejection was evaluated using a competing risks model. Potential predictors of 2R/3R ACR were evaluated using Fine-Gray regression on the marginal subdistribution hazard.

RESULTS

Propensity score matching yielded 122 patients in each group (n = 244). At 12 and 24 months, the cumulative incidence of 2R/3R ACR was 17% and 23% for the CF-LVAD group and 26% and 31%, respectively, for the Primary Tx group (P = .170). CF-LVAD was not predictive of 2R/3R rejection on multivariable Fine-Gray regression (subdistribution hazard ratio, 0.73; 95% confidence interval, 0.40-1.33; P = .301). There was no difference in the 5-year incidence of antibody mediated rejection (10% [n = 12] vs 9% [n = 11]; P = .827).

CONCLUSIONS

After adjusting for covariates, CF-LVAD was not associated with an increased risk of moderate to severe ACR during the 24 months after cardiac transplantation. Further investigation is warranted with larger cohorts, but CF-LVAD may have minimal influence on posttransplant ACR.

The Impact of Left Ventricular Assist Device Infections on Postcardiac Transplant Outcomes: A Systematic Review and Meta-Analysis

Left ventricular assist devices (LVADs) are associated with numerous short- and long-term complications, including infection. The impact LVAD infections have on clinical outcomes after transplantation is not well established. We sought to determine whether the presence of infection while on LVAD support negatively influences outcomes after cardiac transplantation. We searched electronic databases and bibliographies for full text studies that identified LVAD infections during support and also reported on posttransplant outcomes. A meta-analysis of posttransplant survival was conducted using a random effects model. Of 2,373 records, 13 bridge to transplant (BTT) cohort studies were selected (n = 6,631, 82% male, mean age 50.7 ± 2.7 years). A total of 6,067 records (91.5%) received transplant. There were 3,718 (56.1%) continuous-flow LVADs (CF-LVADs), 1,752 (26.4%) pulsatile LVADs, and 1,161 (17.5%) unknown type records. A total of 2,586 records (39.0%) developed LVAD infections. Patients with LVAD infections were younger (50.5 ± 1.5 vs. 51.3 ± 1.5, p = 0.02), had higher body mass indeices (BMIs) (28.4 ± 0.7 vs. 26.8 ± 0.4, p < 0.01), and longer LVAD support times (347.0 ± 157.6 days vs. 180.2 ± 106.0 days, p < 0.01). Meta-analysis demonstrated increased posttransplant mortality in those patients who had an LVAD infection (hazard ratio [HR] 1.30, 95% CI: 1.16-1.46, p < 0.001). Subgroup meta-analyses by continuous-flow and pulsatile device type demonstrated significant increased risk of death for both types of devices (HR 1.47, 95% CI: 1.22-1.76, p < 0.001 and 1.71, 95% CI: 1.19-2.45, p = 0.004, respectively). Patients who develop LVAD infections are younger, have higher BMIs and longer LVAD support times. Our data suggests that LVAD-related infections result in a 30% increase in postcardiac transplantation mortality. Strategies to prevent LVAD infections should be implemented to improve posttransplant outcomes in this high-risk population.

In Full Flow: Left Ventricular Assist Device Infections in the Modern Era

With the rising prevalence of heart disease in the United States, there is increasing reliance on durable mechanical circulatory support (MCS) to treat patients with end-stage heart failure. Left ventricular assist devices (LVADs), the most common form of durable MCS, are implanted mechanical pumps that connect to an external power source through a transcutaneous driveline. First-generation LVADs were bulky, pulsatile pumps that were frequently complicated by infection. Second-generation LVADs have an improved design, though infection remains a common and serious complication due to the inherent nature of implanted MCS. Infections can affect any component of the LVAD, with driveline infections being the most common. LVAD infections carry significant morbidity and mortality for LVAD patients. Therefore, it is paramount for the multidisciplinary team of clinicians caring for these patients to be familiar with this complication. We review the epidemiology, prevention, diagnosis, treatment, and outcomes of LVAD infections.

Vasoplegia following heart transplantation and left ventricular assist device explant is not associated with inferior outcomes

Background

Vasoplegia has been associated with inferior outcomes following heart transplantation (HTx). This observational study was designed to investigate outcomes in recipients with vasoplegia following left ventricular assist device (LVAD) explant HTx.

Methods

Patients undergoing LVAD explant followed by HTx from 01/2013–12/2018 at our centre were included. Vasoplegia was defined as the requirement for high dose vasopressor [noradrenaline (>0.5 μg/kg/min) and vasopressin (>1 U/h)] over the first 24 hours following HTx. Demographic and outcome data were retrieved from the transplant unit database.

Results

During the study period 24 patients underwent LVAD explant HTx. Of these, 13 (54.2%) developed vasoplegia. Both groups had similar duration of LVAD support (median 684 vs. 620 days P=0.62). There was a higher incidence of driveline infection in patients developing vasoplegia (69.2% vs. 18.2% P=0.02). HTx following donation after circulatory death (DCD) occurred in 9 (37.5%) patients and was not associated with a higher incidence of vasoplegia (P=0.21). Vasoplegia developed early following reperfusion and intensive care unit admission vasopressor-inotrope scores were significantly higher in patients with vasoplegia (P=0.002). Patients developing vasoplegia had similar ICU (P=0.79) and hospital (P=0.93) lengths of stay. Survival was equivalent both at 30-day (92.3% vs. 100% P=0.99) and 1-year (67.7% vs. 74.7% P=0.70). Our overall HTx 1-year survival was 89.3% over this period.

Conclusions

Vasoplegia is seen with a high incidence in HTx recipients bridged with an LVAD. This appears to be associated with the presence of driveline infections. Early aggressive management is advocated, resulting in equivalent 1-year survival to those patients not developing vasoplegia.

Heart Transplantation After Ventricular Assist Device Therapy: Benefits, Risks, and Outcomes

Heart transplantation is an established treatment for end-stage heart failure. Due to the increase in demand and persistent scarcity of organ, mechanical circulatory devices have played a major role in therapy for advanced heart failure. Usage of left ventricular assist device (LVAD) has gone up from 6% in 2006 to 43% in 2013 as per the United Network of Organ Sharing database. Majority of patients presenting for a heart transplantation are often bridged with an assist device prior for management of heart failure while on wait-list. On one hand, it is well established that LVADs improve survival on wait-list; on the other hand, the effect of LVAD on morbidity and survival after a heart transplantation is still unclear. In this article, we review the available literature and attempt to infer the outcomes given the risks and benefits of heart transplantation with prior LVAD patients.

Effect of Blood Group on Heart Transplant Waitlist Mortality in the Ventricular Assist Device Era

The effect of blood group on heart transplant list mortality in the era of continuous flow left ventricular assist devices (VADs) is unknown. We sought to examine mortality from the United Network for Organ Sharing (UNOS) database, with focus on mortality among VAD versus non-VAD recipients according to blood group. The UNOS database from 2007 to 2015 was evaluated to compare the rates of waitlist mortality or delisting for clinical worsening at 1-year postlisting among various blood types based on the presence or absence of durable continuous VAD. Patients with pulsatile VAD, temporary VAD, or with incomplete data were excluded. A total of 16,803 patients met the inclusion criteria. Of these, 2,663 had a HeartMate II or HeartWare VAD implanted before listing or by 365th day of listing. The rate of adverse events on the waitlist, irrespective of VAD, was highest among group O patients (odds ratio [OR] 1.54, p < 0.001). The use of VAD was associated with significant relative risk reduction (OR 0.43, p < 0.001) in waitlist adverse events among all patients, with relative risk reduction that overall did not vary by blood group. Among VAD recipients, waitlist adverse events were similar across all blood types. Among listed patients, there is a significantly higher adverse event rate in group O patients compared with others, irrespective of VAD use. With implantation of continuous flow HeartMate II or HeartWare VAD, all blood groups experience similar relative benefit and similar rates of adverse events. All patients, but particularly those with blood group O, eligible for VAD as a bridge to transplant should be considered for VAD placement.

Outcomes of patients with infection related to a ventricular assist device after heart transplantation

BACKGROUND

Despite significant advances in durable mechanical support survival, infectious complications remain the most common adverse event after ventricular assist device (VAD) implantation and the leading cause of early death after transplantation. In this study, we aim to describe our local infectious epidemiology and review short-term survival and infectious incidence rates in the post-transplantation period and assess risk factors for infectious episodes after transplantation.

METHODS

Retrospective single-center study of all consecutive adult heart transplant patients from 2008 to 2017. Survival data were estimated and summarized using the Kaplan-Meier method. We quantified and evaluated the difference in the incidence rate between patients with and without infection using a Fine-Gray model. The outcome of interest is the time to first infection diagnosis with post-transplant death as the competing event.

RESULTS

Among 278 heart transplant patients, 74 (26.5%) underwent LVAD implantation. Twenty-one patients (28.3%) developed an infection while supported by an LVAD. When compared to patients supported by an LVAD without a preceding infection, BMI was significantly greater (31.2 vs 27.8 kg/m² , P = .03). Median follow-up post-transplantation was 3.01 years. Significant risk factors for the competing risk regression for infection after heart transplantation include LVAD infection (HR 1.94, [95% CI] 1.11-3.39, P = .020) and recipient COPD (HR 2.14, [95% CI] 1.39-3.32, P = .001) when adjusted for recipient age, gender, hypertension, diabetes mellitus, and body mass index.

CONCLUSIONS

Patients with LVAD-related infection had a significantly increased risk of infectious complications after heart transplantation. Further research on the avoidance of induction agents and reduced maintenance immunosuppression in this patient population is warranted.

Impact of Bridge to Transplantation With Continuous-Flow Left Ventricular Assist Devices on Posttransplantation Mortality

BACKGROUND

Bridge to transplantation (BTT) with left ventricular assist devices (LVADs) is a mainstay of therapy for heart failure in patients awaiting heart transplantation (HT). Criteria for HT listing do not differ between patients medically managed and those mechanically bridged to HT. The objectives of the present study were to evaluate the impact of BTT with LVAD on posttransplantation survival, to describe differences in causes of 1-year mortality in medically and mechanically bridged patients, and to evaluate differences in risk factors for 1-year mortality between those with and those without LVAD at the time of HT.

METHODS

Using the United Network of Organ Sharing database, we identified 5486 adult, single-organ HT recipients transplanted between 2008 and 2015. Patients were propensity matched for likelihood of LVAD at the time of HT. Kaplan-Meier survival estimates were used to assess the impact of BTT on 1- and 5-year mortality. Logistic regression analysis was used to evaluate the odds ratio of 1-year mortality for patients BTT with LVAD compared with those with medical management across clinically significant variables at various thresholds.

RESULTS

Early mortality was higher in mechanically bridged patients: 9.5% versus 7.2% mortality at 1 year (P<0.001). BTT patients incurred an increased risk of 1-year mortality with an estimated glomerular filtration rate of 40 to 60 mL·min^-1·1.73 m^-2 (odds ratio, 1.69; P=0.003) and <40 mL·min^-1·1.73 m^-2 (odds ratio, 2.16; P=0.005). A similar trend was seen in patients with a body mass index of 25 to 30 kg/m² (odds ratio, 1.88; P=0.024) and >30 kg/m² (odds ratio, 2.11; P<0.001). When patients were stratified by BTT status and the presence of risk factors, including age >60 years, estimated glomerular filtration rate <40 mL·min^-1·1.73 m^-2, and body mass index >30 kg/m², there were significant differences in 1-year mortality between medium- and high-risk medically and mechanically bridged patients, with 1-year mortality in high-risk BTT patients at 17.6% compared with 10.4% in high-risk medically managed patients.

CONCLUSIONS

Bridge to HT with LVAD, although necessary because of organ scarcity and capable of improving wait list survival, confers a significantly higher risk of early posttransplantation mortality. Patients bridged with mechanical support may require more careful consideration for transplant eligibility after LVAD placement.

A Systematic Review of Cost-Effectiveness Analyses of Left Ventricular Assist Devices: Issues and Challenges

BACKGROUND

Advanced heart failure (HF) can be treated conservatively or aggressively, with left ventricular assist devices (LVADs) and heart transplant (HT) being the most aggressive strategies.

OBJECTIVE

The goal of this review was to identify, describe, critique and summarize published cost-effectiveness analyses on LVADs for adults with HF.

METHODS

We conducted a literature search using PubMed and ProQuest DIALOG databases to identify English-language publications from 2006 to 2017 describing cost-effectiveness analyses of LVADs and reviewed them against inclusion criteria. Those that met criteria were obtained for full-text review and abstracted if they continued to meet study requirements.

RESULTS

A total of 12 cost-effectiveness studies (13 articles) were identified, all of which described models; they were almost evenly split between those examining LVADs as destination therapy (DT) or as bridge to transplant (BTT). Studies were Markov or semi-Markov models with one- or three-month cycles that followed patients until death. Inputs came from a variety of sources, with the REMATCH trial and INTERMACS registry common clinical data sources, although some publications also used data from studies at their own institutions. Costs were derived from standard sources in many studies but from individual hospital data in some. Inputs for health utilities, which were used in 11 of 12 studies, were generally derived from two studies. None of the studies reported a societal perspective, that is, included non-medical costs such as caregiving.

CONCLUSIONS

No study found LVADs to be cost effective for DT or BTT with base case assumptions, although incremental cost-effectiveness ratios met thresholds for cost effectiveness in some probabilistic analyses. With constant improvements in LVADs and expanding indications, understanding and re-evaluating the cost effectiveness of their use will be critical to making treatment decisions.

It keeps on turning: Effects of prolonged long-term left ventricular assist device support as a bridge to heart transplantation

OBJECTIVES:

Increasing incidence of end-stage heart failure has moved the therapy with left ventricular assist devices to the forefront of surgical treatment. Moreover, continuous sophistication in this technology has resulted in increasing proportion of patients on prolonged support. Early and late complications after left ventricular assist device as a bridge to transplantation and present factors associated with long-term support and long-term outcomes of patients supported for at least 1 year were compared.

METHODS:

A total of 163 consecutive patients who underwent left ventricular assist device implantation as bridge to transplantation were included. A total of 79 patients were supported for at least 1 year (long-term support), whereas 84 patients were supported for less than 1 year (short-term group).

RESULTS:

Factors associated with a successful long-term support were male gender (p < 0.001), cessation of smoking at least 6 months prior to surgery (p = 0.045), previous implantation of implantable cardioverter defibrillator (p = 0.001) and rapid postoperative extubation (p = 0.018). Regarding echocardiographic parameters, higher left ventricular mass (p = 0.013) and larger left ventricular-end systolic (p = 0.008) and diastolic (p = 0.005) diameters prior to left ventricular assist device implantation were associated with long-term support. Short-term group showed higher mortality and higher proportion of patients who underwent device exchange due to device failure, and left ventricular assist device explantation for myocardial recovery was less frequent in the long-term support (p < 0.001). In addition, patients from the long-term support had significantly higher incidence of higher-grade aortic regurgitation (p = 0.005).

CONCLUSION:

Prolonged left ventricular assist device support as bridge to transplantation is associated with lower mortality and lower incidence of device failure requiring device exchange. However, long-term support reduces the chance of device explantation for myocardial recovery and increases the incidence of higher-grade aortic regurgitation in the follow-up.

The impact of infection among left ventricular assist device recipients on post-transplantation outcomes: A retrospective review

INTRODUCTION

Left ventricular assist device (LVAD) infections are common, and the consequences of LVAD infections on orthotopic heart transplantation (OHT) outcomes are not well described.

AIMS

The aim of this study was to describe clinical characteristics and evaluate risk factors for developing LVAD infections, and examine outcomes of LVAD-specific infections (VSI) after OHT.

METHODS

We retrospectively investigated the records of 74 consecutive patients at two institutions who had undergone LVAD placement and subsequent OHT between January 2007 and December 2012.

RESULTS

Forty-six of 74 (62%) LVAD recipients who underwent OHT had pre-transplant infections, and 18 (24%) had LVAD-specific infection (VSI), of which 71% were caused by gram-negative organisms. Of pre-transplant non-LVAD infections, Clostridium difficile infection (CDI) was the most common (26%) followed by urinary tract infection (UTI, 16%) and pneumonia (PNA 15%). Univariate analysis comparing subjects with VSI to those without VSI showed a significant association with time spent outside the hospital prior to transplantation (median 231.8 days vs 142.2 days, P < 0.03) and total time between VAD placement and OHT (244.0 days and 150.5 days, P < 0.002). Logistic regression was performed and significant predictors for VAD-related infection were age and the presence of diabetes, with type of device as an effect modifier. Six months post-OHT survival was not significantly affected by the presence of VSI prior to transplant. There was a trend toward an association between the presence of any infection and post-transplant rejection (P < 0.09). There were 10 post-transplant deaths by 6 months. Of these deaths, 4/10 (40%) were cardiopulmonary and 6/10 (60%) were related to infections.

CONCLUSIONS

Advanced age and presence of diabetes were predictors of VSI, as well as type of VAD device, although device choice is likely affected by many clinical factors including age and comorbidities, as well as institution-specific preferences. VSI was not associated with a decrease in 6-month post-OHT survival. However, infections remain the major causes of death by 6 months post-transplant. Certain infections are associated with an increased risk of rejection, which merits further investigation.

Mechanical circulatory support as bridge therapy for heart transplant: case series report

BACKGROUND

Mechanical circulatory support (MCS) represents an effective urgent therapy for patients with cardiac arrest or end-stage cardiac failure. However, its use in developing countries as a bridge therapy remains controversial due to costs and limited duration. This study presents five patients who underwent MSC as bridge therapy for heart transplantation in a developing country.

CASE PRESENTATION

We present five patients who underwent MCS as bridge therapy for heart transplant between 2010 and 2015 at Fundación Cardioinfantil-Instituto de Cardiología. Four were male, median age was 36 (23-50) years. One patient had an ischemic cardiomyopathy, one a lymphocytic myocarditis, two had electrical storms (recurrent ventricular tachycardia) and one an ischemic cardiomyopathy with an electrical storm. Extracorporeal life support (ECLS) was used in three patients, left ventricular assistance in one, and double ventricular assistance in one (Levitronix^® Centrimag^®). Median assistance time was 8 (2.5-13) days. Due to the inability of cardiopulmonary bypass weaning, two patients required ECLS after transplant. One patient died in the intensive care unit due to type I graft rejection. Endpoints assessed were 30-day mortality, duration of bridge therapy and complications related to MCS. Patients that died on ECLS, or were successfully weaned off ECLS were not included in this study.

CONCLUSIONS

MCS is often the only option of support for critically ill patients waiting for a heart transplant and could be considered as a short-term bridge therapy.

Adverse Effects of Delayed Transplant Listing Among Patients With Implantable Left Ventricular Assist Devices

BACKGROUND

The timing of transplant listing after implantation of a left ventricular assist device (LVAD) remains uncertain, given high device complication rates and apparent stability of some LVAD-supported patients. This investigation quantifies the effect of delayed transplant listing and transplantation rates on medium-term survival and LVAD complications.

METHODS AND RESULTS

A Markov model was used to simulate the effects of delaying initial transplant listing after LVAD implantation. Modeled parameters were derived from the Standard Transplant Analysis and Research file. When transplant listing was delayed and 5-year results were examined, fewer persons underwent transplantation (53% in base model vs 51% in 180-day-delay model) and the fraction of deaths while waiting increased (17% in base model vs 21% in 180-day delay model). Life expectancy changed minimally from the base model (3.50 y) when initial listing was delayed by 180 days (3.51 y).

CONCLUSIONS

Delaying initial transplant listing increased the likelihood of death while waiting for a transplant and decreased the likelihood of transplantation. In aggregate, life expectancy was unchanged by delays in listing. This study suggests that delaying transplant listing with the expectation of providing additional life expectancy is not likely with current LVAD technology.

Pulmonary Arterial Compliance Improves Rapidly After Left Ventricular Assist Device Implantation

Pulmonary artery compliance (PAC) contributes to right ventricular (RV) afterload, is decreased in the setting of increased left ventricular (LV) filling pressures, and may be an important component of World Health Organization (WHO) group II pulmonary hypertension (PH). Left ventricular assist device (LVAD) implantation can rapidly change LV filling, but its relationship with PAC is unknown. Right heart catheterization was performed preoperatively, postoperatively (between 48 and 72 hours), and >30 days post-LVAD implantation in a cohort of 64 patients with end-stage systolic heart failure. Within 72 hours, LVAD implantation was associated with an increase in PAC (2.0-3.7 ml/mm Hg, p < 0.0001), a decrease in pulmonary vascular resistance (3.5-1.7 Wood units, p < 0.0001). Pulmonary arterial compliance did not increase further at the >30 post-LVAD time point (3.7 ± 1.7 to 3.6 ± 0.44 ml/mm Hg, p = 0.44). Pulmonary artery compliance improves rapidly after LVAD implantation. This suggests that more permanent changes in the pulmonary vascular bed may not be responsible for the abnormal PAC observed in WHO group II PH.

Use of Durable Continuous-Flow Ventricular Assist Devices in Patients on Immunosuppression

Durable ventricular assist device (VAD) therapy remains an important treatment for end-stage heart failure. Despite advancements in device design, postimplant infectious complications continue to plague this population. In this study, we aim to evaluate the use of durable VAD therapy in patients on active immunosuppression. All patients undergoing durable, continuous-flow VAD placement on active immunosuppression at our center from 2004 to 2012 were included in the analysis (group immunosuppressed [IS]; n = 13). Demographic data, comorbidities, device details, immunosuppression details including indication, postimplant infections, and outcomes were collected and compared with patients without immunosuppression (group non-IS; n = 259). Mean age in the IS group was 56.3 ± 12.4 years, and 12 patients (92.3%) were male. Twelve patients (92.3%) were implanted as a bridge to transplant. Incidence of any postimplant infection and device-related infection was 1.15 infections/patient × year and 0.38 infections/patient × year, respectively. Survival to discharge was 84.6% and 93.1% (p = 0.25), and 1 year survival was 75.0% and 83.1% (p = 0.47) in the IS and non-IS group, respectively. Mean duration of support was 384 ± 466 days, and mean follow-up was 2.1 ± 1.5 years. Active immunosuppression may lead to a modest increase in postimplant infection rate in durable VAD patients than in non-IS patients undergoing the same treatment; however, late on-device survival is not affected. Immunosuppression should not be considered an absolute contraindication to device implant.

Anesthesia for Heart Transplantation

This article seeks to evaluate current practices in heart transplantation. The goals of this article were to review current practices for heart transplantation and its anesthesia management. The article reviews current demographics and discusses the current criteria for candidacy for heart transplantation. The process for donor and receipt selection is reviewed. This is followed by a review of mechanical circulatory support devices as they pertain to heart transplantation. The preanesthesia and intraoperative considerations are also discussed. Finally, management after transplantation is also reviewed.

Impact of Socioeconomic Status on Patients Supported With a Left Ventricular Assist Device: An Analysis of the UNOS Database (United Network for Organ Sharing)

BACKGROUND

Low socioeconomic status (SES) is a known risk factor for heart failure, mortality among those with heart failure, and poor post heart transplant (HT) outcomes. This study sought to determine whether SES is associated with decreased waitlist survival while on left ventricular assist device (LVADs) support and after HT.

METHODS AND RESULTS

A total of 3361 adult patients bridged to primary HT with an LVAD between May 2004 and April 2014 were identified in the UNOS database (United Network for Organ Sharing). SES was measured using the Agency for Healthcare Research and Quality SES index using data from the 2014 American Community Survey. In the study cohort, SES did not have an association with the combined end point of death or delisting on LVAD support (P=0.30). In a cause-specific unadjusted model, those in the top (hazard ratio, 1.55; 95% confidence interval, 1.14-2.11; P=0.005) and second greatest SES quartile (hazard ratio 1.50; 95% confidence interval, 1.10-2.04; P=0.01) had an increased risk of death on device support compared with the lowest SES quartile. Adjusting for clinical risk factors mitigated the increased risk. There was no association between SES and complications. Post-HT survival, both crude and adjusted, was decreased for patients in the lowest quartile of SES index compared with all other SES quartiles.

CONCLUSIONS

Freedom from waitlist death or delisting was not affected by SES. Patients with a higher SES had an increased unadjusted risk of waitlist mortality during LVAD support, which was mitigated by adjusting for increased comorbid conditions. Low SES was associated with worse post-HT outcomes. Further study is needed to confirm and understand a differential effect of SES on post-transplant outcomes that was not seen during LVAD support before HT.

Optimal timing of same-admission orthotopic heart transplantation after left ventricular assist device implantation

AIM

To investigate the impact of timing of same-admission orthotopic heart transplant (OHT) after left ventricular assist device (LVAD) implantation on in-hospital mortality and post-transplant length of stay.

METHODS

Using data from the Nationwide Inpatient Sample from 1998 to 2011, we identified patients 18 years of age or older who underwent implantation of a LVAD and for whom the procedure date was available. We calculated in-hospital mortality for those patients who underwent OHT during the same admission as a function of time from LVAD to OHT, adjusting for age, sex, race, household income, and number of comorbid diagnoses. Finally, we analyzed the effect of time to OHT after LVAD implantation on the length of hospital stay post-transplant.

RESULTS

Two thousand and two hundred patients underwent implantation of a LVAD in this cohort. One hundred and sixty-four (7.5%) patients also underwent OHT during the same admission, which occurred on average 32 d (IQR 7.75-66 d) after LVAD implantation. Of patients who underwent OHT, patients who underwent transplantation within 7 d of LVAD implantation (“early”) experienced increased in-hospital mortality (26.8% vs 12.2%, P = 0.0483) compared to patients who underwent transplant after 8 d (“late”). There was no statistically significant difference in age, sex, race, household income, or number of comorbid diagnoses between the early and late groups. Post-transplant length of stay after LVAD implantation was also not significantly different between patients who underwent early vs late OHT.

CONCLUSION

In this cohort of patients who received LVADs, the rate of in-hospital mortality after OHT was lower for patients who underwent late OHT (at least 8 d after LVAD implantation) compared to patients who underwent early OHT. Delayed timing of OHT after LVAD implantation did not correlate with longer hospital stays post-transplant.

Effect of Pretransplant Continuous-Flow Left Ventricular Assist Devices on Cellular and Antibody-Mediated Rejection and Subsequent Allograft Outcomes

The aim of this study was to evaluate the impact of continuous-flow left ventricular assist devices (CF-LVAD) on subsequent rejection after heart transplantation (HT) by using cellular rejection score and antibody-mediated rejection score (AMRS) and correlating with subsequent allograft outcomes. We retrospectively analyzed 108 consecutive patients who underwent HT without (n = 67) or with (n = 41) previous CF-LVAD in 2008 to 2014. The 24 months cumulative effect of rejection was calculated by using cellular rejection scores and AMRS, based on the total number of rejections divided by valid biopsy samples. Vasculopathy was assessed both by routine coronary angiogram and intravascular ultrasound. Patients who underwent pretransplant CF-LVAD demonstrated a significant increase in the number of cellular rejection episodes as compared with the nonbridged patients, for 1 and 2 years of follow-up (p = 0.026 and p = 0.016), respectively. There were no differences in AMRS (p >0.05) and allograft outcomes, such as vasculopathy and overall survival (p >0.05) over the period of follow-up. Implantation of a CF-LVAD before HT impacts cellular rejection during the post-transplant period. Despite these findings, CF-LVAD does not translate to differences in allograft outcomes after transplant, such as vasculopathy and overall survival over the period of the study. In conclusion, whether this affects longer term outcomes than studied remains to be determined.