Impact of long term left ventricular assist device therapy on donor allocation in cardiac transplantation

Comparison of Intraoperative Blood Product Use During Heart Transplantation in Patients Bridged with Impella 5.5 versus Durable Left Ventricular Assist Devices

OBJECTIVE

To determine if the intraoperative transfusion requirements differ based on the mechanical circulatory device used as a bridge to heart transplantation.

DESIGN

A single-center retrospective analysis of intraoperative transfusion requirements in all patients undergoing heart or heart/kidney transplantation between November 2018 and July 2021 who were bridged with a temporary (Impella 5.5) or durable left ventricular assist device (LVAD).

SETTING

A tertiary care hospital.

PARTICIPANTS

Forty-three adult patients bridged to heart or heart/kidney transplantation with a temporary or durable LVAD between 2018 and 2021 INTERVENTIONS: Recording of baseline characteristics and intraoperative transfusion requirements, including packed red blood cells, fresh frozen plasma, cryoprecipitate, autologous blood salvage, and platelets. The difference in cardiopulmonary bypass times, intensive care unit length of stay, and the vasoactive inotrope score following transplantation were also recorded.

MEASUREMENTS AND MAIN RESULTS

The primary outcome was the volume of blood products transfused intraoperatively. Patients who underwent bridge to transplantation using the Impella 5.5 had statistically significant lower median transfusions of cryoprecipitate (155 mL versus 200 mL, p = 0.015), autologous blood salvage (675 mL versus 1,125 mL, p ≤ 0.01), and platelets (412 mL versus 675 mL, p ≤ 0.01). Additionally, there was a trend toward lower transfusion of intraoperative packed red blood cells (4.5 units versus 6.5 units, p = 0.29) and fresh frozen plasma (675 mL versus 800 mL, p = 0.11), but these were not statistically significant.

CONCLUSIONS

The results suggest a reduction in certain intraoperative transfusion requirements in patients undergoing heart transplantation bridged with the Impella 5.5 versus durable left ventricular assist device.

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.

Seasonal trends in donor heart availability: an analysis of the UNOS database

Despite the widespread belief that donor organ availability varies around holidays and seasons, there is little empirical data supporting this long-held belief. Variations in donor heart availability may be of interest to patients and clinicians. The UNOS/OPTN registry was queried for all heart donations from October 1987 through March 2017. Daily heart donation rates were modeled nationally using Poisson regression including splines for year and day of the year. Seasonality was assessed using a likelihood ratio test for the spine terms for day of the year. The holiday effect was assessed using conditional logistic regression. Seasonal plots suggest a significant, although modest, increase in organ availability during the summer months, except for region 1. The regions with the highest amplitude were region 7 (peak: June 21, amplitude: 16.63%) and region 6 (peak: July 5, amplitude: 11.29%). There was no significant difference in the odds of heart donation when comparing holidays vs. non-holidays using national data (odds ratio [95% CI]: 1.01 [0.98, 1.03], P = 0.560) or any regional subsets. There was no observable correlation between donor heart availability and holidays. However, a significant seasonality effect was observed with higher donation rates occurring during warmer months.

A mortality risk score for heart transplants after contemporary ventricular assist device bridging

BACKGROUND

We sought to derive a risk score for 1-year mortality following orthotopic heart transplantation (OHT) in patients bridged with a contemporary centrifugal left ventricular assist device (LVAD).

METHODS

Adult patients (≥18 years) in the United Network for Organ Sharing database undergoing OHT between 2010 and 2019 who were bridged with a HeartWare or HeartMate III device were included. Derivation and validation cohorts were randomly assigned with a 2:1 ratio. Threshold analysis and multivariable logistic regression were utilized to obtain adjusted odds ratios for 1-year post-OHT mortality. A risk score was generated using these adjusted odds ratios in the derivation cohort and the predictive performance of the composite index was evaluated in the validation set.

RESULTS

A total of 3434 patients were identified. In the derivation cohort, the mean age was 53.5 ± 12.1 years and 1758 (76.8%) were male; 1789 (78.1%) were bridged with a HeartWare device. Multivariable logistic regression revealed that recipient age ≥50 years, bilirubin level ≥2.4 mg/dl, ischemic time ≥4 h, and preoperative hemodialysis predicted 1-year post-transplant mortality. Stratification into risk groups in the validation cohort revealed significant differences in postoperative renal failure, stroke, and short-term mortality. One-year post-transplant mortality was 5%, 6.7%, and 14.8% in the low-, moderate-, and high-risk categories, respectively (p < .001).

CONCLUSIONS

Among patients bridged to OHT with newer generation centrifugal LVADs, older age, increasing bilirubin, longer ischemic time, and pre-OHT dialysis independently predicted post-transplant mortality. The composite risk score based on these factors may assist in patient selection and prognostication in those supported with contemporary LVADs.

Renal Function in Patients with or without a Left Ventricular Assist Device Implant During Listing for a Heart Transplant

Background

Left ventricular assist device (LVAD) implantation may improve kidney function, but in patients awaiting heart transplantation, the long-term effects of LVAD implantation on renal function and subsequent clinical outcome are unclear.

Material/Methods

We analyzed data in patients with LVAD implants (n=139) and without LVAD implants (n=1038) who were listed for a heart transplant at our institution between 2000 and 2019. The primary endpoint was an impairment in renal function (decrease of creatinine-based estimated glomerular filtration rate [eGFR] by ≥30%) up to a maximum of 2 years after listing. Secondary endpoints were chronic kidney disease stage 4 or 5, heart transplantation, survival during listing, and 1-year survival after transplantation.

Results

Values for eGFR increased after LVAD implantation (P=0.001) and were higher at the time of waitlisting in the LVAD group than in the non-LVAD group (P=0.002), but were similar between groups at the end of waitlisting (P=0.75). Two-year freedom from renal impairment was 50.6% and 66.7% in the LVAD and non-LVAD groups, respectively, with a multivariable-adjusted hazard ratio for the LVAD versus the non-LVAD group of 1.78 (95% confidence interval 1.19–2.68; P=0.005). Two-year freedom from chronic kidney disease stages 4–5 was similar between study groups (LVAD group: 83.5%; non-LVAD group: 80.1%; =0.50). The 2-year probability of transplantation was slightly lower in the LVAD group than in the non-LVAD group (50.0% and 55.8%, respectively, P=0.017). However, 2-year survival on the waiting list and 1-year survival after transplantation did not differ significantly between study groups (P-values >0.20).

Conclusions

Our data indicate a transient improvement in creatinine-based eGFR values by LVAD implantation without influencing survival.

Ventricular assist devices and middle age reduce heart transplantation rates for waitlist candidates

BACKGROUND

Ventricular assist devices (VADs) are commonly employed as a bridge to transplantation for heart failure. The full effects of VADs on transplantation rates are not fully understood. We sought to compare transplantation rates stratified by age and VAD status.

METHODS

Using the Organ Procurement and Transplantation Network (OPTN) database, we investigated the impact of age and VAD status on heart allocation rates among all transplant-eligible patients from January 2005 to September 2018. Patients were grouped based on the presence (+) or absence (-) of a VAD as well as age (<45, 45-65, and >65 years). Demographics were compared with a multivariate competing risk analysis that yielded risk-adjusted subdistribution hazard ratios (SHR).

RESULTS

Among the 50 602 total waitlist candidates, 18 271 patients with a VAD had higher rates of diabetes and cerebrovascular disease at waitlist entry. Multivariate analysis found statistically significant lower rates of transplantation for all (+)VAD groups compared with age-matched (-)VAD counterparts, with the 45- to 65-year-old (+)VAD group having the lowest transplantation rate (SHR = 0.62; P < .0005). Among (-)VAD patients, transplantation rates increased with increase in age.

CONCLUSIONS

There is a statistically significant reduced rate of transplantation for patients with a VAD compared with those without a VAD, with the lowest rate among those of ages 45 to 65 years with a VAD. The increasing prevalence of this demographic and the deprioritization of VADs in the new heart allocation criteria have the potential to further exacerbate this difference.

Left ventricular assist device is protective against cardiac transplant delisting for medical unsuitability

BACKGROUND

Left ventricular assist device (LVAD) related complications have the potential to disqualify patients for heart transplantation. We sought to determine whether LVAD support was associated with increased rates of delisting due to medical unsuitability or clinical deterioration.

METHODS

The analysis included adult candidates listed for first-time heart transplantation in the UNOS registry in the contemporary, continuous flow (CF)- LVAD era (2010-2016). The exposure variable was LVAD support on the waitlist. The primary outcome was time to delisting due to medical unsuitability or clinical deterioration. As cardiac transplantation and death represent competing risks in this study, a Fine-Gray cox regression analysis was performed.

RESULTS

Data on 16,913 patients listed for heart transplant were analyzed. During a median follow up of 150 days, 1206 (7.1%) patients died, 10,083 (60%) were transplanted, and 1224 (7.2%) were delisted due to medical unsuitability or clinical deterioration. Presence of a LVAD at listing was associated with a reduced rate (hazard) of delisting both in the adjusted and unadjusted models (unadjusted HR 0.63, 95% CI 0.55-0.73, adjusted HR 0.78, 95% CI 0.67-0.90). Delayed LVAD while on the list was not associated with reduced rates of delisting (adjusted HR 0.91, 95% CI 0.79-1.1).

CONCLUSIONS

Continuous flow left ventricular assist device support was protective against delisting in this UNOS analysis. These data would suggest that despite the adverse event rate of mechanical support, improving cardiac output may be important to preserving the overall health of the potential cardiac transplant recipient.

Risk of severe primary graft dysfunction in patients bridged to heart transplantation with continuous-flow left ventricular assist devices

BACKGROUND

Primary graft dysfunction (PGD) remains a significant cause of post-transplant morbidity and mortality. The exact mechanism and risk factors for this phenomenon remain unknown in the contemporary era.

METHODS

In this study we reviewed adult patients undergoing heart transplantation (HT) at our institution between 2009 and 2017. Severe PGD was defined as the need for mechanical circulatory support (MCS) within the first 24 hours after HT. Multivariate logistic regression analysis was used to identify risk factors for severe PGD, focusing on those bridged to transplant (BTT) with a continuous-flow left ventricular assist device (CF-LVAD).

RESULTS

Fifty-six of 480 (11.7%) HT patients experienced severe PGD. Eighty percent of the severe PGD patients were BTT with a CF-LVAD (odds ratio [OR] 3.86, 95% confidence interval [CI] 1.94 to 7.68, p < 0.001). Among the BTT patients, significant associations between >1 year of CF-LVAD support (OR 2.48, 95% CI 1.14 to 5.40, p = 0.022), pre-HT creatinine (OR 3.35, 95% CI 1.42 to 7.92, p = 0.006), elevated central venous pressure/pulmonary capillary wedge pressure (CVP/PCWP) ratio (OR 3.32, 95% CI 1.04 to 10.60, p = 0.043), use of amiodarone before HT (OR 2.69, 95% CI 1.20 to 6.20, p = 0.022), and severe PGD were identified. RADIAL score did not accurately predict severe PGD in this contemporary cohort. Those patients who developed severe PGD had decreased 1-year post-transplant survival (78.3% vs 91.8%, p = 0.007).

CONCLUSIONS

Use of CF-LVAD as BTT is associated with an increased risk of severe PGD. Increased time on device support, renal dysfunction, right ventricular dysfunction as assessed by CVP/PCWP ratio, and pre-transplant amiodarone may identify those patients at high risk. Further research is warranted focusing on optimal timing of device implantation and transplantation, as well as the underlying mechanisms of PGD.

Outcomes in Patients With Hypertrophic Cardiomyopathy Awaiting Heart Transplantation

Background:

Current organ allocation policy and the rapid growth of mechanical support favor heart transplant (HT) candidates on left ventricular assist devices. HT candidates with hypertrophic cardiomyopathy (HCM) are usually not left ventricular assist device candidates and may have a disadvantage compared with dilated forms of cardiomyopathy.

Methods and Results:

Adult HT candidates registered in the Scientific Registry of Transplant Recipients database between 1999 and 2016 were included. HCM candidates were compared with ischemic cardiomyopathy (ICM) and non-ICM patients. Two eras were defined on the basis of the approval date of the first continuous-flow left ventricular assist device for bridge-to-transplant in the United States (2008). Patients outcomes were evaluated while on the waitlist and after HT. The proportion of patients with HCM listed for HT increased by 44% in era 2 compared with era 1. Waitlist mortality in patients with ICM (15.5%–8.7%) and non-ICM (14.2%–8.2%) declined across eras, but minimal decline was observed in HCM patients (11.7%–9.6%; P =0.06). In era 2, the 12-month rate of HT in HCM (64.8%) was comparable to that of ICM (60.9%) and non-ICM (62.7%) patients ( P =0.06). Post-transplant survival in HCM patients was the most favorable in the most recent era (1 year: 91.6% and 5 years: 82.5%; P <0.05 for all comparisons).

Conclusions:

The number of patients with HCM in need of HT is increasing. Although post-transplant survival in HCM is excellent, waitlist mortality is substantial and with minimal decline in the most recent era, despite the frequent use of listing status upgrade by exception in this patient cohort. Different strategies to improve the performance of the organ allocation system in patients with HCM are needed.

Prediction Model for Wait Times in Cardiac Transplantation

Wait times have increased for patients approved for heart transplants. We reviewed United Network for Organ Sharing (UNOS) data for 14,242 patients listed for isolated heart transplant (2009-2013) to develop a risk score model for timing left ventricular assist device (LVAD) implantation in bridge-to-transplant patients. We used a multivariable Cox proportional hazards regression model with subsequent bootstrap resampling for internal validation to develop a scoring system that combined risk factors, weighted by the corresponding regression coefficients, to define an individual's risk score. Four risk factors were identified (body mass index, blood type, region, and urgency status) to be significantly and independently associated with wait time (p < 0.001), showing adequate model discrimination (C = 0.704) and calibration. Higher risk scores correlated with shorter wait times. Our model corresponded closely with observed transplant rates, predicting longer wait times for lower status, larger size, certain blood groups, and some UNOS regions. This tool has the potential to more accurately describe the wait-time duration for an individual patient, which may influence care decisions. The wait-time discrepancies (blood types/regions) reinforce the need to reevaluate the geographic-allocation policy. The proposed review of the UNOS heart allocation policy may make this model especially relevant.

New role of ventricular assist devices as bridge to transplantation: European perspective

PURPOSE OF REVIEW

Progress of ventricular assist devices (VAD) technology led to improved survival and apparently low morbidity. However, from the European perspective, updated analysis of EUROMACS reveals a somewhat less impressive picture with respect to mortality and morbidity.

RECENT FINDINGS

We describe the great demand of cardiac allografts versus the lack of donors, which is larger in Europe than in the United States. Technical progress of VADs made it possible to work out a modern algorithm of bridge-to-transplant, which is tailored to the need of the particular patient. We analyze the burden of patients undergoing bridge-to-transplant therapy. They are condemned to an intermediate step, coupled with additional major surgery and potential adverse events during heart transplantation.

SUMMARY

Based on current registry data, we do have to question the increasingly popular opinion, that the concept of heart transplantation is futureless, which seems to be for someone who treats and compares both patients (VAD and heart transplantation) in daily practice, questionable. Up to now, left ventricular assist device therapy remains a bridge to a better future, which means a bridge to technical innovations or to overcome the dramatic lack of donors in Europe.

Long-term prognosis and cost-effectiveness of left ventricular assist device as bridge to transplantation: A systematic review

BACKGROUND

This systematic review aimed to evaluate the clinical outcomes and cost-effectiveness of left ventricular assist devices (LVADs) used as bridge to transplantation (BTT), compared to orthotopic heart transplantation (OHT) without a bridge.

METHOD

Systematic searches were performed in electronic databases with available data extracted from text and digitized figures. Meta-analysis of short and long-term term post-transplantation outcomes was performed with summation of cost-effectiveness analyses.

RESULTS

Twenty studies reported clinical outcomes of 4575 patients (1083 LVAD BTT and 3492 OHT). Five studies reported cost-effectiveness data on 837 patients (339 VAD BTT and 498 OHT). There was no difference in long-term post-transplantation survival (HR 1.24, 95% CI 1.00-1.54), acute rejection (HR 1.10, 95% CI 0.93-1.30), or chronic rejection and cardiac allograft vasculopathy (HR 0.99, 95% CI 0.73-1.36). No differences were found in 30-day post-operative mortality (OR 0.91, 95% CI 0.42-2.00), stroke (OR 1.64, 95% CI 0.43-6.27), renal failure (OR 1.43, 95% CI 0.58-3.54), bleeding (OR 1.56, 95% CI 0.78-3.13), or infection (OR 2.44, 95% CI 0.81-7.38). Three of the five studies demonstrated incremental cost-effectiveness ratios below the acceptable maximum threshold. The total cost of VAD BTT ranged from $316,078 to $1,025,500, and OHT ranged from $179,051 to $802,200.

CONCLUSION

LVADs used as BTT did not significantly alter post-transplantation long-term survival, rejection, and post-operative morbidity. LVAD BTT may be cost-effective, particularly in medium and high-risk patients with expected prolonged waiting times, renal dysfunction, and young patients.

Left ventricular assist device implantation strategies and outcomes

Over the past 15 years, the field of mechanical circulatory support has developed significantly. Currently, there are a multitude of options for both short and long term cardiac support. Choosing the appropriate device for each patient depends on the amount of support needed and the goals of care. This article focuses on long term, implantable devices for both bridge to transplantation and destination therapy indications. Implantation strategies, including the appropriate concomitant surgeries are discussed as well as expected long term outcomes. As device technology continues to improve, long term mechanical circulatory support may become a viable alternative to transplantation.

Left ventricular assist devices: current controversies and future directions

Advanced heart failure is a growing epidemic that leads to significant suffering and economic losses. The development of left ventricular assist devices (LVADs) has led to improved quality of life and long-term survival for patients diagnosed with this devastating condition. This review briefly summarizes the short history and clinical outcomes of LVADs and focuses on the current controversies and issues facing LVAD therapy. Finally, the future directions for the role of LVADs in the treatment of end-stage heart failure are discussed.

Kidney dysfunction and left ventricular assist device support: a comprehensive perioperative review

Left ventricular assist devices (LVADs) are used increasingly as a bridge to transplantation or as destination therapy in end-stage heart failure patients who do not respond to optimal medical therapy. Many of these patients have end-organ dysfunction, including advanced kidney dysfunction, before and after LVAD implantation. Kidney dysfunction is a marker of adverse outcomes, such as increased morbidity and mortality. This review discusses kidney dysfunction and associated management strategies during the dynamic perioperative time period of LVAD implantation. Furthermore, we suggest potential future research directions to better understand the complex relationship between renal pathophysiology and mechanical circulatory support.

The association of pretransplant HeartMate II left ventricular assist device placement and heart transplantation mortality

Previous United Network for Organ Sharing (UNOS) analysis has shown an increase in posttransplant mortality with pretransplant pulsatile-flow left ventricular assist device (LVAD). Recent studies evaluating continuous-flow LVAD demonstrated improved durability, excellent survival, and improved quality of life. This study investigates the association of preheart transplant continuous-flow LVAD placement and posttransplant mortality using the UNOS database. Heart transplant patients listed after April 2004 (N = 48,090) during the era of HeartMate (HM) II LVAD usage were investigated. Patients with UNOS 1A and 1B status with (n = 1,435) and without HMII (n = 16,379) placement before the heart transplantation were evaluated. Preliminary descriptive statistics suggested an extensive heterogeneity in patient characteristics between HMII LVAD recipients and nonrecipients. Propensity scores (1:2) were used to match HMII LVAD recipients and nonrecipients characteristics and donor characteristics. This resulted in a final sample of 2,265 patients (758 with HMII pretransplant placement and 1,507 without HMII pretransplant placement). The Kaplan-Meier curves were evaluated for the differences in postheart transplant mortality in patients with and without HMII pretransplant placement. A time-dependent Cox regression model was used to study the hazard ratios (HRs) for the association between HMII pretransplant placement and posttransplant survival. The mean age of the study group was 51.9 years old (standard deviation: 12.3). HeartMate II pretransplant placement was associated with no statistically significant difference in the risk of 30 days (HR = 1.23, 95% confidence interval [CI]: 0.79-1.95, p = 0.36) and 1 year posttransplant mortality (HR = 1.31, 95% CI: 0.85-2.01, p = 0.22) compared with non-HMII recipients. The use of HMII LVAD before heart transplantation, however, was associated with a statistically significant 64% lower risk (HR = 0.36, 95% CI: 0.16-0.77, p = 0.01) of mortality among heart transplant patients who survived beyond the first year of transplantation. Continuous-flow LVAD pretransplant placement is associated with improved long-term (>1 year) survival after heart transplantation.

Outcome of cardiac transplantation in patients requiring prolonged continuous-flow left ventricular assist device support

OBJECTIVE

This study assessed the early and late outcomes after cardiac transplantation in patients receiving long-term continuous-flow left ventricular assist device (CF-LVAD) support.

METHODS

Between April 2004 and September 2013, 192 patients underwent HeartMate II (Thoratec, Pleasanton, CA) CF-LVAD placement as a bridge to transplant at our center. Of these, 122 (63%) successfully bridged patients were retrospectively reviewed. Patients were stratified into 2 groups according to their waiting time with CF-LVAD support of <1 year or ≥1 year.

RESULTS

The study cohort was a mean age of 54 ± 13 years, 79% were male, and 35% had an ischemic etiology. The mean duration of CF-LVAD support before transplantation was 296 days (range, 27-1,413 days). The overall 30-day mortality was 4.1%. Overall post-transplant survival was 88%, 84%, 78% at 1, 3, and 5 years, respectively. The 32 patients (26%) with ≥1 year of CF-LVAD support (mean, 635 days) were more likely to have blood type O, a larger body size, and to have been readmitted due to recurrent heart failure and device failure requiring exchange than those with <1 year of CF-LVAD support. Patients who required prolonged support time also had worse in-hospital mortality (16% vs 6.7%, p = 0.12) and significantly lower survival at 3 years after transplantation (68% vs 88%, p = 0.049).

CONCLUSIONS

The overall short-term and long-term cardiac transplant outcomes of patients supported with CF-LVAD are satisfactory. However, patients who require prolonged CF-LVAD support may have diminished post-transplant survival due to adverse events occurring during device support.

Does renal dysfunction and method of bridging support influence heart transplant graft survival?

BACKGROUND

Renal insufficiency is common in status 1B patients supported with inotropes or a continuous flow left ventricular device (CF-LVAD) as a bridge to heart transplantation. We evaluated the association of renal function and inotrope versus CF-LVAD support on posttransplant graft survival in status 1B patients.

METHODS

The Scientific Registry for Transplant Recipients database was analyzed for posttransplant survival in status 1B patients bridged with inotropes or CF-LVAD who underwent transplantation between 2003 and 2012. Pretransplant renal function was measured by estimating glomerular filtration rate (GFR) and was stratified as less than 45 mL · min(-1) · 1.73 m(-2), 45 to 59, and 60 or greater. Univariate Kaplan-Meier and multivariate Cox regression models were used to evaluate the main effects of GFR strata and inotropes versus CF-LVAD, and the interaction effect of GFR strata by CF-LVAD, on graft survival.

RESULTS

This study included 4,158 status 1B patients (74% male, aged 53 ± 12 years). Of those, 659 patients had a CF-LVAD (HeartMate-II [Thoratec, Pleasanton, CA], n = 638; HVAD [HeartWare, Framingham, MA], n = 21), and 3,530 were receiving inotropes (31 CF-LVAD patients were also receiving inotropes). Kaplan-Meier analyses demonstrated reduced graft survival (p = 0.022) in patients with pretransplant GFR less than 45 versus GFR 45 to 59 (p = 0.062) and versus GFR 60 or greater (p = 0.007), and no effect of inotrope versus CF-LVAD support on graft survival (p = 0.402). Multivariate analysis demonstrated that, after adjusting for the main effects of GFR stratum, CF-LVAD, and inotropes, status 1B patients bridged with a CF-LVAD and GFR in the lowest stratum had reduced graft survival (interaction effect p = 0.040).

CONCLUSIONS

Pretransplant renal insufficiency was associated with reduced posttransplant graft survival in status 1B patients. This risk is increased for patients bridged with a CF-LVAD (versus inotropes) who have GFR in the lowest stratum.

Does the UNOS heart transplant allocation system favor men over women?

OBJECTIVES

The aim of this paper was to identify sex differences in survival of patients awaiting orthotopic heart transplantation (OHT).

BACKGROUND

Women have a higher mortality rate while awaiting OHT than men, and the reason has not been fully determined.

METHODS

We included all adult patients in the Scientific Registry of Transplant Recipients (SRTR) placed on the OHT waiting list from 2000 to 2010. The primary endpoint was all-cause mortality before receiving OHT, analyzed using time-to-event analysis. Multivariate Cox proportional hazards models were used to evaluate sex differences in survival, with data stratified by United Network for Organ Sharing (UNOS) status at time of listing.

RESULTS

There were 28,852 patients (24% women) awaiting OHT. This cohort included 6,163 UNOS status 1A (25% women), 9,168 UNOS status 1B (25% women), and 13,521 UNOS status 2 (24% women) patients. During a median follow-up of 3.7 years, 1,290 women and 4,286 men died. Female sex was associated with a significant risk of death among UNOS status 1A (adjusted hazard ratio [HR]: 1.20; 95% confidence interval [CI]: 1.05 to 1.37, p = 0.01) after adjusting for more than 30 baseline variables. In contrast, female sex was significantly protective for time to death among UNOS status 2 patients (adjusted HR: 0.75; 95% CI: 0.67 to 0.84, p < 0.001). No sex differences were noted among UNOS status 1B patients.

CONCLUSIONS

There are sex differences in survival between women and men awaiting heart transplantation, and the current UNOS transplant criteria do not account for this disparity.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Long-term outcome of patients on continuous-flow left ventricular assist device support

OBJECTIVES

Recent advances in technology and improved patient management have enabled the use of mechanical circulatory support for unexpected long-term periods. Improved long-term outcomes may facilitate the use of device therapy as an alternative to heart transplantation. However, there are scarce data about the long-term outcomes of continuous-flow left ventricular assist devices. This study sought to evaluate the long-term outcomes in patients receiving continuous-flow left ventricular assist devices.

METHODS

Between March 2004 and June 2010, 140 patients underwent continuous-flow left ventricular assist device insertion as a bridge to transplantation or a destination therapy. These patients' charts were retrospectively reviewed.

RESULTS

The initial strategy for continuous-flow left ventricular assist device therapy was bridge to transplantation in 115 patients (82%) and destination therapy in 25 patients (18%). Of those, 24 (17%) died on left ventricular assist device support, 94 (67%) were successfully bridged to transplantation, and 1 (0.71%) showed native heart recovery. Twenty-four patients (17%) had been on continuous-flow left ventricular assist device support for more than 3 years (mean, 3.9 years; range, 3.0-7.5 years). Estimated on-device survival at 1, 3, and 5 years was 83%, 75%, and 61%, respectively. Rehospitalizations due to bleeding, cardiac events, and device-related issues were common. The freedom from rehospitalization rates at 1 and 3 years was 31% and 6.9%, respectively. A total of 14 patients (10%) required device exchange.

CONCLUSIONS

Current continuous-flow left ventricular assist devices can provide satisfactory long-term survival. However, rehospitalization is frequently required.

Regional differences in recipient waitlist time and pre- and post-transplant mortality after the 2006 United Network for Organ Sharing policy changes in the donor heart allocation algorithm

OBJECTIVES

This study examined the impact of the United Network for Organ Sharing (UNOS) policy changes for regional differences in waitlist time and mortality before and after heart transplantation.

BACKGROUND

The 2006 UNOS thoracic organ allocation policy change was implemented to allow for greater regional sharing of organs for heart transplantation.

METHODS

We analyzed 36,789 patients who were listed for heart transplantation from January 1999 through April 2012. These patients were separated into 2 eras centered on the July 12, 2006 UNOS policy change. Pre- and post-transplantation characteristics were compared by UNOS regions.

RESULTS

Waitlist mortality decreased nationally (up to 180 days: 13.3% vs. 7.9% after the UNOS policy change, p < 0.001) and within each region. Similarly, 2-year post-transplant mortality decreased nationally (2-year mortality: 17.3% vs. 14.6%; p < 0.001) as well as regionally. Waitlist time for UNOS status 1A and 1B candidates increased nationally 17.8 days on average (p < 0.001) with variability between the regions. The greatest increases were in Region 9 (59.2-day increase, p < 0.001) and Region 4 (41.2-day increase, p < 0.001). Although the use of mechanical circulatory support increased nearly 2.3-fold nationally in Era 2, significant differences were present on a regional basis. In Regions 6, 7, and 10, nearly 40% of those transplanted required left ventricular assist device bridging, whereas only 19.6%, 22.3%, and 15.5% required a left ventricular assist device in regions 3, 4, and 5, respectively.

CONCLUSIONS

The 2006 UNOS policy change has resulted in significant regional heterogeneity with respect to waitlist time and reliance on mechanical circulatory support as a bridge to transplantation, although overall both waitlist mortality and post-transplant survival are improved.

Continuous flow left ventricular assist device technology has influenced wait times and affected donor allocation in cardiac transplantation

OBJECTIVE

Bridge to transplantation patients with continuous flow left ventricular assist devices (cfLVADs) are assigned United Network for Organ Sharing status 1A or 1B priority while awaiting orthotopic heart transplantation. We investigated the influence of cfLVAD on the waitlist times and organ allocation.

METHODS

The United Network for Organ Sharing database was examined from 2005 to 2012 for patients with cfLVAD and pulsatile flow LVAD (pLVAD). These 2 cohorts were compared with patients who did not receive LVAD.

RESULTS

Of 16,476 total orthotopic heart transplantations, 3270 (19.8%) were performed on patients with an LVAD as a bridge to transplantation. The cfLVAD group had the longest total waitlist time (259.6 days) compared with the pLVAD (134.6 days) and non-LVAD (121.7 days) groups (P < .001). The cfLVAD group spent more time in status 1A (44.7 days) than did the pLVAD (32.1 days) and non-LVAD (16.4 days) cohorts (P < .001). The median waitlist survival was better for the cfLVAD group (1234.0 days) than in the pLVAD (441.0 days) and non-LVAD (471.0 days) groups (P < .001). The cfLVAD recipients were older, had a greater body mass index, and more often had diabetes than did pLVAD and non-LVAD patients. The cfLVAD cohort received hearts from older, more often male donors, with a greater body mass index. Post-transplant survival was not significantly different among the 3 groups on Kaplan-Meier analysis (P = .12).

CONCLUSIONS

Despite being older, less favorable recipients, the cfLVAD patients spent more time in status 1A and had greater waitlist survival. This might allow cfLVAD patients to receive preferred donor hearts, which might allow for better post-transplant survival.