Race and ethnic differences in the epidemiology and risk factors for graft failure after heart transplantation

Racial and Ethnic Disparities in Peri-and Post-operative Cardiac Surgery

Purpose of Review

Despite efforts to curtail its impact on medical care, race remains a powerful risk factor for morbidity and mortality following cardiac surgery. While patients from racial and ethnic minority groups are underrepresented in cardiac surgery, they experience a disproportionally elevated number of adverse outcomes following various cardiac surgical procedures. This review provides a summary of existing literature highlighting disparities in coronary artery bypass surgery, valvular surgery, cardiac transplantation, and mechanical circulatory support.

Recent Findings

Unfortunately, specific causes of these disparities can be difficult to identify, even in large, multicenter studies, due to the complex relationship between race and post-operative outcomes. Current data suggest that these racial/ethnic disparities can be attributed to a combination of patient, socioeconomic, and hospital setting characteristics.

Summary

Proposed solutions to combat the mechanisms underlying the observed disparate outcomes require deployment of a multidisciplinary team of cardiologists, anesthesiologists, cardiac surgeons, and experts in health care equity and medical ethics. Successful identification of at-risk populations and the implementation of preventive measures are necessary first steps towards dismantling racial/ethnic differences in cardiac surgery outcomes.

Does Failure to Rescue Drive Race/Ethnicity-based Disparities in Survival After Heart Transplantation?

OBJECTIVE

The objective was to assess whether race/ethnicity is an independent predictor of failure to rescue (FTR) after orthotopic heart transplantation (OHT).

SUMMARY BACKGROUND DATA

Outcomes following OHT vary by patient level factors; for example, non-White patients have worse outcomes than White patients after OHT. Failure to rescue is an important factor associated with cardiac surgery outcomes, but its relationship to demographic factors is unknown.

METHODS

Using the United Network for Organ Sharing database, we included all adult patients who underwent primary isolated OHT between 1/1/2006 snd 6/30/2021. FTR was defined as the inability to prevent mortality after at least one of the UNOS-designated postoperative complications. Donor, recipient, and transplant characteristics, including complications and FTR, were compared across race/ethnicity. Logistic regression models were created to identify factors associated with complications and FTR. Kaplan Meier and adjusted Cox proportional hazards models evaluated the association between race/ethnicity and posttransplant survival.

RESULTS

There were 33,244 adult, isolated heart transplant recipients included: the distribution of race/ethnicity was 66% (n=21,937) White, 21.2% (7,062) Black, 8.3% (2,768) Hispanic, and 3.3% (1,096) Asian. The frequency of complications and FTR differed significantly by race/ethnicity. After adjustment, Hispanic recipients were more likely to experience FTR than White recipients (OR 1.327, 95% CI[1.075-1.639], P =0.02). Black recipients had lower 5-year survival compared with other races/ethnicities (HR 1.276, 95% CI[1.207-1.348], P <0.0001).

CONCLUSIONS

In the US, Black recipients have an increased risk of mortality after OHT compared with White recipients, without associated differences in FTR. In contrast, Hispanic recipients have an increased likelihood of FTR, but no significant mortality difference compared with White recipients. These findings highlight the need for tailored approaches to addressing race/ethnicity-based health inequities in the practice of heart transplantation.

Racial Disparities in Spine Surgery: A Systematic Review

STUDY DESIGN

Systematic Review.

OBJECTIVES

To synthesize previous studies evaluating racial disparities in spine surgery.

METHODS

We queried PubMed, Embase, Cochrane Library, and Web of Science for literature on racial disparities in spine surgery. Our review was constructed in accordance with Preferred Reporting Items and Meta-analyses guidelines and protocol. The main outcome measures were the occurrence of racial disparities in postoperative outcomes, mortality, surgical management, readmissions, and length of stay.

RESULTS

A total of 1753 publications were assessed. Twenty-two articles met inclusion criteria. Seventeen studies compared Whites (Ws) and African Americans (AAs) groups; 14 studies reported adverse outcomes for AAs. When compared with Ws, AA patients had higher odds of postoperative complications including mortality, cerebrospinal fluid leak, nervous system complications, bleeding, infection, in-hospital complications, adverse discharge disposition, and delay in diagnosis. Further, AAs were found to have increased odds of readmission and longer length of stay. Finally, AAs were found to have higher odds of nonoperative treatment for spinal cord injury, were more likely to undergo posterior approach in the treatment of cervical spondylotic myelopathy, and were less likely to receive cervical disk arthroplasty compared with Ws for similar indications.

CONCLUSIONS

This systematic review of spine literature found that when compared with W patients, AA patients had worse health outcomes. Further investigation of root causes of these racial disparities in spine surgery is warranted.

Assessment and management of allosensitization following heart transplant in adults

Immunological injury to the allograft, specifically by antibodies to de novo donor specific human leukocyte antigen (dnDSA) and antibody mediated injury and rejection are the major limitations to graft survival after heart transplantation (HT). As such, our approach to allosensitization remains limited by the inability of contemporaneous immunoassays to unravel pathogenic potential of dnDSA. Additionally, the role of dnDSA is continuously evaluated with emerging methods to detect rejection. Moreover, the timing and frequency of dnDSA monitoring for early detection and risk mitigation as well as management of dnDSA remain challenging. A strategic approach to dnDSA employs diagnostic assays to determine relevant antibodies in conjunction with clinical presentation and injury/rejection of allograft to tailor therapeutics. In this review, we aim to outline contemporary knowledge involving detection, monitoring and management of dnDSA after HT. Subsequently, we propose a diagnostic and therapeutic approach that may mitigate morbidity and mortality while balancing adverse reactions from pharmacotherapy.

Significance of Ethnic Factors in Immunosuppressive Therapy Management After Organ Transplantation

Clinical outcomes after organ transplantation have greatly improved in the past 2 decades with the discovery and development of immunosuppressive drugs such as calcineurin inhibitors, antiproliferative agents, and mammalian target of rapamycin inhibitors. However, individualized dosage regimens have not yet been fully established for these drugs except for therapeutic drug monitoring-based dosage modification because of extensive interindividual variations in immunosuppressive drug pharmacokinetics. The variations in immunosuppressive drug pharmacokinetics are attributed to interindividual variations in the functional activity of cytochrome P450 enzymes, UDP-glucuronosyltransferases, and ATP-binding cassette subfamily B member 1 (known as P-glycoprotein or multidrug resistance 1) in the liver and small intestine. Some genetic variations have been found to be involved to at least some degree in pharmacokinetic variations in post-transplant immunosuppressive therapy. It is well known that the frequencies and effect size of minor alleles vary greatly between different races. Thus, ethnic considerations might provide useful information for optimizing individualized immunosuppressive therapy after organ transplantation. Here, we review ethnic factors affecting the pharmacokinetics of immunosuppressive drugs requiring therapeutic drug monitoring, including tacrolimus, cyclosporine, mycophenolate mofetil, sirolimus, and everolimus.

Racial differences in outcomes after receiving advanced heart failure therapies

PURPOSE OF REVIEW

Despite advances in medical and device-based therapies for advanced heart failure as well as public policy, disparities by race/ethnicity persist in heart failure clinical outcomes. The purpose of this review is to describe disparities in outcomes by race--ethnicity in patients after receipt of heart transplantation and left ventricular assist device (LVAD), and the current understanding of factors contributing to these disparities.

RECENT FINDINGS

The proportion of black and Latinx patients receiving advanced heart failure therapies continues to rise, and they have worse hemodynamic profiles at the time of referral for heart transplantation and LVAD. Black patients have lower rates of survival after heart transplantation, in part because of higher rates of cellular and humoral rejection that may be mediated through unique gene pathways, and increased risk for allosensitization and de-novo donor-specific antibodies. Factors that have previously been cited as reasons for worse outcomes in race--ethnic minorities, including psychosocial risk and lower SES, may not be as strongly correlated with outcomes after LVAD.

SUMMARY

Black and Latinx patients are sicker at the time of referral for advanced heart failure therapies. Despite higher psychosocial risk factors among race--ethnic minorities, outcomes after LVAD appear to be similar to white patients. Black patients continue to have lower posttransplant survival, because of a complex interplay of immunologic susceptibility, clinical and socioeconomic factors. No single factor accounts for the disparities in clinical outcomes for race--ethnic minorities, and thus consideration of these components together is critical in management of these patients.

Racial/Ethnic and Gender Disparities in Heart Failure with Reduced Ejection Fraction

PURPOSE OF REVIEW

This review highlights variability in prescribing of nonpharmacologic heart failure with reduced ejection fraction (HFrEF) therapies by race, ethnicity, and gender. The review also explores the evidence underlying these inequalities as well as potential mitigation strategies.

RECENT FINDINGS

There have been major advances in HF therapies that have led to improved overall survival of HF patients. However, racial and ethnic groups of color and women have not received equitable access to these therapies. Patients of color and women are less likely to receive nonpharmacologic therapies for HFrEF than White patients and men. Therapies including exercise rehabilitation, percutaneous transcatheter mitral valve repair, cardiac resynchronization therapy, heart transplant, and ventricular assist devices all have proven efficacy in patients of color and women but remain underprescribed. Outcomes with most nonpharmacologic therapy are similar or better among patients of color and women than White patients and men. System-level changes are urgently needed to achieve equity in access to nonpharmacologic HFrEF therapies by race, ethnicity, and gender.

The effects of increased donor support time from organ donation referral to donor procurement on heart transplant recipient survival

INTRODUCTION

Given the known deleterious cardiac effects of brain death (BD) physiology, we hypothesized that time from cardiac donation referral to procurement (donor support time [DST]), would negatively impact cardiac transplant recipient survival.

METHODS

The United Network for Organ Sharing database was queried from 2007 to 2018, identifying 22,593 donor hearts for analysis. Multivariate logistic models for 30-day and 1-year survival, as well as Cox models for overall survival and posttransplant rejection, were used to assess adjusted outcomes.

RESULTS

median DST was 3 days (interquartile range: 2-5 days). Ischemic time; distance between donor and recipient hospitals; and recipient age, creatinine, waitlist time, and length of stay were adjusted predictors of survival and rejection. DST was not associated with either outcome in aggregate; however, differential association by donor race was identified, with DST in any race recipient associated with 4% higher odds of 1-year mortality (p = .001; p value for interaction .005) but only a trend towards worse overall mortality (p = .064; p value for interaction .046).

CONCLUSION

Thus, duration of exposure to BD physiology may have a differential impact on recipient outcomes based on donor race, suggesting that additional research is needed on donor immunologic, socioeconomic, and healthcare access factors that may impact cardiac transplant recipient outcomes.

Twenty-year survival following orthotopic heart transplantation in the United States

BACKGROUND

This study evaluated 20-year survival after adult orthotopic heart transplantation (OHT).

METHODS

The United Network of Organ Sharing Registry database was queried to study adult OHT recipients between 1987 and 1998 with over 20-year posttransplant follow-up. The primary and secondary outcomes were 20-year survival and cause of death after OHT, respectively. Multivariable logistic regression was used to identify significant independent predictors of long-term survival, and long-term survival was compared among cohorts stratified by number of predictors using Kaplan Meier survival analysis.

RESULTS

20,658 patients undergoing OHT were included, with a median follow-up of 9.0 (IQR, 3.2-15.4) years. Kaplan-Meier estimates of 10-, 15-, and 20-year survival were 50.2%, 30.1%, and 17.2%, respectively. Median survival was 10.1 (IQR, 3.9-16.9) years. Increasing recipient age (>65 years), increasing donor age (>40 years), increasing recipient body mass index (>30), black race, ischemic cardiomyopathy, and longer cold ischemic time (>4 h) were adversely associated with a 20-year survival. Of these 6 negative predictors, presence of 0 risk factors had the greatest 10-year (59.7%) and 20-year survival (26.2%), with decreasing survival with additional negative predictors. The most common cause of death in 20-year survivors was renal, liver, and/or multisystem organ failure whereas graft failure more greatly impacted earlier mortality.

CONCLUSIONS

This study identifies six negative preoperative predictors of 20-year survival with 20-year survival rates exceeding 25% in the absence of these factors. These data highlight the potential for very long-term survival after OHT in patients with end-stage heart failure and may be useful for patient selection and prognostication.

Joint testing of donor and recipient genetic matching scores and recipient genotype has robust power for finding genes associated with transplant outcomes

Genetic matching between transplant donor and recipient pairs has traditionally focused on the human leukocyte antigen (HLA) regions of the genome, but recent studies suggest that matching for non-HLA regions may be important as well. We assess four genetic matching scores for use in association analyses of transplant outcomes. These scores describe genetic ancestry distance using identity-by-state, or genetic incompatibility or mismatch of the two genomes and therefore may reflect different underlying biological mechanisms for donor and recipient genes to influence transplant outcomes. Our simulation studies show that jointly testing these scores with the recipient genotype is a powerful method for preliminary screening and discovery of transplant outcome related single nucleotide polymorphisms (SNPs) and gene regions. Following these joint tests with marginal testing of the recipient genotype and matching score separately can lead to further understanding of the biological mechanisms behind transplant outcomes. In addition, we present results of a liver transplant data analysis that shows joint testing can detect SNPs significantly associated with acute rejection in liver transplant.

Early Graft Dysfunction Following Heart Transplant: Prevention and Management

Heart transplant can be considered as the “gold standard” treatment for end-stage heart failure, with nearly 5.7 million adults in the United States carrying a diagnosis of heart failure. According to the International Society for Heart and Lung Transplantation registry, nearly 3300 orthotopic heart transplants were performed in 2016 in North America. In spite of significant improvements in overall perioperative care of heart transplant recipients for the past few decades, the risk of 30-day mortality remains 5% to 10%, primarily related to early failure of the allograft. Early graft dysfunction (EGD) occurs within 24 hours after transplant, manifesting as left ventricular dysfunction, right ventricular dysfunction, or biventricular dysfunction. EGD is further classified into primary and secondary graft dysfunction. This review focus on describing overall incidences of EGD, potential risk factors associated with EGD, perioperative preventive measures, and various management options.

The 2018 ISHLT/APM/AST/ICCAC/STSW recommendations for the psychosocial evaluation of adult cardiothoracic transplant candidates and candidates for long-term mechanical circulatory support

The psychosocial evaluation is well-recognized as an important component of the multifaceted assessment process to determine candidacy for heart transplantation, lung transplantation, and long-term mechanical circulatory support (MCS). However, there is no consensus-based set of recommendations for either the full range of psychosocial domains to be assessed during the evaluation, or the set of processes and procedures to be used to conduct the evaluation, report its findings, and monitor patients' receipt of and response to interventions for any problems identified. This document provides recommendations on both evaluation content and process. It represents a collaborative effort of the International Society for Heart and Lung Transplantation (ISHLT) and the Academy of Psychosomatic Medicine, American Society of Transplantation, International Consortium of Circulatory Assist Clinicians, and Society for Transplant Social Workers. The Nursing, Health Science and Allied Health Council of the ISHLT organized a Writing Committee composed of international experts representing the ISHLT and the collaborating societies. This Committee synthesized expert opinion and conducted a comprehensive literature review to support the psychosocial evaluation content and process recommendations that were developed. The recommendations are intended to dovetail with current ISHLT guidelines and consensus statements for the selection of candidates for cardiothoracic transplantation and MCS implantation. Moreover, the recommendations are designed to promote consistency across programs in the performance of the psychosocial evaluation by proposing a core set of content domains and processes that can be expanded as needed to meet programs' unique needs and goals.

Cytomegalovirus infection in heart transplantation: A single center experience

BACKGROUND

Cytomegalovirus (CMV) infection remains a major complication after heart transplantation with varying prophylaxis strategies employed. We sought to determine the impact of valganciclovir (VGC) duration on the epidemiology of CMV infections after heart transplantation.

METHODS

We performed a prospective cohort study of CMV donor (D) or recipient (R) seropositive heart transplant recipients from 2005 to 2012 who completed VGC prophylaxis, ranging from 3 to 12 months according to serostatus and induction immunosuppression. Univariate and multivariate logistic regression was performed.

RESULTS

Among 159 heart transplant recipients during the study period, 130 (82%) were eligible for VGC prophylaxis. CMV D/R serostatus was as follows: 24% D+/R-, 30% D+/R+, and 29% D-/R+. 65% and 21% received basiliximab and thymoglobulin induction, respectively, followed by maintenance tacrolimus, mycophenolate mofetil, and prednisone. Twenty-one (16%) recipients suffered CMV infection. There was no association with comorbidities including diabetes mellitus, chronic kidney disease, or mechanical assist devices, nor were there associations with rejection, treatments of rejection, or mortality. When VGC prophylaxis duration was stratified by ≤6 vs ≥12 months, time from heart transplantation to CMV infection was delayed (median 247 vs 452 days, P = .002) but there was no difference in days from VGC discontinuation to onset of CMV infection (median 72 vs 83 days, P = .31). CMV infection occurred most frequently within 6-16 weeks of VGC cessation, and 95% of infections occurred during the 6 months post-prophylaxis period.

CONCLUSIONS

Relative to ≤6 months, ≥12 months of VGC did not reduce incidence of CMV infection and only delayed time to onset. 95% of CMV infection occurs within 6 months after cessation of VGC.

Noninfectious and Infectious Complications and Their Related Characteristics in Heart Transplant Recipients at a National Institute

OBJECTIVES

Complications, which affect the morbidity and mortality of patients after heart transplant, can be divided into infectious and noninfections com-plications. Here, we analyzed both infectious and noninfectious complications and their relation to clinical, laboratory, and surgical characteristics in a Latin American heart transplant population.

MATERIALS AND METHODS

Data were obtained from records of 35 heart transplant patients in the period from 2010 to 2015. Noninfectious and infectious complications were divided into 3 time intervals: within the first month, from month 2 to 6, and after month 6. Relations between complications and clinical, laboratory and surgical variables in different interval times were analyzed.

RESULTS

In our patient group, 70 infectious and 133 noninfectious complications were reported after heart transplant. Infectious complications occurred more often between months 2 and 6 after heart transplant, whereas noninfectious complications occurred more often during the first month. Bacteria were the most common microorganism, and acute graft rejection was the most common noninfectious complication. Moreover, infectious complications were statistically related to 5 factors at month 1 (intraoperative bleeding, normal postsurgery leukocyte level, mild malnutrition, severe malnutrition, and graft rejection), to 3 factors between months 2 and 6 (diabetes mellitus, stage 2 chronic kidney disease, and cryoprecipitate trans-fusions), and to 2 factors after month 6 (prothrombin time and psychologic diagnosis).

CONCLUSIONS

Our results demonstrated that noninfectious complications should be anticipated first in patients after heart transplant. In addition, there are characteristics associated with infectious complications that can be seen during a specific time period.

Heart Transplantation in Asia

Heart transplantation (HTx) is the effective way to improve quality of life as well as survival in terminal heart failure (HF) patients. Since the first heart transplant in 1968 in Japan and in earnest in 1987 at Taiwan, HTx has been continuously increasing in Asia. Although the current percentage of heart transplants from Asia comprises only 5.7% of cases in the International Society of Heart and Lung Transplantation (ISHLT) registry, the values were under-reported and soon will be greatly increased. HTx in Asia shows comparable with or even better results compared with ISHLT registry data. Several endemic infections, including type B hepatitis, tuberculosis, and cytomegalovirus, are unique aspects of HTx in Asia, and need special attention in transplant care. Although cardiac allograft vasculopathy (CAV) is considered as a leading cause of death after HTx globally, multiple observations suggest less prevalence and benign nature of CAV among Asian populations. Although there are many obstacles such as religion, social taboo or legal process, Asian countries will keep overcoming obstacles and broaden the field of HTx.

The Affordable Care Act Medicaid Expansion Correlated With Increased Heart Transplant Listings in African-Americans But Not Hispanics or Caucasians

OBJECTIVES

The aim of this study was to determine if the Affordable Care Act (ACA) Medicaid Expansion was associated with increased census-adjusted heart transplant listing rates for racial/ethnic minorities.

BACKGROUND

Underinsurance limits access to transplants, especially among racial/ethnic minorities. Changes in racial/ethnic listing rates post-ACA Medicaid Expansion are unknown.

METHODS

Using the Scientific Registry of Transplant Recipients, we analyzed 5,651 patients from early adopter states (implemented the ACA Medicaid Expansion by January 2014) and 4,769 patients from non-adopter states (no implementation during the study period) from 2012 to 2015. Piecewise linear models, stratified according to race/ethnicity, were fit to monthly census-adjusted rates of heart transplant listings before and after January 2014.

RESULTS

A significant 30% increase in the rate of heart transplant listings for African-American patients in early adopter states occurred immediately after the ACA Medicaid Expansion on January 1, 2014 (before 0.15 to after 0.20/100,000; increase 0.05/100,000; 95% confidence interval [CI]: 0.01 to 0.08); in contrast, the rates for African-American patients in non-adopter states remained constant (before and after 0.15/100,000; increase 0.006/100,000; 95% CI: -0.03 to 0.04). Hispanic patients experienced an opposite trend, with no significant change in early adopter states (before 0.03 to after 0.04/100,000; increase 0.01/100,000; 95% CI: -0.004 to 0.02) and a significant increase in non-adopter states (before 0.03 to after 0.05/100,000; increase 0.02/100,000; 95% CI: 0.002 to 0.03). There were no significant changes in listing rates among Caucasian patients in either early adopter states or non-adopter states.

CONCLUSIONS

Implementation of the ACA Medicaid Expansion was associated with increased heart transplant listings in African-American patients but not in Hispanic or Caucasian patients. Broadening of the ACA in states with large African-American populations may reduce disparities in heart transplant listings.

Health Insurance Trajectories and Long-Term Survival After Heart Transplantation

BACKGROUND

Health insurance status at heart transplantation influences recipient survival, but implications of change in insurance for long-term outcomes are unclear.

METHODS AND RESULTS

Adults aged 18 to 64 receiving first-time orthotopic heart transplants between July 2006 and December 2013 were identified in the United Network for Organ Sharing registry. Patients surviving >1 year were categorized according to trajectory of insurance status (private compared with public) at wait listing, transplantation, and 1-year follow-up. The most common insurance trajectories were continuous private coverage (44%), continuous public coverage (27%), and transition from private to public coverage (11%). Among patients who survived to 1 year (n=9088), continuous public insurance (hazard ratio =1.36; 95% confidence interval 1.19, 1.56; P<0.001) and transition from private to public insurance (hazard ratio =1.25; 95% confidence interval 1.04, 1.50; P=0.017) were associated with increased mortality hazard relative to continuous private insurance. Supplementary analyses of 11 247 patients included all durations of post-transplant survival and examined post-transplant private-to-public and public-to-private transitions as time-varying covariates. In these analyses, transition from private to public insurance was associated with increased mortality hazard (hazard ratio =1.25; 95% confidence interval 1.07, 1.47; P=0.005), whereas transition from public to private insurance was associated with lower mortality hazard (hazard ratio =0.78; 95% confidence interval 0.62, 0.97; P=0.024).

CONCLUSIONS

Transition from private to public insurance after heart transplantation is associated with worse long-term outcomes, compounding disparities in post-transplant survival attributed to insurance status at transplantation. By contrast, post-transplant gain of private insurance among patients receiving publicly funded heart transplants was associated with improved outcomes.

Racial and ethnic disparities in outcomes after heart transplantation: A systematic review of contributing factors and future directions to close the outcomes gap

The demographics of patients undergoing heart transplantation in the United States have shifted over the last 10 years, with an increasing number of racial and ethnic minorities undergoing heart transplant. Multiple studies have shown that survival of African American patients after heart transplantation is lower compared with other ethnic groups. We review the data supporting the presence of this outcome disparity and examine the multiple mechanisms that contribute. With an increasingly diverse population in the United States, knowledge of these disparities, their mechanisms, and ways to improve outcomes is essential.

Racial Disparities in Corneal Transplantation Rates, Complications, and Outcomes

Corneal transplantation is a common type of tissue transplantation that aims to improve vision or relieve pain. Given the immune privilege of the cornea, the primary graft often has a high success rate, approaching 90%. Despite the good overall outcome of corneal transplantation in various studies, the individual graft survival rate varies, depending on the preoperative diagnosis and donor and recipient factors. Race and ethnicity have been shown to be important in other types of organ transplantation. The aim of this study was to review the available ophthalmic literature regarding any differences in rates and outcomes of corneal transplantation based on ethnicity and race. A small body of evidence suggests that race might be an important risk factor for graft rejection and graft failure. More robust studies are needed to clarify these associations.