Management of the sensitized adult heart transplant candidate

Preoperative Evaluation and Care of Heart Transplant Candidates

Heart transplantation is recommended for patients with advanced heart failure refractory to medical and device therapy, and who do not have absolute contraindications. When patients become eligible for heart transplantation, they undergo comprehensive evaluation and preparation to optimize their posttransplantation outcomes. This review provides an overview of the processes that are employed to enable the candidates to be transplant-ready when donor hearts are available.

Antibody-medicated rejection after heart transplantation: diagnosis and clinical implications

PURPOSE OF REVIEW

The present article will review the diagnosis of antibody-mediated rejection in heart transplant recipients and further explore the clinical implications.

RECENT FINDINGS

Improved diagnostic techniques have led to increased recognition of antibody-mediated rejection and better understanding of the long-term consequences in heart transplant recipients. Endomyocardial biopsy remains the gold standard for the diagnosis of antibody-medicated ejection; however, several advances in molecular testing have emerged, including the use of gene expression profiling, messenger RNA, and microRNA. Routine surveillance of donor-specific antibodies identifies recipients at high risk for graft compromise. Additionally, new monoclonal antibody therapies have broadened our repertoire in the treatment of rejection.

SUMMARY

Advances in molecular testing for antibody-mediated rejection may improve the associated long-term complication, while minimizing risk to the patient.

Sensitization in Heart Transplantation: Emerging Knowledge: A Scientific Statement From the American Heart Association

Sensitization, defined as the presence of circulating antibodies, presents challenges for heart transplant recipients and physicians. When present, sensitization can limit a transplantation candidate’s access to organs, prolong wait time, and, in some cases, exclude the candidate from heart transplantation altogether. The management of sensitization is not yet standardized, and current therapies have not yielded consistent results. Although current strategies involve antibody suppression and removal with intravenous immunoglobulin, plasmapheresis, and antibody therapy, newer strategies with more specific targets are being investigated.

Recent advances in heart transplantation

Despite advances in medical and electrical therapies for heart failure, morbidity and mortality remain high and patients often progress to end-stage heart failure. Over the last five decades, heart transplantation is considered a standard therapy for select patients with end-stage heart failure. However, while heart transplantation has become a treatment of choice for end-stage heart failure, challenges still exist for improvement in the short- and long-term outcomes. While there is an increase in the number of patients with end-stage heart failure, the number of donor organs remains a major limiting factor. Heart transplantation candidates in the current era are also more complex: older, antigen-sensitized, and on mechanical circulatory support at the time of listing and transplant. Such potential heart transplant recipients have an increased chance of problems, including antibody-mediated rejection and primary graft dysfunction. Recent advances could address the current challenges and include: 1) attempts to expand the pool of donor hearts; 2) changes in heart transplantation allocation policy allowing for more equitable organ distribution; and 3) advances in the management of antibody sensitization. Developments in these areas could result in improved survival and quality of life for heart transplantation recipients.

Changes in the methodology of pre-heart transplant human leukocyte antibody assessment: an analysis of the United Network for Organ Sharing database

BACKGROUND

We sought to investigate temporal trends in the methodology of human leukocyte antibody assessment in heart transplantation.

METHODS

The United Network for Organ Sharing database was queried from June 2004 to March 2013 to obtain pre-heart transplantation human leukocyte antibody results. The % panel reactive antibody for class I and II antibodies was recorded along with the methodology of assessment. Allosensitization was defined as class I and/or II panel reactive antibody of ≥ 10%. The primary outcome measure was graft survival.

RESULTS

During the study period, 12,858 patients with available data underwent heart transplantation. The prevalence of allosensitization increased, with 16.8% in 2005-2006 sensitized at the time of transplantation compared to 23.1% in 2010-2011 (p < 0.001); this occurred in conjunction with an increase in the utilization of flow cytometry (77.2% in 2005-2006; 97.0% in 2010-2011, p < 0.001). Using multivariable analysis, a positive pre-heart transplantation panel reactive antibody by flow cytometry independently predicted graft loss.

CONCLUSIONS

There has been a recent increase in flow cytometric assessment of human leukocyte antibodies prior to heart transplantation, which may be associated with an increase in the prevalence of pre-transplant patients being characterized as allosensitized. Flow cytometry may identify patients with the highest likelihood of graft loss.

Adult heart transplant: indications and outcomes

Cardiac transplantation is the treatment of choice for many patients with end-stage heart failure (HF) who remain symptomatic despite optimal medical therapy. For carefully selected patients, heart transplantation offers markedly improved survival and quality of life. Risk stratification of the large group of patients with end-stage HF is essential for identifying patients who are most likely to benefit, particularly as the number of suitable donors is insufficient to meet demand. The indications for heart transplant and review components of the pre-transplant evaluation, including the role for exercise testing and risk scores such as the Heart Failure Survival Score (HFSS) and Seattle Heart Failure Model (SHFM) are summarized. Common contraindications are also discussed. Outcomes, including survival and common complications such as coronary allograft vasculopathy are reviewed.

Pregnancy-related human leukocyte antigen sensitization leading to cardiac allograft vasculopathy and graft failure in a heart transplant recipient: a case report

In this report, we present a heart transplant recipient who developed cross-reactive paternal and donor-specific human leukocyte antigen (HLA) class II antibodies during pregnancy, leading to accelerated cardiac allograft vasculopathy and severe allograft dysfunction 17 years after transplantation. This resulted in acute heart failure and ventricular arrhythmias requiring repeat heart transplantation.