Rabbit Antithymocyte Globulin Induction in Heart Transplant Recipients at High Risk for Rejection.

Background: Induction with lymphocyte-depleting antibodies may improve allograft outcomes in heart transplant recipients who are at high immunologic risk for rejection. Methods: We conducted a single-center retrospective cohort study that compared outcomes between adult patients receiving rabbit antithymocyte globulin (rATG) induction vs no induction from 2011 through 2017. Key exclusion criteria were patients who did not receive tacrolimus and mycophenolate and patients who did not meet high immunologic risk criteria. Results: A total of 50 patients were included in the analysis. At 1 year, the composite primary outcome of ≥2R rejection as defined by the International Society for Heart and Lung Transplantation, any treated rejection, development of cardiac allograft vasculopathy, or graft loss was not different between groups (P=0.474). Serious infections were also similar between groups (P=0.963). In accordance with institutional guidelines, prednisone exposure was decreased in the rATG induction group at 1 month (24.04 mg ± 13.74 vs 35.18 mg ± 16.95; P=0.014). Conclusion: These results suggest that while rATG induction does not improve heart allograft outcomes, it may enable reducing early corticosteroid exposure in patients at high immunologic risk.

Use of TandemHeart as Bridge to Recovery for Antibody-Mediated Rejection in a Heart Transplant Patient.

Antibody-mediated rejection is a major cause of graft failure, mortality, and morbidity among cardiac transplant recipients. We present the first reported case of TandemHeart (LivaNova, Pittsburgh, Pennsylvania) used in the management of antibody-mediated rejection associated with cardiogenic shock. (Level of Difficulty: Advanced.).

Innovative application of immunologic principles in heart transplantation.

BACKGROUND: Each year, approximately 2,200 heart transplants are performed in the United States. As our understanding of the immune system grows, new tools are being developed to find compatible organ donors and to help with immune surveillance after transplantation. The purpose of this article is to review 3 of these techniques: the virtual crossmatch, the Cylex ImmuKnow assay, and the AlloMap test. METHODS: Two authors (S.A.M. and J.C.) independently performed a literature search with the PubMed database using the key words ImmuKnow, Allomap, and virtual crossmatch in conjunction with heart transplantation. Articles were selected for inclusion if they had a primary focus on the use of virtual crossmatch in heart transplantation, the Cylex ImmuKnow assay, and the AlloMap test. Articles were not excluded on the basis of sample size but were excluded if they did not include heart transplant patients. RESULTS: The virtual crossmatch is a technique that is being used successfully in heart transplant candidates to predict compatibility of donor organs by comparing the potential recipient's HLA-specific antibodies with the HLA type of the prospective donor. The ImmuKnow assay is a noninvasive blood test that measures the strength of immune activity, allowing clinicians to predict risk of infection and possible rejection in heart transplant patients. The AlloMap test is a noninvasive test that quantifies intracellular mRNA levels in mononuclear cells in peripheral blood samples using real-time polymerase chain reaction; this test has been shown to distinguish the dynamic changes in gene expression that occur in the presence or absence of acute cellular rejection. CONCLUSION: As the science of transplant immunology advances, transplant cardiologists are taking advantage of the growing fund of knowledge to help their sensitized transplant candidates increase their chances of finding a compatible donor heart and are using commercially available tests to monitor the immune system and rule out rejection after transplantation.

Metabolic parameters derived from cardiopulmonary stress testing for prediction of prognosis in patients with heart failure: the ochsner experience.

Cardiopulmonary parameters, particularly peak oxygen consumption, have proven utility in prognostic stratification for patients with heart failure. These have been typically corrected for total body weight as opposed to lean body mass (LBM). For practical purposes, fat consumes virtually no oxygen and receives minimal perfusion. Based on this rationale and on observations from previous studies, several investigations conducted at the Ochsner Clinic Foundation have assessed the prognostic value of metabolic parameters when corrected for LBM. Three studies reviewed in this discussion consistently found greater prognostic value for LBM-corrected parameters, especially peak oxygen consumption and oxygen pulse. These findings lead to a strong recommendation for LBM correction of cardiopulmonary exercise stress test-derived parameters for more accurate prognostic stratification in patients with heart failure, especially in the obese population. Other centers have studied additional parameters such as the ventilation to carbon dioxide production slope, oxygen uptake efficiency slope, and partial pressure of end-tidal carbon dioxide during exercise and rest. In multiple studies, these ventilation-dependent parameters have shown prognostic superiority compared with the standard peak oxygen consumption even when obtained from submaximal exercise data. However, no study to our knowledge has compared these parameters with LBM-adjusted values as described herein. The prognostic validity of cardiopulmonary exercise stress test-derived parameters requires further investigation in patients treated with ß-blockers.

Impact of obesity on the risk of heart failure and its prognosis.

Obesity is becoming a global epidemic in both children and adults, and it is associated with numerous comorbidities such as coronary heart disease, stroke/cerebrovascular disease, type 2 diabetes, hypertension, certain cancers, and sleep-disordered breathing. Over the past 2 decades, the incidence of and mortality from coronary heart disease and cardiovascular diseases has been continuously declining. In contrast, the incidence of and mortality from heart failure (HF) have been increasing, with HF diagnosed in approximately 5 million Americans and 550,000 new cases diagnosed each year and a death rate looming at 300,000 per year. Over the years, conventional risk factors including hypertension, type 2 diabetes, and dyslipidemia have been implicated for these unsavory statistics, and recently many studies have highlighted the important role of obesity as an independent risk factor for HF. Here, the authors review the available literature on the effects of overweight and obesity on a variety of cardiac structural adaptations and alterations, the effects on left ventricular systolic and diastolic function, and their role in the development and prognosis of HF. Numerous studies have demonstrated an "obesity paradox" regarding prognosis, however, in that obese patients with established HF tend to have a more favorable prognosis than do lean patients. Finally, the authors discuss the role of cardiopulmonary exercise testing in the risk stratification of obese patients with advanced HF.