Two case reports of fulminant giant cell myocarditis treated with rabbit anti-thymocyte globulin.

Background: Giant cell myocarditis (GCM) is an inflammatory form of acute heart failure with high rates of cardiac transplantation or death. Standard acute treatment includes multi-drug immunosuppressive regimens. There is a small but growing number of case reports utilizing rabbit anti-thymocyte globulin in severe cases. Case summary: Two cases are presented with similar presentations and clinical courses. Both are middle-aged patients with no significant past medical history, who presented with new acute decompensated heart failure that quickly progressed to cardiogenic shock requiring inotropic and mechanical circulatory support. Both underwent endomyocardial biopsies that diagnosed GCM. Both were treated with a multi-agent immunosuppressive regimen, notably including rabbit anti-thymocyte globulin, with subsequent resolution of shock and recovery of left ventricular ejection fraction. Both remain transplant-free and without ventricular arrhythmias at 7 months and 26 months, respectively. Discussion: In aggregate, these cases are typical of GCM. They add to growing observational data that upfront rabbit anti-thymocyte globulin may reduce morbidity and mortality in GCM, including potentially preventing the need for complex interventions like orthotopic heart transplantation.

Biventricular Assist Devices as a Bridge to Heart Transplantation Under the New Donor Heart Allocation System in the United States.

Biventricular assist devices (BiVADs) for pre-heart transplant care is rare. The outcomes of pretransplant BiVAD support after the 2018 heart transplant allocation policy change are entirely unknown at this time. The United Network of Organ Sharing database was retrospectively queried from October 2018 to June 2022 to identify patients supported to transplant with BiVADs. They were compared to patients listed as Status 2 for heart transplantation with an isolated VAD (uni-VAD). The primary outcome of interest was 1 year survival. Secondary outcomes included length of stay, posttransplant stroke, dialysis, and pacemaker implantation. The frequency of BiVAD use for heart transplantation has remained unchanged after the 2018 allocation policy change, making up approximately 2% of transplant recipients annually. Patients supported with BiVADs appeared to be similar to patients supported with uni-VADs. One year survival was similar between the groups (88.57% vs. 87.90%). Length of stay was longer and there was a trend toward higher frequencies of posttransplant dialysis use. Patients supported to transplant with BiVADs appear to have posttransplant outcomes comparable to patients commonly listed as Status 2 with an isolated VAD. Compared to past analyses, there is a suggestion of improved survival with the 2018 allocation policy change.

Transmethylamine-N-Oxide Is Associated With Diffuse Cardiac Fibrosis in People Living With HIV.

Background People living with HIV are at increased risk of developing diastolic dysfunction, heart failure, and sudden cardiac death, all of which have been characterized by higher levels of myocardial fibrosis. Transmethylamine-N-oxide (TMAO), a dietary gut metabolite, is linked to the development of myocardial fibrosis in animal models. However, it is unclear whether TMAO plays a role in the development of myocardial fibrosis in people living with HIV. Methods and Results The study population consisted of participants enrolled in the multisite cross-sectional study called CHART-HIV (Characterizing Heart Function on Anti-Retroviral Therapy). Participants underwent echocardiography, cardiac magnetic resonance imaging, biomarker analysis, and targeted assessment of gut-related circulating metabolites; diastolic dysfunction was determined by study-specific criteria. Multivariable linear regression models were performed to examine the relationship of gut-related metabolites with serum and imaging measures of myocardial fibrosis. Models were adjusted for traditional cardiovascular, inflammatory, and HIV-related risk factors. Diastolic dysfunction was present in 94 of 195 individuals (48%) in CHART-HIV; this cohort demonstrated higher prevalence of hypertension, hyperlipidemia, and chronic kidney disease as well as higher plasma levels of both TMAO and choline. TMAO levels were associated with parameters reflecting increased left ventricular filling pressures and with a marker of the innate immune system. TMAO levels correlated with diffuse myocardial fibrosis (R=0.35; P<0.05) as characterized by myocardial extracellular volume fraction as well as biomarkers reflective of myocardial fibrosis. Conclusions In this study of people living with HIV, the gut metabolite TMAO was associated with underlying diffuse myocardial fibrosis and found to be a potential marker of early structural heart disease. The mechanistic role of the gut microbiome in HIV-associated cardiovascular disease warrants further investigation. Registration URL: https://clinicaltrials.gov; Unique identifier: NCT02860156.