How Do Mechanical Circulatory Support Patients Die? Autopsy Findings for Bridge to Transplant LVAD/TAH Patients Who Do Not Survive to Transplant

Abstract

Purpose Despite being life saving for end-stage heart failure patients, permanent mechanical circulatory support (MCS) is often the proximate cause of death in those that do not make it to transplant. Autopsy is the gold standard for causes of mortality, and is a vital tool for better understanding of pathology in this patient cohort. The aim of this study was to determine the frequency and outcomes of autopsy investigations over the course of a MCS program in a single center. Methods The autopsy findings of all patients who had a left ventricular assist device (LVAD) and total artificial heart (TAH) inserted between June 1994 and December 2016 as a bridge to transplant but subsequently died on pump were reviewed. Results A total of 187 patients had an LVAD or TAH implanted during the study. The cohort who died on pump (n=59; M=45, F=14) had an average age at implant of 53 ± 14 yrs, average INTERMACS score of 2, and average time on pump of 325 ± 316 days. Autopsies were conducted in 24/59 (41%) of patients. At autopsy, 8 patients had infection sited as cause of/contributing to the cause of death, one with purulent material obstructing the function of the pump. Six had explant swabs available. These were positive for MRSA, candida glabrata, pseudomonas fluorescens, scedosporium in 4 patients respectively, and 3/6 had positive explant swabs for pseudomonas aeruginosa. Lung injury was common, with 4 patients having acute respiratory distress syndrome, and 5 patients with diffuse alveolar damage. Four patients had intracranial hemorrhage, 2 patients had other bleeding (small bowel, haemopericardium), 1 patient had pump thrombus, 1 active myocarditis, and there was 1 accidental disconnection of the driveline. Conclusion Over an observational period of 22 years, the frequency of autopsies ordered was low. In order to keep patients alive to transplant, clinicians require a better understanding of causes of death. Patients with mechanical circulatory support have complex physiology and are at high risk of infection and bleeding complications.