Coronary Artery Remodeling and Fibrosis With Continuous-Flow Left Ventricular Assist Device Support.

Abstract

Coronary artery fluid dynamics may be altered because of the nonphysiological flow seen in continuous-flow left ventricular assist devices (CF-LVADs). Our aim was to study the structure and composition of coronary vessels after CF-LVAD. Coronary arteries were collected from patients with heart failure (HF) at the time of transplantation, of whom 15 were supported with a CF-LVAD before transplant (HF+LVAD group) and 9 were not (HF non-LVAD group). In addition, coronary samples were obtained from 5 nonfailing age-matched donors (nonfailing group). Histological analysis was performed to quantify coronary morphology, composition, vascular fibrosis, and vasa vasorum density. The age and sex mix of the 3 groups were similar, and the mean duration of LVAD support was 213 days. Compared with patients with HF and nonfailing donors, the arteries from patients with HF+LVAD had expansion of the adventitia, breakdown of the internal elastic lamina, and increased adventitial collagen deposition and density of vasa vasorum. Among patients supported with CF-LVADs, the coronary arteries develop marked remodeling with increased adventitial fibrosis. The physiological consequences of these structural changes are unknown, but it is possible that arterial contractility may be impaired, thus limiting coronary flow reserve and promoting myocardial ischemia. This may contribute to CF-LVAD complications, such as ventricular arrhythmias and right ventricular failure. As more patients receive CF-LVADs and new pump technology attempts to modulate flow profiles and pulsatility, further research is needed to understand the mechanisms and long-term sequela of these changes in coronary arteries and other vascular beds.