Mechanical Support for The Failing Single Ventricle at Pre-Fontan Stage: Current State of The Field and Future Directions.

With the substantial growth of pediatric ventricular assist device (VAD) support, there has been an expansion of the target population towards more complex patients, including congenital heart disease (CHD) with single ventricle (SV) physiology. The outcomes of Stage I and Stage II SV-CHD patients on VAD support from the Pedimacs database are poor, with less than 50% survival on VAD by the 3-month mark in both. The primary objective of this article is to describe the current state of VAD support for the failing Stage I and II SV-CHD circulation, to provide insight into potential areas of outcome improvement. We reviewed the published literature in the form of database and registry reports as well as single-center studies to discuss the outcomes of Stage I and Stage II SV-CHD patients on VAD support. Registry-based studies suggest that VAD support for the failing Stage I and Stage II SV-CHD circulations is challenging. However, the more promising outcomes in several single-institutional reports for both Stage I and Stage II SV-VAD indicate that the grim picture from the databases does not reflect the best outcomes that are possible to be achieved, potentially at experienced centers with higher volumes. Areas of future study and potential improvement including timely initiation of VAD support in the cohort of patients expected to not be a candidate for standard SV palliations, pump selection and the benefits of continuous-flow devices, and the decision-making for setting up the optimum circulation for VAD support, be it Fontan completion if feasible or takedown to shunt physiology.