Support with Single Ventricle-Ventricular Assist Device (sVAD) in Patients with Functionally Univentricular Circulation Prior to Fontan Operation

Some patients with functionally univentricular circulation develop cardiac failure refractory to maximal management and are supported with a ventricular assist device (VAD). The purpose of this manuscript is to summarize our previous publications related to single ventricle-ventricular assist device (sVAD) support in patients with functionally univentricular circulation and to describe our current institutional approach at University of Florida to sVAD support in neonates, infants, and children prior to Fontan. Our programmatic philosophy at University of Florida is to strive to identify the minority of neonates with functionally univentricular circulation who are extremely high-risk prior to initiating staged palliation and to stabilize these neonates with primary preemptive sVAD in preparation for cardiac transplantation; our rationale for this approach is related to the challenges associated with failed staged palliation and subsequent bail-out sVAD support and transplantation. A subset of extremely high-risk neonates and infants with functionally univentricular ductal-dependent circulation undergo primary preemptive sVAD insertion and subsequent cardiac transplantation. Support with VAD clearly facilitates survival on the waiting list during prolonged wait times and optimizes outcomes after Norwood (Stage 1) by providing an alternative pathway for extremely high-risk patients. Therefore, the selective utilization of sVAD in extremely high-risk neonates facilitates improved outcomes for all patients with functionally univentricular ductal-dependent circulation.

At University of Florida, our programmatic approach to utilizing sVAD support as a bridge to transplantation in the minority of neonates with functionally univentricular circulation who are extremely high-risk for staged palliation is associated with Operative Mortality after Norwood (Stage 1) Operation of 2.9% (2/68) and a one-year survival of 91.1% (82/90) for all neonates presenting with hypoplastic left heart syndrome (HLHS) or HLHS-related malformation with functionally univentricular ductal-dependent systemic circulation.

Meanwhile, at University of Florida, for all 82 consecutive neonates, infants, and children supported with pulsatile paracorporeal VAD: Kaplan-Meier survival estimated one year after VAD insertion = 73.3% (95% confidence interval [CI] = 64.1–83.8%), and Kaplan-Meier survival estimated five years after VAD insertion = 68.3% (95% CI = 58.4–79.8%). For all 48 consecutive neonates, infants, and children at University of Florida with biventricular circulation supported with pulsatile paracorporeal VAD: Kaplan-Meier survival estimated one year after VAD insertion = 82.7% (95% CI = 72.4–94.4%), and Kaplan-Meier survival estimated five years after VAD insertion = 79.7% (95% CI = 68.6–92.6%). For all 34 consecutive neonates, infants, and children at University of Florida with functionally univentricular circulation supported with pulsatile paracorporeal sVAD: Kaplan-Meier survival estimated one year after VAD insertion = 59.7% (95% CI = 44.9–79.5%), and Kaplan-Meier survival estimated five years after VAD insertion = 50.5% (95% CI = 35.0–73.0%). These Kaplan-Meier survival estimates for patients supported with pulsatile paracorporeal VAD are better in patients with biventricular circulation in comparison to patients with functionally univentricular circulation both one year after VAD insertion (P=0.026) and five years after VAD insertion (P=0.010).

Although outcomes after VAD support in functionally univentricular patients are worse than in patients with biventricular circulation, sVAD provides a reasonable chance for survival. Ongoing research is necessary to improve the outcomes of these challenging patients, with the goal of developing strategies where outcomes after sVAD support in functionally univentricular patients are equivalent to the outcomes achieved after VAD support in patients with biventricular circulation.