Successful Bridge-to-Transplant of Functionally Univentricular Patients With a Modified Continuous-Flow Ventricular Assist Device

Abstract

A continuous flow extracorporeal ventricular assist device (VAD) was modified to support functionally univentricular infants and children awaiting heart transplantation. A centrifugal VAD, designed to flow from 1.5 to 8 L/min, was used as a bridge-to-transplant in four patients with functionally univentricular circulation. A variable restrictive recirculation shunt permitted lower flow ranges in small patients. In hypoxic patients, an oxygenator was incorporated into the circuit. From 2012 to 2015, the modified VAD was placed in four patients with Glenn physiology. Age ranged from 0.97 to 6.98 years (median = 2.2 yrs). Body surface area ranged from 0.41 to 0.84 m (median = 0.54 m ). One patient was on extracorporeal membrane oxygenation prior to VAD. A recirculation shunt was used in three patients. Three patients required temporary use of an oxygenator for 4, 10, and 27 days. Median time on the VAD was 32.3 days (range = 23-43 days). A decrease in the cavopulmonary pressure was noted in all patients, as was a fall in the B-type natriuretic peptide. Three patients survived transplant and were discharged at 28-82 days post-transplantation. One patient died after 35 days of support. Two patients experienced major bleeding events. Two patients experienced cerebrovascular accidents, one major and one minor. The centrifugal VAD successfully supported palliated functionally univentricular patients awaiting heart transplantation. The modified recirculation shunt facilitated the successful support of patients in whom optimal flows were substantially lower than that recommended by the manufacturer. The continuous-flow VAD effectively decompressed the cavopulmonary system. The design allowed placement of an in-line oxygenator in hypoxic patients. Further investigation is required to decrease the thromboembolic events, and associated morbidity, in patients supported with this device.

Mechanical circulatory support using modified TandemHeart ventricular assist device in neonates with CHD

“…4 There are reports of successful TandemHeart ventricular assist device support with modified circuit for mechanical circulatory support in children with CHD for multiple indications including heart failure and bridge-to-transplant. [6][7][8] Our modification includes placing an oxygenator and a haemoconcentrator unit within the circuit, a setup that would modulate lower flow to younger children and provide cardiac, pulmonary, and renal support.…”

“…In paediatrics, several reported circuit modifications provide lower flow including recirculation shunt, flow occlusion clamps, and, in some cases, an oxygenator. 6,7 Although there are reports of successful TandemHeart ventricular assist device support using a modified circuit in children, [6][7][8] there is a lack of data on its application in neonates and infants. We previously published our experience using TandemHeart ventricular assist device with a modified circuit in a 2-month-old infant with single-ventricle physiology.…”

Paracorporeal Lung Devices: Thinking Outside the Box

“…In 2017, Monge et al reported a small case series utilizing an adult paracorporeal continuous-flow VAD (Tandem Heart, Cardiac Assist, Pittsburgh, USA) in 13 pediatric patients (0.4–2.1 m 2 BSA), including three patients with single ventricle physiology ( 20 , 38 ). All patients had their left atrium (or common atrium for single ventricles) cannulated using a standard metal-tip right-angle bypass cannula.…”

Artificial Organs 2017: A Year in Review

“…Mongé et al of the Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA reported on the use of a continuous flow extracorporeal ventricular assist device (VAD) to support functionally four univentricular infants and children awaiting heart transplantation. A variable restrictive recirculation shunt permitted lower flow ranges in small patients.…”