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 m2 (median = 0.54 m2 ). 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.
Subject(s)
Heart Transplantation , Heart-Assist Devices , Child , Child, Preschool , Equipment Design , Extracorporeal Membrane Oxygenation , Female , Fontan Procedure/adverse effects , Fontan Procedure/methods , Heart-Assist Devices/adverse effects , Humans , Infant , Male , Natriuretic Peptide, Brain/analysis , Oxygenators, MembraneABSTRACT
BACKGROUND: A continuous-flow "adult" ventricular assist device (VAD) was modified to support infants and children waiting for heart transplantation. METHODS: A centrifugal VAD, designed to flow at 1.5 to 8 L/min, was used as a bridge to transplantation in pediatric patients. In smaller children and infants, a modified recirculation shunt permitted lower flow ranges. In hypoxic patients, an oxygenator was spliced into the circuit. RESULTS: From 2010 to 2015, the VAD was placed in 13 consecutive patients. Age ranged from 0.9 to 16 years (median, 7 years). Body surface area (BSA) ranged from 0.4 to 2.1 m(2) (median, 0.8 m(2)). Ten patients had a BSA less than 1.0 m(2). Four patients were receiving extracorporeal membrane oxygenation (ECMO) before VAD. Three patients had single-ventricle physiology. Five patients had a recirculation shunt and 3 underwent insertion of an oxygenator. Median time on the VAD was 20 days (range, 2-140 days). In patients with a recirculation shunt, mean patient flow was 1.5 L/min (mean flow/BSA, 2.7 L/min/m(2)), with mean total VAD flow of 3.4 L/min. Twelve patients underwent transplantation, and 1 patient underwent VAD explantation. All patients survived and were discharged at a median of 26 days (range, 17-83 days) after transplantation. Three patients experienced major bleeding events. There were 2 cerebrovascular accidents. VAD mortality dropped from 33% (3 of 9) during 2007 to 2010 to 0% (0 of 13) between 2011 and 2015 (p = 0.05). Wait-list mortality dropped from 10% (5 of 52) to 4% (4 of 91) for these periods (p = 0.29). CONCLUSIONS: The centrifugal VAD successfully supported pediatric patients awaiting heart transplantation. The modified recirculation shunt facilitated the successful support of patients in whom optimal flows were substantially lower than those recommended by the manufacturer. The design allows placement of an in-line oxygenator. Compared with pulsatile devices, use of this VAD was associated with a trend toward decreased mortality associated with VAD use.
Subject(s)
Heart Defects, Congenital/surgery , Heart-Assist Devices , Adolescent , Child , Child, Preschool , Equipment Design , Female , Follow-Up Studies , Heart Transplantation , Heart Ventricles , Humans , Infant , Male , Retrospective StudiesABSTRACT
PURPOSE: The development of pediatric ventricular assist device (VAD) circuits with lower flow ranges for infants and small children is ongoing. We present our results with modifying a readily available adult VAD to support the pediatric population. DESCRIPTION: The TandemHeart VAD (CardiacAssist, Pittsburgh, PA) circuit was modified to include a variable restrictive recirculation shunt to permit lower flow ranges in small pediatric patients. EVALUATION: Initial benchtop flow rates and pressures were studied. Hemolysis trials were performed using whole bovine blood to compare plasma-free hemoglobin levels between modified and unmodified VAD circuits. The modified VAD was surgically implanted in 7 piglets (6 to 14 kg) and which supported them for 4 hours. Levels of hemolysis did not increase and full hemodynamic support was achieved. The modified TandemHeart VAD with a recirculation shunt was subsequently implanted in 2 pediatric patients who were bridged to transplant successfully. CONCLUSIONS: Because of its simplicity, availability, low prime volume, greater patient flow range, and lower cost, the modified TandemHeart VAD with a recirculation shunt should be considered as an alternative to extracorporeal membrane oxygenation and other pulsatile VADs in children.
