Implantation of HIA-Medos system in children with and without cardiopulmonary bypass

Introduction

Mechanical circulatory assistance is a routine procedure in severe heart failure. The goal of the HIA-Medos system is to develop two miniaturized ventricles for cardiovascular support in children. We report our experiences with implantation of the HIA-Medos system in children with and without cardiopulmonary bypass.

Method

A HIA-Medos system was implanted by cannulation in the right atrium and the pulmonary artery for right heart support. In bridge-to-transplant patients, the left ventricle and the ascending aorta were cannulated for left heart support. In those patients who were expected to recover, the left atrium was cannulated. Cardiopulmonary bypass was instituted using standard techniques.

Results

Five patients (ages 5 days, 5 months, and 1, 5 and 8 years) were supported. Body weights ranged from 3.5 to 20 kg, and body surface area from 0.19 to 0.83 m². The underlying disease was myocarditis in two patients, dilatative cardiomyopathy in one patient, d-transposition of the great arteries in one patient, and undetected Bland-White-Garland syndrome in one patient. Four patients underwent biventricular support, and one had left heart support. One patient had postoperative low-output syndrome, who could be weaned after a support time of 5 days. The HIA-Medos system was implanted in three out of the four bridge-to-transplant patients, with cardiopulmonary bypass. In these three patients re-exploration was necessary because of bleeding complications due to disturbed coagulation cascade. They received a mean of 2.9 erythrocyte concentrates per support day. The patients died because of multiple organ failure, among other complications. In the fourth child the HIA-Medos system was implanted without cardiopulmonary bypass. No bleeding complication occurred. Pre-existant organ dysfunction recovered. Disturbances of coagulation system were not apparent.

Conclusion

Postoperative bleeding is the most frequent complication in children supported by the HIA-Medos system with cardiopulmonary bypass. Multiple transfusions were necessary, and the patients treated died because of multiple organ failure. Implantation without cardiopulmonary bypass appears to prevent bleeding complications, with nearly normal coagulation conditions. Recovery of all pre-existent major organ dysfunctions occurred.