901-77 Reduction in β2-Receptor Autoantibody Level in Patients with Idiopathic Dilated Cardiomyopathy During Mechanical Cardiac Assist System Support

Abstract

Ten patients (pts) with idiopathic dilated cardiomyopathy were implanted with mechanical left ventricular assist devices (Novacor, TCI) as a bridge to transplantation. The following pre-implantation data was observed: right and left ventricular ejection fraction <20%, x-ray heart-lung ratio >0.68, left ventricular diameter > 7.9 cm, and central venous pressure >25 mmHg. All pts were in NYHA class IV and at least on a medium dose of catecholamines. β-receptor autoantibody (RAAB) levels were measured by bioassay before implantation and once a week postoperatively. All pts clinically recovered within 6-8 weeks, RAABs were not detected in two pts while in eight pts who preoperatively exhibited a relative level of 25 ± 8 the level decreased during the ensuing 14 weeks to zero in 6 pts. These 6 pts were supported with a device which operated synchronously with the patient's heart rate thus leading to optimal reduction in the afterload of the left ventricle (Fig.). The RAAB level decreased more gradually in the other 2 pts reaching zero three weeks later. A non-synchronized device which did not provide the same degree of afterload reduction was implanted in these pts (Fig.). Although they exhibited a reduction in RAABs and heart rate, a significant improvement in cardiac function, and a decrease in heart size, the two pts with no detectable RAABs exhibited neither an improvement in cardiac function nor a reduction in cardiac diameter. Mechanical cardiac assist device support not only leads to an improvement in the hemodynamic condition of pts, but apparently also in immunological changes, such as a diminished presentation of specific antigens and a consecutive reduction of autoantibodies, which in the future may be important in assessing the indication for weaning from cardiac assist devices instead of performing transplantation.