EFFECTS OF THE IMMUNOSUPPRESSANT CYCLOSPORINE ON THE CIRCULATION OF HEART-TRANSPLANT RECIPIENTS

The effect of cyclosporine on the systemic circulation and on heart rate is unknown for heart transplant recipients. Thirty-four heart transplant recipients were studied by right-sided cardiac catheterization after endomyocardial biopsy. A direct linear relation was found between systemic and pulmonary vascular resistance and cyclosporine trough blood levels, which were negatively related to heart rate. The effect of cyclosporine on pulmonary vascular resistance, however, was not statistically significant by multivariate analysis when patient age was considered. In contrast, renal function appeared unrelated to systemic vascular resistance or heart rate. It appears that cyclosporine trough blood levels may have a direct effect on systemic vascular resistance as well as an unexplained negative chronotropic effect on heart rate.