Cardiac Output, and Vascular Resistance in Cardiac Transplant Recipients

Background An attenuated or absent nocturnal decline in blood pressure has repeatedly been documented in cardiac transplant recipients. The present study was aimed at investigating the hemodynamic mechanism underlying this abnormality. Methods and Results In 23 cardiac transplant recipients (11 to 36 months after transplantation) and in 23 control subjects matched for age and 24-hour mean arterial pressure, invasive 24-hour ambulatory blood pressure was measured by means of the Oxford technique. Beat-to-beat relative values of stroke volume were determined by means of a pulse-contour method, and relative changes of cardiac output (stroke volumexheart rate) and total peripheral vascular resistance (blood pressure/ cardiac output) over the 24-hour period were calculated. The nocturnal decline in blood pressure was 20±8% (mean±SD) in control subjects but only 5+9% (P<.001) in cardiac transplant recipients. In control subjects, the nocturnal decline in blood pressure was associated with a nocturnal fall in cardiac output of 24±13%, whereas vascular resistance compared with