The effects of pulmonary vascular impedance on right ventricular function pre- and post-heart transplantation

Purpose: The purpose of this study was to investigate the effects of donor brain death (BD) on right ventricular (RV) function in the setting of elevated pulmonary vascular resistance (PVR). RV failure is a leading cause of early morbidity and mortality following cardiac transplantation (TX) and is attributed to the donor RV inability to acutely compensate for the recipient's elevated PVR. Methods: Forty-eight 23-30 kg mongrel dogs underwent 24 bicaval orthotopic TX from 12 control donors (CTL) and 12 brain dead donors and were exposed to a significant increase in PVR. The hearts were instrumented with ultrasonic pulmonary artery flow probe, dimension transducers and micromanometers to measure donor and recipient RV preload-independent recruitable stroke work (PRSW). Fourier analysis was used to calculate RV power and its components (total power, mean and oscillatory power) as well as pulmonary impedance pre/post brain death, 4 hrs of hypothermic preservation and subsequent TX. Comparison of changes between baseline and groups were made using ANOVA and paired/unpaired Student's t-test (*denotes p<0.05). Results: Cardiopulmonary bypass times ranged between 72 and 86 min and were not significantly different between the groups. Fig. 1 shows the significant changes in RV power and impedance pre/post TX: RV-POWER (Graph Presented) BD-TX CTL-TX IMPEDANCE BD-TX CTL-TX Conclusions: Post transplant RV-PRSW were significantly decreased in the BD donor group compared to controls and 50% of the transplanted hearts required dopamine (p<0.0025) to support cardiac function. Transplant RV power decreased and pulmonary impedance increased significantly posttransplant and may contribute to RV Clinical Implications: The data suggest that manipulating pulmonary impedance may assist to stabilize RV function in the donor as well as in the transplant recipient.

Duke Scholars

Author Edward Po-Chung Chen Surgery, Cardiovascular and Thoracic Surgery