Relation between recipient: donor body size match and hemodynamics three months after heart transplantation

Cardiac allograft hemodynamics were compared with respect to donor and recipient body weights to determine whether recipient: donor body size match played a significant role in subsequent recipient hemodynamics. Thirty-four stable outpatients underwent resting right-sided cardiac catheterizations 3 months after heart transplantation. As expected, resting cardiac output correlated positively with recipient body weight (r = 0.50, p = 0.002), and mean cardiac index (2.7 +/- 0.6 L/min/m2) was normal. There was, however, only a weak and statistically insignificant correlation between recipient body weight and stroke volume (r = 0.31, p = 0.072). There was a statistically significant negative correlation between donor: recipient body weight ratio and right arterial pressure (r = 0.41, p = 0.017), pulmonary wedge pressure (r = 0.38, p = 0.027), and heart rate (r = 0.39, p = 0.024). These data demonstrate that although cardiac output is maintained at levels appropriate for recipient size after heart transplantation, patients who receive small hearts rely on an increased heart rate and elevated filling pressures to achieve this end. These data suggest that the cardiac allograft may not adapt to recipient body size by 3 months after transplantation.