Pulmonary vascular resistance and the risk of heart transplantation.

Elevated pulmonary vascular resistance was an incremental risk factor for premature death after heart transplantation (p = 0.0002). Its effect was continuously variable and not dichotomous (yes or no). The rate of rise in risk of death corresponded quite evenly to the progressive increase in pulmonary vascular resistance from low to high values, rather than abruptly increasing at a certain point. This effect was incremental to the risk imposed by congenital heart disease (in contrast to idiopathic or ischemic cardiomyopathy). Expression of the pulmonary vascular resistance in units times square meters provides more accurate predictions than expression in Wood units (p for difference = 0.03).