Reevaluating the significance of pulmonary hypertension before cardiac transplantation: Determination of optimal thresholds and quantification of the effect of reversibility on perioperative mortality

Objectives: Right-sided circulatory failure resulting from severe preoperative pulmonary hypertension is a source of mortality early after cardiac transplantation. We undertook the present study (1) to analyze the association of elevated pulmonary hemodynamic indices with 30-day mortality, (2) to define threshold ranges associated with an increase in 30-day mortality, and (3) to evaluate the effect of vasodilator reversibility on 30- day mortality. Methods: Preoperative hemodynamic profiles were evaluated in 476 patients who ultimately underwent cardiac transplantation. From these data, receiver-operating characteristic curves and stratum-specific likelihood ratios were generated to compare the efficacy of each hemodynamic index. A subset of patients with elevated hemodynamic profiles at baseline additionally underwent graded sodium nitroprusside infusion. Results: Analysis of receiver-operating characteristic curves demonstrated no statistically significant difference among the indices in their ability to predict 30-day mortality. Analysis of stratum-specific likelihood ratios demonstrated three risk strata that correlated with significant differences in 30-day mortality, with patients in the high-risk stratum having a 3.2 to 4.4 increase in odds of 30-day mortality when compared with patients in the low-risk stratum. Nitroprusside data demonstrated that although 30-day mortality was better in patients with reversible pulmonary hypertension than in those with fixed pulmonary hypertension, it was not comparable with that of patients without pulmonary hypertension at baseline. Conclusions: Candidates for cardiac transplantation may be categorized into three risk strata on the basis of their preoperative pulmonary hemodynamic profile; the association of this profile with 30-day mortality is not linear. Reversibility with nitroprusside appears to confer some improvement in the risk of 30-day mortality, but it may not eliminate the risk entirely.