PREDICTORS OF REVERSIBILITY OF PULMONARY-HYPERTENSION IN CARDIAC TRANSPLANT RECIPIENTS IN THE FIRST POSTOPERATIVE YEAR

Background Pulmonary hypertension remains a risk factor for early post operative mortality in heart transplantation and may reduce the long-t erm benefits of the procedure. This study was undertaken to assess the value of baseline hemodynamic studies with nitroprusside used to pred ict the degree of postoperative reversibility of pulmonary hypertensio n in cardiac transplant recipients and to identify clinical risk facto rs for fixed pulmonary hypertension. Methods and Results Hemodynamic d ata from 55 consecutive patients who underwent orthotopic cardiac tran splantation from June 1988 through September 1993 were analyzed. The e ffects of nitroprusside and transplantation on pulmonary artery pressu re, cardiac output, and pulmonary vascular resistance were compared. M ultiple regression analysis was used to identify the predictors of rev ersibility of pulmonary hypertension. Nitroprusside reduced pulmonary vascular resistance by increasing cardiac output and, to a lesser exte nt, by reducing the transpulmonary gradient. Pulmonary hypertension wa s less reversible in patients with ischemic heart disease (versus dila ted cardiomyopathy) and in former smokers (versus nonsmokers). Patient s with nonischemic heart failure and no smoking history had significan tly lower posttransplant pulmonary vascular resistance (1.24+/-0.45 Wo od units) than ischemic patients (who were all former smokers; 2.20+/- 1.01 Wood units) or nonischemic former smokers (1.72+/-0.70 Wood units ). The correlation of pulmonary vascular resistance during nitroprussi de challenge with posttransplant pulmonary vascular resistance was bet ter than that of baseline pulmonary vascular resistance with posttrans plant pulmonary vascular resistance. Conclusions Nitroprusside testing improves the prediction of late posttransplant pulmonary vascular res istance; hence, it provides data that may be relevant to both early op erative risk and later long-term effectiveness of cardiac transplantat ion. The finding of increased risk of fixed pulmonary hypertension ass ociated with ischemic heart disease and smoking suggests that underlyi ng atherosclerotic vascular disease may contribute to the irreversibil ity of pulmonary vascular resistance.