Long-term clinical results after vasodilator evaluation in patients with primary (unexplained) and secondary precapillary pulmonary hypertension: acute hemodynamic comparisons and long-term survival

Abstract

Acute hemodynamic and long-term clinical effects of 6 different vasodilators (oxygen, isoproterenol, isosorbide, phentolamine, diazoxide, and hydralazine) were evaluated in 16 consecutive patients with precapillary pulmonary hypertension. Acute symptomatic and quantitative hemodynamic responses to different vasodilators in different patients were nonuniform and unpredictable. For the whole patient group, cardiac outputs increased slightly after all drugs except oxygen. Mean pulmonary pressure decreased after oxygen and increased after isoproterenol. In general, the hemodynamic effects of vasodilators in primary and secondary precapillary pulmonary hypertension were similar. In 10 patients, an acute increase in cardiac output (4.4 to 5.4 l/min, P<0.005) was associated with a small but significant decrease in the mean pulmonary artery pressures (59 to 53 mm Hg, P<0.05) after one of the oral vasodilators, and continued treatment with this drug transiently decreased symptoms in 6 of these 10 patients. However, only 1 patient could be continued on treatment beyond 5 months. Long-term survival was related to initial New York Heart Association Functional Class ( P<0.02) and the initial cardiac output ( r 2=0.84, P<0.002). Patient stratification according to these variables may be useful in future clinical trials treating patients with precapillary pulmonary hypertension.