Hemodynamic action of captopril in coronary patients with heart failure tolerant to nitroglycerin

At present there is little dispute that clinical tolerance of organic nitrates occurs during long-term treatment of patients with stable angina pectoris and congestive heart failure.

Captopril exerts a favorable hemodynamic effect in coronary patients with heart failure who are clinically tolerant to nitroglycerin.

Development of nitrate tolerance was observed during intravenous nitroglycerin treatment (10 mg/h) in 16 of 19 patients (7 women, 12 men; mean age 56 +/- 8 years) with coronary heart disease [stenosis > or = 75%, New York Heart Association (NYHA) classes II-III). The criterion applied was a loss of efficacy of at least 50% with regard to mean pulmonary capillary wedge pressure compared with the maximum effect of nitrate. The effect of captopril (50 mg p.o.) was determined in a blank test. Captopril (50 mg p.o.) was administered again at the stage of clinically manifest nitrate tolerance.

Compared with the effect of captopril alone, significantly more pronounced reductions in mean pulmonary capillary wedge pressure (33% compared with 27%) and in mean pulmonary arterial pressure (36% compared with 17%) and significantly greater increases in cardiac index (14% compared with 7%) and stroke work index (34% compared with 18%) (p < 0.05 in each case; Wilcoxon test for linked random samples) were measured. Maintaining nitroglycerin infusion, the effect of captopril (at least 90% of the maximum effect) lasted for 123 +/- 24 min. The baseline values (at least 75% decline in the effect of captopril) were only reached after 369 +/- 34 min.

The results document a favorable hemodynamic effect of captopril in nitrate tolerance which is significantly better than that of captopril alone.