HEMODYNAMIC ACTION OF CAPTOPRIL IN CORONARY PATIENTS WITH HEART-FAILURE TOLERANT TO NITROGLYCERIN

Background: At present there is little dispute that clinical tolerance of organic nitrates occurs during long-term treatment of patients wit h stable angina pectoris and congestive heart failure. Hypothesis: Cap topril exerts a favorable hemodynamic effect in coronary patients with heart failure who are clinically tolerant to nitroglycerin. Methods: Development of nitrate tolerance was observed during intravenous nitro glycerin treatment (10 mg/h) in 16 of 19 patients (7 women, 12 men mea n age 56 +/- 8 years) with coronary heart disease [stenosis greater th an or equal to 75%, New York Heart Association (NYHA) classes II-m). T he criterion applied was a loss of efficacy of at least 50% with regar d to mean pulmonary capillary wedge pressure compared with the maximum effect of nitrate. The effect of captopril (50 mg p.o.) was determine d in a blank test. Captopril (50 mg p.o.) was administered again at th e stage of clinically manifest nitrate tolerance. Results: Compared wi th the effect of captopril alone, significantly more pronounced reduct ions 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 m aximum effect) lasted for 123 +/- 24 min. The baseline values (at leas t 75% decline in the effect of captopril) were only reached after 369 +/- 34 min. Conclusion: The results document a favorable hemodynamic e ffect of captopril in nitrate tolerance which is significantly better than that of captopril alone.