[Intracoronary isosorbide mononitrate versus placebo. A double-blind study with quantitative coronary angiography].

Purpose: To evaluate the vasodilation effect of intracoronary isosorbide mononitrate (ISMN) on the coronary arteries, systolic aortic pressure (SAP) and cardiac rhythms.

Methods: Forty patients aged 61 (40-72) years, 30 (75%) male, were randomized to receive on a double blind fashion, 20 mg of ISMN or placebo. The two groups had similar baseline characteristics. Quantitative coronary arteriography [by cardiovascular measurement system (CMS)] and SAP were compared before and after ISMN. We also observed the cardiac rhythm.

Results: There were no arrhythmias. Reference vessel diameter increased from 2.6 +/- 0.5 mm before to 2.9 +/- 0.4 mm after ISMN and did not change, mean 2.9 +/- 0.5 mm, before and after placebo. There was a difference between ISMN and placebo (p < 0.0001). There was no difference in the SAP change between the two groups, 4.2 +/- 0.7 mmHg with ISMN and 1.8 +/- 0.5 mmHg with placebo (p = NS).

Conclusion: ISMN promotes a safe and effective vasodilation of the coronary arteries with no major effects in cardiac rhythm and systolic aortic pressure.