Endothelial dysfunction of the non-infarct related, angiographically normal, coronary artery in patients with an acute myocardial infarction

Abstract

Background: Patients with acute myocardial infarction and single-vessel disease may have early atherosclerosis in other angiographically normal coronary arteries. Methods: Coronary endothelial responses were analysed in 20 non-diabetic patients with an acute myocardial infarction and one-vessel disease. In an angiographically normal, non-infarct related, coronary artery serial acetylcholine doses of 10-7 M, 10-6 M, 10-5 M and 10-4 M and nitroglycerin 40 μg were infused over 3 min. The responses of the coronary vessel were measured with quantitative angiography. Coronary blood flow was also measured with a Doppler catheter in 11 of the 20 patients. Results: Four patients showed a trend towards vasodilation during acetylcholine infusion in the proximal and distal segments: from 2.49 ± 0.23 mm to 2.95 ± 0.42 mm and 2.43 ± 0.56 mm to 2.81 ± 0.66 mm, respectively. Coronary vascular resistance decreased to 57 ± 4% (P = 0.03). The other 16 patients presented vasoconstriction in the proximal and distal segments: 2.61 ± 0.75 mm to 2.03 ± 0.65 mm (P = 0.0001), and 2.40 ± 0.58 to 1.81 ± 0.56 mm (P = 0.0036), respectively. Nitroglycerin caused vasodilation in the proximal (2.69 ± 0.61 mm, P = 0.017, ANOVA) and distal segments (2.48 ± 0.45 mm, P = 0.009, ANOVA). Coronary vascular resistance increased to 141 ± 43% (P = 0.03) over the basal value in this group of patients. Conclusion: Endothelial dysfunction of the epicardial and resistance vessels was found in angiographically normal coronary arteries of patients with one-vessel disease in 75% of this population.