Objective: To evaluate the prognostic impact of endothelial function in patients with angina and angiographically normal coronary arteries.
Methods: In 147 consecutive patients with angina and normal coronary arteries on coronary angiography, we studied endothelial function by incremental intracoronary bolus of acetylcholine (ACh). Patients were divided in two groups according to their vasomotor response to ACh: 1) ACh+ group (n = 95), those with diffuse vasoconstriction during ACh administration; and 2) ACh- group (n = 52): those showing normal endothelial function. Cardiovascular events, including hospital admissions for unstable angina, myocardial infarction, coronary revascularization, stroke and cardiac death, were studied during a mean follow-up of 7 years.
Results: A total of 33 patients (22%) had cardiac events, 29 in the ACh+ group and 4 in the ACh- group (p = 0.002). ACh+ group patients had less time free of cardiovascular events (p = 0.001). Cox proportional regression analysis after controlling for conventional risk factors demonstrated that endothelial dysfunction was an independent predictor of cardiovascular events. If hospital admissions for unstable angina were excluded from the analysis, only 6 patients had major cardiac events, 5 patients in the ACh+ group vs. 1 patient in the ACh- group (p = 0.2).
Conclusion: A simple endothelial function test performed in patients with angina and normal coronary angiograms may identify a subgroup of patients with high probability of cardiovascular events on long-term follow-up, mainly hospital readmissions for worsening angina.