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Impaired endothelium-dependent cholinergic coronary vasodilation in patients with angina and normal coronary
1Department of Cardiology, University Hospital, Antwerp, Belgium.
Insights
Patients with normal coronary arteries and angina may have impaired endothelium-dependent vasodilation, leading to abnormal vasoconstriction and contributing to chest pain and myocardial ischemia.
Area of Science:
- Cardiology
- Vascular Biology
- Clinical Medicine
Background:
- Endothelial dysfunction is a key factor in coronary artery disease.
- The role of endothelial function in patients with angina and normal coronary arteries is not fully understood.
Purpose of the Study:
- To investigate coronary vasomotor responses to acetylcholine in patients with normal coronary arteries and angina, compared to those with coronary artery disease.
- To determine if impaired endothelium-dependent vasodilation contributes to angina in patients with normal coronary arteries.
Main Methods:
- Quantitative coronary arteriography was used to assess vasomotor responses.
- Acetylcholine was selectively infused into the left anterior descending artery at graded concentrations.
- Patients included those with normal coronary arteries (atypical and typical angina) and coronary artery disease.
Main Results:
- Patients with normal coronary arteries and atypical chest pain showed vasodilation.
- Patients with coronary artery disease and those with typical anginal pain and normal arteries exhibited dose-dependent vasoconstriction in response to acetylcholine.
- Isosorbide dinitrate relieved pain and dilated vessels in patients with typical angina and normal arteries.
Conclusions:
- Patients with normal coronary arteries and angina pectoris display impaired endothelium-dependent vasodilation, similar to patients with coronary atherosclerosis.
- Abnormal coronary vasoconstriction may play a role in the development of myocardial ischemia and angina in these patients.
Abstract:
The coronary vasomotor responses to selective infusion of graded concentrations (10(-6) to 10(-4) M) of acetylcholine into the left anterior descending artery were assessed by quantitative coronary arteriography in 24 patients with normal coronary arteriograms (12 patients with atypical symptoms and 12 patients with typical anginal pain) and 36 patients with coronary artery disease with different degrees of atherosclerosis of the left anterior descending artery. In the patients with normal coronary arteries and atypical chest pain, acetylcholine induced predominantly a vasodilator response, which was maximal during a 10(-5) M acetylcholine infusion. In contrast, in patients with coronary artery disease, acetylcholine caused dose-dependent vasoconstriction, which was observed even if the left anterior descending artery itself was smooth. Marked vasoconstriction was also induced in the patients with typical anginal pain and angiographically normal coronary arteries. In nine of these patients, this constrictor response was associated with anginal pain and electrocardiographic evidence of myocardial ischemia. Intracoronary administration of isosorbide dinitrate (1 mg) relieved the anginal pain and dilated all vessels. These data suggest that 1) patients with normal coronary arteriograms and angina pectoris manifest impairment of endothelium-dependent vasodilation similar to that observed in patients with overt coronary atherosclerosis; and 2) abnormal coronary vasoconstrictor responses resulting from this impairment may contribute to the pathogenesis of myocardial ischemia and angina in these patients.