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Variable response of the peripheral circulation to acetylcholine in patients with coronary artery disease
M Testa1, L M Biasucci, M Cacciola
1Institute of Cardiology, Catholic University, Rome, Italy.
Insights
Patients with coronary artery disease show reduced and variable peripheral vasodilation in response to acetylcholine, indicating impaired endothelial function. This contrasts with normal responses to nitroglycerin, highlighting specific endothelial dysfunction in coronary artery disease patients.
Area of Science:
- Cardiovascular Medicine
- Vascular Biology
- Diagnostic Imaging
Background:
- Endothelial dysfunction is a key factor in coronary artery disease (CAD).
- Peripheral circulation can reflect systemic endothelial health.
- Assessing peripheral vasodilation may offer insights into CAD-related endothelial impairment.
Purpose of the Study:
- To evaluate endothelium-mediated vasodilation in the peripheral arteries of patients with CAD.
- To compare peripheral vascular responses to acetylcholine and nitroglycerin in CAD patients versus controls.
Main Methods:
- Doppler ultrasonography was used to measure vascular response in the superficial femoral artery.
- Endothelium-dependent vasodilation was tested using acetylcholine (10-7 to 10-5 mol/L).
- Endothelium-independent vasodilation was tested using nitroglycerin (10-8 to 10-6 mol/L).
Main Results:
- Vascular responses to nitroglycerin were similar between CAD patients and controls.
- Responses to acetylcholine were significantly different, showing reduced vasodilation in CAD patients (e.g., acetylcholine 10-6 mol/L flow velocity ratio: 1.15 +/- 0.35 vs. 2.20 +/- 1.06).
- Acetylcholine response in CAD patients exhibited high variability compared to controls.
Conclusions:
- Patients with angiographically proven CAD exhibit reduced and highly variable peripheral vasodilation to acetylcholine.
- This suggests impaired endothelial function in the peripheral circulation of CAD patients.
- Peripheral vascular assessment may serve as a marker for endothelial dysfunction in CAD.
Abstract:
The purpose of this study was to assess endothelium-mediated vasodilation in the peripheral circulation of patients with coronary artery disease who are free from hypertension, hypercholesterolemia, diabetes mellitus, and congestive heart failure. The vascular response of the superficial femoral artery to an endothelium-dependent (i.e., acetylcholine 10-7, 10-6, and 10-5 mol/L) and to an endothelium-independent (i.e., nitroglycerin 10-8 and 10-6 mol/L) dilator was compared in 13 patients with angiographically documented coronary artery disease and in 7 patients with normal coronary angiograms. Vascular response was assessed by Doppler ultrasonography. Whereas the vascular responses to nitroglycerin in patients with abnormal and normal findings on coronary angiograms were similar, the responses to acetylcholine were clearly different. The ratio of mean blood flow velocity (+/-SD) measured during administration of acetylcholine 10-6 mol/L and mannitol was significantly lower in patients with abnormal versus normal results of coronary angiography (1.15 +/- 0.35 vs 2.20 +/- 1.06; p < 0.05). The vascular response to acetylcholine 10-5 mol/L in patients with an abnormal finding on their coronary angiogram was highly variable when compared with that in patients with normal results. Thus, in patients with angiographically proven coronary artery disease, the response of the peripheral circulation to acetylcholine is characterized by a great variability and a reduced sensitivity, when compared with that in patients with normal findings on coronary angiography.