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[Endothelial dysfunction and coronary vasomotricity. Contribution of endocoronary echography]
A Castaigne1, P Dupouy, H Geschwind
1Service de cardiologie, hôpital Henri-Mondor, Créteil.
Insights
Coronary artery disease impairs endothelial function, causing abnormal blood vessel responses. This study shows loss of flow-dependent vasodilation and reversed responses to stimuli in patients with atherosclerosis.
Area of Science:
- Cardiovascular Physiology
- Endothelial Function Research
- Atherosclerosis Pathophysiology
Background:
- Coronary artery diameter and flow are normally coupled, dependent on intact endothelial function.
- Endothelial dysfunction and atherosclerotic lesions disrupt normal vasomotor responses to stimuli.
- Loss of flow-dependent vasodilation is an early sign in cardiovascular risk factors.
Purpose of the Study:
- To investigate the impact of coronary atherosclerosis on vasomotor responses and endothelial function.
- To compare angiographic and endocoronary ultrasonography findings in assessing vasomotor abnormalities.
- To confirm global endothelial function alterations in atherosclerotic coronary artery disease.
Main Methods:
- Utilized angiographic techniques and endocoronary ultrasonography to assess coronary vasomotor responses.
- Administered vasodilators (papaverine, Sin 1) and physiological stimuli (cold pressor test) to normal subjects and patients.
- Measured changes in coronary artery diameter in response to stimuli and flow alterations.
Main Results:
- Normal subjects exhibited flow-dependent increases in coronary diameter; this was lost in patients with atherosclerosis.
- Acetylcholine induced abnormal vasoconstriction in patients, even in non-lesioned segments.
- Vasodilatation responses to papaverine and cold pressor test were blunted in patients, while Sin 1 showed comparable effects in both groups.
Conclusions:
- Endothelial function is globally impaired in patients with atherosclerotic coronary artery disease.
- Loss of flow-dependent vasodilation is a key indicator of endothelial dysfunction in atherosclerosis.
- Endocoronary ultrasonography can effectively document these altered vasomotor responses.
Abstract:
The regulation of flow and diameter of the coronary arteries depends on many factors. In normal subjects, increased coronary flow is associated with an increase in diameter of the epicardial coronary vessels. The coupling of these two independent variables depends on the integrity of endothelial function. In isolated arteries suppression of the endothelium induces an abnormal vasomotor response to acetylcholine. The presence of atherosclerotic lesions on the coronary vessels also induces the opposite response to the administration of acetylcholine, even in apparently normal segments. Other physiological coronary vasodilator stimuli, especially those which increase the concentration of noradrenaline, become vasoconstrictor in diseased coronary vessels. Finally, increasing coronary blood flow is not associated with increases in coronary diameter in patients with coronary atherosclerosis. This loss of flow-dependent vasodilatation is an early and diffuse phenomenon in subjects with cardiovascular risk factors. The authors have shown that this inversion of vasomotor responses observed by angiographic techniques, may also be documented by endocoronary ultrasonography. Their results demonstrate that the vasodilatation induced by papaverine or by the cold pressor test in 6 normal subjects is lost in 20 patients with coronary atherosclerosis and that the administration of Sin 1 induces a comparable vasodilatation in normal and diseased vessels. This study confirms that endothelial function is globally altered in atherosclerotic coronary artery disease.