[Vasomotor activity and coronary insufficiency]

Abstract

Provocative testing has provided a method of evaluating the important role of vasomotor tone in coronary artery disease. The most sensitive test is the ergonovine (Methergin) test. This is a specific and reliable method of defining the clinical situations in which coronary spasm is common: --focal coronary artery spasm is mainly observed in resting angina alone or in association with effort angina. The prognosis of spasm is excellent with calcium antagonist therapy provided there is no other associated pathology such as left ventricular failure or triple vessel disease; --in the six weeks following myocardial infarction, focal coronary artery spasm is a common event: 20% of coronary angiographies. After six weeks, spasm is much less frequent. It does not influence the prognosis. This type of spasm is probably related to the scarring process; --coronary artery spasm is frequently associated with restenosis after coronary angioplasty, a process which is histologically related to proliferation of smooth muscle; --diffuse increase in coronary vasomotor tone is a much rarer pathology, perhaps related to global changes in vascular tone as its association with the Raynaud syndrome and with migraine would suggest. It presents clinically with resting angina and sometimes by typical Prinzmetal angina; --finally, vosomotor tone plays an important role in the daily life of coronary patients. Holter recordings for the detection of silent myocardial ischemia have shown episodes of myocardial ischemia at lower myocardial oxygen consumption levels than those usually recorded during exercise stress testing, which suggests a reduction in oxygen supply, that is to say coronary vasoconstriction. Changes in coronary vasomotor tone can modify the diameter of healthy coronary arteries by 100%.(ABSTRACT TRUNCATED AT 250 WORDS)