Unstable angina: from physiopathology to therapeutics]

Unstable angina is a term which encompasses several clinical syndromes (crescendo angina, angina de novo, resting angina, postinfarction angina), intermediary between stable angina and myocardial infarction. The results of coronary angioscopy have allowed differentiation of accelerated effort angina which seems related to ulceration of an atheromatous plaque from resting angina, more commonly associated with intraluminal thrombosis. The diagnosis of unstable angina is clinical and justifies immediate hospital admission to a coronary care unit because of the risk of myocardial infarction and/or sudden death. Medical management comprises triple anti-ischemic therapy (nitrate derivatives, betablockers, calcium antagonists), anticoagulants and platelet antiagregants. Randomised therapeutic trials versus placebo have shown that this treatment decreases the incidence of refractory angina and myocardial infarction. Several studies are under way to assess the role of thrombolytic therapy in unstable angina. When unstable angina is refractory to maximal medical therapy, emergency coronary angiography should be performed. However the outcome is usually favourable and coronary angiography can be performed several days after the acute event. The coronary lesion responsible for unstable angina is often "complex", an eccentric, irregular, severe stenosis or appearances of thrombosis. Whenever possible, depending on the coronary lesion, myocardial revascularisation by coronary angioplasty or aorto-coronary bypass should be proposed. Surgical treatment has been shown to be more effective (symptomatic relief, improved survival) than medical therapy in patients with triple vessel disease. However, the results of studies comparing medical or surgical treatment with coronary angioplasty are not yet available.