Evaluating risk in unstable angina: role of pharmacological stress echocardiography.

The appropriate management of the individual patient presenting with unstable angina remains challenging for physicians, despite improved knowledge of the pathophysiology of acute coronary syndromes and considerable increased availability of diagnostic techniques and treatment regimens. Unstable angina is most frequently the consequence of acute disruption of a vulnerable, usually lipid-rich, atherosclerotic plaque. Plaque erosion or rupture predisposes to platelet aggregation, thrombus formation, platelet and/or thrombin-dependent vasoconstriction, microembolization and microvascular damage. Imbalance between myocardial oxygen supply and demand provokes ischaemia, with or without electrocardiographic changes. Increased thrombogenicity carries the risk of progression to complete coronary occlusion leading to myocardial infarction or cardiac death. Patients with suspected unstable angina should be and usually are rapidly admitted to the emergency department of a hospital where diagnosis and risk stratification must be obtained. In the presence of ongoing chest pain and ST segment elevation on the admission electrocardiogram (ECG), the diagnosis is acute myocardial infarction and a strategy of immediate reperfusion should be initiated.