Unstable angina: current concepts of pathogenesis and treatment.

During the past 15 years, we have learned an enormous amount about the pathogenesis and treatment of unstable angina. In most cases of unstable rest angina, the pathogenesis is a mural thrombus formation on a ruptured or eroded atherosclerotic plaque. However, any process that acutely changes the supply-demand ratio (decreased supply or increased demand in the presence of a decrease in supply) can precipitate the clinical presentation of unstable angina. Standard acute antithrombotic drug therapy is effective in decreasing progression to infarction. Newer agents (low-molecular-weight heparin and platelet glycoprotein IIb/IIIa inhibitors) are more effective, and their use is evolving. Percutaneous intervention and bypass surgery can reduce symptoms and multiple hospitalizations, in most cases without a decrease in the long-term mortality rate. Because the cost of hospitalization is extremely high and the clinical presentation and outcome are heterogeneous, better triage methods are required.