Interventional therapy of the acute coronary syndromes

The acute coronary syndromes (ACS) have in common rupture of a vulnerable plaque, leading to exposure of the subendothelial surface and plaque core. The resultant thrombosis leads to a variable degree of flow occlusion, the extent of which differentiates the three syndromes and their treatment by percutaneous coronary intervention (PCI). The guiding principle in the decision when to use PCI in the ACS is that the more time critical and high risk the clinical situation, the more likely it is that PCI will improve ultimate outcome. The use of risk stratification by clinical variables can lead to better triage of patients with non-ST-elevation myocardial infarction (MI) and unstable angina between PCI and medical management. Patients presenting with symptoms suggestive of prolonged ischemia should have an electrocardiogram searching for ST changes, a targeted physical, and blood drawn for rapid assay of cardiac enzymes. In the event that ST elevations suggest infarction, while medical therapy is initiated, emergency cardiac catheterization can be organized. PCI in ACS requires adjunctive antiplatelet and antithrombin therapy, and, in general, coronary stenting is advisable. Among patients with non-ST-elevation MI or unstable angina who can be medically stabilized, the presence of high clinical risk scores would favor early coronary angiography. In their absence, medical therapy can be pursued, unless recurrent ischemia occurs. When the patient's condition is stable, evaluation by stress testing can be used to guide further decisions.