Patients with acute STEMI were randomly assigned to undergo infarct-vessel-only PCI or preventive PCI (PCI to noninfarct arteries with stenoses). The rate of the primary outcome of cardiac death, myocardial infarction, or refractory angina was lower with preventive PCI. Patients with acute ST-segment elevation myocardial infarction (STEMI) are effectively treated with emergency angioplasty, hereafter called percutaneous coronary intervention (PCI), to restore blood flow to the coronary artery that is judged to be causing the myocardial infarction (infarct artery, also known as culprit artery). 1 – 5 These patients may have major stenoses in coronary arteries that were not responsible for the myocardial infarction, 6 but the value of performing PCI in such arteries for the prevention of future cardiac events is not known. Some physicians have taken the view that stenoses in noninfarct arteries may cause serious adverse cardiac events that could . . .