International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA)

ISCHEMIA is an international comparative effectiveness study. The primary objective of this study is to determine whether an invasive (INV) strategy of routine early cardiac catheterization with intent for optimal revascularization in addition to optimal medical therapy in patients with stable ischemic heart disease (SIHD) and at least moderate ischemia on stress imaging reduces the incidence of the composite of cardiovascular death or nonfatal myocardial infarction compared with a conservative (CON) strategy of optimal medical therapy alone with cardiac catheterization and revascularization reserved for patients with refractory angina, acute coronary syndrome, acute ischemic heart failure or resuscitated cardiac arrest. Secondary to this, the study aims to determine whether an INV strategy is more effective than CON strategy in improving angina control, as assessed by the Seattle Angina Questionnaire (SAQ) Angina Frequency scale, and disease-specific quality of life, as assessed by the SAQ Quality of Life scale. Enrollment will occur over approximately 4 years with an expected minimum of 18-24 months follow-up and an average of approximately 4 years follow-up. Approximately 8,000 patients with at least moderate ischemia will be randomized in a 1:1 fashion to an INV or CON strategy. This sample size is expected to provide over 90% power to detect a 15% reduction in the primary composite event rate in participants randomized to INV as compared with CON strategy.