During this long period many trials comparing an early invasive strategy with a conservative strategy in patients with unstable angina or NSTEMI have produced conflicting results that have delayed the current general consensus regarding the benefit of an early invasive strategy, which is more evident in high-risk patients and mainly driven by the decrease in MI and the need for percutaneous or surgical coronary revascularization. This troubled history might be explained at least in part by the design of most studies that randomized patients before cardiac catheterization and the use of a wide temporal windows—from 24 to 48 h to 5 days—for the definition of "early" intervention. Randomization before cardiac catheterization resulted in the enrolment of a high percentage (>30%) of patients who did not receive coronary revascularization, because of mild or absent atherosclerotic coronary artery disease in most of them, making the comparison of an early invasive strategy versus a conservative or a delayed invasive strategy in selected patients distorted by the high number of patients at low risk of events whatever the strategy adopted. The use of temporal windows as long as 24 to 48 h to several days
During this long period many trials comparing an early invasive strategy with a conservative strategy in patients with unstable angina or NSTEMI have produced conflicting results that have delayed the current general consensus regarding the benefit of an early invasive strategy, which is more evident in high-risk patients and mainly driven by the decrease in MI and the need for percutaneous or surgical coronary revascularization. This troubled history might be explained at least in part by the design of most studies that randomized patients before cardiac catheterization and the use of a wide temporal windows—from 24 to 48 h to 5 days—for the definition of "early" intervention. Randomization before cardiac catheterization resulted in the enrolment of a high percentage (>30%) of patients who did not receive coronary revascularization, because of mild or absent atherosclerotic coronary artery disease in most of them, making the comparison of an early invasive strategy versus a conservative or a delayed invasive strategy in selected patients distorted by the high number of patients at low risk of events whatever the strategy adopted. The use of temporal windows as long as 24 to 48 h to several days