Angiographic Follow-up in the Evaluation of New Technologies for Coronary Intervention

T he choice of a primary end point for evaluating the long-term results of percutaneous coronary interventions has come full circle since Andreas Gruentzig first evaluated the initial Zurich experience.' At that time, he equated the long-term success of percutaneous transluminal coronary angioplasty (PTCA) (predominantly in patients with single-vessel disease) to ongoing freedom from a composite of ischemic clinical events that included death, myocardial infarction, angina, and repeat revascularization. Subsequently (after 1986), these broadbased clinical end points were largely supplanted by follow-up quantitative angiography, which provided a more precise measurement of late-term failure in terms of the extent of local renarrowing at the initial treatment site. Given the then-current view of restenosis as a binary outcome (prevalent until 1992), however, a variety of definitions of restenosis were used to dichotomize late angiographic findings, many of which did not completely parallel the late clinical recurrence of ischemia. This clinical-angiographic disparity has increasingly troubled many investigators and has led to their devaluing the importance of follow-up angiography.2 Within the past year, there has been a renewed interest in bringing back composite clinical events as the principal outcome by which the long-term benefits of coronary intervention are measured.