Chronic Total Coronary Occlusions, Percutaneous Coronary Intervention, and Mortality: A "Hybrid Approach" to Interpretation.

C hronic total coronary occlusions (CTOs) represent one of the final frontiers in the evolution of revascularization with percutaneous coronary intervention (PCI). Although CTO revascularization relieves symptoms, reduces ischemic burden, improves left ventricular systolic function, and attenuates remodeling, convincing proof of improved survival remains elusive (1–3). Ongoing randomized trials such as EXPLORE (Evaluating XIENCE V and Left Ventricular Function in PCI on Occlusions After STEMI; NTR1108) (4), DECISION-CTO (Drug-Eluting Stent Implantation Versus Optimal Medical Treatment in Patients With Chronic Total Occlusion; NCT01078051), and EuroCTO (European Study on the Utilization of Revascularization Versus Optimal Medical Therapy for the Treatment of Chronic Total Coronary Occlusions; NCT01760083) will augment our understanding of long-term CTO outcomes (5), but none of these trials is statistically designed to detect mortality differences. Estimates of the mortality risks associated with CTO and the potential survival benefits of CTO PCI therefore remain founded in estimates from robust observational series (6–11).