Utility of CT Angiography to Guide Coronary Intervention of CTO.

SEE PAGE 804 T he procedural success rates of percutaneous intervention for chronic total coronary occlusions (CTOs) over the past decade have been increasing, driven by the development of specialized guidewires and microcatheters and the introduction of new technical strategies, including antegrade subintimal re-entry and the retrograde transcollateral approach. An ongoing challenge is to select the most promising strategy early to reduce total procedure time, to reduce radiation and contrast exposure, and to further improve complication-free procedural success rates. In this regard, procedural planning is typically based on the angiographic assessment of the occluded lesion, including features of the proximal cap, the extent of calcification, and the apparent length of the lesion (1). Pre-procedural coronary computed tomographic angiography (CTA) with modern high-resolution scanners may provide incremental information about the features of the coronary occlusion, which might enhance procedural planning and outcomes. In early studies in which coronary CTA was used to visualize CTOs, the prominent features observed were the extent of calcification, occlusion length, and identification of the vessel course within a long occluded segment (2,3). In more recent studies with improved resolution computed tomography (CT) scanners, the degree and distribution of calcification has remained the most relevant predictor of CTO procedural success (4–6). However, it is well known