Histological Insight into the Pathology of Coronary Chronic Total Occlusion and Intervention

Abstract

A number of patients with coronary artery disease present with chronic total occlu-sion (CTO) on autopsy. The success rate of percutaneous coronary intervention (PCI) for CTO has improved thanks to the development of interventional devices and techniques. However, there is no proven therapy and the management of these patients remains a real challenge for coronary interventionalists. However, the precise understanding of the pathology of CTO would be of great help to PCI operators in selecting the best PCI strategy for CTO. 20.1 Angiographic vs. Histological CTO A pathological study showed that 78% of angiographic CTO lesions were not totally occluded on autopsy [1]. Histologically, only 22% of angiographic CTO cases presented 100% cross-sectional stenosis on histology (histological total occlusion) 25%, 24% and 29% of angiographic CTO were 90-95%, 96-98%, and 99% cross-sectionalstenosis on histology, respectively. The study did not show a relationship between histological stenosis and CTO age. Those data suggested that substantial proportions of angiographic CTO cases have residual small lumen shown through histological examination. Therefore, these lesions could be passed through via the antegrade approach [2], especially using small-diameter guidewires [3]. The tapering type of angiographic CTO is more frequently associated with histologic residual small lumen than the abrupt type. The residual small lumen penetrates into the distal segment of short-length CTO, while the residual lumen is occasionally blind-ending in long-length CTO [4].