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A virtual histology intravascular ultrasound analysis of coronary chronic total occlusions


  • Conflict of interest: Drs. Jun Guo, Jun Pu, and Yunpeng Shang have received grant from Boston Scientific Corporation (Beijing, China). Drs. Maehara and Mintz have received research/grant support from Volcano Corporation (Ranco Cordova, California) and Boston Scientific Corporation (Boston, Massachusetts). Dr. Mintz is a consultant for Volcano Corporation. Drs. Leon and Stone are the members of the advisory boards for Boston Scientific Corporation. Dr. Moses is a consultant for Boston Scientific Corporation. Dr. Ochiai is a member of speakers' bureau of Boston Scientific Corporation.

Correspondence to: Akiko Maehara, MD, 111E 59th Street, New York, NY 10022. E-mail:



We used virtual histology intravascular ultrasound (VH-IVUS) to investigate plaque composition of chronic total occlusions (CTO).


There are limited data on the composition of CTOs, especially in vivo.


VH-IVUS was performed in 50 CTO lesions (49 patients) after guidewire crossing or pre-dilation using a 1.5–2 mm balloon. Plaque composition in the proximal reference, distal reference, and CTO segment (subsequently divided into proximal, middle, and distal subsegments) was analyzed and reported as median and interquartile range. VH-IVUS phenotype was also assessed. The definition of a fibroatheroma was >10% confluent necrotic core (NC) in more than three consecutive frames.


Overall, the maximum NC within the CTO [35.5% (28.7, 44.3%)] was similar to the proximal reference [35.6% (24.1, 42.1%)] and greater than the distal reference [31.5% (22.6, 35.2%), P < 0.01]. There was no difference in maximum NC observed among proximal [31.4% (25.2, 10.4%)], middle [31.0% (23.3, 38.3%)], and distal CTO subsegments [30.4% (22.0, 39.5%)]. Overall, 42/50 CTOs contained a VH-fibroathroma; and 8/50 did not. CTOs containing a VH-fibroatheroma had more NC and dense calcium while CTOs not containing a fibroatheroma had more fibrotic and fibrofatty plaque. Importantly, 60.5% of VH-fibroatheroma-containing CTOs had a thin-cap fibroatheroma (NC abutted to the lumen) in the proximal reference.


Using VH-IVUS, CTO morphology can be divided into two patterns: (1) CTO with VH-fibroatheroma or (2) CTO without VH-fibroatheroma. This suggests two mechanisms of CTO formation—the majority evolving from acute coronary syndrome and thrombosis and the minority from atherosclerosis progression. © 2012 Wiley Periodicals, Inc.

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