Morphological assessment of chronic total occlusions by combined coronary computed tomographic angiography and intravascular ultrasound imaging.
Aims
The relationship between CTO morphology and vessel remodelling is unclear. We described chronic total occlusion (CTO) morphology using coronary computed tomographic angiography (CCTA) combined with intravascular ultrasound (IVUS).


Methods and results
Pre-intervention CCTA and IVUS of 130 CTO lesions (128 patients) were evaluated. Based on CCTA, positive CTO lesion remodelling [PR, maximum CTO segment vessel diameter > proximal reference vessel diameter (RVD)] was seen in 44 (33.8%) lesions. In the other 86 lesions without PR, 74 (56.9%) had a minimum CTO segment vessel diameter >50% of the proximal RVD and were classified as non-PR; 12 (9.2%) lesions had a minimum CTO segment vessel diameter ≤50% of the proximal RVD and were classified as collapse. Comparing the three groups, CTO with PR had the greatest maximum atheroma cross-sectional area (CSA) while the collapse group had the least atheroma CSA (16.0 mm2 [12.0, 19.4] vs. 9.1 mm2 [6.0, 15.9], P < 0.001). The maximum arc of attenuated plaque was greatest in the PR group (51° [0, 167]); and the maximum arc of calcium was greatest in the non-PR group (91° [51, 174]). In the collapse group distal to the occluded segment, there was a normal-appearing vessel by IVUS that corresponded to the collapsed segment by CCTA; its minimum plaque burden was 33.2% [19.9, 38.1] with a smooth concave-shaped lumen surface, implying that the CCTA collapse segment was not occluded.


Conclusion
Not all CTOs are the same with regard to lesion remodelling and underlying morphology. The combination of IVUS and CCTA can help to categorize CTO morphology.
['Yamamoto|Myong Hwa|MH|', 'Maehara|Akiko|A|', 'Poon|Michael|M|', 'Guo|Jun|J|', 'Yamashita|Kennosuke|K|', 'Yakushiji|Tadayuki|T|', 'Saito|Shigeo|S|', 'Koyama|Kohei|K|', 'Mintz|Gary S|GS|', 'Ochiai|Masahiko|M|']
D000368:Aged D002908:Chronic Disease D015331:Cohort Studies D000072226:Computed Tomography Angiography D016001:Confidence Intervals D017023:Coronary Angiography D054059:Coronary Occlusion D057510:Endovascular Procedures D005260:Female D006801:Humans D008297:Male D008875:Middle Aged D064847:Multimodal Imaging D061214:Patient Safety D011300:Preoperative Care D012189:Retrospective Studies D012720:Severity of Illness Index D018084:Ultrasonography, Interventional
Chronic total occlusion Coronary computed tomographic angiography Intravascular ultrasound