Computed tomographic angiography-verified plaque characteristics and slow-flow phenomenon during percutaneous coronary intervention

Objectives: This study sought to identify whether computed tomographic angiographic (CTA) plaque characteristics are associated with slow-flow phenomenon (SF) during percutaneous coronary intervention (PCI). Background: SF during PCI is associated with myocardial damage and prolonged hospitalization. Intracoronary ultrasound-verified large echolucent lesions have been reported to predict SF. Methods: The authors evaluated pre-PCI CTA plaque characteristics in 40 consecutive patients (male/female, 31/9; age, 69 ± 10 years) with stable angina pectoris who developed SF during PCI; patients with <600 Agatston coronary artery calcium score were not included. They were compared with 40 age-, sex-, and culprit coronary artery-matched patients (male/female, 31/9; age, 69 ± 9 years) who underwent PCI during the same period and did not develop SF. Plaque characteristics, including vascular remodeling, plaque consistency, including low-attenuation plaques representing lipid-rich lesions and high-attenuation plaque patterns of calcium deposition, were analyzed. Results: Calcium deposition in the perimeter of a plaque, or circumferential plaque calcification (CPC), was significantly more frequent in the SF group (25 of 40, 63%) than the no-SF group (2 of 40, 5.0%) (p < 0.001). Presence of CPC on CTA was confirmed at the same location in the nonenhanced CT during Agatston coronary artery calcium score calculation. The positive remodeling index was significantly higher (1.5 [1.3 to 1.8] vs. 1.2 [1.0 to 1.5]; p < 0.001) and plaque density significantly lower (23.5 [9.5 to 40] HU vs. 45 [29 to 86] HU; p = 0.001) in the SF group. The conditional logistic regression analysis revealed that CPC, plaque density, and dyslipidemia were the predictors of SF, with CPC being the strongest (odds ratio: 79; 95% confidence interval: 8 to 783, p < 0.0001). Conclusions: CTA-verified CPC with low-attenuation plaque and positive remodeling were determinants of SF during PCI. If CTA findings are available in patients undergoing PCI, the interventionists should be aware of the likelihood of SF.