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. (J Am Coll Cardiol Intv 2012;5:636-43) (c) 2012 by the American College of Cardiology Foundation