Fate of lumen size in distal coronary segment following successful chronic total occlusion recanalization

Abstract

Background: Restoration of anterograde blood flow leads to alterations in vascular wall stress that may influence lumen size distal to chronic total occlusion (CTO) lesions. We sought to assess changes in lumen diameter of segments distal to the stent segment of successfully recanalized CTO.

Methods: We analyzed 507 consecutive CTO cases with stent implantation that underwent follow-up angiography at a single high-volume center (mean follow-up of 13.5 months). Segments ≤40 mm distal to the stent edge were analyzed using quantitative coronary angiography.

Results: At follow-up, lumen diameters significantly increased; diameter changes of 0.26 ± 0.47 (percent diameter change of 18.2%) at 5 mm distal, mean lumen diameter changes of 0.23 ± 0.35 (14.3%) and minimal lumen diameter changes of 0.22 ± 0.80 (24.7%) (all p < 0.001). Lumen enlargement was similar between visually shrunken and stenosed vessels (degree of stenosis ≥20% with luminal irregularities) distal to stents; 5 mm distal (0.32 ± 0.48 vs. 0.30 ± 0.48, p = 0.76), mean lumen diameter changes (0.26 ± 0.37mm vs. 0.26±0.33 mm, p = 0.94), minimal lumen diameter changes (0.28 ± 0.43 mm vs. 0.22 ± 1.30 mm, p = 0.48). There was no association between degree of in-stent narrowing and changes in distal lumen diameter (Spearman r = -0.02, p = 0.59). Multivariate logistic regression for the predictors of greater lumen enlargement indicated that patients with left ventricle dysfunction (ejection fraction ≤45%) had greater enlargement [odds ratio (OR): 2.53, 95% confidence interval (CI): 1.23-5.23, p = 0.01]. Conversely, a low hematocrit (male <40%, and female <35%) was associated with attenuated lumen enlargement (OR: 0.68 95% CI: 0.47-0.98; p = 0.04).

Conclusions: Lumen diameter distal to CTO lesions significantly increased following successful revascularization, regardless of diseased status of the distal bed or degree of in-stent narrowing. These findings implicate appropriate determination of stent size, stent coverage length, as well as management strategies of distal vessels.

Keywords: Chronic total occlusion; Lumen size; Percutaneous coronary intervention; Quantitative coronary angiography.