Chronic total occlusions (CTO) are the final stage of coronary atherosclerosis. Coronary arteries with CTO have shown large plaque burden and negative remodeling of the occluded region and the segments located distal to the occlusion. Lumen and plaque changes located distal to successfully re-canalized CTO remain unknown at follow-up.

Ninety-one CTO successfully treated with drug-eluting stents in 86 patients underwent quantitative angiography at baseline and 12-18 months follow-up. Thirty-one lesions were investigated with IVUS. All analyses were performed after nitroglycerin. Angiographic changes of were assessed with quantitative coronary angiography as differences in minimal, mean and maximal lumen diameter (MinLD, MeanLD and MaxLD, respectively). Vessel remodeling was assessed with IVUS as changes in lumen, plaque and vessel volume.

At follow-up, MinLD increased 23.9% (from 0.88±0.32 to 1.09±0.35mm: p<0.01), MeanLD 16.4% (from 1.59±0.44 to 1.85±0.45mm; p<0.01) and MaxLD 11.7% (from 2.39±0.67 to 2.67±0.70mm; p<0.01). Lumen enlargement was greater in non-restenotic lesions, small lumen area at baseline and low LDL-cholesterol levels during the study period. By IVUS, lumen increased 26.9% (from 108.1±89.2 to 137.3±115.3mm3; p<0.01), vessel increased 12.1% (from 207.1±170.2 to 232.2±196.0 mm3; p<0.01) and plaque tended to decrease (-3.9%, from 98.9±88.7 to 94.9±89.3 mm3; p=0.07). Small lumen at baseline was related to greater lumen enlargement.

Distal segments to re-canalized CTO show a notable lumen and vessel enlargement with a trend towards of mild plaque regression. Low LDL-Cholesterol levels during the study increases lumen enlargement. Angiographic lesions distal to CTO may change and stent implantation must be discouraged.