Change in the distal vessel luminal diameter following chronic total occlusion revascularization

Coronary chronic total occlusions (CTO) occur when there is complete, or near complete occlusion of a vessel, angiographically appreciated by the presence of a collateral circulation with late filling of the occluded vessel. With restoration of anterograde blood flow there is alteration in vascular wall stress which may influence distal vessel size. We sought to determine if the distal vessel size changes following revascularization of the CTO. We retrospectively reviewed patients who underwent successful CTO revascularization and who subsequently underwent repeat angiography. We measured the size of the vessel proximal and distal to the stented segment to assess for change in luminal diameter. Thirty-seven successful CTO revascularization procedures were reviewed. The mean age was 70.3, with 81% male. The most commonly revascularised artery was the right coronary artery (RCA). The median time between angiograms was 194 days. The indexed luminal diameter distal to the stented segment had a greater increase in size compared to the proximal segment (31.1 vs 4.8%, p < 0.0001). The increase in distal vessel was seen in both RCA (34.5 vs 8%, p < 0.001) and non-RCA (28.7 vs 1.9%, p < 0.001). The distal vessel had a more marked increase in distal luminal diameter if there was no resting hypokinesis in the territory supplied by the CTO (35.6 vs 15.0%, p < 0.01). The luminal diameter distal to a revascularized CTO has a greater increase in size compared to the proximal vessel and persists over time. This may have implications on determining stent sizing during CTO procedures as well as determining suitable vessels for attempted revascularization.