Influence of parent vessel - side branch distal angle on restenosis rates after main vessel stenting in coronary bifurcation lesion.

Background and Aim: This study explores predictors of side branch (SB) compromise in the main vessel only stenting group and its influence on long-term follow-up of the patients.
Methods: We hypothesised that the geometric factors determining plaque distribution in branching regions influence SB compromise. Angiographic analysis of bifurcation lesions (all Medina types) was performed before, immediately after, and 9-12 months after the procedure. Control angiography was performed when clinically indicated. Specific attention was given to the influence of angle alpha - the angle between main vessel and SB axes.
Results: Fifty-five patients (62 lesions) formed the study group. The LAD lesions were dominant (73%). Drug-eluting stents were used in 48% and kissing balloon inflation in 31%. The value of angle alpha was associated with significant SB stenosis. There was significant worsening of ostial SB stenosis (from 48% to 69%) after main vessel stenting, with the only independent predictor angle alpha. For SB ostial MLD independent predictors were angle alpha, SB vessel diameter and MB reference diameter. Predictors of SB occlusion (6.5%) were angle alpha <30 degrees and age >82 years. At follow-up (mean 11 months) SB restenosis rate was 52%, but was associated with symptoms only if the main vessel was affected (8/55, 15%). Angle alpha and main vessel reference diameter, main branch minimal diameter after stenting and stent type were predictors of target vessel revascularisation rate (25%).
Conclusion: Angle alpha predicts SB compromise after main vessel stenting and is the main predictor of restenosis in the main vessel.