Predictors of side branch compromise in calcified bifurcation lesions treated with orbital atherectomy

Objectives: The aim of the study was to identify the predictors of side branch (SB) compromise in severely calcified bifurcation lesions treated with orbital atherectomy (OA). Background: SB compromise remains a major complication of bifurcation lesion percutaneous coronary intervention (PCI). Higher prevalence of lipid-rich plaques and spotty calcification by optical coherence tomography (OCT) and SB ostial stenosis by angiography have been previously suggested as predictors of SB occlusion after main vessel (MV) stenting. Methods: Patients with chronic stable angina and severely calcified bifurcation lesions, in whom provisional stenting strategy was planned, were enrolled in the study. OA was used for lesion preparation in all cases. OCT imaging of the MV was performed before and after stenting. SB compromise was defined as a composite of SB occlusion (TIMI flow grade ≤ 2) and SB intervention after MV stenting. Results: Thirty stable CAD patients with 30 severely calcified bifurcation lesions were included in the study. Twelve patients (40%) had a compromised SB after MV stenting. Compromised SB was characterized by a greater angiographic diameter stenosis (55.4 ± 8.1% vs. 35.0 ± 14.4%, P < 0.01) and a smaller minimal lumen diameters (0.79 ± 0.17 vs. 1.12 ± 0.30 mm, P = 0.002) before PCI compared to noncompromised SB. The prevalence of OCT lipid-rich plaques was low and did not differ between the groups (18 vs. 19%, P = 0.68). There was no difference in other OCT plaque characteristics including the presence of spotty calcification. Conclusion: The severity of SB ostial disease and not MV plaque morphology contributed to SB compromise in severely calcified bifurcation lesions.