Background: Myocardial infarction (MI) after drug-eluting stent placement has been associated with an unfavorable late prognosis. Although the etiology of periprocedural MI is multifactorial, sidebranch occlusion may be an important contributing factor. We sought to identify the incidence of sidebranch occlusion during zotarolimus-eluting stent (ZES) and paclitaxel-eluting stent (PES) placement and to relate sidebranch occlusion to the occurrence of periprocedural MI.
Methods and results: Angiograms were reviewed from patients randomly assigned to treatment with a ZES (597 patients; 943 sidebranches) or a PES (619 patients; 977 sidebranches). Sidebranch occlusion was defined as Thrombolysis in Myocardial Infarction flow grade 0 or 1. Sidebranch occlusion was correlated with frequency of MI, as assessed by the creatine phosphokinase MB isoenzyme. Sidebranch occlusion occurred less often after the first stent deployment in patients treated with ZES (2.2%) than in patients treated with PES (4.0%; P=0.032). A similar reduction in the frequency of sidebranch occlusion at any point during the procedure was found in patients treated with ZES (2.9% versus 4.8% in PES patients; P=0.042). Multivariable predictors of sidebranch occlusion included baseline sidebranch stenosis, complex lesion morphology, smaller baseline minimal lumen diameters, and the use of a PES. Of the 20 patients with MI within 30 days of the procedure, 30% had evidence of sidebranch occlusion during the stent procedure.
Conclusions: Patients treated with ZES were less likely to develop sidebranch occlusion during stent placement than patients treated with PES. Less frequent sidebranch occlusion with ZES may have contributed to the lower frequency rates of periprocedural MI in this study.