Side branch occlusion with everolimus-eluting and paclitaxel-eluting stents: three-year results from the SPIRIT III randomised trial.

Aims and methods: T he rates of side branch occlusion and subsequent periprocedural MI during everolimuseluting stent (EES) and paclitaxel-eluting stent (PES) placement were examined in the randomised SPIRIT III trial. Periprocedural myocardial infarction (MI) following drug-eluting stent placement is associated with long-term adverse outcomes. Occlusion of side branches may be an important factor contributing to periprocedural MIs. Consecutive procedural angiograms of patients randomly assigned to EES (n=669) or PES (n=333) were analysed by an independent angiographic core laboratory. Side branch occlusion was defined as Thrombolysis In Myocardial Infarction (TIMI) flow grade 0 or 1. Clinical outcomes through three years were compared by stent type and presence of side branch occlusion. Conclusions: A total of 2,048 side branches were evaluated (EES N=1,345 side branches in 688 stented lesions, PES N=703 side branches in 346 stented lesions). Patients with compared to those without transient or final side branch occlusion had significantly higher non-Q-wave MI (NQMI) rates in-hospital (9.0% vs. 0.5%, p<0.0001). By multivariable analysis side branch occlusion was an independent predictor of NQMI (OR 4.45; 95% CI [1.82, 10.85]). Transient or final side branch occlusion occurred less frequently in patients receiving EES compared to PES (2.8% vs. 5.2%, p=0.009), contributing to the numerically lower rates of in-hospital NQMI with EES arm compared to PES (0.7% vs. 2.3%, p=0.05). Patients treated with EES rather than PES were less likely to develop side branch occlusion during stent placement, contributing to lower rates of periprocedural MI with EES compared to PES.