Unintended Deformation of Stents During Bifurcation PCI: An OCTOBER Trial Substudy

Background Unintended deformation of implanted coronary stents can lead to loss of coronary access, stent thrombosis and coronary events during follow-up. The incidence, mechanisms and clinical outcomes of unintended stent deformations (USD) during complex bifurcation stenting are not well characterized. Objectives In a prespecified analysis of the OCTOBER (European Trial on Optical Coherence Tomography Optimized Bifurcation Event Reduction) trial, we aimed to: 1) determine the incidence and characterize mechanisms of USD identified by optical coherence tomography (OCT); and 2) evaluate physician's detection and correction of accidental abluminal rewiring and USD. Methods OCT scans were analyzed for accidental abluminal rewiring and USD. When USD was identified, the plausible mechanism was determined by analysis of all procedural OCT scans and the corresponding angiograms. Results USD was identified by the core lab in 9.3% (55/589) of OCT-guided cases. Accidental abluminal rewiring was the cause in 44% (24/55), and guide catheter collision was the cause in 40% (22/55) of cases. USD was found in 18.5% of all cases with left main bifurcation percutaneous coronary intervention. The total incidence of abluminal rewiring was 33 in 32 OCT-guided cases (5.4%) and was corrected by physicians in 18 of 33 appearances (54.5%). The 2-year major adverse cardiac event rate for patients with untreated USD (n = 30) was 23.3%, whereas patients with confirmed or possibly corrected USD (n = 25) had no events during follow-up. Conclusions USD was associated with adverse procedural complications and cardiac events during follow-up when not identified and corrected. The predominant mechanisms were undetected abluminal rewiring and guide catheter collision. Left main bifurcation percutaneous coronary intervention was a particular risk with USD detected in 18.5% of cases.