Stent Optimization Using Optical Coherence Tomography and Its Prognostic Implications After Percutaneous Coronary Intervention

BACKGROUND: Stent underexpansion has been known to be associated with worse outcomes. We sought to define optical coherence tomography assessed optimal stent expansion index (SEI), which associates with lower incidence of follow‐up major adverse cardiac events (MACEs). METHODS AND RESULTS: A total of 315 patients (involving 370 lesions) who underwent optical coherence tomography–aided coronary stenting were retrospectively included. SEI was calculated separately for equal halves of each stented segment using minimum stent area/mean reference lumen area ([proximal reference area+distal reference area]/2). The smaller of the 2 was considered to be the SEI of that case. Follow‐up MACE was defined as a composite of all‐cause death, myocardial infarction, stent thrombosis, and target lesion revascularization. Average minimum stent area was 6.02 (interquartile range, 4.65–7.92) mm(2), while SEI was 0.79 (interquartile range, 0.71–0.86). Forty‐seven (12.7%) incidences of MACE were recorded for 370 included lesions during a median follow‐up duration of 557 (interquartile range, 323–1103) days. Receiver operating characteristic curve analysis identified 0.85 as the best SEI cutoff (<0.85) to predict follow‐up MACE (area under the curve, 0.60; sensitivity, 0.85; specificity, 0.34). MACE was observed in 40 of 260 (15.4%) lesions with SEI <0.85 and in 7 of 110 (6.4%) lesions with SEI ≥0.85 (P=0.02). Least absolute shrinkage and selection operator regression identified SEI <0.85 (odds ratio, 3.55; 95% CI, 1.40–9.05; P<0.01) and coronary calcification (odds ratio, 2.47; 95% CI, 1.00–6.10; P=0.05) as independent predictors of follow‐up MACE. CONCLUSIONS: The present study identified SEI <0.85, associated with increased incidence of MACE, as the optimal cutoff in daily practice. Along with suboptimal SEI (<0.85), coronary calcification was also found to be a significant predictor of follow‐up MACE.