Optical coherence tomography derived cut-off value of uncovered stent struts to predict adverse clinical outcomes after drug-eluting stent implantation

Although the presence of uncovered struts may be associated with occurrence of stent thrombosis, the impact of uncovered struts detected routinely by optical coherence tomography (OCT) on subsequent long-term clinical outcomes remains unclear. The objective of this study was to determine the cut-off value of uncovered struts that predicted adverse clinical outcomes after drug eluting stent (DES) implantation. Major safety events (MSEs, a composite occurrence of cardiovascular death, myocardial infarction, and stent thrombosis) were evaluated in 489 DES-treated patients (535 lesions) during the median 851 days after follow-up OCT. MSEs occurred in six patients (four definite stent thrombosis and two sudden cardiac death). The best cut-off value of percentage of uncovered struts for predicting MSE was 5.9 % using the maximal χ² method: area under the receiver-operating characteristic curve = 0.779, 95 % confidence interval (CI) = 0.648–0.910, p = 0.019, a sensitivity of 83.3 % and a specificity of 70.3 %. Independent predictors for MSE were post-intervention minimal lumen diameter (odds ratio 0.019, 95 % CI = 0.001–0.513, p = 0.018) and percentage of uncovered struts ≥5.9 % (odds ratio 19.781, 95 % CI = 2.071–188.968, p = 0.010). A greater percentage of uncovered struts (the cut-off value of ≥5.9 % uncovered struts) might be significantly associated with occurrence of MSE after DES implantation.