Objective To propose a nomogram for individual risk assessment of in-stent restenosis (ISR) after vertebral artery origin stenosis (VAOS) stenting.
Methods We included 793 patients with VAOS treated with stenting from October 2006 to May 2013, with a median follow-up of 27.8 months. Cox regression and the least absolute shrinkage and selection operator (LASSO) regression were adopted for variable selection. The nomogram was formulated and validated by concordance indexes (C-indexes) and calibration curves. An in-stent restenosis risk table (ISR-RT) was subsequently generated for risk stratification. Differences between low-, intermediate-, and high-risk levels were shown by Kaplan-Meier curves and compared by log-rank test.
Results The training and validation set included 594 and 199 patients, with a mean ISR rate of 37.2% and 35.2%, respectively. Stent type (HR=1.64, 95% CI 1.26 to 2.14), stent diameter (HR=2.48, 95% CI 1.77 to 3.48), history of peripheral vascular disease (HR=2.17, 95% CI 1.17 to 4.00), history of transit ischemic attack (HR=1.45, 95% CI 1.05 to 2.14), and left-side involvement (HR=1.33, 95% CI 1.04 to 1.69) were included in the nomogram. The C-indexes at 6 and 12 months were 0.650 and 0.611 in the training set, and 0.713 and 0.603 in the validation set, respectively. Compared with low-risk patients, the intermediate- and high-level group had 1.46 (95% CI 1.05 to 2.04; p=0.0235) and 2.28 (95% CI 1.64 to 3.17; p<0.0001) higher chances of developing ISR in 2 years, respectively.
Conclusions A nomogram and a risk evaluation table were developed with good predictive ability for in-stent restenosis among patients with VAOS, which could serve as a practical approach for individualized risk evaluation.
Data availability statement
Data are available upon reasonable request.
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KY, SF and XZ contributed equally.
Contributors KY, SF, and XZ contributed equally to this work and share first authorship. LJ and YY are co-corresponding authors. KY, SF, and XZ contributed substantially in data acquisition, analysis, interpretation, manuscript drafting, and revising. YF and TW contributed to data acquisition and manuscript drafting. KY, TW, LJ, and YY conceptualized this study and provided funding. All authors gave their final approval of the manuscript to be published. YY is the guarantor responsible for the overall content.
Funding This study was funded by Xuanwu Hospital Hospital-Level Foundation (XWJL-2019001); Beijing Municipal Administration of Hospitals Incubating Program (PX2021034).
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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