Long-Term Predictors of Clinical Events after Off-Label Use of Drug-Eluting Stent beyond 1 Year

Background and Objectives: We evaluated the long-term outcomes and predictors of clinical events after off-label use of drug-eluting stents (DES) beyond 1 year after procedure. Subjects and Methods: A total of 518 patients who underwent DES implantation for off-label indications and did not have any major adverse cardiac events (MACE) during the first year were analyzed. The occurrence of MACE, including cardiac death, myocardial infarction (MI), stent thrombosis and target vessel revascularization, were evaluated for a median 1179 days (interquartile range 769-1541) after the first year. Results: Major adverse cardiac events occurred in 43 patients (8.3%) including 8 cases (1.5%) of cardiac death, 9 cases (1.7%) of MI, 24 cases (4.6%) of target vessel revascularization, and 11 cases (2.1%) of stent thrombosis. Patients with MACE had a higher serum creatinine level, higher incidence of in-stent restenosis lesion, more overlapping stents, a greater number of stents, and longer stents than did patients without MACE. Multivariate analysis revealed that serum creatinine level >1.5 mg/dL {hazard ratio (HR) 2.3, p=0.019}, stent length >33 mm (HR 2.4, p=0.035), and in-stent restenosis lesions (HR 2.4, p=0.040) were independent risk factors for MACE. Patients with DES length >33 mm had a higher incidence of MACE than those with DES length ${\leq}33mm$ (HR 2.7, log rank p=0.002). Conclusion: The risk of stent thrombosis and target vessel revascularization persisted in patients undergoing off-label DES implantation beyond 1-year follow-up. A total DES length >33 mm was a significant procedural predictor associated with the incidence of MACE.