Efficacy Over Time With DES in SVG Lesions
What are the long-term (5-year) clinical outcomes in patients randomized to treatment of saphenous vein graft (SVG) lesions with drug-eluting stents (DES) or bare-metal stents (BMS)?
The ISAR-CABG (Is Drug-Eluting-Stenting Associated with Improved Results in Coronary Artery Bypass Grafts?) trial investigators randomized patients (1:1:1:3) to receive DES (either permanent-polymer paclitaxel-eluting stents, permanent-polymer sirolimus-eluting stents, or biodegradable-polymer sirolimus-eluting stents) or BMS. The primary endpoint was the combined incidence of death, myocardial infarction (MI), or target lesion revascularization (TLR). Secondary endpoints were the composite of death or MI and TLR. Event rates are shown as Kaplan-Meier estimates. Hazard ratios (HRs), confidence intervals (CIs), and p values were calculated from univariate Cox proportional hazards models or log-rank tests.
A total of 610 patients were allocated to treatment with DES (n = 303) or BMS (n = 307). At 5 years, the primary endpoint occurred in 159 (55.5%) versus 157 (53.6%) patients in the DES and BMS groups, respectively (HR, 0.98; 95% CI, 0.79-1.23; p = 0.89). There was interaction between treatment effect and time (pinteraction = 0.005), with a lower event rate in the DES group at 1 year (HR, 0.64; 95% CI, 0.44-0.94; p = 0.02), but a numerically higher rate between 1 and 5 years (HR, 1.24; 95% CI, 0.94-1.63; p = 0.13). Death or MI occurred in 93 (32.8%) versus 108 (36.6%) patients, respectively (HR, 0.85; 95% CI, 0.64-1.12; p = 0.24), without significant interaction between treatment effect and time (pinteraction = 0.57). TLR occurred in 84 (33.1%) versus 69 (25.5%) patients in the DES and BMS groups, respectively (HR, 1.20; 95% CI, 0.87-1.64; p = 0.27). There was interaction between treatment effect and time (pinteraction < 0.001). TLR was significantly lower in the DES group at 1 year (HR, 0.49; 95% CI, 0.28-0.86; p = 0.01), but significantly higher thereafter (HR, 2.02; 95% CI, 1.32-3.08; p = 0.001).
The authors concluded that the advantage of DES over BMS demonstrated at 1 year for SVG percutaneous coronary intervention (PCI) was lost at 5 years due to higher attrition of efficacy in the DES group.
This study reports that in patients with SVG lesions treated by PCI, the advantage of DES over BMS with respect to clinical outcomes observed at 1 year was not sustained at 5 years, with comparable event rates in both treatment groups at this time. Between 1 and 5 years, the rate of TLR with DES was more than twice that in the BMS group, offsetting the initial advantage at 1 year. Additional randomized trials with long-term follow-up are needed to compare the durability of newer-generation DES with BMS in SVG disease.
Keywords: Cardiac Surgical Procedures, Drug-Eluting Stents, Myocardial Infarction, Myocardial Revascularization, Paclitaxel, Percutaneous Coronary Intervention, Polymers, Saphenous Vein, Secondary Prevention, Sirolimus, Stents
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