Late Thrombosis of Drug-Eluting Stents: A Meta-Analysis - Late Thrombosis of Drug-Eluting Stents: A Meta-Analysis

Description:

The goal of the study was to evaluate the effect of treatment with drug-eluting stents (DES) compared with bare-metal stents (BMS) on stent thrombosis among randomized trials in patients undergoing percutaneous coronary intervention (PCI).

Study Design

Study Design:

Patients Enrolled: 6,675
Mean Follow Up: Up to 4 years

Primary Endpoints:

Angiographic stent thrombosis, defined as a filling defect in proximity to a previously placed stent on repeat coronary angiogram

Drug/Procedures Used:

Data were drawn from randomized trials of DES compared with BMS. Trials included in the meta-analysis were RAVEL, SIRIUS, E-SIRIUS, C-SIRIUS, SES-SMART, SCANDSTENT, DIABETES, Pache et al., and STRATEGY (sirolimus-eluting stents [SES]; n = 1,587 for SES and n = 1,575 for BMS), and TAXUS I, II, IV, V, and VI (paclitaxel-eluting stents [PES]; n = 1,755 for PES and n = 1,758 for BMS).

Principal Findings:

For the comparison of DES with BMS, the rate of stent thrombosis >30 days was 5.0 per 1,000 patients for DES vs. 2.8 per 1,000 patients for BMS (relative risk [RR] 1.56, p = 0.22). By DES stent type, the rate was significantly higher with PES vs. BMS (6.3 per 1,000 for PES vs. 1.1 per 1,000 patients for BMS, RR 3.59, p = 0.034), but did not differ for SES vs. BMS (3.5 per 1,000 for SES vs. 4.9 per 1,000 patients for BMS, RR 0.77, p = 0.61). The median time of late stent thrombosis was later with DES versus BMS both in the PES group (18 months for PES vs. 3.5 months for BMS) and in the SES group (15.5 months for SES vs. 4 months for BMS).

Very late stent thrombosis, defined as >1 year after the index procedure, was 5 times higher in the DES group compared with the BMS group (5.0 events per 1,000 vs. 0 events per 1,000 patients, RR 5.02, p = 0.02). By type of DES, the rates for PES versus BMS were 5.9 per 1,000 versus 0 per 1,000 patients (RR 5.72, p = 0.049) and for SES versus BMS were 3.6 per 1,000 versus 0 per 1,000 patients (RR 3.99, p = 0.22).

Interpretation:

In a meta-analysis of randomized trials of patients undergoing PCI with stenting, use of DES was associated with a significant fivefold increase in late stent thrombosis compared with BMS.

Late stent thrombosis has emerged as a concern with DES use, possibly due to a reduction in initial endothelialization. Several meta-analyses and observational studies have suggested that both late stent thrombosis and mortality may be increased with DES use. Randomized trials of DES compared with BMS in de novo coronary lesions have consistently shown reductions in the need for repeat revascularization following protocol-driven angiography. However, none has been adequately powered to evaluate harder endpoints of death or myocardial infarction, and follow-up is only now beginning to be long enough to more fully assess late thrombosis.

Unlike stent thrombosis, restenosis is a nonfatal event and has not been linked to increased mortality. While the rates appear low overall, the fivefold increase in stent thrombosis with DES warrants further evaluation of these devices in much larger studies. An additional concern is whether PCI is being overused compared with medical therapy or bypass surgery in certain groups of patients for whom data favor the latter treatments.

References:

Bavry AA, Kumbhani DJ, Helton TJ, Borek PP, Mood GR, Bhatt DL. Late thrombosis of drug-eluting stents: a meta-analysis of randomized clinical trials. Am J Med 2006;119:1056-61.

Clinical Topics: Invasive Cardiovascular Angiography and Intervention

Keywords: Paclitaxel, Risk, Myocardial Infarction, Follow-Up Studies, Thrombosis, Drug-Eluting Stents, Sirolimus, Angioplasty, Balloon, Coronary, Diabetes Mellitus, Stents


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