Bare Metal vs. Drug-Eluting Stents for Extracranial Vertebral Artery Disease: A Meta-Analysis of Nonrandomized Comparative Studies

Purpose: To compare through meta-analysis the use of drug-eluting stents (DES) vs. bare metal stents (BMS) in the treatment of extracranial vertebral artery (EVA) disease. Methods: A literature search of the Pub Med database was conducted to identify English-language articles in which both BMS and DES stenting were performed for EVA stenosis by the same investigator(s). Further, eligible studies had to provide data on in-stent restenosis during follow-up. The search identified 9 nonrandomized studies that met the inclusion criteria. The random effects model was employed to pool data. Meta-regression analyses were performed to evaluate the relationships between risk of restenosis and the age of patients, the length of follow-up, or the percentage of male patients. Results: Reported technical success was high (range 99.2%-100%) and comparable for BMS [100% (276/276)] and DES [99.4% (166/167)]. The use of DES was associated with significantly lower (p<0.0001) overall restenosis rates [8.2% (14/170) over follow-up periods averaging 16 to 43 months] compared to BMS [23.7% (68/287) over mean follow-up periods of 19 to 46 months]. Moreover, DES showed significantly lower symptomatic restenosis rates as compared to BMS [4.7% (8/169) for DES vs. 11.6% (32/275) for BMS; p=0.005]. There was no change in the risk of restenosis for any factor explored in the meta-regression analysis. Conclusion: This meta-analysis demonstrates that the use of DES for extracranial vertebral artery stenting significantly reduces both the rate of restenosis and recurrence of symptoms as compared to BMS. In future, randomized trials are needed to support these findings.