Comparison of drug-eluting and bare metal stents for extracranial vertebral artery stenting

Introduction
Drug-eluting stents of the first (DES I) and second generation (DES II) proved superior to bare metal stents (BMS) in the coronary territory. However, there are limited data on whether they have any advantage over BMS in vertebral artery stenosis (VAS).

Aim
To compare outcomes of DES (DES I, DES II) and BMS in the treatment of symptomatic extracranial VAS.

Material and methods
During 13-year study period (2003–2016), 392 consecutive patients underwent VAS angioplasty in 428 arteries, including implantation of 148 DES (DES I: 21; DES II: 127 lesions), and 280 BMS.

Results
The technical success rates for DES and BMS groups were 96.7% and 94.6% (p = 0.103), with similar periprocedural complication rates (1.4% vs. 2.2%; p = 0.565). VAS degree was reduced from 86 ±9.7 to 2.7 ±5.0% in DES (p < 0.001) and from 84.1 ±9.4 to 4.3 ±6.9% in BMS (p < 0.001). Angiography confirmed in-stent restenosis/occlusion (ISR/ISO) 50–99% in 53 (14.2%) and 21 (5.6%) out of 373 patients (409 arteries) with at least 6-month follow-up. ISR/ISO rates were similar in DES vs. BMS (22.8% vs. 19.4%; p = 0.635), as well as in DES I vs. DES II (6/19; 31.6% vs. 25/92; 27.2%, p = 0.325). Stainless steel (24/135; 17.8%) and cobalt-chromium (23/121;19%) BMS had significantly lower incidence of ISR/ISO, as compared to platinum-chromium (7/18; 38.9%), p = 0.034. ISR/ISO was associated with age (p = 0.01) and CRP level > 5 mg/l (p = 0.043), while greater stent length was associated with ISR only in the DES group (p = 0.024).

Conclusions
Our results do not support significant differences in ISR/ISO rates between DES and BMS, although differences between particular stent types and ISR rates require further investigation.