Cobalt Chromium or Stainless Steel Balloon-Expandable Bare Metal Stents for Iliac Occlusive Disease?

Background: To compare the performance of a new-generation cobalt-chromium balloon-expandable bare metal stent with a stainless steel platform for the treatment of iliac occlusive disease.

Methods: Consecutive patients treated for symptomatic iliac occlusive disease between 2014 and 2021 with the cobalt-chromium Dynetic-35 or the stainless steel Dynamic platform were retrospectively evaluated. Outcome measures included technical success, device- or procedure-related death, clinically-driven target lesion revascularization (CD-TLR), primary patency, and major index limb amputation up to 12 months.

Results: In total, 222 Cobalt chromium (CC) stents were used in 159 patients (34.6% female; mean age 66.9 ± 9.5 years) for the treatment of 216 lesions, while 234 iliac lesions of 182 patients (34.6% female; mean age 66.3 ± 9.9 years) were treated with 252 stainless steel (SS) stents. The mean lesion length (30.2 ± 12.8 mm vs 28.7 ± 22.5 mm, p=0.36) and the mean calcification grade (2.0 vs 1.9, p=0.07) did not differ significantly between the 2 groups. Patients treated by the CC platform were more frequently on statins (p<0.001), whereas more active smokers and subjects with higher Rutherford class underwent a SS deployment (p<0.001). Technical success was significantly higher in the SS group (100% vs 97.3%; p=0.01). This was due to longitudinal deformation or stent dislocation after passing the Dynetic-35 with endovascular material. After 1 year, no difference was found following CC and SS stent deployment in terms of device- or procedure-related deaths (0.6% vs 1.1%, p=0.99), target limb amputations (1.9% vs 1.6%, p=0.99), primary patency (91.3% vs 93.5%), and CD-TLR (6.5% vs 2.8% p=0.07).

Conclusions: Through 1 year, cobalt-chromium and stainless steel balloon-expandable stents are safe and effective in the treatment of iliac occlusive disease. Enhanced attention should be given passing the cobalt-chromium stent with endovascular devices to avoid procedural complications.

Clinical impact: Stents with a thin-strut structure improve the flexibility and deliverability. The lower profile also increases the applicability lowering the risk of vascular access complications. In this study newer-generation cobalt chromium balloon-expandable stent did not confer advantages over stainless steel bare metal stent. On contrary, the technical success was inferior to stainless steel stents as longitudinal deformation or dislocation of the Dynetic-35 occurred. Therefore, enhanced attention should be given passing a Cobalt chromium stent with wires, catheters or sheaths to avoid stent deformation.