Optical Coherence Tomography Study of Chronic-phase Vessel Healing After Implantation of Bare Metal and Paclitaxel-eluting Self-expanding Nitinol Stents in the Superficial Femoral Artery

Background: This study aimed to assess chronic-phase suppression of neointimal proliferation and arterial healing following paclitaxel-coated (PTX) and bare metal stent (BMS) implantation in the superficial femoral artery using optical coherence tomography (OCT).

Methods: Twenty-five patients with 68 stents underwent an 8-month OCT follow-up. Besides standard OCT variables, neointimal characterization and frequencies of peri-strut low-intensity area (PLIA), macrophage accumulation, and in-stent thrombi were evaluated.

Results: The mean neointimal thickness was significantly less with PTX stents (544.9±202.2 μm vs. 865.0±230.6 μm, p<0.0001). The covered and uncovered strut frequencies were significantly smaller and larger, respectively, in the PTX stent group vs. the BMS group (93.7% vs. 99.4%; p<0.0001, 4.0% vs. 0.4%; p<0.0001, respectively). Heterogeneous neointima was only observed in the PTX stent group (12.5% vs. 0%, p=0.017). The frequencies of PLIA and macrophage accumulation were significantly greater in the PTX stent group (87.2% vs. 67.6%, p=0.001 and 46% vs. 9.1%, p=0.003, respectively).

Conclusion: After 8 months, reduced neointimal proliferation was observed with PTX stent implantation. On the other hand, delayed arterial healing was observed compared with BMS.