Hypoechoic Halo Imaging Findings Following Femoropopliteal Artery Stent Implantation: Risk Factors and Clinical Outcomes

Abstract

BackgroundHypoechoic peri-stent areas in duplex ultrasonography (DUS) (ie, “halo”) have been noted following femoropopliteal artery stenting. ObjectivesThis study sought to investigate the prevalence, risk factors, and potential safety implications of hypoechoic halos identified with DUS following stent implantation in the IMPERIAL (ELUVIA Drug-Eluting Stent Versus Zilver PTX Stent) and EMINENT (Trial Comparing ELUVIA Versus Bare Metal Stent in Treatment of Superficial Femoral and/or Proximal Popliteal Artery) trials. MethodsThe IMPERIAL and EMINENT studies of femoropopliteal artery stenting included polymer-based drug-eluting stent, nonpolymer drug-coated stent, and bare metal stent treatment arms. A dedicated DUS protocol was implemented for core laboratory assessment of halo presence at study follow-up visits. Logistic regressions were used to investigate risk factors for a halo sign and its impact on clinically driven target lesion revascularization and primary patency. ResultsDiagnostic DUS imaging from 659 patients was obtained at time points ranging from 6 months to 5 years post–stent implantation. Halo prevalence ranged from 20% to 35% of patients with diagnostic DUS and was present at all time intervals. Halos were identified surrounding all stent types. In analyses of patients with diagnostic imaging from at least 2 visits, halo presence typically persisted, with occasional cases of regression and development at later times. No statistically significant association was found for halo status (ie, halo vs no halo) on 1-year clinically driven target lesion revascularization (OR: 1.27; 95% CI: 0.70-2.30; P = 0.4240) or primary patency (OR: 0.68; 95% CI: 0.43-1.07; P = 0.0927). ConclusionsA hypoechoic halo following a femoropopliteal stent procedure is a common occurrence associated with all studied stent types. The presence of a halo appears to be benign with no associated clinical sequelae or effect on target vessel revascularization rates within 1 year of stent implantation.