Trends and outcomes associated with intravascular ultrasound use during femoropopliteal revascularization in the Vascular Quality Initiative

Objective: Intravascular ultrasound (IVUS) use in lower extremity interventions is growing in popularity owing to its imaging in the axial plane, superior detail in imaging lesion characteristics, and its enhanced ability to delineate lesion severity and extent compared with catheter angiograms. However, there are conflicting data regarding whether IVUS affects outcomes. The purpose of this study was to assess the effect associated with IVUS implementation in femoropopliteal interventions. Methods: This retrospective cohort study used Vascular Quality Initiative data. Patients undergoing an index endovascular femoropopliteal revascularization from 2016 to 2021 were included. Patients were differentiated by whether or not IVUS was used to assess the femoropopliteal segment during intervention (no IVUS, IVUS). Propensity score matching, based on preoperative demographics and measures of disease severity was used. Primary outcomes were major amputation-free survival (AFS), femoropopliteal reintervention-free survival (RFS), and primarily patent survival (PPS) at 12 months. Results: IVUS use grew steadily throughout the study period, comprising 0.6% of interventions in 2016 and increasing to 8.2% of interventions by 2021; growth was most dramatic in ambulatory surgical center or office-based laboratory settings where IVUS use grew from 4.4% to 43% to 47% of interventions. In unmatched cohorts, patients receiving interventions using IVUS tended to have lower prevalence of multiple cardiovascular comorbidities (eg, congestive heart failure, hypertension, diabetes, and dialysis dependence) and presented more often with claudication and less often with chronic limb-threatening ischemia (CLTI). Intraoperatively, IVUS was used more often in complex femoropopliteal lesions (Transatlantic Intersociety grade D vs A), and more often in conjunction with stenting and/or atherectomy. IVUS use was associated with improved AFS, but similar RFS and PPS at 12 months. However, in multivariable analysis IVUS was not associated with any of the primary outcomes independently; rather, all outcomes were influenced primarily by CLTI, dialysis dependence, and prior major amputation status; technical outcomes (ie, RFS and PPS loss) were further driven by complexity of lesion (worse in Transatlantic Intersociety grade D vs A lesions) and treatment setting (ie, ambulatory surgical center or office-based laboratory setting associated with increased hazard for RFS and PPS loss). Conclusions: IVUS implementation in femoropopliteal interventions is growing, with rapid adoption among interventions in ambulatory surgical centers and office-based laboratories. IVUS was not associated with an effect on technical outcomes at 12 months; improvement in major AFS was observed; however, multivariable analysis suggests this finding may be an effect of confounding by multiple factors highly associated with IVUS use, namely, in patients with lower prevalence of CLTI, dialysis dependence, and prior major amputations, thus conveying baseline lower risk for major amputation and death.