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 due to its imaging in the axial plane, superior detail in imaging lesion characteristics, and its enhanced ability to delineate lesion severity and extent compared to catheter angiogram. 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 was a retrospective cohort study of Vascular Quality Initiative (VQI) data. Patients undergoing an index endovascular femoropopliteal revascularization during years 2016-2021 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 pre-operative 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 .6% of interventions in 2016 and rising to 8.2% of interventions by 2021; growth was most dramatic in ASC/OBL settings where IVUS utilization grew from 4.4% to 43-47% of interventions. In unmatched cohorts, patients receiving interventions using IVUS tended to have lower prevalence of multiple cardiovascular comorbidities (e.g. CHF, hypertension, diabetes, dialysis-dependence) and presented more often with claudication, and less often with CLTI. Intraoperatively, IVUS was utilized more often in complex femoropopliteal lesions (TASC 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 independently associated with any of the primary outcomes, rather, all outcomes were primarily influenced by CLTI, dialysis-dependence, and prior major amputation status; technical outcomes (i.e. RFS and PPS loss) were further driven by complexity of lesion (worse in TASC D vs A lesions) and treatment setting (i.e. ASC/OBL setting associated with increased hazard for RFS and PPS loss).

CONCLUSIONS: Intravascular ultrasound implementation in femoropopliteal interventions is growing, with rapid adoption amongst 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 amputation-free survival was observed, however multivariable analysis suggests this 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.