Abstract
BACKGROUND: Chronic limb-threatening ischemia (CLTI) affects over 2 million Americans and carries high risks of amputation and mortality. Use of ambulatory surgical centers (ASCs) and outpatient-based laboratories (OBLs) for revascularization has increased, but outcomes in these settings remain poorly characterized.
OBJECTIVES: The authors sought to evaluate national trends in CLTI revascularization from 2016 to 2023 across clinical settings (hospital-based inpatient, hospital-based outpatient, and ASC/OBL) and compare outcomes of peripheral vascular intervention (PVI) by setting.
METHODS: This retrospective cohort study used Medicare fee-for-service claims data from January 1, 2016, to December 31, 2023, including 925,905 beneficiaries aged ≥66 years undergoing lower extremity PVI for CLTI. Clinical setting of the index procedure was the primary exposure. The primary outcome was a composite of all-cause mortality or major amputation. Secondary outcomes included components of the primary outcome, repeat revascularization, and changes in ambulatory status. Outcomes were analyzed via Kaplan-Meier methods via multivariable Cox regression, adjusting for clinical, sociodemographic, and hospital-level factors.
RESULTS: Of 820,381 total revascularizations, the proportion performed in ASC/OBLs increased to 46.72% by 2023. ASC/OBLs treated a higher proportion of Black patients (18.25%) and dual-eligible beneficiaries (29.94%), whereas hospital inpatient settings treated more patients with gangrene and complex comorbidities. Over a median follow-up of 657 days (Q1-Q3: 204-1,378 days), 188,033 patients (56.4%) experienced the composite of death or major amputation, including 176,140 deaths (52.9%) and 36,743 major amputations (11.0%). Median follow-up for the composite outcome was 413 days (Q1-Q3: 95-1,093 days) after inpatient, 840 days (Q1-Q3: 307-1,579 days) after hospital-based outpatient, and 745 days (Q1-Q3: 285-1,417 days) after ASC/OBL procedures. After multivariable adjustment, ASC/OBLs were associated with lower risk of the primary outcome compared with hospital-based outpatient (HR: 0.93; 95% CI: 0.92-0.94) and inpatient settings (HR: 0.47; 95% CI: 0.45-0.49). However, ASC/OBLs had higher rates of repeat revascularization and similar changes in ambulatory status.
CONCLUSIONS: By 2023, ASC/OBLs emerged as the dominant setting for CLTI revascularization among Medicare beneficiaries. Although ASC/OBLs were associated with improved outcomes, the observational nature of this analysis and residual confounding limit causal conclusions. Rather, the improved outcomes suggest appropriate patient selection has supported the migration of PVI to ambulatory environments.