Gaps in Vascular Evaluation Before Major Lower-Extremity Amputation Among Medicare Beneficiaries With Chronic Limb-Threatening Ischemia

BackgroundGuidelines recommend vascular specialist evaluation and revascularization consideration before major amputation in chronic limb-threatening ischemia (CLTI). Whether patients consistently receive pre-amputation vascular workup is poorly characterized nationally. MethodsWe conducted a retrospective cohort study of Medicare fee-for-service beneficiaries [≥]66 years with CLTI undergoing incident major lower-extremity amputation (2021-2022) with [≥]12 months continuous enrollment. Using claims in the 180 days preceding hospitalization for amputation, we classified patients into mutually exclusive pathway phenotypes: (A) no specialist, no imaging, no revascularization attempt; (B) specialist only, no revascularization attempt; (C) imaging, no revascularization attempt; or (D) revascularization attempted. Mixed-effects multinomial regression with hospital random intercepts identified predictors of phenotype membership. Post-amputation outcomes were compared across phenotypes. ResultsAmong 10,666 patients (mean age 76.6 years; 35% female; 70% White, 21% Black), phenotype distribution was: A, 9.4%; B, 7.1%; C, 50.7%; D, 32.7%. Thus, 16.6% had no vascular imaging before amputation. Dementia (OR 2.0; 95% CI, 1.61-2.52), paralysis (OR 4.1; 2.62-6.34), and dual eligibility (OR 1.2; 1.01-1.42) were independently associated with phenotype A. Higher comorbidity burden was inversely associated with A (OR 0.49 for >6 vs 0-3 Elixhauser comorbidities). Phenotype A patients had lower 1-year mortality (40% vs 51% for D), fewer readmissions (90-day OR 0.54; 0.47-0.64), and lower costs (adjusted 50% lower at 180 days). Results were robust to acuity adjustment, exclusion of early deaths, and propensity-score matching (n=824 pairs). Phenotype A prevalence varied widely across hospital referral regions, ranging from 3% (Boston, Atlanta) to 16% (Little Rock) among regions with >100 patients. ConclusionsOne in six CLTI amputees had no vascular imaging before amputation. Patients without evaluation were characterized by cognitive impairment, functional limitation, lower healthcare engagement, and socioeconomic disadvantage rather than extreme medical complexity. Hospital-level variation suggests system-level interventions could address these gaps. WHAT IS KNOWNO_LIPrior studies have shown that 50-63% of Medicare patients with chronic limb-threatening ischemia undergo major amputation without receiving revascularization, with substantial racial and geographic disparities in pre-amputation vascular care. C_LI WHAT THE STUDY ADDSO_LIThis study documents the extent to which CLTI patients proceed with amputation without first being evaluated by a vascular specialist, which suggests lack of guideline-recommended care. C_LIO_LIAbout 1 in 10 Medicare CLTI amputees had no vascular specialist contact and no vascular imaging in the 6 months before amputation. C_LIO_LIPatients reaching amputation without evaluation were characterized not by extreme medical complexity but by dementia, paralysis, depression, and dual eligibility--suggesting populations unable to self-advocate within the healthcare system. C_LIO_LISubstantial hospital-level and geographic variation (3-16% phenotype A prevalence across large hospital referral regions) indicates that system-level factors, not just patient characteristics, drive these gaps. C_LI