Abstract 101: Variation in Patient Characteristics and Outcomes Between Clinical Settings for Endovascular Femoropopliteal Artery Revascularization

Abstract

Background: After CMS modified reimbursement rates for outpatient peripheral vascular intervention (PVI) in 2008, clinicians began to increasingly perform PVIs in hospital outpatient centers and ambulatory surgery centers (ASCs)/office-based laboratories (OBLs). Little is known about the characteristics of patients treated in freestanding ASCs/OBLs and their respective long-term outcomes compared to those treated in other settings. Methods: Medicare fee-for-service beneficiaries ≥66 years undergoing femoropopliteal artery PVI between 4/1/15-12/31/17 in ambulatory settings and 10/1/15-12/31/17 in inpatient centers were identified using carrier files linked to institutional outpatient files and MedPAR data. The vital status file was used to determine mortality through 4/30/19. Patients required ≥1 year of data prior to PVI to allow for ascertainment of comorbidities. An area deprivation index of ≤15 th percentile was used to identify those who reside in regions of lower socioeconomic status (SES). Results: Of 147,573 patients undergoing femoropopliteal PVI, 62,673 (42.5%) were treated as inpatients, 82,135 (55.7%) in hospital outpatient centers, and 2,765 (1.9%) in ASCs/OBLs. Patients treated in ASCs/OBLs had a greater burden of comorbidities, and were more likely to be Black (20.5% vs 11.6% outpt vs 14.1% inpt), dually-enrolled in Medicaid-Medicare (32.7% vs 18.5% outpt vs. 24.8% inpt), and reside in lower SES regions (44.8% vs 26.6% oupt vs 34.4% inpt). The unadjusted cumulative incidence of long-term mortality was similar between patients treated at ASCs/OBLs and inpatient centers, whereas hospital outpatients had higher survival (Figure 1). After adjusting for patient characteristics (demographics, comorbidities, and markers of SES), individuals treated in ASCs/OBLs had lower mortality rates than inpatient centers (HR 0.67, 95% CI 0.61-0.73) and attenuated mortality rates compared to outpatient centers (HR 1.10, 95% CI 1.01-1.20). Conclusions: Medicare beneficiaries undergoing femoropopliteal PVI at ASCs/OBLs are more socioeconomically disadvantaged and have a higher burden of comorbidities compared with other clinical settings. These differences in patient characteristics largely explain heterogeneity in long-term survival between facilities.