Institutional Volume and County-Level Socioeconomic Characteristics in Transcatheter Aortic Valve Replacement Outcomes

BACKGROUND: Although socioeconomic disparities in transcatheter aortic valve replacement (TAVR) access are well described, whether county-level socioeconomic context influences short-term outcomes independent of institutional procedural experience remains uncertain. STUDY DESIGN: We performed a retrospective cohort study of 336 hospital-measure observations from 85 California hospitals performing TAVR (2022-2023) using the CMS TAVR database. Hospital risk-adjusted adverse event rates (RAAERs) for 30-day mortality and stroke were linked to county-level household income, insurance coverage, and racial composition. Precision-weighted mixed-effects models with hospital random intercepts adjusted for year and log(1+TAVR volume) were performed, with sensitivity analyses using log-transformed observed-to-expected ratios. RESULTS: Higher log(TAVR volume) was independently associated with lower 30-day mortality (β=-0.334; 95% CI, -0.651 to -0.018; p=0.046) and stroke (β=-0.541; 95% CI, -0.844 to -0.237; p=0.001). The association with stroke persisted in sensitivity analysis (β=-0.229; 95% CI, -0.399 to -0.060; p=0.010), whereas mortality was no longer statistically significant (p=0.072). County income and racial composition were not associated with mortality. Lower-income counties demonstrated lower unadjusted stroke RAAER (β=-0.719; p=0.044), but this association was not maintained in the fully adjusted model (p=0.854). No significant interaction between income and hospital volume was identified (interaction p=0.133). CONCLUSIONS: Institutional TAVR procedural volume was the most reproducible correlate of favorable short-term outcomes, particularly stroke, whereas county-level socioeconomic and demographic characteristics demonstrated limited, model-dependent associations. These ecological findings do not exclude patient-level disparities and support further investigation of care-delivery characteristics associated with experienced TAVR centers.