*Purpose: As part of a broader study on Biopsy, Anatomy, and Resistance Effects on Transplant Outcomes (BARETO), we aim to characterize the poorly understood relationship between vascular changes and long-term kidney graft survival to help inform decision making.

*Methods: DonorNet anatomy attachments were manually entered into electronic format for a preliminary cohort of 3,697 solitary, biopsied, ECD kidney transplants from 2008-2011. Chronic vascular changes (arteriosclerosis) were characterized as absent/minimal, mild (1-25%), or mild-moderate (26-50%)/severe(>50%). Analyses include Kaplan-Meier all-cause graft survival and 3 types of Cox models (propensity weighted, multivariable regression, and doubly robust regression (DRR)) to adjust for 19 possible confounders.

*Results: Unadjusted, 10-year graft survival was slightly worse with more severe vascular changes (p=0.016, Fig 1). However, risk adjustment suggests these observed differences may be attributable to correlations with other factors, in particular glomerulosclerosis, interstitial fibrosis, CIT, and KDPI. Nominally, the graft failure hazard ratio for mild-moderate+ vs. absent/minimal was 1.19 (1.02, 1.37) but was attenuated to 1.12 (0.91, 1.34) in DRR (Fig 2).

*Conclusions: Early results suggest renal vascular changes have little or no independent effect on post-transplant outcomes in a causal inference adjusting for confounding factors.

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