Cumulative contrast exposure and renal outcomes: current evidence and management

Abstract Background Patients with complex conditions often need repeated contrast‑enhanced imaging, making renal risk assessment essential. Methods This narrative review explore how repeated contrast exposure influences kidney function, summarizing short- and long-term effects across varied clinical contexts. A targeted search of PubMed, EMBASE, and the Cochrane Library (inception–December 2025) identified 75 records, from which 41 studies most relevant to repeated exposure were included. Main body Evidence directly addressing repeated contrast exposure indicates that short-term contrast-associated acute kidney injury (CA-AKI) risk is highest when large contrast volumes—especially during the same hospitalization —are given over short intervals (< 72 h, limiting renal recovery), and in patients with advanced chronic kidney disease, diabetes, prior acute kidney injury, or ongoing clinical instability. Reported CA-AKI rates in high-risk cohorts generally range from 5 to 15%, and most episodes are reversible. In contrast, evidence for an independent long-term cumulative nephrotoxic effect remains limited, heterogeneous, and largely observational however, stable populations with wide variation in cumulative contrast exposure have not consistently demonstrated accelerated chronic kidney disease progression after adjustment for baseline risk and the number of contrast-enhanced procedures does not appear to independently drive long-term renal decline. Data in renal allograft recipients, and dialysis patients remain limited and are often extrapolated from single-exposure studies rather than dedicated repeated-exposure cohorts. Conclusions Repeated contrast exposure should not be avoided when clinically necessary, but decisions should be individualized. The clearest short-term risks are high per-procedure dose, short inter-exposure interval, intra-arterial administration, advanced chronic kidney disease, and concurrent clinical instability. Long-term renal decline appears to be driven mainly by baseline disease burden rather than cumulative contrast alone, although residual confounding remains substantial.