Periprocedural Oral Hydration Patterns and Early Renal Function after Coronary Angiography and Intervention: A Prospective Real-World Cohort Study.

introductionGuidelines recommend oral hydration (OH) to prevent contrast-associated acute kidney injury (CA-AKI) after coronary angiography or intervention, but quantitative protocols are lacking, and practice varies. Shorter hospital stays limit opportunities for post-procedure creatinine monitoring, and real-world OH patterns and their early renal effects remain poorly described. This study aimed to characterize periprocedural weight-adjusted OH trajectories and to assess whether trajectory membership was associated with a change in serum creatinine within 24 h.

methodsThis single-center prospective cohort study enrolled 192 inpatients undergoing coronary angiography or intervention between November 2024 and May 2025. We recorded weight-adjusted oral intake in four windows: pre-12 h, post-0-6 h, 6-12 h, and 12-24 h. We computed partial-overlap dynamic time warping distances and clustered trajectories using partitioning around medoids. Group comparisons used nonparametric tests. The primary outcome was percent change in serum creatinine, and dose-response was assessed with generalized additive models (GAMs) adjusted for baseline creatinine, estimated glomerular filtration rate, comorbidities, procedural indication, contrast volume, and intravenous hydration.

resultsAfter excluding 18 patients for missing periprocedural oral intake or post-procedure creatinine, 174 patients were analyzed (median age 65.0 years, IQR 57.2 to 72.0; 71.8% male). Median weight-adjusted cumulative oral intake was 10.9, 18.6, 23.9, and 33.3 mL/kg for the pre-12 h, post-0-6 h, 0-12 h, and 0-24 h windows. Time-series clustering produced two stable groups (low-OH n = 85, high-OH n = 89; average silhouette = 0.393; bootstrap adjusted Rand index = 0.845). The largest between-group difference occurred in the 0-6 h window (median 4.12 vs. 2.00 mL/kg/h, p < 0.001). No patient met CA-AKI criteria. In adjusted GAMs, the 0-6 h OH rate was not a significant smooth term (edf = 3.79, p = 0.795), and cluster membership was not associated with creatinine change. However, the high-OH cluster had substantially greater 6-h urine output and a larger positive fluid balance (p < 0.001), while serum potassium was similar between clusters.

conclusionPeriprocedural OH was generally ample and formed two reproducible patterns. Concentrating oral intake in the first 6 h increased early urine output and positive fluid balance but did not show a significant dose-response association with early serum creatinine change. This null result should be interpreted cautiously because the cohort was generally low-risk, follow-up was short, and the study had limited power. Future studies should validate whether early concentrated OH protects renal function using earlier sensitive biomarkers and by targeting high-risk patients.