Exploratory Analysis of Early Renal Function Changes After Transcatheter Aortic Valve Implantation (TAVI): Limited Predictive Value Beyond Baseline Renal Function

Background: In elderly, multimorbid patients, renal function changes are frequent following transcatheter aortic valve implantation. However, the early renal recovery following the relief of aortic stenosis is not sufficiently characterized. Methods: This retrospective single-center study comprised 410 consecutive patients who underwent TAVI. Serum creatinine and estimated glomerular filtration rate (eGFR) were measured prior to and within 72 h of TAVI to evaluate renal function. Primary outcomes were defined as absolute alterations (Δcreatinine and ΔeGFR). Spearman’s correlation and multivariable regression were implemented to assess associations. Results: The mean age was 82.0 ± 8.7 years, and 46.9% of the participants were female. The eGFR demonstrated modest improvement (mean ΔeGFR +3.83 mL/min/1.73 m2), while creatinine showed minimal change (mean Δ −0.015 mg/dL). Renal function exhibited bidirectional alterations. Baseline creatinine was inversely associated with Δcreatinine (ρ = −0.127, p = 0.010), which was consistent with regression to the mean. Conversely, baseline eGFR was not associated with ΔeGFR (ρ = 0.004, p = 0.934). There were no significant correlations between renal changes and BMI (ρ = −0.041 and ρ = 0.047; both p > 0.30). In multivariable analysis, baseline creatinine remained independently associated with Δcreatinine (β = −0.279, p < 0.001), whereas ejection fraction exhibited a modest association (β = 0.012, p = 0.020). Acute kidney injury was observed in 13.9% of the population (57/410) and was not independently correlated with baseline variables. Conclusions: Early renal alterations following TAVI are frequent and frequently favorable; however, they are primarily indicative of baseline renal function, with limited independent predictive value of other variables. The results should be regarded as hypothesis-generating.