Clinical Utility of Urinary Liver‐Type Fatty Acid‐Binding Protein Measured via Point‐of‐Care Testing in Acute Kidney Injury After Transcatheter Aortic Valve Implantation

AIM: This study evaluated the clinical usefulness of urinary liver-type fatty acid-binding protein (L-FABP) measured via point-of-care testing (POCT) based on immunochromatography for the early prediction of acute kidney injury (AKI) following transcatheter aortic valve implantation (TAVI). METHODS: This retrospective observational study was conducted at a single-centre university hospital and included 186 patients who underwent TAVI. The onset of AKI was defined according to the Acute Kidney Injury Network classification. Urine samples were collected preoperatively, immediately after surgery, 4 h postoperatively and on postoperative days 1, 2 and 3 to measure urinary L-FABP using POCT. RESULTS: Of the 186 patients who underwent TAVI, 24 (12.9%) developed AKI postoperatively. Patients with AKI exhibited a decreased left ventricular ejection fraction, the co-occurrence of both hypertension and advanced-stage chronic kidney disease and a longer hospital stay. During the observational period, patients with AKI were found to have significantly higher urinary L-FABP levels than those without. Preoperative urinary L-FABP showed the highest predictive performance for AKI onset, with an area under the receiver operating characteristic curve of 0.74 (cutoff value, 4.24 ng/mL; sensitivity, 0.61; specificity, 0.82; diagnostic accuracy, 0.79). Elevated urinary L-FABP levels above the cutoff value in the early phase of the perioperative period independently predicted AKI onset after adjusting for ejection fraction and the presence of renal dysfunction in the multivariable logistic regression analysis. CONCLUSION: This study indicated for the first time that urinary L-FABP levels measured via POCT were independently associated with the development of AKI following TAVI, indicating potential utility for early risk assessment.