The role of Proenkephalin A 119-159 in the detection of acute kidney injury after open thoracoabdominal aortic repair.

Background: Acute kidney injury (AKI) after open thoracoabdominal aortic aneurysm repairs (TAAA) is a common postoperative complication, associated with increased mortality and morbidity. Early detection and management of the kidney tissue damage remains of paramount importance. The aim of this prospectively conducted, observational trial was to evaluate the clinical applicability of Proenkephalin A 119-159 (penKid) for the detection of postoperative AKI. Patients and methods: Thirty-six patients, planned for elective open TAAA repairs from January 2019 to December 2022, were recruited in two German centres (University Hospital Aachen and Charité - University Hospital Berlin). Blood samples were collected pre-surgery (baseline), directly postoperatively and at 12, 24 and 48 hours after surgery. The penKid concentration in plasma was measured using the immunoluminometric sphingotest^® assay kit and they were statistically tested for association with AKI and other clinical parameters. Results: Twenty-four patients (62%) developed moderate or severe AKI postoperatively (Stage 2 or 3 of the KDIGO classification) and they had a significantly increased risk for the development of acute respiratory distress syndrome (p=.023) or a fatal outcome (p=.035). Starting from the 12^th hour after surgery, we found penKid correlating with AKI stage 2/3 (12 hour penKid mean in pmol/L: 93.9 vs. 43.1; c index .776, p=.0037) and renal replacement therapy (12 hour c index .779, p=.0035). Patients with multi-organ dysfunction syndrome had significantly increased penKid levels at all timepoints. Conclusions: We found penKid to be a promising biomarker for the early detection of postoperative AKI and in-hospital mortality after open TAAA repair, which may enable the early initiation of organ-protective strategies and reduction of further complications associated with AKI.