# Urinary Vitamin D Binding Protein and Kidney Injury Molecule-1 Are Potent Predictors of Acute Kidney Injury After Left Ventricular Assist Device Implantation

## TL;DR

This study shows that measuring two urine proteins can help predict kidney damage after heart surgery, improving patient care.

## Contribution

The study identifies urinary VDBP and KIM-1 as novel, potent predictors of AKI after LVAD implantation.

## Key findings

- Urinary VDBP and KIM-1 levels were significantly higher in patients who developed AKI.
- Pre-LVAD biomarker levels were associated with a nearly two-fold increased AKI risk.
- Combining biomarkers with kidney function and hemodynamic status improved predictive performance.

## Abstract

Background/Objectives: Acute kidney injury (AKI) is a frequent and serious complication following left ventricular assist device (LVAD) implantation. This study aimed to predict AKI within 90 days post-LVAD by evaluating urinary levels of vitamin D binding protein (VDBP) and kidney injury molecule-1 (KIM-1). Methods: We prospectively enrolled 29 advanced heart failure patients undergoing LVAD implantation and categorized them into four groups based on pre-LVAD kidney function and hemodynamic stability. Early-morning urine samples were collected 24 h before and 1 week after surgery. Urinary VDBP and KIM-1 levels, normalized to creatinine, were measured. Results: Thirteen patients developed AKI postoperatively. Both biomarkers were significantly elevated in patients with pre-existing kidney dysfunction and hemodynamic instability, as well as in those who developed AKI. Pre-LVAD VDBP and KIM-1 levels were associated with a nearly two-fold increased AKI risk. After adjusting for kidney function and hemodynamic status, this risk rose to 776% for KIM-1 and 674% for VDBP. Conclusions: Urinary VDBP and KIM-1 are promising non-invasive biomarkers for predicting AKI in LVAD patients. The predictive performance can be greatly improved after combining with pre-LVAD kidney function and hemodynamic stability. Early measurement may help identify high-risk individuals and guide perioperative management.