Introduction: Acute kidney injury (AKI) is a serious complication of coronary artery bypass graft (CABG), occurring in up to 30% of patients. Renal ischemia-reperfusion injury (IRI) is a major contributor. Preclinical data suggest antioxidants like CoQ10 and GSH can protect against renal IRI, but human studies are lacking. We hypothesize that perioperative supplementation attenuates IRI-induced AKI. Methods: This is a double-blinded RCT involving patients (age 18-70) undergoing CABG with glomerular filtration rate ≥ 45 mL/min. Patients were randomized (1:1) to either a placebo or daily CoQ10 and GSH starting the day before surgery and up to post-op day 5. Blood and urine samples were collected preoperatively, on the day of surgery, and 24 hours postoperatively. The primary outcome was AKI incidence during the first 7 days defined by KDIGO criteria. DNA was isolated and absolute quantification was performed by qPCR. Mann-Whitney U tests and Fisher’s exact tests were used for statistical analyses. Results: Among 16 patients (7 in the treatment group and 9 in the placebo group), the incidence of AKI was 28.6% in the treatment group and 55.6% in the placebo group (RR 0.51, 95% CI 0.14-1.62, p=0.358). Urinary mitochondrial DNA (mtDNA) levels from Day -1 to Day 1 showed no statistically significant association with the development of AKI on any of the seven days (p-values > 0.05). In contrast, plasma mtDNA levels from only Day -1 were significantly elevated in patients who developed AKI on Days 2 to 5 (p = 0.0167, 0.0198, 0.0036, and 0.0036, respectively). Conclusions: Elevated plasma mtDNA levels on the day before surgery were significantly associated with AKI development between Days 2 and 5. In contrast, urinary mtDNA did not predict AKI. These findings suggest that preclinical elevations in blood mtDNA may serve as an early biomarker for impending AKI in patients undergoing CABG.
Kumar et al. (Sun,) studied this question.