Risk factors for developing acute kidney injury after heart transplant: A systematic review and meta-analysis

Acute kidney injury (AKI) is a common and serious complication following heart transplantation, significantly impacting patient outcomes and survival rates. AKI after transplantation can lead to prolonged hospital stays, increased morbidity, and even mortality.

To identify and quantify significant risk factors associated with AKI following heart transplantation through a systematic review and meta-analysis. This study aims to distinguish predictive variables that may inform perioperative risk stratification and clinical decision-making.

Electronic searches on MEDLINE, Google Scholar, ScienceDirect, ClinicalTrials.gov, and Cochrane databases were conducted from inception up till September 1. Included studies were randomized controlled trials, clinical trials, retrospective cohort, and observational studies. Exclusion criteria encompassed studies with pediatric populations, non-English publications, case reports, and studies lacking sufficient data on AKI outcomes. Statistical analysis was performed using RevMan 5.4, reporting dichotomous outcomes as odds ratios (OR) and continuous outcomes as mean differences (MD) with 95% confidence intervals (CI). Quality assessment of the included studies was performed using the New Castle Ottawa Scale.

Out of 1345 articles, 13 studies with 3330 patients were included. Significant risk factors included age [overall MD = 2.27 years (95%CI: 0.13 to 4.41)], body mass index (BMI) [MD = 1.42 (95%CI: 0.60 to 2.24)], diabetes [overall OR = 1.47 (95%CI: 1.16 to 1.85)], chronic kidney disease (CKD) [OR = 2.67 (95%CI: 1.73 to 4.14)], chronic obstructive pulmonary disorder (COPD) [OR = 0.49 (95%CI: 0.27 to 0.89)], previous thoracic surgery [(OR) = 1.27, 95%CI: (1.05 to 1.54)], cardio-pulmonary bypass time [(MD) = 17.10, 95%CI: (6.12 to 28.08)], mechanical ventilation duration [(MD) = 30.87 hours, 95%CI: (10.69 to 51.05)] and extracorporeal membrane oxygenation [(OR) = 2.31, 95%CI: (1.25 to 4.26)]. Factors not associated with AKI after heart transplantation included Recipients' male sex (P = 0.55), donor sex (P = 0.11), hypertension (P = 0.13), smoking (P = 0.20), coronary artery disease (P = 0.90), pulmonary artery disease (P = 0.81), dilated cardiomyopathy (P = 0.79), ventilation duration (P = 0.24), ischemic time (P = 0.06), use of intra-aortic balloon pump (P = 0.14), LVAD transplantation (P = 0.83), and Inotropes use (P = 0.78).

Age, BMI, diabetes, CKD, COPD, previous thoracic surgery, prolonged CPB time, extended mechanical ventilation, and ECMO use are significant predictors of AKI following heart transplantation, necessitating vigilant monitoring and individualized risk assessment. Conversely, factors such as LVAD implantation and inotrope use showed no significant association, highlighting the need for further investigation into their roles. Future prospective studies are essential to validate these findings, elucidate underlying mechanisms, and develop targeted interventions to mitigate AKI risk and improve patient outcomes.