Pharmacological and non-surgical renal protective strategies for cardiac surgery patients undergoing cardiopulmonary bypass: a systematic review.

BACKGROUND: Post-operative acute kidney injury after cardiopulmonary bypass (AKI-CPB) for cardiac surgery is a frequent complication. It may require renal replacement therapy (RRT), which is associated with an increased morbidity and mortality. This review explores the efficacy of proposed pharmacological and non-surgical renal protective strategies.

METHODS: A comprehensive literature search was done using Ovid MEDLINE, Embase and Scopus databases. Keywords included were cardiopulmonary bypass, cardiac surgery, coronary artery bypass, renal protection and renal preservation. Eligible articles consisted of all studies on patients who had undergone cardiac surgery via CPB with an outcome of AKI and/or RRT reported. All studies underwent a quality check via the risk of bias tool. The three most researched interventions (based on number of randomized controlled trials and total patients analysed) and their renal outcomes were then analysed with Review Manager Software.

RESULTS: Eighty-eight articles were extracted. A total of 26 management strategies for renal protection following CPB were identified. N-acetylcysteine (NAC), remote ischaemic preconditioning (RIPC) and the use of volatile anaesthetic agents (VAAs) were further analysed. NAC, RIPC and VAA had no statistically significant benefit in reducing either AKI-CPB or the need for RRT following CPB.

CONCLUSION: NAC, RIPC and VAA were found to have no statistical significant benefit in reducing either AKI-CPB or the need for RRT following CPB. There remains clinical uncertainty with all currently proposed pharmacological and non-surgical renal protective strategies for CPB. Future research in this area should analyse the effects of combined interventions or specifically focus on 'at-risk' patients.