Additive Effect on Survival of Anaesthetic Cardiac Protection and Remote Ischemic Preconditioning in Cardiac Surgery: A Bayesian Network Meta-Analysis of Randomized Trials

Remote ischemic preconditioning in patients undergoing cardiovascular surgery: Evidence from a meta-analysis of randomized controlled trials

BACKGROUND

Remote ischemic preconditioning (RIPC) has been associated with reduced risk of myocardial injury in patients undergoing cardiovascular surgery, but uncertainty about clinical outcomes remains, particularly in the light of 2 recent large randomized clinical trials (RCTs) which were neutral. We performed a meta-analysis to evaluate the efficacy of RIPC on clinically relevant outcomes in patients undergoing cardiovascular surgery.

METHODS

We searched PubMed, Cochrane CENTRAL, EMBASE, EBSCO, Web of Science and CINAHL databases from inception through November 30, 2015. RCTs that compared the effects of RIPC vs. control in patients undergoing cardiac and/or vascular surgery were selected. We calculated summary random-effect odds ratios (ORs) and 95% confidence intervals (CI).

RESULTS

The analysis included 5652 patients from 27 RCTs. RIPC reduced the risk of myocardial infarction (MI) (OR 0.72, 95% CI, 0.52 to 1.00; p=0.05; number needed to treat (NNT)=42), acute renal failure (OR 0.73, 95% CI, 0.53 to 1.00; p=0.05; NNT=44) as well as the composite of all cause mortality, MI, stroke or acute renal failure (OR 0.60, 95% CI, 0.39 to 0.90; p=0.01; NNT=25). No significant difference between RIPC and the control groups was observed for the outcome of all-cause mortality (OR 1.10, 95% CI, 0.81 to 1.51). Randomization to RIPC group was also associated with significantly shorter hospital stay (weighted mean difference -0.15days; 95% CI -0.27 to -0.03days).

CONCLUSIONS

RIPC did not decrease overall mortality, but was associated with less MI and acute renal failure and shorter hospitalizations in patients undergoing cardiac or vascular surgery.

Remote preconditioning and cardiac surgery: regrouping after Remote Ischemic Preconditioning for Heart Surgery (RIPHeart) and Effect of Remote Ischemic Preconditioning on Clinical Outcomes in Patients Undergoing Coronary Artery Bypass Surgery (ERICCA)

Remote ischaemic preconditioning (RIPC) is an attractive cardioprotective strategy. Although results from animal studies and phase II study on humans are convincing, it cannot have a role in clinical practice until benefits in clinical outcomes are proven in phase III study. Two phase III studies were recently published [Remote Ischemic Preconditioning for Heart Surgery (RIPHeart) and Effect of Remote Ischemic Preconditioning on Clinical Outcomes in Patients Undergoing Coronary Artery Bypass Surgery (ERICCA)] and this article discusses their design, results and implications.

Renal protection in cardiovascular surgery

Acute kidney injury (AKI) is one of the most relevant complications after major surgery and is a predictor of mortality. In Western countries, patients at risk of developing AKI are mainly those undergoing cardiovascular surgical procedures. In this category of patients, AKI depends on a multifactorial etiology, including low ejection fraction, use of contrast media, hemodynamic instability, cardiopulmonary bypass, and bleeding. Despite a growing body of literature, the treatment of renal failure remains mainly supportive (e.g. hemodynamic stability, fluid management, and avoidance of further damage); therefore, the management of patients at risk of AKI should aim at prevention of renal damage. Thus, the present narrative review analyzes the pathophysiology underlying AKI (specifically in high-risk patients), the preoperative risk factors that predispose to renal damage, early biomarkers related to AKI, and the strategies employed for perioperative renal protection. The most recent scientific evidence has been considered, and whenever conflicting data were encountered possible suggestions are provided.