Protective effects of remote ischemic preconditioning in patients undergoing isolated valve replacement surgery: a meta-analysis

Background Valve replacement, often involving cardiopulmonary bypass (CPB), can induce myocardial ischaemia and reperfusion injury despite cardioplegia. Remote ischaemic preconditioning (RIPC), involving brief ischaemia/reperfusion cycles in a remote limb, has emerged as a potential strategy to mitigate this injury. While some trials suggest benefits, others show no effect. This meta-analysis investigates the protective effects of RIPC in patients undergoing isolated valve replacement surgery, considering its impact on myocardial injury markers. Purpose This meta-analysis aims to resolve conflicting findings regarding the efficacy of RIPC in valve replacement. By synthesising available evidence, we seek to determine if RIPC reduces myocardial injury and has protective pulmonary and renal effects. Our study will help clinicians make informed clinical decisions and potentially improve patient outcomes. Methodology A comprehensive search of major databases like PubMed, Scopus, Embase, Cochrane, and Google Scholar was conducted to retrieve eligible studies. The inverse variance random-effects model was used to generate pooled effects estimates of outcomes as mean difference (MD) and standard mean difference (SMD) and risk ratios (RR) with a 95% confidence interval. Results 9 studies were included in the analysis, with 1269 patients (636: RIPC; 633: Control). Remote ischaemic preconditioning (RIPC) significantly reduced CK-MB levels [SMD: -0.24; 95% CI: -0.41, -0.06; p = 0.008] and cTnI levels [SMD: -2.09; 95% CI: -3.15, -1.04; p = 0.0001], indicating myocardial protection. Additionally, RIPC significantly decreased the duration of invasive ventilation [MD: -0.78; 95% CI: -1.48, -0.08; p = 0.03]. However, it had no significant effect on the risk of acute kidney injury (AKI) [RR: 0.95; 95% CI: 0.80, 1.13; p = 0.57], ICU stay duration [MD: -2.60; 95% CI: -9.35, 4.14; p = 0.45], or hospital length of stay [MD: -0.30; 95% CI: -0.62, 0.01; p = 0.06]. Conclusion RIPC significantly reduces myocardial injury and the duration of the invasive ventilation required in valve replacement, demonstrating cardiopulmonary protective effects. However, we found no significant impact on clinical outcomes such as AKI, ICU stay, or hospital length of stay. This discrepancy suggests that while RIPC may offer biochemical myocardial protection, its impact on broader clinical outcomes requires further investigation, potentially focusing on specific patient subgroups.