Statin prophylaxis and inflammatory mediators following cardiopulmonary bypass: a systematic review

INTRODUCTION: Induction of an inflammatory response is thought to have a significant role in the complications that follow cardiopulmonary bypass (CPB). The statin drugs are increasingly being recognized as having potent anti-inflammatory effects and hence have potential to influence an important mechanism of injury in CPB, although there is no current confirmation that this is indeed the case. Our objective was to systematically review if pre-operative prophylactic statin therapy, compared with placebo or standard of care, can decrease the inflammatory response in people undergoing heart surgery with CPB. METHODS: We performed a systematic and comprehensive literature search for all randomized controlled trials (RCTs) of open heart surgery with CPB in adults or children who received prophylactic statin treatment prior to CPB, with reported outcomes which included markers of inflammation. Two authors independently identified eligible studies, extracted data, and assessed study quality using standardized instruments. Weighted mean difference (WMD) was the primary summary statistic with data pooled using a random effects model. Descriptive analysis was used when data could not be pooled. RESULTS: Eight RCTs were included in the review, with the number of trials for each inflammatory outcome being even more limited. Pooled data demonstrated benefit with the use of statin to attenuate the post-CPB increase in interleukins 6 and 8 (IL-6, IL-8), peak high sensitivity C-reactive protein (hsCRP), and tumor necrosis factor-alpha (TNF-α) post-CPB (WMD [95% confidence interval (CI)] -23.5 pg/ml [-36.6 to -10.5]; -23.4 pg/ml [-35.8 to -11.0]; -15.3 mg/L [CI -26.9 to -3.7]; -2.10 pg/ml [-3.83 to -0.37] respectively). Very limited RCT evidence suggests that prophylactic statin therapy may also decrease adhesion molecules following CPB including neutrophil CD11b and soluble P (sP)-selectin. CONCLUSIONS: Although the RCT evidence may suggest a reduction in post-CPB inflammation by statin therapy, the evidence is not definitive due to significant limitations. Several of the trials were not methodologically rigorous and statin intervention was highly variable in this small number of studies. This systematic review demonstrates that there is a significant gap that exists in the current literature in regards to the potential anti-inflammatory effect of statin therapy prior to CPB.