Meta-analysis of the effect of high-intensity statin on coronary microvascular dysfunction

Objective: The purpose of this meta-analysis is to evaluate the role of high-intensity statin pretreatment on coronary microvascular dysfunction in patients with coronary heart disease undergoing percutaneous coronary intervention (PCI). Methods: PubMed, Cochrane and Embase were searched. This meta-analysis selection included randomized controlled trials (RCTs), involving high-intensity statin pretreatment as active treatment, and measurement of thrombolysis in myocardial infarction (TIMI), myocardial blush grade (MBG) or index of microvascular resistance (IMR) in coronary heart disease (CHD) patients undergoing PCI. I 2 test was used to evaluate heterogeneity. Pooled effects of continuous variables were reported as Standard mean difference (SMD) and 95% confidence intervals (CI). Pooled effects of discontinuous variables were reported as risk ratios (RR) and 95% confidence intervals (CI). Random-effect or fix-effect meta-analyses were performed. Benefit was further examined based on clinical characteristics including diagnosis and statin type by using subgroup analyses. Publication bias was examined by quantitative Egger’s test and funnel plot. We performed sensitivity analyses to examine the robustness of pooled effects. Results: Twenty RCTs were enrolled. The data on TIMI ＜ 3 was reported in 18 studies. Comparing with non-high-intensity statin, high-intensity statin pretreatment significantly improved TIMI after PCI (RR=0.62， 95%CI： 0.50 to 0.78， P＜0.0001). The data on MBG＜2 was reported in 3 studies. The rate of MBG＜2 was not different between groups (RR=1.29，95% CI： 0.87 to 1.93，P=0.21). The data on IMR was reported in 2 studies. High-dose statin pretreatment significantly improved IMR after PCI comparing with non-high-dose statin (SMD=-0.94，95% CI：-1.47 to-0.42，P=0.0004). There were no significant between-subgroup differences in subgroups based on statin type and diagnosis. Publication bias was not indicated by using quantitative Egger’s test (P=0.97) and funnel plot. Sensitivity analyses confirmed the robustness of these findings. Conclusions: Comparing with non-high-intensity statin, high-intensity statin pretreatment significantly improved TIMI and IMR after PCI. In the future, RCTs with high quality and large sample are needed to test these endpoints.