Comparison of infarction size, complete ST-segment resolution incidence, mortality and re-infarction and target vessel revascularization between remote ischemic conditioning and ischemic postconditioning in ST-segment elevation myocardial infarction patients undergoing primary percutaneous coronary intervention

Introduction
Due to higher morbidity and mortality, ST-segment elevation myocardial infarction (STEMI) causes many public health problems.

Aim
To observe effects of remote ischemic conditioning (RIC) and ischemic postconditioning (IPC) on patients diagnosed as STEMI undergoing primary percutaneous coronary intervention (pPCI).

Material and methods
This meta-analysis was conducted using indirect comparison by conducting a network meta-analysis (NMA). We conducted searches by utilizing PubMed and the other databases to identify randomized controlled trials (RCTs) that described IPC or RIC treated patients diagnosed with STEMI during processes of pPCI. Enzymatic infarct size and infarction size were evaluated and cardiac events were assessed during the follow-up.

Results
Pooled results showed that lower enzymatic infarction size was associated with the RIC group compared to the IPC group (IPC vs. RIC: standardized mean difference (SMD) = 1.126; 95% confidence interval (CI): 0.756–1.677). Compared with IPC, RIC significantly reduced infarction size, which was assessed using cardiac magnetic resonance (CMR) (SMD = 1.113; 95% CI: 0.674–1.837). We noted a potential toward greater complete ST-segment resolution in RIC patients compared with IPC patients (odds ratio (OR) = 0.821; 95% CI: 0.166–4.051). No significant difference existed in all-cause mortality (OR = 2.211; 95% CI: 0.845–5.784), Target vessel revascularization (TVR) (OR = 0.045; 95% CI: 0.001–.662) or re-infarction (OR = 1.763; 95% CI: 0.741–4.193).

Conclusions
This meta-analysis suggested RIC was correlated with significantly smaller infarction size compared to IPC. No significant superiority between RIC and IPC has been observed in this study on cSTR incidence, mortality and re-infarction or TVR.