Abstract Body (Do not enter title and authors here): Background: Pressure-controlled intermittent coronary sinus occlusion (PiCSO) is an innovative therapeutic approach that enhances myocardial perfusion and minimizes reperfusion injury by intermittently occluding the coronary sinus, thereby increasing retrograde coronary perfusion. To date, no meta-analysis has comprehensively evaluated the efficacy and safety of PiCSO in this setting. This meta-analysis aimed to evaluate the addition of PiCSO to primary percutaneous coronary intervention (pPCI) in patients with STEMI, providing a comprehensive assessment of its potential benefits and risks in the clinical setting.

Methods: A comprehensive literature search was conducted using the PubMed, Embase, and Google Scholar databases. Using the inverse variance method, random-effect models were used to calculate standardized mean differences (SMDs) with 95% confidence intervals (CIs). Statistical significance was set at p < 0.05. The primary endpoints were the mean infarct size (% LV mass), LV end-systolic volume (LVESV), LV end-diastolic volume (LVEDV), LV ejection fraction (LVEF), and microvascular obstruction extent (MVO) (%LV) at follow-up (2-5 days).

Results: Six studies, encompassing 467 STEMI patients, were included in the analysis. PiCSO in addition to pPCI did not significantly alter infarct size (SMD = 0.16; 95% CI -0.31 to 0.63; p= 0.51), LVEF (SMD = 0.07; 95% CI - 0.14 to 0.28; p= 0.51), LVESV (SMD = -0.13; 95% CI -0.34 to 0.08, p= 0.21) and LVEDV (SMD = -0.11; 95% CI -0.32 to 0.10; p=0.31) compared with conventional treatment with pPCI alone. There was no significant difference in the extent of microvascular obstruction (MVO) between the two groups (SMD = -0.12; 95% CI -0.39 to 0.16; p = 0.37).

Conclusion: Our meta-analysis suggests that PiCSO as an adjunct to pPCI does not significantly improve myocardial protection or ventricular function in STEMI patients. Future research should investigate whether specific patient subgroups might benefit from this intervention.