Pretreatment of patients with ST-segment elevation myocardial infarction with heparin: a systematic review and meta-analysis

BackgroundUnfractionated heparin (UFH) is frequently administered before percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). However, current guidelines do not provide clear recommendations for UFH pretreatment before arrival at the coronary catheterisation laboratory. MethodsBetween June and July 2023, we systematically searched PubMed, Embase and Cochrane databases for studies comparing UFH pretreatments in patients with STEMI. A random-effects meta-analysis and meta-regression analyses were performed. ResultsFourteen studies were included, of which four were randomised clinical trials (RCTs). A total of 76446 patients were included: 31238 in the pretreatment group and 39208 in the control group. Our meta-analysis revealed a lower all-cause mortality for the pretreatment strategy when compared with the control group, albeit with high heterogeneity (pooled odds ratio (OR) = 0.61, 95% confidence interval (CI) [0.49 - 0.76], P < 0.01; I{superscript 2} = 77%); lower in-hospital cardiogenic shock (pooled OR = 0.68, 95% CI [0.58, 0.78], P < 0.21; I{superscript 2} = 27%) and a higher rate of spontaneous reperfusion events (pooled OR = 1.68, 95% CI [1.47, 1.91], P < 0.01; I{superscript 2} = 79%). In terms of major bleeding, the UFH pretreatment strategy further revealed a decreased rate of events (pooled OR = 0.85, 95% CI [0.73, 0.99], P = 0.40; I{superscript 2} = 4%). ConclusionsOur study suggests that UFH pretreatment in patients with STEMI undergoing primary PCI was associated to reduced all-cause mortality, cardiogenic shock, enhancing reperfusion rates, whilst diminishing major bleeding events.