Sweden: Heparin Pretreatment in STEMI Patients

Pretreatment with heparin reduces the risk of coronary artery occlusion in ST-segment elevation myocardial infarction (STEMI) patients without increasing the risk of significant bleeding, according to a report from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR).

The study's findings, published in EuroIntervention, also found that pretreatment with unfractionated heparin (UFH) reduced mortality with a number needed to treat (NNT) of 94; this effect, however, was not robust.

Considering that UFH is administered frequently before percutaneous coronary intervention (PCI) in STEMI patients, Oskar Love Emilsson, Department of Cardiology, Clinical Sciences, Lund University, Lund, Sweden, and colleagues aimed to examine if pretreatment with UFH before arrival at the catheterization laboratory impacts mortality, coronary artery occlusion, and major in-hospital bleeding in STEMI patients undergoing PCI.

For this purpose, the researchers extracted patients with a first STEMI event undergoing PCI between 2008 and 2016 from the Swedish Coronary Angiography and Angioplasty Registry. Using adjusted Poisson regression models, they obtained risk ratios for UFH pretreatment versus no pretreatment concerning coronary artery occlusion at presentation in the cath lab, bleeding, and 30-day mortality. To get absolute risk differences, propensity score (PS)-matched groups were analyzed.

Study Findings

• Forty-one thousand six hundred thirty-one patients were included, 38% with and 62% without UFH pretreatment.
• Adjusted risk ratios were 0.89 for coronary artery occlusion, 0.87 for mortality, and 1.01 for bleeding.
• In the PS-matched analyses, the absolute risk differences were −0.087 for coronary artery occlusion, −0.011 for mortality, and 0 for bleeding.

"In patients with STEMI, pretreatment with UFH was tied to a reduction in coronary artery occlusion, with a number needed to treat 12 without raising the risk of major in-hospital bleeding," the researchers wrote. "A decrease in mortality was seen with the pretreatment with heparin, with an NNT of 94; this effect was not robust; overall residual confounding and sensitivity analyses cannot be excluded."

Reference

Emilsson OL, Bergman S, Mohammad MA, Olivecrona GK, Götberg M, Erlinge D, Koul S. Pretreatment with heparin in patients with ST-segment elevation myocardial infarction: a report from the Swedish Coronary Angiography and Angioplasty Registry (SCAAR). EuroIntervention. 2022 Oct 21;18(9):709-718. doi: 10.4244/EIJ-D-22-00432. PMID: 36036797.