Adding parenteral anticoagulation in STEMI undergoing PCI: safety and efficacy?

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Antithrombotic therapy is the cornerstone treatment for acute coronary syndromes. Often, parenteral anticoagulation (AC) is added to the dual antiplatelet treatment, till primary percutaneous coronary intervention (PCI). This strategy is recommended by latest guidelines, due to large experience, however, there has been no placebo-controlled trial evaluating the efficacy or safety of AC in primary PCI. Purpose This study aims to evaluate the efficacy and safety of treatment with parenteral AC, either with UFH or with low molecular weight heparin (LMWH), in ST segment elevation myocardial infarction (STEMI), undergoing PCI. Methods Retrospective, multicenter, cohort of 1052 STEMI patients, admitted to primary PCI was divided in two groups: one undergoing parenteral AC and one with no AC. We did a sub analyze comparing the group treated with UFH and LMWH, against placebo. The primary efficacy endpoints were in-hospital and one year follow-up mortality, major adverse cardiovascular events (MACE) during hospitalization (re-infarction, mechanical complication, sudden cardiac death averted, ventricular arrhythmia, heart failure, stroke, and cardiogenic shock) and glycoprotein IIaIIIb inhibitor bailout strategy (GPIIaIIIb). The safety endpoints were TIMI major bleeding and decrease of hemoglobin (Hb) value greater than 3g/dL. Results Of the total of 1052 patients: 564 (54%) were treated with parenteral anticoagulation and 488 were not. In the anticoagulation sample, 207 patients were treated with UFH (37%), and 357 patients were treated with LMWH (63%). There were no statistically significant differences in both groups, in terms of age and sex distribution, with a 18-26% of women and mean age of 62,8-66,2±0,9 years old. AC, and LMWH, had a statistically significant association with lower in-hospital mortality (p<0,01), with odds ratio (OR) 0,3 and 0,28 respectively. UFH did not have a statistically significant association with lower mortality (p=0,8). In terms of follow-up mortality, there was no statistically significant association in either group. In terms of MACE and GPIIaIIIb, AC, LMWH and UFH had a statistically significant association with lower MACE and GPIIaIIIB (p<0,01), with a OR 0,9, OR 0,56 and OR 0,77 respectively, on MACE, and with OR 0,1, OR 0,3 and OR 0,2, on GPIIaIIIB. Regarding safety, neither AC, nor LMWH or UFH, had a statistically significant association with TIMI major bleeding (p=0,24, p=0,2, and p=0,8). LMWH had a statistically significant association with Hb value decrease greater than 3g/dL (p=0,03 RR 6%), that was not verified in AC or UFH samples (p=0,1), against placebo. Conclusion Adding AC, in STEMI patients admitted to primary PCI, to the antithrombotic therapy strategy is associated with lower in-hospital mortality, MACE and GPIIaIIIB bailout strategy, without increasing rates of TIMI major bleeding or Hb value decrease greater than 3g/dL.