Pretreatment with dual antiplatelet therapy in acute myocardial infarction

Abstract Background Combined antithrombotic therapy prevents thrombus progression and its components embolization, and thus, it has an essential role in coronary microcirculation (re)perfusion in acute myocardial infarction (AMI). Pretreatment with P2Y12 inhibitors, on top of aspirin, before primary angioplasty has not been satisfactorily studied in STEMI. Purpose To investigate the impact of combined antiplatelet therapy on-treatment on the outcome of patients with STEMI. Methods Patients who suffered STEMI during the 7 years (1/2016-12/2022) were included. The analysis is based on population data from the National Health Information System (NHIS). Information on AMIs from the Intervention Module of the Registry of Cardiovascular Operations and Interventions was combined with prescription data from the Registry of Reimbursed Health Services 6 months before MI and identification of deceased patients from the Registry of Death Records. Data from the NHIS covers almost 100% of all cases in the population. Standard descriptive statistics and test were applied in the analysis. Multivariate logistic regression adjusted for clinical and procedural characteristics was adopted to analyze the influence of pretreatment on the risk of 1) out-of-hospital cardiac arrest (OHCA), 2) clinical condition at admission – need of mechanical ventilation and circulatory instability (Killip III,IV), 3) initial TIMI flow through the infarct-related coronary artery (IRA ), and 4) short term mortality. Results The study sample consisted of data from 40,383 STEMIs of which 1,601 patients were on dual antiplatelet therapy (DAPT) with aspirin plus iP2Y12 lasting 1 to 6 months before the event occurred. Patients on chronic oral anticoagulation (N 2101) were excluded. Patients on DAPT versus those without antiplatelet therapy or on aspirin at a daily dose of 100 mg were older, had higher comorbidity rates, and were at higher risk of mortality (Table). The multivariate logistic regression analysis showed that patients on DAPT at the time of MI onset and lasting for at least one month had a higher likelihood of preserved perfusion through the IRA (Odds ratio and 95% Confidence interval, OR (95% CI) 1. 193 (1.074; 1.326), p=0.001). However, the DAPT pretreatment did not reduce the risk of OHCA, the need for mechanical ventilation, or initial circulatory destabilization. It did not positively affect the prognosis of the patients (Figure ). Conclusion The significant benefit of the DAPT pretreatment on the preservation of infarct-related coronary artery flow did not translate into a positive effect on the prognosis of STEMI patients.