Effect of prehospital treatment in STEMI patients undergoing primary PCI.

Background: The appropriate timing to administer antithrombotic therapies in ST-elevation myocardial infarction (STEMI) remains uncertain. This study aims to evaluate the role of antithrombotic therapy administration at first medical contact (FMC) compared with the administration in the Cathlab.

Methods: We conducted a "before-after" observational study enrolling STEMI undergoing primary percutaneous coronary intervention (PCI). Outcomes were evaluated during two successive periods, before (control group: aspirin only at FMC) and after (pretreated intervention group: heparin, aspirin plus ticagrelor at FMC) the introduction of a new regional pretreatment protocol.

Results: A total of 537 consecutive patients (300 in control vs. 237 in intervention group) were enrolled. The pretreated compared with no pretreated population showed better basal reperfusion, expressed as basal Thrombolysis in Myocardial Infarction (TIMI)-flow (p for trend p < 0.001). Pretreated population showed lower frequency of TIMI 0 (56.5% vs. 73.7%, odds ratio [OR]: 0.46, 95% confidence interval [CI]: 0.32-0.67, p < 0.001) and higher frequency of TIMI 2-3 (33.3% vs. 19.3% OR: 2.0, 95% CI: 1.38-2.00, p < 0.001) and TIMI 3 (14.3% vs. 9.7%, OR: 1.56, 95% CI: (0.92-2.65), p = 0.094). Pretreated compared with no pretreated population showed reduced infarct size expressed as Troponin Peak (20,286 (8726-75,027) versus 48,676 (17,229-113,900), p = 0.001), and higher left ventricular ejection fraction at discharge (53% (44-59) vs. 50% (44-56), p = 0.027). In-hospital BARC ≥ 2 bleeding were similar (2.1% vs. 2.0%, p = 0.929, in pretreated versus no pretreated population, respectively).

Conclusion: This study provides support for an early pretreatment strategy in STEMI patients and confirmed the importance of an efficient organization of STEMI networks which allow initiation of antithrombotic treatment at FMC.