Pre-hospital heparin use for ST-elevation myocardial infarction is safe and improves angiographic outcomes

Abstract

Aims This study aims to evaluate if pre-hospital heparin administration by paramedics is safe and improves clinical outcomes. Methods and results Using the multicentre Victorian Cardiac Outcomes Registry, linked with state-wide ambulance records, we identified consecutive patients undergoing primary percutaneous coronary intervention for STEMI between January 2014 and December 2018. Information on thrombolysis in myocardial infarction (TIMI) flow at angiography was available in a subset of cases. Patients receiving pre-hospital heparin were compared to those who did not receive heparin. Findings at coronary angiography and 30-day clinical outcomes were compared between groups. Propensity-score matching was performed for risk adjustment. We identified a total of 4720 patients. Of these, 1967 patients had TIMI flow data available. Propensity-score matching in the entire cohort yielded 1373 matched pairs. In the matched cohort, there was no observed difference in 30-day mortality (no-heparin 3.5% vs. heparin 3.0%, P = 0.25), MACCE (no-heparin 7% vs. heparin 6.2%, P = 0.44), and major bleeding (no-heparin 1.9% vs. heparin 1.4%, P = 0.64) between groups. Propensity-score analysis amongst those with TIMI data produced 552 matched pairs. The proportion of cases with TIMI 0 or 1 flow in the infarct-related artery (IRA) was lower among those receiving pre-hospital heparin (66% vs. 76%, P < 0.001) compared to those who did not. Conclusion In this multicentre, propensity-score matched study, the use of pre-hospital heparin by paramedics was safe and is associated with fewer occluded IRAs in patients presenting with STEMI.

Outcome of Out-of-Hospital Cardiac Arrest Patients Stratified by Pre-Clinical Loading with Aspirin and Heparin: A Retrospective Cohort Analysis

“…In STEMI patients-in whom coronary artery occlusion is likely-pre-hospital administration of heparin did not affect clinical outcomes in prior analyses. Heparin use led to fewer coronary artery occlusions, but major adverse cardiac events or 30 day survival were not affected [35][36][37]. In accordance, the current analysis did not reveal clinically significant differences between loaded and non-pretreated STEMI group.…”

Incidence and Outcomes of Nontraumatic Shock in Adults Using Emergency Medical Services in Victoria, Australia

“… 19 , 22 , 23 Additionally, over the study period, prehospital care of ST-elevated myocardial infarction has evolved, with EMS scope of practice expanding to allow for the administration of fibrinolytic therapy in patients with an estimated time greater than 120 minutes to percutaneous reperfusion, which may reduce symptom-to-reperfusion times and potentially contribute to a reduction in cardiogenic shock incidence. 24 , 25 Finally, in Victoria, our group has shown a temporal reduction in the adjusted annual incidence of out-of-hospital cardiac arrest due to cardiac etiology, which likely further contributed to the observed reduction in incidence of shock over the study period. 26 …”

“…This improvement is likely because of several factors, including public health initiatives to reduce modifiable risk factors for cardiovascular disease and effective local education campaigns promoting community members to seek early medical attention with the onset of symptoms suggestive of myocardial infarction . Additionally, over the study period, prehospital care of ST-elevated myocardial infarction has evolved, with EMS scope of practice expanding to allow for the administration of fibrinolytic therapy in patients with an estimated time greater than 120 minutes to percutaneous reperfusion, which may reduce symptom-to-reperfusion times and potentially contribute to a reduction in cardiogenic shock incidence . Finally, in Victoria, our group has shown a temporal reduction in the adjusted annual incidence of out-of-hospital cardiac arrest due to cardiac etiology, which likely further contributed to the observed reduction in incidence of shock over the study period …”

“…Transport times were similar among groups, with a median (IQR) of 18 (IQR 11-28) minutes. However, the median (IQR) time spent at the scene was significantly longer for the cardiogenic shock without cardiac arrest group (29 minutes; septic, 27[20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] minutes; hypovolemic, 26[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36] minutes; other, 27 minutes; P < .001). Among patients with cardiogenic shock, those who experienced prehospital cardiac arrest had significantly longer median (IQR) time spent at the scene by EMS compared with admitted to the intensive care unit (ICU) directly from the ED in 19.3% of cases, with a median (IQR) ICU length of stay of 59 (25-114) hours.…”

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

“…Despite the widespread use of UFH during PCI, robust evidence is scarce on the benefits of administering anticoagulation at earlier stages within a PCI context. To date, only four small randomised controlled trials (RCTs) (2,(5)(6)(7) and several observational studies (8)(9)(10)(11)(12)(13)(14)(15)(16)(17) with varying results on patient-relevant outcomes have investigated UFH pretreatment in patients with STEMI undergoing PCI. Additionally, the evidence on mortality outcomes remains inconclusive.…”