BACKGROUND: Morphine adversely impacts the action of oral adenosine diphosphate (ADP)-receptor blockers in ST-segment elevation myocardial infarction (STEMI) patients, and is possibly associated with differing patient characteristics. This retrospective analysis investigated whether interaction between morphine use and pre-percutaneous coronary intervention (pre-PCI) ST-segment elevation resolution in STEMI patients in the ATLANTIC study was associated with differences in patient characteristics and management.

METHODS: ATLANTIC was an international, multicenter, randomized study of treatment in the acute ambulance/hospital setting where STEMI patients received ticagrelor 180 mg ± morphine. Patient characteristics, cardiovascular history, risk factors, management, and outcomes were recorded.

RESULTS: Opioids (97.6% morphine) were used in 921 out of 1862 patients (49.5%). There were no significant differences in age, sex or cardiovascular history, but more morphine-treated patients had anterior myocardial infarction and left-main disease. Time from chest pain to electrocardiogram and ticagrelor loading was shorter with morphine (both p = 0.01) but not total ischemic time. Morphine-treated patients more frequently received glycoprotein IIb/IIIa inhibitors (p = 0.002), thromboaspiration and stent implantation (both p < 0.001). No significant difference between the two groups was found regarding pre-PCI ≥ 70% ST-segment elevation resolution, death, myocardial infarction, stroke, urgent revascularization and definitive acute stent thrombosis. More morphine-treated patients had an absence of pre-PCI Thrombolysis in Myocardial Infarction (TIMI) 3 flow (85.8% vs. 79.7%; p = 0.001) and more had TIMI major bleeding (1.1% vs. 0.1%; p = 0.02).

CONCLUSIONS: Morphine-treatment was associated with increased GP IIb/IIIa inhibitor use, less pre-PCI TIMI 3 flow, and more bleeding. Judicious morphine use is advised with non-opioid analgesics preferred for non-severe acute pain.

TRIAL REGISTRATION: clinicaltrials.gov identifier: NCT01347580.