Abstract
The emergency management of ST-elevation myocardial infarction (STEMI) involves treatment
with dual-antiplatelet therapy (DAPT) and primary percutaneous coronary intervention
(PPCI). Pain is generally treated with opiates, which may delay gastric transit and
reduce DAPT absorption. We sought to assess the effect of morphine on reperfusion,
infarct size and thrombotic status in 300 patients presenting for PPCI. Morphine was
given in a non-randomized fashion as required by emergency teams en route to the heart attack centre. All patients received DAPT and PPCI according to standard
care, with optional glycoprotein IIb/IIIa inhibitor (GPI) use. Patients were assessed
for ST-segment resolution, coronary flow, thrombotic status and peak troponin. Patients
receiving morphine (n = 218; 72.7%) experienced less spontaneous ST-segment resolution pre-PPCI, lower
rate of TIMI 2/3 flow in the infarct-related artery pre-PPCI and higher peak troponin
level post-PPCI (median [interquartile range]; 1,906 [1,002–4,398] vs. 1,268 [249–2,920]
ng/L; p = 0.016) than those who did not. Patients receiving morphine exhibited significantly
enhanced platelet reactivity and impaired endogenous fibrinolysis on arrival, compared
with no-morphine patients. Morphine administration was an independent predictor of
failure of spontaneous ST-segment resolution after adjustment for other variables
(odds ratio: 0.26; confidence interval: 0.08–0.84; p = 0.025). Among patients receiving GPI, there was no difference in pre-PPCI flow
or peak troponin according to morphine use, suggesting that the adverse effects of
morphine relate to delayed DAPT absorption, which may be overcome by GPI. Our hypothesis-generating
data suggest that morphine use in STEMI is associated with enhanced platelet reactivity,
reduced spontaneous myocardial reperfusion (pre-PPCI) and larger infarct size, and
these adverse effects may be influenced by GPI use.
Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT02562690.
Keywords
opiates - morphine - percutaneous coronary intervention - thrombosis - endogenous
fibrinolysis
