Intravenous morphine administration and reperfusion success in ST-elevation myocardial infarction: insights from cardiac magnetic resonance imaging

Aims: Intravenous (IV) morphine has been shown to be independently associated with adverse clinical outcome in patients with non-STEMI. Currently, there are no data on the association of IV morphine and reperfusion success in STEMI. Thus, we thought to analyse the impact of IV morphine on ischemic injury and salvaged myocardium assessed by cardiac magnetic resonance imaging (CMR) in patients with STEMI reperfused by primary coronary intervention (PCI). Methods and results: STEMI patients reperfused by primary PCI (n = 276) within 12 h after symptom onset underwent CMR 3 days after the index event [interquartile range (IQR) 2–4]. IV morphine administration was recorded in all patients. IV morphine was administered in 44.7 % (n = 123) of all patients. Patients in the IV morphine group displayed larger infarct size, higher extent of MO and lower myocardial salvage index (MSI) in comparison to the non-IV morphine group (all p < 0.05). In multivariable logistic regression analysis adjusted for TIMI-flow pre-PCI, time from symptom onset to PCI, Killip class and left ventricular ejection fraction, IV morphine was identified as an independent predictor for MSI <median (odds ratio 1.71, 95 % CI 1.02–2.87, p = 0.04). Conclusion: In patients with STEMI, IV morphine administration prior to PCI is independently associated with suboptimal reperfusion success. These findings warrant randomised clinical trials assessing the effect of IV morphine on clinical outcome.