OBJECTIVES: To investigate the clinical implications of microvascular obstruction (MVO) and intramyocardial haemorrhage (IMH) in acute myocardial infarction (AMI).
METHODS: Ninety patients with a first AMI undergoing primary percutaneous coronary intervention (PCI) were studied. T2-weighted, cine and late gadolinium-enhanced cardiovascular magnetic resonance imaging was performed at 5â€‰Â±â€‰2 and 103â€‰Â±â€‰11 days. Patients were categorised into three groups based on the presence or absence of MVO and IMH.
RESULTS: MVO was observed in 54% and IMH in 43% of patients, and correlated significantly (râ€‰=â€‰0.8, pâ€‰<â€‰0.001). Pre-PCI thrombolysis in myocardial infarction 3 flow was only observed in MVO(-)/IMH(-) patients. Infarct size and impairment of systolic function were largest in MVO(+)/IMH(+) patients (nâ€‰=â€‰39, 23â€‰Â±â€‰9% and 47â€‰Â±â€‰7%), smallest in MVO(-)/IMH(-) patients (nâ€‰=â€‰41, 8â€‰Â±â€‰8% and 55â€‰Â±â€‰8%) and intermediate in MVO(+)/IMH(-) patients (nâ€‰=â€‰10, 16â€‰Â±â€‰7% and 51â€‰Â±â€‰6%, pâ€‰<â€‰0.001). LVEF increased in all three subgroups at follow-up, but remained intermediate in MVO(+)/IMH(-) and was lowest in MVO(+)/IMH(+) patients. Using random intercept model analysis, only infarct size was an independent predictor for adverse LV remodelling.
CONCLUSIONS: Intramyocardial haemorrhage and microvascular obstruction are strongly related. Pre-PCI TIMI 3 flow is less frequently observed in patients with MVO and IMH. Only infarct size was an independent predictor of LV remodelling.