The relation between hypointense core, microvascular obstruction and intramyocardial haemorrhage in acute reperfused myocardial infarction assessed by cardiac magnetic resonance imaging.

Abstract

BackgroundIntramyocardial haemorrhage (IMH) and microvascular obstruction (MVO) represent reperfusion injury after reperfused ST-elevation myocardial infarction (STEMI) with prognostic impact and “hypointense core” (HIC) appearance in T2-weighted images. We aimed to distinguish between IMH and MVO by using T2 *-weighted cardiovascular magnetic resonance imaging (CMR) and analysed influencing factors for IMH development.Methods and resultsA total of 151 patients with acute STEMI underwent CMR after primary angioplasty. T2-STIR sequences were used to identify HIC, late gadolinium enhancement to visualise MVO and T2 *-weighted sequences to detect IMH. IMH+/IMH− patients were compared considering infarct size, myocardial salvage, thrombolysis in myocardial infarction (TIMI) flow, reperfusion time, ventricular volumes, function and pre-interventional medication. Seventy-six patients (50 %) were IMH+, 82 (54 %) demonstrated HIC and 100 (66 %) MVO. IMH was detectable without HIC in 16 %, without MVO in 5 % and HIC without MVO in 6 %. Multivariable analyses revealed that IMH was associated with significant lower left ventricular ejection fraction and myocardial salvage index, larger left ventricular volume and infarct size. Patients with TIMI flow grade ≤1 before angioplasty demonstrated IMH significantly more often.ConclusionsIMH is associated with impaired left ventricular function and higher infarct size. T2 and HIC imaging showed moderate agreement for IMH detection. T2 * imaging might be the preferred CMR imaging method for comprehensive IMH assessment.Key Points• Intramyocardial haemorrhage is a common finding in patients with acute reperfused myocardial-infarction. • T 2 * imaging should be the preferred CMR method for assessment of intramyocardial haemorrhage. • Intramyocardial haemorrhage can be considered as an important influencing factor on patient’s outcome.