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

ABSTRACT:

Background

Intramyocardial 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 results

A 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.

Conclusions

IMH 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.

SUBMITTER: Kandler D

PROVIDER: S-EPMC4231283 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background Invasive measures of microvascular resistance in the culprit coronary artery have potential for risk stratification in acute ST-segment-elevation myocardial infarction. We aimed to investigate the pathological and prognostic significance of coronary thermodilution waveforms using a diagnostic guidewire. Methods and Results Coronary thermodilution was measured at the end of percutaneous coronary intervention, (PCI) and contrast-enhanced cardiac magnetic resonance imaging (MRI) was intended on day 2 and 6 months later to assess left ventricular (LV) function and pathology. All-cause death or first heart failure hospitalization was a pre-specified outcome (median follow-up duration 1469 days). Thermodilution recordings underwent core laboratory assessment. A total of 278 patients with acute ST-segment elevation myocardial infarction EMI (72% male, 59±11 years) had coronary thermodilution measurements classified as narrow unimodal (n=143 [51%]), wide unimodal (n=100 [36%]), or bimodal (n=35 [13%]). Microvascular obstruction and myocardial hemorrhage were associated with the thermodilution waveform pattern ( P=0.007 and 0.011, respectively), and both pathologies were more prevalent in patients with a bimodal morphology. On multivariate analysis with baseline characteristics, thermodilution waveform status was a multivariable associate of microvascular obstruction (odds ratio [95% confidence interval]=5.29 [1.73, 16.22];, P=0.004) and myocardial hemorrhage (3.45 [1.16, 10.26]; P=0.026), but the relationship was not significant when index of microvascular resistance (IMR) >40 or change in index of microvascular resistance (5 per unit) was included. However, a bimodal thermodilution waveform was independently associated with all-cause death and hospitalization for heart failure (odds ratio [95% confidence interval]=2.70 [1.10, 6.63]; P=0.031), independent of index of microvascular resistance>40, ST-segment resolution, and TIMI (Thrombolysis in Myocardial Infarction) Myocardial Perfusion Grade. Conclusions The thermodilution waveform in the culprit coronary artery is a biomarker of prognosis and may be useful for risk stratification immediately after reperfusion therapy.

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