1069Cardiovascular Magnetic Resonance: a trial to assess its utility for “infarction with normal coronary arteries”

Abstract

Introduction: “Infarction with normal coronary arteries(CA)” is a catch-all term because it includes such different diseases as tachycardia-mediated cardiomyopathy, myocarditis, coronary vasospasm, infarction with rapid clot lysis and some others. Cardiovascular Magnetic Resonance (CMR) enables us to distinguish between them in many cases. Purposes: 1. With the assistance of CMR, to make the differential diagnosis of patients presenting with chest pain, typical rise in biomarkers of myocyte injury (I Troponin, ITn) and exclusion of significant CA disease.2.To find out whether there is a cut off value of troponin under which CMR does not provide additional information. Methods: We prospectively enrolled 73 patients who had been admitted to hospital with chest pain and elevated ITn from October 2008 to April 2011. We collected data on demographics,electrocardiographics, echocardiogarphics and maximum value of ITn. These subjects underwent a CMR protocol for the assessment of global and regional morphology and systolic function, T2-weighted images and late gadolinium enhancement (LGE) studies. The CA were evaluated with computed tomography or with coronary angiography. Results: Based on CMR images we classified the patients in two groups: myocarditis (55 patients)and non-myocarditis. In the second group, we diagnosed 6 patients with infarction because they had subendocardial and/or transmural LGE, and 8 patients with Takotsubo because they had transient systolic dysfunction of the apical and/or mid segments of the left ventricle. In our sample, the ITn value was not statistically different between the two groups, but it correlated with the presence of edema or LGE on CMR. The area under the receiver operating characteristic curve of ITn vs edema was 0,79 (95%CI 0,88-0,99) with a cut off value of 0,21ng/ml ITn, under which no patients had edema signal on CMR. With regard to basal characteristics, female gender, old age and presence of CV risk factors were associated with the “non-myocarditis group”.13 Conclusion: The ratio of the myocardium to blood pool null points, or Tio Myocardium/Blood Pool, provides a quantitative method to identify cardiac amyloidosis. This method can be performed at the scanner and does not require off line post processing.