PB2391 MYOCARDIAL CONTRACTILE FRACTION BY MAGNETIC RESONANCE AND RISK OF CARDIAC COMPLICATIONS IN THALASSEMIA MAJOR

Abstract

Background:The analysis of cine cardiovascular magnetic resonance (CMR) images allows the quantification of the myocardial contraction fraction (MCF), a volumetric analog of myocardial deforming, that is calculated by dividing left ventricular (LV) stroke volume by LV myocardial volume.Aims:We verified the association of this new marker with myocardial iron overload and cardiac events (heart failure, arrhythmias and pulmonary hypertension) in thalassemia major (TM) patients.Methods:We considered 1492 TM patients (771 females, 31.06 ± 8.95 yrs) enrolled in the MIOT network. Myocardial iron overload (MIO) was quantified by the multislice multiecho T2∗ technique and biventricular morphological and functional parameters by cine sequences.Results:MCF values were significantly lower in males (0.94 ± 0.22 vs 1.01 ± 0.22; P < 0.0001) and decreased with increasing age (R = −0.129 P < 0.0001).Patients with MIO (global heart T2∗ < 20 ms; N = 400) showed significant lower MCF values than patients without MIO (0.91 ± 0.20 vs 1.00 ± 0.22; P < 0.0001).The patient population was randomly divided in two groups of equal size (N = 746).In the first group 99 patients had at least one cardiac complication and at receiver‐operating characteristic (ROC) curve analysis a MCF ≤ 0.87 was the best predictor of cardiac complications (area under the curve 0.659, 95% CI 0.64 to 0.69; sensitivity 60%, specificity 67%).In order to validate the result, the obtained value was tested in the remaining 746 patients (group 2). One hundred and thirty‐five patients had a cardiac complication and patients with a MCF ≤ 0.87 were more likely to have cardiac complications (odds ratio – OR = 2.73, 95%CI = 1.86‐4.01; P < 0.0001), also adjusting for cardiac iron (see Figure).Summary/Conclusion:Contractile function is reduced in patients with MIO. A MCF ≤0.87 can help to identify patients with a significant higher risk of adverse cardiovascular events, independently by the presence of MIO.image