Iron overload in polytransfused patients without heart failure is associated with subclinical alterations of systolic left ventricular function using cardiovascular magnetic resonance tagging

Abstract

Background: It remains incompletely understood whether patients with transfusion related cardiac iron overload without signs of heart failure exhibit already subclinical alterations of systolic left ventricular (LV) dysfunction. Therefore we performed a comprehensive evaluation of systolic and diastolic cardiac function in such patients using tagged and phase-contrast CMR. Methods: 19 patients requiring regular blood transfusions for chronic anemia and 8 healthy volunteers were investigated using cine, tagged, and phase-contrast and T2* CMR. LV ejection fraction, peak filling rate, end-systolic global midventricular systolic Eulerian radial thickening and shortening strains as well as left ventricular rotation and twist, mitral E and A wave velocity, and tissue e' wave and E/e' wave velocity ratio, as well as isovolumic relaxation time and E wave deceleration time were computed and compared to cardiac T2*. Results: Patients without significant iron overload (T2* > 20 ms, n = 9) had similar parameters of systolic and diastolic function as normal controls, whereas patients with severe iron overload (T2* < 10 ms, n = 5), had significant reduction of LV ejection fraction (54 ± 2% vs. 62 ± 6% and 65 ± 6% respectively p < 0.05), of endsystolic radial thickening (+6 ± 4% vs. +11 ± 2 and +11 ± 4% respectively p < 0.05) and of rotational twist (1.6 ± 0.2 degrees vs. 3.0 ± 1.2 and 3.5 ± 0.7 degrees respectively, p < 0.05) than patients without iron overload (T2* > 20 ms) or normal controls. Patients with moderate iron overload (T2* 10-20 ms, n = 5), had preserved ejection fraction (59 ± 6%, p = NS vs. pts. with T2* > 20 ms and controls), but showed reduced maximal LV rotational twist (1.8 ± 0.4 degrees). The magnitude of reduction of LV twist (r = 0.64, p < 0.001), of LV ejection fraction (r = 0.44, p < 0.001), of peak radial thickening (r = 0.58, p < 0.001) and of systolic (r = 0.50, p < 0.05) and diastolic twist and untwist rate (r = -0.53, p < 0.001) in patients were directly correlated to the logarithm of cardiac T2*.

Altered regional cardiac wall mechanics are associated with differential cardiomyocyte calcium handling due to nebulette mutations in preclinical inherited dilated cardiomyopathy

“…Ventricular dimensions were calculated using Segment v1.x (http://segment.heiberg.se, E. Heiberg, In Proceedings of IEEE Computers in Cardiology 2005). LV torsion, ρ , was calculated as rotation in degrees (°) of the heart apex relative to the base and LV twist was calculated as torsion normalized by a geometric constant, as described previously [12]. Ventricular dimensions were calculated using Segment v1.x (http://segment.heiberg.se, E. Heiberg, In Proceedings of IEEE Computers in Cardiology 2005).…”

“…As recoil of torsion, or LV untwisting, is independent of left atrial pressure, it is considered a sensitive measure of LV diastolic function [12, 13]. Therefore, untwisting rate was calculated as the maximum of the derivative of ρ with respect to time and normalized for geometric changes by the geometric constant.…”

Cardiovascular Function and Treatment in β-Thalassemia Major

“…Alternative measures of systolic LV function such as tagging and myocardial phase mapping may be more sensitive to myocardial T2*, but further experience is needed to evaluate their possible clinical role. 152 …”

Review of Journal of Cardiovascular Magnetic Resonance 2012

“…Recent advances include identification of the lack of myocardial fibrosis [88], the involvement of the right ventricle [89], early strain abnormalities [90], and improved prognosis [91]. Combination therapy with deferoxamine and oral deferiprone is superior to deferoxamine alone in removing cardiac iron and improving left ventricular ejection fraction (LVEF).…”