Abstract
Introduction: Recently two novels indicators of left ventricular (LV) performance assessed by Cardiovascular Magnetic Resonance (CMR) have been introduced: the LV global function index (LVGFI) and the LV mass/volume ratio (LVMVR). The LVGFI combines LV stroke volume, end-systolic and end diastolic volumes, as well as LV mass, integrating structural as well as mechanical behaviour. Elevated LVMVR is indicative of concentric remodelling. A LVGFI <37% and a LVMVR>1 were shown to be associated with the occurrence of cardiovascular events in no-thalassemic populations.
This retrospective cohort study aimed to systematically evaluate in a large historical cohort of thalassemia major (TM) in the CMR era whether the LVGFI and the LVMVR were associated with a higher risk of heart failure.
Methods: We considered 812 TM patients (391 M, 30.4±8.6 years), consecutively enrolled in the Myocardial Iron Overload in Thalassemia (MIOT) network. LVGFI and LVMRI were quantitatively evaluated by SSFP cine images. The T2* value in all the 16 cardiac segments was evaluated and a global heart T2* value <20 ms was considered indicative of myocardial iron overload (MIO).
Results: Eighty (9.9%) patients had a LVGFI<37% and, compared to the patients with a normal LVGFI, they showed a significant higher frequency of heart failure (43.8% vs 4.2%; P<0.0001). Patients with a LVGFI<37% had a significant higher risk of heart failure (odds-ratio-OR=17.59, 95%CI=9.95-21.09; P=<0.001). The risk remained significant also adjusting for the presence of MIO (OR=15.54, 95%CI=8.05-26.27; P=<0.001).
Thirty (3.7%) patients had a LVMVR≥1% and, compared to the patients with a normal LVMRI, they showed a significant higher frequency of heart failure (20.0% vs 7.7%; P=0.015). Patients with a LVMVR≥1% had a significant higher risk of heart failure (OR=3.01, 95%CI=1.18-7.64; P=0.021). The risk remained significant also adjusting for the presence of MIO (OR=3.44, 95%CI=1.31-9.01; P=0.012).
In a multivariate model including LVGFI, LVMVR and heart iron, the significant predictors of heart failure were a LVGFI<37% (OR=14.05, 95%CI=7.66-25.77; P=<0.001) and a global heart T2*<20 ms (OR=1.94, 95%CI=1.08-3.47; P=0.026).
Conclusions: In TM patients a LVGFI<37% was associated with an higher risk of heart failure, independent by the presence of MIO. A widespread program using CMR exploiting its multi-parametric potential can have considerable power for the early identification and treatment of patients at risk for heart failure.
No relevant conflicts of interest to declare.
Author notes
Asterisk with author names denotes non-ASH members.
