Ventricular volume asymmetry as a risk marker for heart failure and all-cause mortality in transfusion-dependent thalassemia

Aim: We measured the left-to-right ventricular volume ratio (LRVR) in a large cohort of patients with transfusion-dependent thalassemia (TDT) and assessed its cross-sectional correlations and its prognostic value in predicting heart failure (HF) and all-cause mortality. Methods: 1,481 TDT patients underwent cardiovascular magnetic resonance for assessment of biventricular volumes and ejection fractions (cine images) and myocardial iron overload (T2* technique) and for detection of replacement myocardial fibrosis (late gadolinium enhancement-LGE images). The LRVR was defined as the ratio between the left ventricular (LV) and right ventricular (RV) end-diastolic volume indexes. Results: 1160 (78.3%) patients had normal ventricular symmetry, 220 (14.9%) LV dominant asymmetry (LRVR > 118%), and 101 (6.8%) RV dominant asymmetry (LRVR < 89%). Cardiac iron levels and LGE were comparable among the three groups. LV dominance was associated with reduced LV function. RV dominance was correlated with aging, reduced RV function, and a history of arrhythmias. The mean follow-up time was 4.82 ± 2.06 years. HF death occurred in 15 (1.01%) patients. The risk for HF death was significantly higher in the group with RV dominant asymmetry compared to that with normal ventricular symmetry (hazard ratio, HR = 6.07). All-cause death occurred in 42 (2.8%) patients. RV dominant asymmetry was associated with a significantly increased risk of all-cause mortality compared to normal ventricular symmetry [hazard ratios (HR) = 3.57] and LV dominant asymmetry (HR = 6.17). RV dominance remained associated with an increased risk of HF and all-cause mortality even after adjusting for other risk factors such as cardiac iron, LGE, or biventricular ejection fractions. Conclusion: The LRVR may play a significant role in enhancing death risk stratification in TDT.