Role of Left Atrial Structure and Function in the Early Prediction of Cardiac Iron Overload in Transfusion-Dependent β-Thalassemia Patients

Abstract

<span><strong><em>Background: </em></strong><span>β<span>-thalassemia is the most common monogenic disease caused by abnormalities in<span> the synthesis of the <span>β<span>-chain of hemoglobin.<br /><span><strong><em>Methods: </em></strong><span>From January 2018 to September 2018, 90 patients (age <span>>18 y) with β<span>-thalassemia<span> major or intermedia who referred to Rajaei Cardiovascular, Medical, and Research<span> Center, Tehran, Iran, for the assessment of myocardial iron overload were enrolled. All<span> the patients were receiving regular blood transfusions and chelating therapy.<span> Comprehensive transthoracic echocardiographic studies consisting of 2D<span> echocardiography, tissue Doppler imaging, and real-time 3D echocardiography were<span> performed.<br /><span><strong><em>Results: </em></strong><span>A total of 90 patients were enrolled in the study. Cardiac iron toxicity (ie, T2* < 20 ms)<span> was seen in 28 (31%) patients; whereas in 62 (69%) patients, the cardiac iron level was<span> undetectable (ie, T2* > 20 ms). Patients with T2* < 20 ms had significantly higher serum<span> ferritin levels than those with T2* > 20 ms (<span><em>P </em><span>= 0.02). No significant correlation was<span> found between the serum ferritin level and T2* (<span><em>r </em><span>= <span>−<span>0.08, <span><em>P </em><span>= 0.41). The left ventricular<span> ejection fraction was statistically similar in the 2D and 3D examinations. Left atrial endsystolic and end-diastolic volumes were greater in the patients with iron cardiotoxicity<span> than in those with no detectable cardiac iron deposition (<span><em>P </em><span>= 0.01 and <span><em>P </em><span><0.001,<span> respectively). Left atrial strain was also significantly lower in the patients with critical<span> iron overload. The patients with T2* < 20 ms also had lower left atrial ejection fractions<span> than those with T2* >20 ms, both in 2D and 3D examinations (both <span><em>P</em><span>s <0.001).<br /><span><strong><em>Conclusions: </em></strong><span>Our study showed that changes in the left atrial structure and function precede<span> impairment in the left ventricular systolic function in thalassemia patients with critical<span> myocardial iron loading.</span></span></span><br /></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span></span>