Cardiac complications in thalassemia major

Abstract

The myocardium is particularly susceptible to complications from iron loading in thalassemia major. In the first years of life, severe anemia leads to high-output cardiac failure and death if not treated. The necessary supportive blood transfusions create loading of iron that cannot be naturally excreted, and this iron accumulates within tissues, including the heart. Free unbound iron catalyzes the formation of toxic hydroxyl radicals, which damage cells and cause cardiac dysfunction. Significant cardiac siderosis may present by the age of 10 and may lead to acute clinical heart failure, which must be treated urgently. Atrial fibrillation is the most frequently encountered iron-related arrhythmia. Iron chelation is effective at removing iron from the myocardium, at the expense of side effects that hamper compliance to therapy. Monitoring of myocardial iron content is mandatory for clinical management of cardiac risk. T2* cardiac magnetic resonance measures myocardial iron and is the strongest biomarker for prediction of heart failure and arrhythmic events. It has been calibrated to human myocardial tissue iron concentration and is highly reproducible across all magnetic resonance scanner vendors. As survival and patient age increases, endothelial dysfunction and diabetes may become new factors in the cardiovascular health of thalassemia patients. Promising new imaging technology and therapies could ameliorate the long-term prognosis.

MRI evaluation of hepatic and cardiac iron burden in pediatric thalassemia major patients: spectrum of findings by T2*

“…2). T2* is inversely related to intracellular iron, increased tissue iron displays a moderate decrease in T1 signals and extreme decrease in T2 signal intensities [10,20,21].…”

“…T2* is a simple, non-invasive and rapid technique that is gained in a single breath-hold [1,8,9,11,14]. Owing to the late development of the clinical findings and echocardiographic abnormalities, MR-T2* has become the strongest biomarker for simultaneous evaluation of liver and heart iron burden [1,19] plus prediction of iron-induced cardiac complications such as heart failure and arrhythmia in TM patients [18][19][20].…”

“…Auger and Pennelle [20] reported that assessment of cardiac iron loading should be started between the age of 6 and 10 years and that cardiac siderosis may present at the age of ten by acute heart failure. In this study, the youngest subject who developed cardiac siderosis based on abnormal cardiac T2* results was an 8-year-old female ( Fig.…”

Long‐term improvement in cardiac magnetic resonance in β‐thalassemia major patients treated with deferasirox extends to patients with abnormal baseline cardiac function

“…The cardiac events we observed were restricted to arrhythmias, exclusively supraventricular reported in 10% of patients, half of them with preexisting cardiac disease. Arrhythmias may occur in patients with or without iron overload, and atrial fibrillation has been recognized as the most common cardiac complication in aging TM patients, even without evidence of current iron overload . This is confirmed by a recent study on a large cohort of TM adults, reporting arrhythmia as a prevalent cardiac complication increasing with the age and not correlated to myocardial iron overload .…”

Aortic Valve Replacement in a Patient with β-Thalassemia

“…Aşırı demir birikimine bağlı olarak perikardit, aritmiler ve myokardiyal yetmezlik görü-lebilir. Bu nedenle özellikle puberte sonrası kardiyovasküler açıdan hastaların mutlaka sıkı takip altında olmaları gerekmektedir [3] .…”