Department of Pediatrics, Cairo University, Cairo, Egypt,
Ann Hematol. 2014 Mar;93(3):375-9. doi: 10.1007/s00277-013-1876-0. Epub 2013 Aug 15.
Myocardial siderosis in thalassemia major remains the leading cause of death in developing countries. Once heart failure develops, the outlook is usually poor with precipitous deterioration and death. Cardiovascular magnetic resonance (CMR) can measure cardiac iron deposition directly using the magnetic relaxation time T2*. This allows earlier diagnosis and treatment and helps to reduce mortality from this cardiac affection. This study aims to determine the prevalence of cardiac siderosis in Egyptian patients who are heavily iron loaded and its relation to liver iron concentration, serum ferritin, and left ventricular ejection fraction. Eighty-nine β-thalassemia patients receiving chelation therapy (mean age of 20.8 ± 6.4 years) were recruited in this study. Tissue iron levels were determined by CMR with cardiac T2* and liver R2*. The mean ± standard deviation (range) of cardiac T2* was 28.5 ± 11.7 ms (4.3 to 53.8 ms), the left ventricular ejection fraction (LVEF) was 67.7 ± 4.7 % (55 to 78 %), and the liver iron concentration (LIC) was 26.1 ± 13.4 mg Fe/g dry weight (dw) (1.5 to 56 mg Fe/g dw). The mean serum ferritin was 4,510 ± 2,847 ng/ml (533 to 22,360 ng/ml), and in 83.2 %, the serum ferritin was >2,500 ng/ml. The prevalence of myocardial siderosis (T2* of <20 ms) was 24.7 % (mean age 20.9 ± 7.5 years), with mean T2* of 12.7 ± 4.4 ms, mean LVEF of 68.6 ±5.8 %, mean LIC of 30.9 ± 13 mg Fe/g dw, and median serum ferritin of 4,996 ng/ml. There was no correlation between T2* and age, LVEF, LIC, and serum ferritin (P = 0.65, P = 0.085, P = 0.99, and P = 0.63, respectively). Severe cardiac siderosis (T2* of <10 ms) was present in 7.9 %, with a mean age of 18.4 ± 4.4 years. Although these patients had a mean T2* of 7.8 ± 1.7 ms, the LVEF was 65.1 ± 6.2 %, and only one patient had heart failure (T2* of 4.3 ms and LVEF of 55 %). LIC and serum ferritin results were 29.8 ± 17.0 mg/g and 7,200 ± 6,950 ng/ml, respectively. In this group of severe cardiac siderosis, T2* was also not correlated to age (P = 0.5), LVEF (P = 0.14), LIC (P = 0.97), or serum ferritin (P = 0.82). There was a low prevalence of myocardial siderosis in the Egyptian thalassemia patients in spite of very high serum ferritin and high LIC. T2* is the best test that can identify at-risk patients who can be managed with optimization of their chelation therapy. The possibility of a genetic component for the resistance to cardiac iron loading in our population should be considered.
地中海贫血症患者的心肌含铁血黄素沉着症仍然是发展中国家的主要死亡原因。一旦心力衰竭发展，预后通常较差，病情急剧恶化，导致死亡。心血管磁共振（CMR）可以使用磁共振弛豫时间 T2直接测量心脏铁沉积。这可以更早地诊断和治疗，并有助于降低这种心脏疾病的死亡率。本研究旨在确定埃及重度铁负荷患者的心脏含铁血黄素沉着症的患病率及其与肝铁浓度、血清铁蛋白和左心室射血分数的关系。本研究招募了 89 名接受螯合治疗的β-地中海贫血患者（平均年龄 20.8±6.4 岁）。通过 CMR 用心脏 T2和肝脏 R2来确定组织铁水平。心脏 T2的平均值±标准偏差（范围）为 28.5±11.7 ms（4.3 至 53.8 ms），左心室射血分数（LVEF）为 67.7±4.7%（55 至 78%），肝铁浓度（LIC）为 26.1±13.4 mg Fe/g 干重（dw）（1.5 至 56 mg Fe/g dw）。平均血清铁蛋白为 4510±2847ng/ml（533 至 22360ng/ml），83.2%的血清铁蛋白>2500ng/ml。心肌含铁血黄素沉着症（T2*<20ms）的患病率为 24.7%（平均年龄 20.9±7.5 岁），平均 T2为 12.7±4.4 ms，平均 LVEF 为 68.6±5.8%，平均 LIC 为 30.9±13 mg Fe/g dw，中位数血清铁蛋白为 4996ng/ml。T2与年龄、LVEF、LIC 和血清铁蛋白之间无相关性（P=0.65，P=0.085，P=0.99，P=0.63）。严重的心肌含铁血黄素沉着症（T2*<10ms）的患病率为 7.9%，平均年龄为 18.4±4.4 岁。尽管这些患者的平均 T2为 7.8±1.7 ms，但 LVEF 为 65.1±6.2%，只有 1 名患者患有心力衰竭（T2为 4.3 ms，LVEF 为 55%）。LIC 和血清铁蛋白结果分别为 29.8±17.0 mg/g 和 7200±6950ng/ml。在这组严重的心肌含铁血黄素沉着症患者中，T2也与年龄（P=0.5）、LVEF（P=0.14）、LIC（P=0.97）或血清铁蛋白（P=0.82）无相关性。尽管血清铁蛋白和 LIC 均很高，但埃及地中海贫血患者的心肌含铁血黄素沉着症患病率较低。T2是能够识别高危患者的最佳检查方法，高危患者可以通过优化螯合治疗来进行管理。应考虑我们人群中对心脏铁负荷的抵抗力是否存在遗传因素。
