P5263Genotype and cardiac findings in non transfusion dependent thalassemia patients

Abstract

Background In non transfusion dependent thalassemia (NTDT) the lack of a clear genotype-phenotype relationship complicates the already complex and extensive scenario in clinical practice. Purpose Our aim was to detect if the presence of a β°/β° homozygous genotype was associated to different rate of cardiac findings by Cardiovascular Magnetic Resonance (CMR) and cardiac complications. Methods We considered 81 patients with thalassemia intermedia never transfused o who received occasional transfusions (37.7±11.4 years, 39 females) consecutively enrolled in the Myocardial Iron Overload in Thalassemia project. CMR was used to quantify iron overload (T2* technique), biventricular morphological and functional parameters (cine sequences), and the presence of myocardial fibrosis (late gadolinium enhancement-LGE technique). All cardiac complications were classified according to international guidelines. Results Two groups of patients were identified: non homozygous β°/β° genotype (N=61) and homozygous β°/β° genotype (N=20.) No significant differences for sex and age were found between the groups. Patients with homozygous β°/β° genotype had lower mean haemoglobin levels (8.6±1.1g/dl vs 9.2±1.2 g/dl) but the difference did not reach the statistical significance (P=0.060). No patient showed cardiac iron and global heart T2* values were comparable between the two groups. Left atrial area index, left ventricular (LV) end-diastolic, end-systolic and stroke volume indexes, LV mass index, right ventricular end-diastolic and end-systolic volume indexes were significantly higher in the homozygous β°/β° group (see Table). Frequencies of heart failure and arrhythmias were comparable between the groups. Non-β0/β0 homozygous genotype β0/β0 homozygous genotype P Left Atrial Area (cm2/m2) 13.87±2.59 16.63±2.59 0.001 LV EDVI (ml/m2) 94.88±15.59 112.94±21.52 0.003 LV ESVI (ml/m2) 35.22±9.55 41.88±9.70 0.018 LV SVI (ml/m2) 61.98±12.57 69.81±11.20 0.029 LV mass index (g/m2) 61.26±10.15 68.63±15.89 0.030 RV EDVI (ml/m2) 91.27±23.50 107.53±23.87 0.019 RV ESVI (ml/m2) 33.93±17.55 40.81±15.20 0.043 Conclusions Heart remodelling related to a high cardiac output state cardiomyopathy was more pronounced in patients with homozygous β°/β° genotype. These data can support the knowledge of different phenotypic groups in the management of NTDT patients.