Fedai A. B. Evaluation of the relationship of cardiac iron overload with atrial and ventricular function and geometric measurement values in patients with thalassemia major by 4-dimensional transthoracic echocardiography

Fedai A. B. Evaluation of the relationship of cardiac iron overload with atrial and ventricular function and geometric measurement values in patients with thalassemia major by 4-dimensional transthoracic echocardiography. Hacettepe University Faculty of Medicine, Internal Diseases Specialty Thesis, ANKARA, 2022. Cardiac iron overload is one of the most important causes of mortality in thalassemia major patients. Transthoracic echocardiography (TTE) is a more accesible method compared to cardiac MR (CMR) T2*, which is routinely recommended in the follow up of patients with thalassemia major and various parameters measured by transthoracic echocardiography predicting cardiac involvement have been defined. In this study, 2 dimensional (2D) and 4 dimensional (4D) echocardiographic measurements used to evaluate ventricular systolic and diastolic functions, strain measurements, ventricular volume and geometry in patients with thalassemia major. Thus, we aimed to evaluate cardiac involvement with TTE. The study included 44 thalassemia major patients who were followed up in Hacettepe University Hematology Clinic. Demographic, clinical and laboratory features of the patients were recorded retrospectively. 2D and 4D echocardiographic examination was performed on patients in control visits. On baseline 4D echocardiographic examination, ejection fraction (EF) 62.2%, end sistolic volume (ESV) 42.3 ml, end diastolic volume (EDV) 111.93 ml, stroke volume (SV) 69.2 ml, cardiac output (CO) 5.23 l/min, mass index 78.4 g/m², global longitudinal strain (GLS) -19.07%, global circumferencial strain (GCS) 16.57%, global area strain (GAS) -29.11%, global radial strain (GRS) 39.91% were measured in beta thalassemia major patients. Mean value of sphericity index (SI) was 0.44. In thalassemia patients, left ventricular shape was more globular than normal patients. In patients with ferritin >1000 ng/ml, lateral early diastolic myocardial velocity (e') (13.4 cm/s, p=0.015), SV (64 ml, p=0.037), GLS (-18.17%, p=0.032) were significantly lower. There was no difference between other strain analyzes and cardiac volumes. In patients with CMR T2* <20 ms, lateral e' (12.3 cm/s, p=0.027) was significantly lower and diastolic dysfunction was significantly higher. Grade 3 diastolic dysfunction was recorded in 5 of the 6 patients with diastolic dysfunction. In patients with CMR T2* <20 ms, GLS (-17.08 %, p<0.001) was significantly lower. Cut off value of GLS was found -18.5% for predicting cardiac involvement (AUC 0.845, sensitivity %91.7, specificity %71.9). As a result, cardiac involvement can be predicted in thalassemia major patients by evaluating cardiac geometry and strain values with 4D echocardiography. 4D echocardiography studies with more patients are needed to evaluate cardiac involvement of thalassemia major. Keywords: Thalassemia Major, 4 Dimensional Echocardiography, Global Longitudinal Strain, Sphericity İndex.