Combined Atrioventricular Coupling Index in Transfusion‐Dependent Thalassemia: Insights From a Cross‐Sectional Analysis

Purpose: The purpose of this cross-sectional study was to investigate the association between the combined atrioventricular coupling index (CACI) and demographic characteristics, clinical variables, cardiovascular magnetic resonance (CMR) findings, and cardiac complications (heart failure, pulmonary hypertension, and arrhythmias) in patients with transfusion-dependent tlhalassemia (TDT). Methods: We evaluated 292 consecutive patients with TDT (151 females; mean age 36.72 ± 11.76 years) enrolled in the Extension–Myocardial Iron Overload in Thalassemia (E-MIOT) project. In addition, 32 age- and sex-matched healthy controls (12 females; mean age 40.78 ± 14.35 years) were included. The CACI was calculated as the sum of the left atrioventricular coupling index (LACI) and the right atrioventricular coupling index (RACI). Results: Compared with healthy controls, patients with TDT exhibited significantly higher CACI values (50.83% ± 20.34% vs. 34.62% ± 12.59%; p < 0.0001). Moreover, CACI demonstrated superior discriminatory performance compared with LACI in distinguishing TDT patients from controls (p = 0.001). Aging was significantly and positively associated with CACI, and higher CACI values were observed in patients with prior splenectomy, diabetes, and the presence of late gadolinium enhancement (LGE). In stepwise regression analysis, LGE emerged as an independent predictor of CACI (F = 15.40; p < 0.0001). Finally, TDT patients with cardiac complications showed significantly higher CACI values than those without cardiac complications. Conclusion: CACI values were higher in patients with TDT, enabling discrimination of TDT patients. Higher CACI values were significantly associated with the presence of LGE. Furthermore, patients with cardiac complications exhibited impaired CACI.