Right ventricular-pulmonary arterial coupling in transfusion-dependent thalassemia: a cross-sectional cardiac MRI study.

Abstract

The aim of this cross-sectional study was to investigate the association between right ventricle-pulmonary artery coupling (RVPAc) and demographic characteristics, clinical variables, cardiac magnetic resonance imaging (MRI) findings, and heart failure in patients with transfusion-dependent thalassemia (TDT). We evaluated 1154 consecutive patients with TDT (52.9% female; mean age 37.46 ± 10.67 years) enrolled in the Extension-Myocardial Iron Overload in Thalassemia (E-MIOT) project. In addition, we included 167 age- and sex-matched healthy controls (54.5% female; mean age 36.33 ± 15.78 years). RVPAc was calculated as the ratio of the right ventricle (RV) end-systolic volume index to the RV stroke volume index, according to Sanz's method. TDT patients showed significantly higher RVPAc than healthy controls (0.68 ± 0.28 vs 0.59 ± 0.15, p < 0.0001). Among TDT patients, RVPAc was higher in males, inversely associated with age and pre-transfusion hemoglobin levels, and positively associated with mean serum ferritin levels. RVPAc was increased in patients with myocardial iron overload and correlated positively with liver iron concentration and biventricular end-diastolic volumes and inversely with biventricular ejection fractions. Replacement fibrosis was not associated with RVPAc overall, whereas junctional late gadolinium enhancement (LGE) was associated with higher RVPAc. In the multivariable model, increased RVPAc was independently associated with higher odds of heart failure (odds ratio = 3.99, p = 0.049). In patients with TDT, RVPAc was higher than in control subjects and was significantly associated with iron burden. Higher RVPAc was linked to junctional LGE and independently associated with increased odds of heart failure. Question RVPAc remains an unexplored cardiac MRI biomarker for detecting subclinical maladaptive changes and heart failure risk in TDT. Findings TDT patients showed higher RVPAc than controls, which was associated with myocardial iron burden, junctional fibrosis, and a fourfold higher odds of heart failure. Clinical relevance RVPAc provides an integrative, reproducible marker of right ventricular performance and pulmonary vascular load in patients with TDT. By capturing subclinical maladaptive changes from standard cine images, it offers a practical tool for advanced risk stratification.