Pulmonary artery (PA) dilatation is a common feature of pulmonary hypertension (PH). While lung transplantation (LTx) leads to significant hemodynamic improvements, the effect on PA diameter remains u Show more
Pulmonary artery (PA) dilatation is a common feature of pulmonary hypertension (PH). While lung transplantation (LTx) leads to significant hemodynamic improvements, the effect on PA diameter remains unclear. This study aims to evaluate changes in PA diameter following LTx in patients with preexisting PH and determine whether structural vascular changes regress alongside pulmonary pressure normalization. We retrospectively assessed 18 patients with PH who underwent LTx between 2002 and 2023. Main PA, right PA (RPA), and left PA (LPA) diameters were measured via computed tomography (CT) imaging pre-transplant and annually post-transplant (up to 12 years). Systolic pulmonary arterial pressure (SPAP) was assessed by echocardiography. Despite a significant reduction in SPAP, PA diameter remained largely unchanged (mean pre-LTx: 29.7 mm; post-LTx: 30.0 mm, P=0.670). The aorta diameter increased slightly (P=0.0027), and the PA-to-aorta (PA/Ao) ratio decreased (from 1.08 to 1.00; P=0.027). RPA and LPA showed no significant dimensional changes. Correlation between PA size and SPAP was weak and not significant both pre- and post-LTx (r=0.087 and 0.388, respectively). In contrast to some previous reports suggesting vascular remodeling post-LTx, our findings suggest that PA diameter may remain dilated in some PH patients, even after normalization of pulmonary pressures. This could reflect the presence of structural changes that are less responsive to hemodynamic improvements and warrants a careful interpretation of persistent PA dilation on chest CTs following LTx. Show less