We read with great interest the study by Dardi and colleagues investigating the haemodynamic determinants and prognostic implications of pulmonary artery dilation in pulmonary arterial hypertension (PAH) [1]. The authors found that a pulmonary artery diameter of at least 40 mm was independently associated with sudden death, with an adjusted subdistribution hazard ratio of 3.93, despite not being independently associated with all-cause mortality. This finding is clinically important because pulmonary artery diameter is readily available from routine computed tomography pulmonary angiography and may identify an anatomical risk phenotype that is not fully captured by conventional PAH risk assessment.
