Pulmonary artery aneurysms in pulmonary arterial hypertension: prevalence, predictors, progression and clinical impact

Background Pulmonary artery aneurysms (PAA) are a potentially severe structural complication of pulmonary arterial hypertension (PAH). However, data regarding their prevalence, risk factors, natural history and prognostic impact remain limited and mainly derive from small series. Purpose To assess the prevalence, predictors, progression, complications and prognostic impact of PAA in a large PAH cohort. Methods A retrospective observational study of 356 patients with PAH followed at a European reference centre with at least one computed tomography or cardiac magnetic resonance allowing measurement of the main pulmonary artery (MPA) diameter was conducted. PAA was defined as MPA diameter ≥40 mm. Patients were classified according to presence or absence of PAA at first imaging. Demographic, clinical characteristics, and haemodynamics were compared between groups. Multivariable regression analysis identified independent predictors of PAA. In patients with serial imaging (≥6 months apart), progression was defined as incident PAA or diameter growth of PAA from first imaging. PAA-related complications and time-to-event analyses for all-cause mortality and lung transplantation were performed. Results Mean age at PAH diagnosis was 45.9±15.8 years, 112 patients (31.5%) were male. Among the 356 patients, 145 (40.7%) had PAA at first imaging. Median time from PAH diagnosis to first imaging was 25 months (1–88), among the 145 patients with PAA, time to detection was 74 months (7–130.5). Patients with PAA had younger age, more frequently PAH associated with congenital heart disease or toxic rapeseed oil and less commonly with connective tissue or veno-occlusive disease, and worse haemodynamics (Table 1). In multivariable analysis, age at PAH diagnosis and congenital heart disease were independently associated with PAA, whereas connective tissue disease was protective (Table 2). Among 164 patients with serial imaging, PAA progression occurred in 62 (37.8%) during a median follow-up of 91.5 months (28.5–126). At final follow-up, 168 patients had PAA, of whom 25 (14.9%) developed PAA-related complications: 4 (2.4%) dissection, 12 (7.1%) thrombosis, and 11 (6.6%) left main coronary artery compression requiring stenting. During follow-up, 132 patients (37.1%) died and 47 (13.2%) underwent lung transplantation. Median time to death or lung transplantation was not significantly different in patients with versus without PAA (Log-rank p = 0.87). Conclusion In a large quaternary PAH cohort, PAA were frequent and development independently associated with age at diagnosis and disease aetiology. Aneurysm progression was common during follow-up. Although PAA were not associated with increased mortality or lung transplantation, they were linked to severe complications. Further prospective studies are needed to better define clinical and prognostic implications of PAA and to establish optimal surveillance and management strategies.