Demythologizing pulmonary artery aneurysm: prevalence and associated complications in a large pulmonary arterial hypertension population

Purpose: Pulmonary artery aneurysm (PAA) is a rare condition, usually described as an autopsy finding. Severe pulmonary hypertension (PH) is an important factor involved in its pathogenesis. Few data is available about PAA prevalence in group 1 PH patients, but incidence is increasing in living individuals due to PA imaging techniques. Nevertheless, evolution, prognosis and treatment of this disease are not well established. Potentially fatal complications associated to PAA can occur, and its prevalence and management remain uncertain

Methods: Among 566 patients followed in our national reference PH unit, 393 were categorized as group 1 and 1' PH of Dana Point Classification. PAA was defined as PA diameter>40 mm. Computed tomography or magnetic resonance was performed as part of PH study protocol or due to symptoms suggesting complications. Haemodynamic and clinical parameters were collected. Average follow-up time from PAA diagnosis was 2,58±1,5 years

Results: 48 PAA (12,2% of cohort, mean pulmonary vascular resistances 13,7±8,7mmHg) were detected by CT (92%) or MR (8%). Associated PH etiologies: idiopathic (31%), congenital (35%), toxic oil syndrome (14%), connective tissue diseases (6%), veno-oclusive disease (4%) and others (8%). Mean PA diameter was 48±8 mm, and both right (RPA) and left (LPA) PA were dilated in 64% cases. 10 patients died during follow-up (21%) and 1 (2%) underwent lung transplantation. 37 patients (77%) were asymptomatic and PAA was an incidental finding. 11 patients (23%) showed symptoms suggesting associated complications: 5 left main coronary artery compression (LCMAC); 2 both LMCAC and PAA partial thrombosis; 2 compressive lung atelectasis; 1 LPA dissection and 1 RPA thrombosis. Complicated PAA showed higher diameter than non-complicated PAA (58±10 vs 46±5 mm). There was no mortality related to complications. No changes were observed in mean PA diameter (49±12mm) during follow-up, despite optimization of specific PH treatment (49% received endothelin receptor antagonists, 56% phosphodiesterase type 5 inhibitors, 35% prostanoids)

Conclusion: Prevalence of PAA in our group 1 PH cohort was 12,2%. Immediate diagnosis when clinical suspicion of complicated PAA is high, could explain why even though complications rate was 23%, there was no mortality associated with them. According to our results a closer follow-up might be considered in those PAA with diameters greater than 55 mm. Treatment of these complications in this high risk patients remain uncertain. To the best of our knowledge, this is the largest series of PAA in group 1 PH patients reported in literature