Low pressure giant pulmonary artery aneurysms in the adult: natural history and management strategies

Objective: To describe aspects of the natural history and pathophysiology of giant low pressure pulmonary artery aneurysms and to propose potential surgical strategies. Design: Cross sectional retrospective review. Setting: Supraregional tertiary referral centre. Patients: All adult patients referred for assessment of giant pulmonary artery aneurysm retrospectively identified from the Mayo Adult Congenital Heart Disease Clinic database. Methods: Patient data were reviewed from hospital records, including echocardiograms, magnetic resonance images, radiographs, and histology slides. Results: Four patients were identified with a median age of 52 years ( range 37-64 years). Presenting symptoms were effort related dyspnoea, chest discomfort, and hoarseness in one patient. All patients had pulmonary regurgitation and clinical evidence of right ventricular enlargement in association with a pulsatile mass at the upper left sternal edge. Transthoracic echocardiography showed the giant pulmonary artery aneurysm involving the main pulmonary artery and proximal branches, and confirmed severe pulmonary regurgitation in all patients. None of the patients had intimal tearing, medial dissection, or pulmonary arterial rupture. The pulmonary valve was replaced to relieve symptoms and preserve right ventricular function. Pulmonary arterial histology showed medial degeneration of elastic fibres with accumulation of basophilic ground substance. Conclusions: Rupture or dissection of these low pressure aneurysms is rare. The timing of surgical intervention should be determined by changes in right ventricular size and function resulting from pulmonary regurgitation or pulmonary stenosis, and not the size of the aneurysm.