An anatomopathologic study of membranous septum aneurysms and significance of their surgical treatment

The purpose of the study: We analyzed 14 patients with menbranous septal aneurysms presenting with a left-to-right communication, by comparing the angiographic, operative and pathological findings. We decided to use medical treatment on two patients and operated on the rest (12 cases). Basic methods: The mean age of the patients was 19±9 yr; nine were female, five were male. Cine-angiography of all patients revealed a saccular abnormality protruding into the right ventricle at the uppermost part of the interventricular septum, just below the aortic valve. The sac had the appearance of a glove finger, a cauliflower, a diverticulum, or it was dome-shaped on angiography. Principal findings: Perioperative exploration revealed a perforated true aneurysmal sac in seven patients. In three patients, the perimembranous tissues were severely fibrotic, thickened or had more than one perforation. Two patients had a defect under the septal leaflet of the tricuspid valve at the postero–inferior part of the septum, hidden between the chordae of the valve. Conclusions: Defining the membranous septal abnormalities clearly is not always possible by cine-angiography. Echocardiography provides additional information. Pathological examination of the resected specimens showed almost total loss of elastic fibers and extensive accumulation of mucopolysaccharides.