Aneurysm of the membranous septum with ventricular septal defect and infective endocarditis

Infective endocarditis, Transesophageal echocardiography, Ventricular septal defect, Aneurysm of the membranous septum, Aortic valve prolapse

A 36-year-old female, with a history of aneurysm of the membranous septum (AMS) and ventricular septum defect (VSD), was evaluated because of fever 3 weeks after dental extraction without endocarditis prophylaxis.

The inflammatory parameters were elevated. The blood cultures were positive for Streptococcus viridans . TEE showed AMS with a small vegetation, prolapse of the aortic valve with mild regurgitation and a left-to-right shunt ( Fig. 1a ). A systolic gradient of 70 mmHg was measured with CW-Doppler through the VSD ( Fig. 1b and c ). The peripheral blood pressure was 110/65 mmHg and the systolic right ventricular pressure was 40 mmHg.

Figure 1

(a) TEE image at 122° showing the left-to-right shunt through the ventricular septal defect (VSD); (b) small vegetation (V) attached to the aneurysm of the membranous septum (AMS) and prolapse of the aortic valve; (c) TEE image at 0° demonstrates the close anatomic relation between the AMS and the subtricuspid region. LA = left atrium, LV = left ventricle, RV = right ventricle, AA = ascending aorta, MV = mitral valve, TV = tricuspid valve.

Infective endocarditis (IE) was treated with intravenous penicillin and tobramycin. Four months later, a Qp/Qs shunt of 1.4 was calculated during invasive work-up. She was submitted for surgical closure of the VSD, to prevent recurrent endocarditis and progressive aortic regurgitation. The AMS was resected partially and VSD was closed subsequently.

In the studies on VSD, the reported figures of infective endocarditis vary widely, ranging from 0% ¹ to 11.2% ² to 13.7%. ³

Although the AMS has often been considered as relatively benign, Yilmaz et al. ³ noted 6 main complications in patients affected with AMS and VSD: aortic valve prolapse (47%), aortic regurgitation (29.4%), tricuspid insufficiency (17.6%), IE (13.7%), obstruction of the right ventricular outflow tract (4%) and rupture of the aneurysm (2%).