Aneurysm: Sinus of valsalva or ventricular septal?
Monish S Raut1, Arun Maheshwari1, Sumir Dubey2 1 Department of Cardiac Anesthesia, Dharam Vira Heart Center, Sir Ganga Ram Hospital, New Delhi, India 2 Department of Cardiac Surgery, Dharam Vira Heart Center, Sir Ganga Ram Hospital, New Delhi, India
A 37-year-old woman presented with a history of shortness of breath on mild exertion. The Transthoracic echocardiographic evaluation suggested severe rheumatic mitral stenosis with a mean gradient of 12 mmHg across the mitral valve. She was referred to our center for mitral valve replacement. After induction of anesthesia, transesophageal echocardiography (TEE) was done before going on cardiopulmonary bypass. TEE was suggestive of severe rheumatic mitral stenosis [Figure 1] and Clip 1] with a mean gradient of 10 mmHg. As the TEE comprehensive examination was done, the mid-esophageal aortic valve short axis view showed aneurysmal sac of area 1.04 cm 2 protruding from right coronary cusp area into the right ventricular cavity [Figure 2] and Clip 2]. The same observations were also made in different TEE views [Figure 3]. In transgastric TEE view, the aneurysmal sac was seen coming into right ventricular outflow tract (RVOT), however, the gradient across RVOT was not significant ruling out any obstruction [Figure 4]. Color Doppler did not show any rupture of aneurysm nor aortic regurgitation. TEE findings were suggestive of the possible sinus of valsalva aneurysm without any other congenital cardiac defects. The surgeon decided to open aortic root after going on bypass. No aneurismal sac was noticed in the right coronary sinus of valsalva. As left atrium was opened for mitral valve replacement, surgeon palpated membranous ventricular septum, which appeared to be saggy and aneurysmally dilated. So it was the membranous ventricular septal aneurysm mimicking as the sinus of valsalva aneurysm on TEE. Septal aneurysm was not surgically altered. The patient was weaned from cardiopulmonary bypass smoothly after mitral valve replacement.
A membranous interventricular septal aneurysm is an extremely uncommon cardiac anomaly with very few reported incidences in the literature. It is mostly reported in association with congenital heart conditions in 0.3% of cases and association with ventricular septal defects (VSDs) in 19% of cases. , Majority of cases are congenital in origin, , and other etiological factors include the spontaneous closure of a preexisting VSD, infections, trauma or idiopathic. ,,,, Patients with membranous interventricular septal aneurysm may be asymptomatic or may have hemodynamic compromise  due to complications like RVOT obstruction, aneurysm rupture, conduction abnormalities, endocarditis, and thromboembolism.
The condition is rare and diagnosed usually incidentally. , Naidu etal. have reported incidental detection of aneurysm of the membranous ventricular septum during echocardiography and confirmed on computed tomography and second case reported by the same author while investigating symptomatic aortic stenosis due to a sclerotic bicuspid valve.  Yavuz etal. reported a case of ventricular septal aneurysm during elective surgery for a calcified bicuspid aortic valve.  Linhart and Razi have suggested that a late systolic murmur heard primarily along the left sternal border could give a clue to the diagnosis of aneurysm of the membranous ventricular septum. 
Yavuz etal., suggested surgical correction of such aneurysm can be considered if it is associated with hemodynamic abnormalities and other aneurysm-related complications.  However, Yilmaz et al. advocated preventive surgical intervention to avoid further enlargement and likely complications even in the absence of cardiac symptoms. 
Patients who have been incidentally diagnosed membranous septal aneurysms should be investigated for associated cardiac anomalies and further diagnostic evaluation.  In the present case, isolated mitral valve replacement was performed without addressing the surgical management of aneurysm due to the potential for an iatrogenic conduction block. No guidelines or recommendations about the management have been advised in the literature. Such patients should be carefully followed and cautioned about the possible complications.
Espinoza J, Kalache K, Gonçalves LF, Lee W, Chaiworapongsa T, Schoen ML, et al. Prenatal diagnosis of membranous ventricular septal aneurysms and their association with absence of atrioventricular valve offsetting. Ultrasound Obstet Gynaecol 2004;24:787-92.