Discrete subpulmonic membrane in association with isolated severe pulmonary valvar stenosis

Abstract

BackgroundSubpulmonic membrane as a cause of right ventricular outflow tract obstruction in patients with concordant ventriculoarterial connection and intact ventricular septum is considered to be rare.Case presentationA 7 – year – old boy was referred to a tertiary care hospital with complaints of dyspnea on moderate exertion and palpitations of about 2 years duration. Physical examination revealed parasternal lift, systolic thrill and a 4/6 ejection systolic murmur, best heard over the left 2nd intercostal space. His oxygen saturation was 88% on room air. Two-dimensional echocardiography showed a thickened pulmonary valve with fused leaflets that show severe systolic doming. There was a discrete subpulmonic membrane about 1.3 cm below the pulmonary valve annulus. Continuous wave Doppler interrogation showed peak systolic pressure gradient of 185 mmHg across the pulmonary valve. Balloon dilation of the pulmonary valve was performed and the pressure gradient came down to 50 mmHg. Follow-up transthoracic echocardiography showed residual pressure gradient of about 50 – 60 mmHg across the pulmonary valve. The residual pressure gradient appeared to be mainly subvalvar, as seen on the continuous wave Doppler tracing. The patient reported marked improvement in terms of exercise tolerance and subjective symptoms.ConclusionsAssociation of subpulmonic membrane with severe pulmonary valvar stenosis, concordant ventriculoarterial connection and intact ventricular septum is rare. When it occurs, the result of percutaneous valve dilation may be suboptimal.

Subpulmonary membrane: A rare cause of right ventricular outflow tract obstruction

“…Balloon dilatation has been done in two of these case reports (with intact ventricular septum) and the result in both the cases was suboptimal and the need of future surgical intervention was felt. [ 2 , 5 ] Based on two previous case reports and one case from our series, it can be said that surgical excision of subpulmonary membrane is the preferred mode of treatment. Balloon dilatation in our first case was done in 2014; the literature on this rare entity was even scarce at that time.…”

Successful balloon valvuloplasty of a subpulmonic membrane associated with cor triatriatum dexter: a case report

“…A single case of RVOT obstruction resulting from a tuberculoma in a patient with VSD and aneurysm of the membranous septum has also been reported [16]. Subpulmonic membrane as a cause of RVOT obstruction is rare, and only a few cases have been reported, mostly in association with other congenital defects like aortic regurgitation and VSD [2], supracristal VSD [3], severe pulmonary valvar stenosis [4], and congenitally corrected transposition of the great vessels, and, in this particular case, balloon valvuloplasty of the subpulmonic membrane was successful [5]. Isolated subpulmonary membranes are rare and only two cases have been reported in the literature [6, 7].…”

Rheology of right ventricular outflow tract obstruction: sub-pulmonary membrane developing months after primary intervention to treat pulmonary atresia with intact interventricular septum

“…On cardiac MRI, the right ventricular outflow tract and the right ventricular outflow tract/pulmonary atresia angle showed no morphological abnormalities. Sub-pulmonary membrane is a rare disease and was described in relation to supracristal ventricular septal defects with or without aortic insufficiency, 1,2 with valvular pulmonary stenosis, 3 and as an isolated form causing critical neonatal sub-pulmonic stenosis. 4 Van Praagh believes that the fibrous membrane is a developmental condition related to the semilunar valve rather than the infundibulum, whereas the muscular membrane arises from the pulmonary infundibulum.…”