Membranous VSD with Aneurysm Tissue Closure

Some defects in the conoventriclular septum diminish in size by the development of fibrous tissue at the margins of the defect coupled with adhesion by some components of the septal leaflet of the tricuspid valve. This process has been referred to as aneurysm formation, and this is generally a favorable sign that the ventricular septal defect is becoming progressively more restrictive to flow and may close spontaneously. 

Echo exam:

Virtually all ventricular septal defects can be well visualized by echocardiography. 2D echo and color Doppler imaging allow accurate assessment of the location of the defect as well as an estimation of the volume of shunting. Pulsed and continuous wave Doppler measurements of the shunt flow, in combination with measurement of regurgitation of the tricuspid and pulmonary valves should allow for an estimate of the pulmonary artery pressure. 

The perimembranous (conoventricular) defects are best visualized from the parasternal long axis, apical four chamber and subcostal view, as these windows profile the membranous septum which lies just beneath the aortic valve. Doppler estimation of the pressure gradient between the two ventricles is best achieved with the Doppler interrogation beam parallel to the flow from left to right ventricle (the parasternal short axis view). 



Management:



Many ventricular septal defects become smaller and even close spontaneously with time. Defects in the muscular septum often close by what is thought to be a process on ingrowth of muscle at the margins. Some defects in the conoventriclular septum diminish in size by the development of fibrous tissue at the margins of the defect coupled with adhesion by some components of the septal leaflet of the tricuspid valve. This process has been referred to as aneurysm formation, and this is generally a favorable sign that the ventricular septal defect is becoming progressively more restrictive to flow and may close spontaneously. 

The exact frequency with which ventricular septal defect closes is not clearly known, though it has been shown that as many as 70% of all ventricular septal defects diagnosed at birth will undergo resolution. This most typically occurs within the first year or two of life, but may continue to occur through childhood. Though most small defects undergo spontaneous closure during childhood, not all do. Therefore, a significant number of adults have small, asymptomatic ventricular septal defects. Some may continue to undergo closure, even well in to adulthood. 



Management:



The management of the patient with a ventricular septal defect depends entirely on the clinical manifestations of the hemodynamic effects of the shunt. Small defects will require no therapy and will often undergo spontaneous closure. Moderate and large defects may initially be managed medically with anticongestive pharmacological therapy such as Digoxin, diuretics and afterload reduction. As the pulmonary vascular resistance continues to fall, and the volume of left to right shunting progresses, some patients will have congestive heart failure, which cannot be managed with medical therapy alone. These patients are then referred for surgical repair of their ventricular septal defects. Whenever possible, a trans-atrial approach from the right atrium is preferable to a ventricular incision. 





Echo
The apical 5 chamber view shows the out-pouching of the membranous septal aneurysm into the RVOT.

Echo
High resolution apical 5 chamber view shows the out-pouching of the membranous septal aneurysm into the RVOT.

Echo
Apical 5 chamber doppler view shows that the out-pouching membranous septal aneurysm does not shunt into the RVOT.
Short axis color doppler view shows that the out-pouching membranous septal aneurysm does not shunt into the RVOT.