**5.4 Progression to aortic insufficiency**

While most spontaneous VSD closures are due apposition of tricuspid valve tissue against the VSD, sometimes aortic valve cusps prolapse down towards the VSD to produce partial or complete closure. This may either be due to prolapse of an aortic valve cusp into the VSD or lack of support to the aortic root. This complication appears to occur more commonly with doubly committed subarterial VSDs than with other types.

Combination of VSD and aortic regurgitation (AR) due to prolapse of right coronary or, less frequently, non-coronary cusp is known as Laubry-Pezzi syndrome. Aortic valve prolapse can be seen in some patients with perimembranous defects and more commonly those with the subarterial defects where the tissue supporting aortic cusp is lacking. It is commonly seen in those with smaller defects due to venturi effect on the leaflets. The lifetime risk of developing aortic valve prolapse in patients with VSD is ~6.3% [18]. Long term follow up is recommended in these patients and surgery is indicated in patients with more than trivial AR. Based on a recent study of 261 pediatric and adult patients with VSD and AR, it was found that AR tends to be detected between the ages of 3–8 years [19]. Only the patients with aortic valve abnormalities or delayed operation had AR progression or persistence of more than mild degree of AR. The study authors concluded that surgical closure of subarterial VSD is indicated in patients with significant leaflet deformity as well as those with subarterial VSDs with moderate to severe AR.

## **5.5 Other natural history events**
