Indications for Surgery : Congenital pulmonic stenosis is the most common lesion requiring relief. Very rarely it could be due to rheumatic involvement along with disease of other cardiac valves. Carcinoid syndrome can cause thickening and fusion of the valve cusps and also produce outflow obstruction. Extrinsic pulmonary obstruction could be caused by cardiac tumors or aneurysm of sinus of Valsalva.