**3. Pathophysiology**

AVS operations were designed for patients with aortic root or ascending aortic aneurysms and competent or regurgitant aortic valve function in the setting of normal cusps. Highly stenotic valves are rarely able to be preserved. The most common cause of aortic insufficiency in North America is annuloaortic ectasia. Young patients develop aortic root aneurysms beginning with dilatation of the sinus segments, followed by annular and STJ dilatation. Elderly patients can develop aortic insufficiency from ascending aortic aneurysms and subsequent dilatation of the STJ. In these patients, the aortic annulus and sinus segments are relatively normal. Marfan syndrome is the most common cause of aortic root aneurysms in young patients. Other connective tissue disorders such as ankylosing spondylitis, Ehlers-Danlos, osteogenesis imperfecta, rheumatoid arthritis, and lupus can cause aortic insufficiency. Aortic dissection is another common indication for an AVS operation. This dissection flap can extend into the aortic root and disconnect one of the aortic valve commissures from the aortic wall causing cusp prolapse and aortic insufficiency (2).
