The aortic root: structure, function, and surgical reconstruction.

Aortic valve insuYciency may be caused by abnormalities of the leaflets, the root, or a combination of both. In some patients, the primary pathology is confined to the aortic root itself, the leaflets remaining anatomically normal. These patients have progressive dilatation of the aortic sinuses and, on occasion, dilatation and distortion of the annulus which results in valvar incompetence. Most cases are “idiopathic” (annuloaortic ectasia) but it may be associated with a wide spectrum of pathological conditions which include the Marfan syndrome, aortic dissection and aortitis, 4 along with rare systemic disorders such as Ehlers-Danlos syndrome. Aortic root pathology has now been reported as the most common cause of aortic valve incompetence in the United States, an observation which probably reflects the decline of rheumatic valve disease. Current conventional treatment for patients with significant aortic incompetence caused by a dilated, aneurysmal aortic root is replacement of the ascending aorta using a synthetic graft, replacement of the aortic valve with a mechanical prosthesis (the graft and prosthesis are usually combined as a “composite graft”), and reimplantation of the coronary arteries. In selected cases where there is no suspicion about the future integrity of the sinuses but there is dilatation of the ascending aorta, the valve and ascending aorta may be replaced separately. Despite the success of these operations, they both involve implantation of a prosthetic valve; complications such as thromboembolism, endocarditis, and problems related to the long term anticoagulation required have provided the impetus for the development of a surgical procedure which will preserve the native aortic valve. In this article we review the structure and function of the aortic root, the pathophysiological changes that may lead to aortic incompetence despite anatomically normal valve leaflets, and the surgical procedure which has been developed as a result of a better understanding of the anatomy and physiology of the aortic root during which the native aortic valve is preserved.