Matching the type of aortic valve-sparing to the aortic root pathology.

Abstract

The development of aortic valve-sparing operations (AVS) was founded on the knowledge of functional anatomy of the aortic root, the pathophysiology of degenerative disorders of the aortic root and ascending aorta, and already established procedure to address aortic cusps abnormalities (1). We named these procedures AVS to differentiate them from aortic valve repair which implies repairing the aortic cusps, something that may or may not be necessary during AVS. We classified AVS in two basic types: remodeling of the aortic root and reimplantation of the aortic valve (2). Remodeling of the aortic root includes a variety of operative procedures that range from simple correction of the dilated sinotubular junction (STJ) to correct aortic insufficiency (AI) due to outward displacement of the aortic commissures, to more complex operations that involve replacement of one or more aortic sinuses, aortic cusp repair, aortic annuloplasty, and reimplantation of one or both coronary arteries (3). Reimplantation of the aortic valve describes an operation whereby the aortic sinuses and coronary arteries are detached from the aortic root, and the skeletonized aortic valve is sutured inside a tubular Dacron graft and the coronary arteries are reimplanted (3). We believe that each one of these various types of AVS has a place in the surgical armamentarium to treat patients with dilated ascending aorta and aortic root with or without AI. Echocardiography is the best diagnostic tool to examine the aortic root and determine the feasibility of AVS. The aortic cusps are the most important component to the aortic root and must be carefully interrogated to assess their number, size, thickness, pliability, and excursion during the cardiac cycle. Cusp prolapse can be seen by echocardiography. Plain computed tomography (CT) scan is probably more accurate than echocardiography to determine the extent of calcification in the aortic cusps. In our experience, even small specks of calcium predict future failure of AVS, particularly in patients with bicuspid aortic valve (BAV). The diameters of the aortic annulus, aortic sinuses, STJ and ascending aorta should be obtained in multiple views as part of preoperative assessment. The final decision as to whether to preserve or to replace the aortic valve is done after opening the aorta and visually inspecting the aortic cusps and other components of the aortic root. The quality of the tissues that make the aortic cusps are the most important component because unlike the aortic annulus, aortic sinuses and STJ, there are limitations on how they can be modified. The diameter of the normal aortic annulus ranges from 19 to 25 mm in adults (4). Dilatation of the aortic annulus is common in patients with degenerative aneurysms, and probably the most important factor in deciding what type of AVS to use. Dilatation of the aortic annulus causes a mismatch between the area of the aortic orifice and the area that the cusps must seal during diastole. Reduction of the aortic annulus diameter is required to allow the cusps to coapt inside of the aortic root and completely seal the aortic orifice. This can be accomplished by various types of annuloplasty: an internal rigid ring (HAART Aortic Annuloplasty Technologies-BioStable Science & Engineering, Austin, TX, USA), an external annuloplasty band of polyester fabric such as the Extra-Aortic Ring Matching the type of aortic valve-sparing to the aortic root pathology