Highlights on Aortic Valve Repair Surgery

Abstract

The human aortic valve is a complicated structure with four primary components (the cusps, the anatomic annulus, the sinus segments, and the sinotubular junction or ridge) that each play an important role in the valve’s mechanics and durability. None of the structures are fixed in either dimension or position throughout the cardiac cycle. The dynamic nature of root geometry includes serial expansion and contraction of different segments of the apparatus throughout systole and diastole, forming a system that serves to maximize blood flow through the valve and reduce the stress and strain on the aortic cusps promoting their longevity. Despite this nearly perfect construction, alterations in form and function do occur because of congenital abnormalities, comorbid conditions, environmental insults, degenerative processes, and aneurysmal disease of the aortic root such that valves can become regurgitant, stenotic, or both. Aortic valve repair and valve-sparing aortic root replacement are attractive concepts because they offer the possibility of valve competence without structural deterioration due to non viability and they preclude the need for anticoagulation. Enthusiasm for aortic valve repair has waxed and waned over the past 45 years due in part to the inherent technical difficulties and poor mid- term results. The results of isolated aortic valve repair are considerably worse than mitral valve repair. The reasons for this are manifold but include both the difficulty in determining what portions of the aortic valve and the aortic root require correction and the difficulty in completely correcting the deficits to eliminate all regurgitation. Because the zone of coaptation of the aortic cusps is so short (relative to the zone of coaptation of the mitral valve), the margin for error with repair is considerably smaller than it is for mitral valve repair. Consequently, residual aortic insufficiency appears to predict longterm failure.