The art of aortic valve repair

Abstract

See Commentaries on pages 126 and 128. In cardiac surgery, as with many endeavors, there is a point to which science can take you, and then art—namely observation, hands-on skill, craft, imagination, and mental imputation—must take over. And so it is with aortic valve repairs. Certainly, there are some important physics principles to note: (1) the greater the contact area of leaflet to leaflet apposition, the less leakage; (2) according to Poiseuille equation, small changes in the diameter of an orifice lead to large gradient increases by radius to the fourth power; (3) the longer the leaflets, the greater likelihood of turbulence and gradients (ie, increased shear over a longer distance at the boundary layer disrupting laminar flow); (4) tension and the risk of leaflet tear or perforation are increased with less apposition of leaflets to relieve linear edge stress; (5) greater leaflet height increases the contact area of apposition without sacrificing orifice area; and (6) there is increased stasis and likelihood of clot formation (Virchow’s triad) with sinuses that are too deep, particularly with added pericardium. Based on these principles, usually with aortic valve repair, regurgitation is less with increasing pressure load on the leaflets when coming off pump compared with mitral valve repair, in which case worsening of regurgitation occurs. There is no shortcut to successful aortic valve repairs. It is a matter of observation, experience, and time “spent” on the learning curve to understand what a normal tricuspid leaflet valve should look like, and for bicuspid valves, what works. After performing well over 1000 aortic valve repairs, reimplantations, and remodelings, I am convinced that achieving a competent and nonstenotic aortic valve is more art than science. Measurements are of little value when, for