Surgical Anatomy of the Aortic Annulus: Landmarks for External Annuloplasty in Aortic Valve Repair

External dissection of the aortic annulus allows subvalvular placement of an external aortic ring below the left and NC cusps and below or within 3 mm of the right cusp nadir in 80% of cases. An external aortic annuloplasty would induce at least a 5-mm reduction of annulus diameter, corresponding to tissue thickness. Precise anatomical landmarks are important to standardize aortic valve annuloplasty.