Sinotubular junction size affects aortic root geometry and aortic valve function in the aortic valve reimplantation procedure: an in vitro study using the Valsalva graft.

Background: Sinotubular junction (STJ) size in aortic valve reimplantation procedures is usually predetermined on the basis of experience or intraoperative mathematical calculations. Given the small coaptation reserve of aortic valve leaflets, small errors can produce an incompetent aortic valve. We tested in vitro the effect of geometrically changing the relationship between aortic annulus size and STJ size on aortic root geometry and aortic valve function.

Methods: Twenty-five-millimeter diameter scalloped porcine aortic roots were reimplanted into 32-mm Valsalva grafts (Vascutek, Renfrewshire, Scotland), suspending commissures into the expandable region of the graft itself. Neoaortic roots were pressurized up to 100 mm Hg. Sinotubular junction size was then changed by wrapping the neocommissural ridge with Dacron rings of decreasing size. Geometry of the aortic root, anatomy of aortic valve leaflets, and extent of their coaptation were analyzed by direct endoscopic view and by ultrasound imaging techniques.

Results: Pressurizing unwrapped aortic root resulted in centrifugal displacement of commissures, aortic leaflets tethering and bending, and central aortic regurgitation. By reducing STJ size, coaptation height of aortic valve leaflets first increased to reach a maximum for an STJ size corresponding to 30 mm, and then decreased for further reduction of STJ size. Excess reduction of STJ size also resulted in prolapsed aortic leaflets and eccentric aortic regurgitation.

Conclusions: In the reimplantation procedure performed with a Valsalva graft, aortic valve function and leaflet coaptation can be optimized by optimizing STJ size.