Evaluation of native valve-sparing aortic root reconstruction with direct imaging - Reimplantation or remodeling?

Background. Aortic root reimplantation, and remodeling have been used to preserve the native aortic valve. However, direct observation of valve motions with these techniques has not been performed. Methods. Mongrel dogs were studied. The beating heart model was created using modified Tyrode's solution. Normal aortic valves and aortic valves preserved with the remodeling or reimplantation procedure were observed with an endoscope, and behavior was recorded on a high-speed video (200 frames/s). The aortic valve orifice area was measured at 11 data points per beat. A predictable maximum valve orifice area was defined as an area encircled by the three commissures. A ratio of each aortic valve orifice area to the predictable maximum valve orifice area was calculated. The control group, the reimplantation group, and the remodeling group were compared. Results. The preserved aortic valve with reimplantation showed bending and asymmetric motion. The ratio of aortic valve orifice area and predictable maximum valve orifice area in the reimplantation group was significantly smaller compared with the control and remodeling groups. Conclusions. The opening and closing behavior of the aortic valve preserved with the reimplantation procedure was impaired. It was speculated that the remodeling procedure may preserve more physiologic root function compared with the reimplantation procedure.