The function of the aortic valve depends on a complex interplay between the four main components, including the leaflets and aorta. In people with abnormal aorta tissue, the dilated aorta should be removed when it is higher than 45mm, and 50mm if no abnormality detected.
Two main procedures can restore the competence of the valve: remodeling procedure, or reimplantation procedure. In the first, the abnormal aortic wall is removed from the valve tissue and an artificial graft attached on the edges of the valve without explicitly addressing any dilation of the annulus of the valve.
In the second procedure, often referred to as the David Procedure, the artificial material is sewn down below the valve annular attachment, thus reinforcing and strengthening this critical component of the valve, as well as reducing the size of the aorta. In both of these procedures, it is essential to ensure that the valve leaflets are meeting appropriately, so there is often some procedure performed directly on them at the same time. Long term results of this procedure are durable and reproducible in the hands of many teams worldwide.
During Valve-Sparing Root Replacement (also called the David Procedure, to give credit to the surgeon who initially conceived the operation, Tirone David, MD), the patient's aortic valve is kept (although it may be repaired and reimplanted) and reconnected to a new section of aortic tissue. By preserving the native aortic valve, patients avoid the need for lifelong anticoagulation therapy (Coumadin).
The patient is placed on the heart-lung machine (cardiopulmonary bypass), which takes over the function of the heart and lungs during the operation.
The heart is cooled and stopped, and a clamp is placed across the aorta. The aorta is transected (divided) just above where the coronary arteries originate. The coronary ostia (openings) are removed as small buttons of tissue. The remainder of the ascending aorta is removed except for the valve tissue.
Sutures (stitches) are placed under the valve and passed outside of the aortic annulus (ring of tissue surrounding the valve). A proper vascular graft is selected and attached to the heart with the prepared sutures.
The valve is then carefully positioned within the graft to eliminate leaking. A fair bit of customized tailoring is then performed to ensure that the valve leaflets will open and close properly. The valve tissue is wholly attached to the graft with a continuous suture technique. Two small holes are created in the graft for reattachment of the coronary arteries.
Finally, in select cases, the end of the graft is attached to the aortic arch while the brain is carefully protected with a unique perfusion technique known as antegrade cerebral perfusion (ACP).