A new method to improve outcomes in the surgical treatment of aortic aneurysm
What is the aortic root?
The aortic root is the section of the aorta (the large artery leaving the heart) that is attached to the heart. The aortic root includes the annulus (tough, fibrous ring) and leaflets of the aortic valve; and the openings where the coronary arteries attach (coronary ostia).
What is an aortic root aneurysm?
An aneurysm is an abnormal bulge in the wall of a blood vessel. In some patients, an aneurysm can occur at the aortic root, causing the aorta to dilate or widen and the aortic valve to leak.
Without treatment, a life-threatening condition called aneurysm dissection can occur. In this condition, blood flows through a tear in the inner layer of the aorta, causing the layers to separate. Blood flow becomes interrupted and causes the arterial wall to burst.
How is it treated?
The David's valve-sparing aortic root replacement method is a surgical treatment for aortic root aneurysms. With this method, the aneurysm is repaired while the patient's own aortic valve is preserved. This method helps to avoid the use of long-term anticoagulant (blood-thinner) medication and may reduce the risk of stroke or endocarditis.
If the patient's own aortic valve is diseased or cannot be used during the aorta surgery, a bioprosthetic valve can be used to avoid the use of long-term anticoagulation.
What is the Modified David's Reimplantation Procedure?
Illustration of aortic root aneurysm before aorta surgery.
While the David's valve-sparing aortic root replacement method has many benefits, it is also a technically difficult aorta surgery procedure. Dr. Lars G. Svensson, Director of the Center for Aortic Surgery, Marfan Syndrome and Connective Tissue Disorders Clinic at Cleveland Clinic, has developed a modified version of the David's procedure. The Modified David's Reimplantation Procedure helps to determine the appropriately sized aorta graft, maintain the left ventricular outflow tract (the passageway out of the left ventricle), and improve outcomes when using the valve-sparing method.
The aorta is cut, just above the aortic valve annulus and the coronary ostia (openings where the coronary arteries are attached to the aortic root). The diseased portion of aorta is removed.
Sutures are placed just below the aortic valve, around the left ventricular outflow tract.
A collagen-coated, polyester graft is used for the portion of the aorta being replaced.
Sutures are placed through the graft. See Figure 2.1
A special piece of equipment, called a Hegar's dilator, is placed in the left ventricular outflow tract, through the aortic valve. The size of the dilator is based on the patient's body size and the expected size of a normal left ventricle outflow tract.
The sutures are then tied around the Hegar's dilator, to shape the bottom portion of the aorta graft, similar to a natural aortic root.
Next, either the aortic valve is repaired or remodeled and re-implanted or a new bioprosthetic aortic valve is sewn into position within the aorta graft. The valve is tested to make sure it opens and closes properly. See Figure 2.2
Then, small holes are produced in the aorta graft for the coronary ostia (openings). The coronary arteries are re-attached through the small holes.
The graft is then sewn to the aorta. If the aortic arch needs to be replaced, a separate graft is sewn from the aortic arch to the aortic root graft (as illustrated).
Early results show the Modified David approach is successful. The use of the Hegar dilator ensures the outflow tract size is maintained, a more normal aortic root is established, and valve function is improved. Follow-up evaluations will be conducted with patients who have undergone this procedure to determine if these results occur long-term. See Figure 2.3
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