Aortic valve-sparing operations are intended to treat aortic root aneurysm while sparing the native aortic valve. The following are points to remember:
- There are two main types of aortic valve-sparing operations:
The absence of aortic sinuses results in abnormally rapid opening and closing of the aortic valve leaflets, potentially increasing mechanical stress on the leaflets; creation of neo-aortic sinuses as part of an aortic valve-sparing operation reduces the opening and closing velocities, although they remain faster than normal.
Remodeling of the aortic root is physiologically superior to reimplantation of the aortic valve, because it preserves the normal movement of the aortic annulus during the cardiac cycle. However, aortic root remodeling might not provide as durable a result among patients with aortic root aneurysm associated with genetic syndromes or bicuspid aortic valve, likely related to dilation of the aortic annulus that can be present at the time of, or occur later after, surgery. However, remodeling of the aortic root is probably a good option among older patients with degenerative aortic root aneurysm with dilated sinuses of Valsalva, but a normal aortic annulus.
Dilation of the sinotubular junction can cause elongation of the free margin of one or more aortic leaflets, and the development of commissural stress fenestrations. In that setting, surgical correction of sinotubular dilation can result in prolapse of one or more leaflets. Leaflet prolapse can be corrected by plication of the central part of the leaflet along the node of Arantius. The risk of rupture of a fenestrated leaflet can be reduced through reinforcement of the free margin from commissure to commissure.
Aortic root aneurysms associated with genetically predisposing conditions (e.g., Marfan syndrome, Loeys-Dietz syndrome, familial aneurysms, and bicuspid aortic valve) typically occur during the second to fourth decades of life, with dilation starting at the aortic sinuses and expanding into the sinotubular junction and ascending aorta. In contrast, degenerative ascending aortic aneurysms typically occur in the fifth to seventh decades of life, and start at the mid-portion of the ascending aorta with proximal and distal expansion.
Surgical timing largely is based on the diameter of the aortic aneurysm. Intervention is recommended based on threshold diameters of 55 mm for degenerative or atherosclerotic aneurysms, or in association with bicuspid aortic valve; 50 mm for Marfan syndrome, familial aneurysm syndrome, or bicuspid aortopathy with additional risk factors; and 42 mm for Loeys-Dietz syndrome, aneurysm-osteoarthritis syndrome, and transforming growth factor aneurysm.
Transesophageal echocardiography (TEE) is recommended to determine the feasibility of repair of the aortic valve; with special attention paid to the diameter of all portions of the aortic root and ascending aorta imaged in multiple views; and the height of the aortic leaflets. Leaflet height <13 mm precludes satisfactory repair in adults because the annulus would have to be excessively reduced to allow adequate leaflet coaptation.
The following procedures are recommended based on the underlying pathology:
- Reimplantation of the aortic valve is performed by detaching the coronary arteries from the aortic root, excising the aneurysmal aortic sinuses except for a few millimeters of arterial wall left attached to the annulus, freeing the annulus from surrounding tissues, reimplanting the aortic valve inside a tubular Dacron graft, reimplanting the coronary arteries into their respective neo-aortic sinuses, and suturing the reconstructed aortic root to the ascending aorta.
- Remodeling of the aortic root is performed by similarly detaching the coronary arteries and excising the aneurysmal aortic sinuses, but leaving the aortic valve in place with interposition of a tailored tubular Dacron graft with neo-aortic sinuses.
Elective aortic valve-sparing operations should be associated with a low (≤1%) operative mortality. Excluding patients operated for acute type A dissection, long-term survival after an aortic valve-sparing operation should be similar to the general population matched for age and sex.
The main long-term issue with aortic valve-sparing operations is the development of aortic regurgitation and need for reoperation. Ten-year freedom from reoperation and freedom from moderate or severe aortic regurgitation after aortic valve-sparing operations have been reported in the ranges of 87-97% and 87-96%, respectively.
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- Older patients with ascending aortic aneurysm, aortic regurgitation, and normal leaflet height should undergo remodeling of the aortic root. Symmetrical dilation of the sinuses and a diameter ≤45 mm can be treated with simple replacement of the ascending aorta with a graft sized to restore the sinotubular junction to normal. A single diseased sinus (dilation, effacement, or dissection) should be replaced with a tailored graft.
- In young patients with aortic root aneurysm, reimplantation of the aortic valve should be performed.
- Patients with bicuspid aortic valve and aortic regurgitation caused by dilation of the aortic annulus (with thin, pliable leaflets and adequate height) might experience more durable results with an aortic valve reimplantation procedure.
- Patients with acute aortic dissection can be treated with aortic valve reconstruction; however, the addition of a complex reconstructive procedure might be problematic in a setting with high mortality risk and surgery intended to save the patient’s life.
- Patients with prior Ross procedure and dilation of the pulmonary autograft can be treated with either remodeling or reimplantation as long as there are no degenerative changes affecting the leaflets; because annular dilation is common in this scenario, reimplantation of the aortic valve provides a more durable repair.