Several repair techniques have been described to correct aortic valve dysfunction. In contrast to mitral valve repair techniques, few of them have become the gold standard because of the unpredictability of their results. This is primarily attributable to the small amount of tissue and consequent small surface of coaptation present in the aortic leaflets, as compared to the large amount of tissue found in the mitral and tricuspid valves. Nonetheless, certain aortic valve lesions are amenable to reconstructive valvular techniques, particularly in young patients.
The aortic valve is approached through a transverse aortotomy 5 mm above the sino-tubular junction ( Fig. 22-1, a ). Whenever the exposure is suboptimal, the aortotomy can be extended towards the non–coronary sinus of Valsalva. Two atraumatic aortic retractors are used to apply gentle traction on the edge of the right coronary sinus and the non–coronary sinus ( b ). The surgeon then proceeds to a careful analysis of both the aortic root and the leaflets to recognize the lesions responsible for the leaflet dysfunction identified by echocardiography.
The three fundamental principles of aortic valve reconstruction are:
- 1.
Restore or preserve full leaflet mobility.
- 2.
Provide a large surface of leaflet coaptation.
- 3.
Remodel and stabilize the annulus.
The surgeon’s findings guide the choice of the reconstructive technique according to the “One lesion one technique principle.” Similar to mitral valve reconstruction, three basic principles of valve reconstruction should be respected to achieve optimal and stable result: (1) restore or preserve full leaflet mobility; (2) provide an optimal surface of leaflet coaptation; and (3) remodel and stabilize the annulus.
TYPE I—AORTIC VALVE REGURGITATION
Aortic valve regurgitation with normal leaflet motion is rare and often amenable to valve reconstruction. The techniques vary depending upon the lesions.
Isolated Aortic Annular Dilatation
Annular dilatation without involvement of the sino-tubular junction is rare ( Fig. 22-2 ). However, it may occur in dilated cardiomyopathy and in rheumatic valvular diseases, causing mild to moderate regurgitation in association with concomitant mitral valve dysfunction. If the leaflets display minimal thickening and/or retraction, a circular annuloplasty is carried out to ensure adequate leaflet coaptation. A double-row circular annuloplasty provides a homogeneous narrowing. This technique employs a continuous vertical braided 2-0 mattress suture passed through the annulus, successively downward from the aorta toward the ventricle and then upward from the ventricle toward the aorta (a) . Optimal remodeling of the orifice is obtained when the leaflets coapt without excessive folding of their edges (b) . A second row of sutures is then added that opposes the mattress loops so as to obtain a continuous line of suture (c) .
Leaflet Perforation
In the setting of chronic bacterial endocarditis, leaflet perforation may involve only the belly of the leaflet, while the free edge is preserved ( Fig. 22-3 ). The defect is usually limited and displays a healed fibrotic edge (a) . This condition is favorable for valve reconstruction by patching using glutaraldehyde-treated autologous pericardium (b) . The patch is tailored according to the shape and size of the defect, adding a 2-mm margin for suturing. It is then sutured to the edge of the defect using 5-0 monofilament interrupted sutures tied on the aortic side of the leaflet. In the presence of a large defect, continuous suture can be used provided that narrow or locked bites are employed to avoid a purse-string effect.
Vegetations
Small and pedicled vegetations can usually be sharply excised with scissors without producing a perforation ( Fig. 22-4, a ). Once the excision has been completed, local application of 0.6% glutaraldehyde for 2 to 3 minutes followed by generous rinsing with saline achieves local sterilization (b) . Larger vegetations must be resected and the valve repaired by patching. In all instances, the ventricular aspect of the mitral valve should be carefully inspected to detect potential kissing lesions. An associated annular dilatation producing a lack of coaptation between leaflets would require an additional annuloplasty.
Leaflet Tear or Avulsion
A leaflet tear or avulsion from the annulus resulting from blunt trauma can also be reconstructed in many instances ( Fig. 22-5 ). The most favorable lesion is a tear of the belly of the leaflet that leaves the commissural areas intact (a) . This type of lesion can occasionally be treated by direct suture. If a significant lack of tissue is present, the patch is secured to the edges of the tear (c) . Leaflet avulsion is best treated by pericardial patching.
TYPE II—AORTIC VALVE REGURGITATION
Type II aortic valve regurgitation may be corrected by reconstructive techniques, particularly when the prolapse is limited and involves only one leaflet as in some congenital malformations or rheumatic valve diseases. Since the mechanism of prolapse is usually a distension of the free edge of the leaflet, appropriate tension can be restored by a triangular resection ( Fig. 22-6, a ). This technique implies that the commissures are still preserved and functional. The amount of triangular resection is calculated by measuring the length of the free margin of the corresponding halves of the adjacent leaflets and adding 2 mm on each side of the triangle for suturing (b) . The two sides of the resected triangle should be tailored with a convex curvature to restore optimal bulging of the belly of the leaflets. It is particularly important to remember that a triangular leaflet resection tends to be too extensive, leading to restricted leaflet motion. Leaflet continuity is restored using interrupted 5-0 monofilament sutures tied on the aortic side (c) since knots positioned on the ventricular side may lead to abrasion of the adjacent leaflets and/or hemolysis.
