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March 29, 2017
Rheumatic Valve Disease Surgical Management & Results

Surgical Management & Results

Prior to cardiopulmonary bypass, an intraoperative transesophageal echocardiography is performed in all patients. A careful valve analysis should be performed to determine the mechanism of mitral regurgitation. Most patients present with type IIIa dysfunction. The association of a restricted posterior leaflet motion (type IIIa dysfunction) with a prolapse of the anterior leaflet (type II-A2 dysfunction) is very characteristic. It is also important to assess the mobility of the anterior leaflet and the extent of subvalvular lesions as they both predict the feasibility of valve reconstruction. Finally, mitral valve area and transvalvular gradient should be calculated. In patients with rheumatic valve disease, it is critical to evaluate the aortic and tricuspid valves as associated lesions are very common. (See also section echocardiography)

Post-cardiopulmonary bypass, transesophageal echocardiography is used to assess: 1) the deairing of the cardiac chambers, 2) the quality of repair, 3) the transvalvular gradient and the orifice area, and 4) the right and left ventricular functions.

After the exposure of the mitral valve, the surgeon should perform a detailed valvular analysis and make a full inventory of the lesions: commissural fusion, leaflet thickening/retraction, chordae fusion and shortening, and annular dilatation. The presence and the severity of valvular calcification should be assessed. In patients with anterior leaflet prolapse, the responsible lesion is either a posterior or a lateral displacement of the paramedial chordae. Occasionally the marginal chordae can be thickened and elongated.

These complex and multiple lesions raise the question of the feasibility of valve reconstruction which ultimately depends upon two factors: 1) the surface area and pliability of the anterior leaflet and 2) the extent of subvalvular lesions. Following valvular analysis, the appropriate reconstructive techniques are selected according to Carpentier's one-lesion- one-technique principle.

From Carpentier A, Adams DH, Filsoufi F. Carpentier's Reconstructive Valve Surgery. Saunders (Elsevier), 2010
From Carpentier A, Adams DH, Filsoufi F. Carpentier's Reconstructive Valve Surgery. Saunders (Elsevier), 2010
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In patients with commissural fusion, mitral commissurotomy is performed to increase the opening of the mitral valve. Commissural fusion is usually more intense at the postero-medial commissure than the antero-lateral commissure. Locating the site of the commissure can be difficult in the presence of advanced rheumatic lesions. Traction on the main chordae of the anterior leaflet opposite to the commissure is key to identify the commissural groove. Commissurotomy is started along this groove while leaving a 5mm tissue ridge from the annulus and is directed toward the center of the orifice. When fused chordae beneath the commissure are identified, they should be fenestrated using a triangular wedge resection. Care should be taken to leave one chordae on each side of the commissural opening. The incision should be extended to the papillary muscle leaving a greater thickness on the anterior leaflet side than on the posterior leaflet side. The latter procedure further enhances the commissural opening. Calcified nodules in the commissural area should be excised.

From Carpentier A, Adams DH, Filsoufi F. Carpentier's Reconstructive Valve Surgery. Saunders (Elsevier), 2010

Subvalvular lesions are addressed by the resection of thickened secondary chordae. The marginal chordae are fenestrated with a small triangular wedge resection or split. The corresponding papillary muscle should also be split. Marginal chordae can also be resected provided that the free margin is supported every 4mm along its entire length.

Leaflet thickening/retraction is best treated with patch extension using Glutaraldehyde-treated autologous pericardium. The principle objectives of the patch extension are to increase leaflet mobility, to enhance the surface of coaptation and to allow the implantation of a larger prosthetic ring.

Patch extension can be applied to both the anterior or posterior leaflet depending upon the localization and extent of the lesions. In practice, patch extension of the posterior leaflet is performed more commonly. Following the detachment of the posterior leaflet and the resection of secondary chordae, a diamond-shaped patch of appropriate size is tailored and implanted using a running suture technique. The height of the reconstructed posterior leaflet should be between 15 to 20 mm. It is not advisable to increase the height to more than 2 cm as that may create a curtain effect with a risk of mitral stenosis. Following the patch extension, a ring is selected which is one or two size bigger than the size of the measured anterior leaflet. Typically a ring 30 or 32 mm is selected in female whereas a ring 32 or 34 mm is selected in male. The insertion of smaller rings is associated with the risk of mitral stenosis and early repair failure.

From Carpentier A, Adams DH, Filsoufi F. Carpentier's Reconstructive Valve Surgery. Saunders (Elsevier), 2010

In patients with mitral stenosis and annular dilatation, an isolated commissurotomy may result in mitral regurgitation. In this scenario, it is necessary to implant a remodeling prosthetic ring to prevent post-commissurotomy regurgitation.

In patients with mitral regurgitation and type II dysfunction, minor prolapse of the anterior leaflet should be identified and corrected with chordae repositioning.

Post bypass TEE is critical in patients with rheumatic disease. A mild degree of mitral regurgitation does not require a second look provided that a large surface of coaptation has been created. Residual mean transvalvular gradient less than 5 mmHg is acceptable, but gradients greater than 8 mmHg indicates the need for a second exploration and valve replacement.

 

Results

Open commissurotomy for pure mitral stenosis carries an operative risk of less than 0.5%. The procedure is associated with excellent early and late outcomes. Long-term survival at 10 and 20 years is about 87% and 57-70% respectively. Freedom from reoperation is 78-90% at 10 years and greater than 50% at 20 years. The progression of the disease with constitution of advanced rheumatic lesions (recurrent commissural fusion with calcification, leaflets thickening and calcification) is the principle indication for reoperative mitral valve replacement.

Mitral valve reconstructive surgery can be performed safely with good long-term outcomes in a significant number of patients with rheumatic mitral valve regurgitation. The overall durability of the repair in this group of patients is, however, inferior compared to patients with degenerative disease. These inferior results are best reflected by a linearized rate of reoperation which is 2-3% per patient-year. We reported our very long-term results in a series of 951 patients who underwent reconstructive surgery for mitral valve regurgitation from 1970 to 1994. The mean follow-up was 12 years with a maximum at 29 years. In this series, type I, II, and IIIa valvular dysfunction was noted in 7%, 33% and 36% of patients respectively. The prolapse of the anterior leaflet combined with restricted motion of the posterior leaflet (Type II anterior, IIIa posterior) was present in 224 patients (24%). Valve reconstruction was performed in 95% of patients. The overall hospital mortality was 2%. Actuarial survival was 89% and 82% at 10 and 20 years respectively.

Freedom from reoperation was 82% and 55% at 10 and 20 years respectively. In this study, the reoperation rate for type II dysfunction was 1.9% per patient-year whereas it was 2.7% per patient-year for type IIIa dysfunction. Progression of the disease with advanced fibrosis of the mitral valve was the predominant cause of reoperation (83% of cases). The presence of leaflet thickening and commissural fibrosis at the first operation had a negative impact on the late outcomes. The young age of the patients at the first operation was not a predictor of reoperation. Finally, freedom from valve related complications was 82% and 52% at 10 and 20 years respectively. During the last two decades, other groups have reproduced similar results and confirmed our findings.




REFERENCES

Carpentier A. Cardiac valve surgery - the "French correction". J Thorac Cardiovasc Surg 1983;86:323-337

Deloche A, Jebara VA, Relland JY, et al. Valve repair with Carpentier techniques. The second decade. J Thorac Cardiovasc Surg 1990;99(6):990-1002

Chauvaud S, Jebara V, Chachques JC, et al. Valve extension with glutaraldehyde-preserved autologous pericardium. Results in mitral valve repair. J Thorac Cardiovasc Surg 1991 ;102(2):171-8

Carpentier A, Adams DH, Filsoufi F. Carpentier's reconstructive valve surgery. Philadelphia, Elsevier (Saunders), 2010

Phan KP, Nguyen vP, Pham NV, et al. Mitral valve repair in children using Carpentier's techniques. Semin Thorac Cardiovasc Surg Pediatr Card Surg Annu 1999;2:111-120.

Chauvaud S, Fuzellier JF, Berrebi A, et al. Long-term (29 years) results of reconstructive surgery in rheumatic mitral valve insufficiency. Circulation 2001 18;104(12 Suppl 1):I 12- I 15


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