J Thorac Cardiovasc Surg 1999;118:490-491
© 1999 Mosby, Inc.
SURGERY FOR ACQUIRED CARDIOVASCULAR DISEASE |
Commentary
Tirone E. David, MD,
Toronto, Ontario, Canada
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Introduction
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Choudhary and colleagues from the All India Institute of Medical Sciences documented a high failure rate after aortic root replacement with pulmonary autografts in young patients with rheumatic heart valve disease. Of 68 patients available for follow-up, 13 patients had moderate or severe aortic insufficiency 1 to 2 years after the operation. In addition, 5 other patients had echocardiographic evidence of leaflet thickening, but the valve function was satisfactory at the time of the study. The diagnosis of rheumatic disease in the leaflets of the pulmonary autograft was confirmed at reoperation in 2 patients. On the basis of these findings, the authors concluded that aortic valve replacment with pulmonary autograft might be inappropriate for young patients with rheumatic heart disease.
Other reports have also suggested that the pulmonary valve may become involved by the rheumatic process when transferred to the aortic position in young patients with rheumatic involvement, particularly if they have concomitant mitral valve disease.
1,2 According to Choudhary’s study, antibiotic prophylaxis against recurrent streptococcal infection does not seem to protect the pulmonary autograft from rheumatic disease.
Choudhary and colleagues had excellent results with aortic root replacement with a pulmonary autograft in a small number of patients with bicuspid aortic valve disease. On the basis of their findings, could we then conclude that this procedure is bad for young patients with rheumatic aortic valve disease but good for those patients with bicuspid aortic valve disease? The answer is yes to the first part of the question and no to the second for the following reasons: Young patients with bicuspid aortic valve frequently have a dilated aortic root as the result of premature degeneration of the media of the aorta. 3 This degenerative process also involves the media of the pulmonary artery because both the aortic and pulmonary roots have the same embryologic origin. 3 Aortic root replacement with pulmonary autograft in these patients exposes the pulmonary root to systemic pressures that may cause dilatation of the sinuses of Valsalva and sinotubular junction. 3 In the study of Choudhary and colleagues, only 2 patients with rheumatic aortic valve disease had dilatation of the pulmonary autograft, and the authors did not mention dilatation in patients with bicuspid aortic valve. In our experience with this operation on patients with congenital aortic valve disease, dilatation of the pulmonary autograft is common when used for aortic root replacement. 3 The freedom from dilatation of 20% or more of the sinotubular junction at 5 years was only 30%. The technique of aortic root inclusion was protective against dilatation of the sinuses of Valsalva and sinotubular junction. The freedom from dilatation of the sinotubular junction at 5 years was 87% on patients who had the aortic root inclusion technique. Dilatation of the sinotubular junction increases the mechanical stress on the leaflets, which in turn may stretch, develop fenestrations along the commissures, prolapse, and cause aortic insufficiency.
Aortic valve replacement with pulmonary autograft can be performed with various techniques. Although aortic root replacement is the simplest and the most reproducible method, it may not be the most appropriate method because of our inability to predict which patients will experience the development of dilatation of the pulmonary autograft. The techniques of aortic root inclusion and of subcoronary implantation, albeit more complicated, are more likely to provide lasting results. 3 In the first 131 patients who survived the operation performed by Donald Ross, 107 patients had the pulmonary autograft implanted in the subcoronary position, and the overall freedom from autograft failure was 75% at 20 years. 4
Although aortic valve replacement with pulmonary autograft was described more than 3 decades ago, it became popular only during the past decade. We no longer perform it the way Ross described and do not know which patients are the ideal candidates for this operation. We have learned that it is not appropriate for young patients with rheumatic heart valve disease and that the autograft may dilate if used for aortic root replacement in patients with congenital aortic valve disease. There is yet much more to be learned about this operation!
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References
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DeVries H, Bogers AJJC, Schoof PH, et al. Pulmonary autograft failure caused by a relapse of rheumatic fever. Ann Thorac Surg 1994;57:750-1.[Medline]
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Al-Halees Z, Kumar N, Gallo R, Gometza B, Duran CMG. Pulmonary autograft for aortic valve replacement in rheumatic disease: a caveat. Ann Thorac Surg 1995;60:S172-6.
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David TE, de Sa MPL, Ivanov J, et al. Dilation of the pulmonary autograft after the Ross procedure. Presented at the 79th Annual Meeting of The American Association for Thoracic Surgery, New Orleans, April 18-21, 1999.
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Chambers JC, Somerville J, Stone S, Ross DN. Pulmonary autograft procedure for aortic valve disease: long term results of the pioneer series. Circulation 1997;96:2206-14.[Abstract/Free Full Text]
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Introduction
References