Ann Thorac Surg 2009;87:82. doi:10.1016/j.athoracsur.2008.11.014
© 2009 The Society of Thoracic Surgeons
Original Articles: Adult Cardiac
Invited Commentary
Hans-Hinrich Sievers, MD
Klinik fur Herzchirurgie, Universitätsklinikum Schleswig-Holstein Campus Luebeck, Ratzeburger Alle 160, Luebeck, 23538 Germany
(Email: sievers{at}medinf.mu-luebeck.de).
This article by Lad and colleagues [1] reports the coincidence of bicuspid aortic valve (BAV) disease and mitral regurgitation and as such adds considerably to the understanding of the BAV complex. Their classification system of the BAV includes 27 patients presenting with BAVs, with 1 raphe and 3 aortic sinuses, and was related to the spatial position of that raphe (types 1, 2, and 3). However, 2 patients without a raphe and 2 aortic sinuses, the "purely" BAV, could not be classified.
We recently reported a simple classification system that covers the entire spectrum of BAV phenotypes using the number of raphes for categorization in types (type 0, without a raphe; type 1, with 1 raphe; and type 2, with 2 raphes) and also includes positional characteristics of the raphes or leaflets, respectively [2]. By using this system, the authors could have systematically classified all presented 29 cases as 27 type 1, L-R (1 raphe between left and right coronary sinus); and 2 type 0, lat (no raphe with free edge of cusps orientated lateral).
These efforts and those of others [3] signal an increasing interest in the surgical community to classify BAVs for more precise scientific communication; however, different classification systems may cause confusion. Thus, there is a growing need to agree on a uniform global classification system for BAVs, favorably supported by our societies.
The described combination of a significantly diseased bicuspid aortic and mitral valve requiring surgical intervention represents one extreme of the continuous spectrum of a specific BAV entity, the Weak Aorto-Mitral BIcuspid RElation (WAMBIRE), consisting to a more or less extent of (1) BAV type 1, L-R [2] with prolapsing fused or noncoronary leaflet, or both, (2) aortic insufficiency, (3) anterolateral ascending aorta dilatation, (4) isolated noncoronary sinus dilatation with normal sized left and right coronary sinuses, (5) malalignment of noncoronary sinus in the left ventricular outflow tract in relation to left and right coronary sinus, (6) dilatation of aortic annulus, (7) dilatation of the interleaflet triangles adjacent to the noncoronary sinus, (8) dilatation of anterior mitral annulus, and (9) enlargement of anterior leaflet of mitral annulus with or without prolapse and mitral insufficiency. This WAMBIRE entity has surgical significance earlier in life compared with other BAV phenotype complexes and affects predominantly men.
There is now consensus that BAV is a congenital lesion, most likely genetically determined. Several candidate genes have been described, the Notch pathway seems to be of major importance [4]. Nevertheless, the basic genetics are still unclear. It may be speculated that a more complex genetic mechanism leads to the described phenotype characterized by tissue weakness progressing over time due to inherent matrix deficiency rather than degeneration [3, 5].
Awareness of this entity is not only of interest for histologic, morphologic, and genetic aspects but also has practical relevance. For example, careful follow-up and, in case of operation, reinforcement of the aortic annulus and matched alignment of the autograft is advocated in the Ross operation and reconstructive techniques.
The authors are to be congratulated for presenting these interesting data.
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References
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- Lad V, David TE, Vegas A. Mitral regurgitation due to myxomatous degeneration combined with bicuspid aortic valve disease is often due to prolapse of the anterior leaflet of the mitral valve Ann Thorac Surg 2009;87:79-82.[Abstract/Free Full Text]
- Sievers HH, Schmidtke C. A classification system for the bicuspid aortic valve from 304 surgical specimens J Thorac Cardiovasc Surg 2007;133:1226-1233.[Abstract/Free Full Text]
- Russo CF, Cannata A, Lanfranconi M, Vitaly E, Garatti A, Bonacina E. Is aortic wall degeneration related to bicuspid aortic valve anatomy in patients with valvular disease? J Thorac Cardiovasc Surg 2008;136:937-942.[Abstract/Free Full Text]
- Niessen K, Karsan A. Notch signaling in cardiac development Circ Res 2008;102:1169-1181.[Abstract/Free Full Text]
- Bechtel JFM, Noack F, Sayk F, Erasmi AW, Bartels C, Sievers HH. Histopathological grading of ascending aortic aneurysm: comparison of patients with bicuspid versus tricuspid aortic valve J Heart Valve Dis 2003;12:54-61.[Medline]
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References