Ann Thorac Surg 2002;73:695-696
© 2002 The Society of Thoracic Surgeons
Correspondence
Valved stentless composite graft
Paul P. Urbanski, MDa
a Herz- und Gefaess-Klinik, Salzburger Leite 1, 97616 Bad Neustadt, Germany
e-mail: urbanski{at}kardiochirurg.de
To the Editor
I read the article of Dr De Paulis and colleagues [1] with great interest. I believe the stentless composite graft is a valuable alternative to other heterografts, homografts, or autografts. However, I doubt the aortic root prosthesis described by Dr De Paulis will withstand long-term clinical use. Franke and colleagues [2] reported that woven Dacron (Hemashield, Meadox Medicals, Oakland, NJ) prostheses used for ascending aorta replacement dilate to more than 12% of the original diameter. Because of the crimping direction parallel to the aortic longitudinal axis the neo-sinuses will dilate even more than usual and eventually cause valve insufficiency. The early postoperative aortogram demonstrated by De Paulis and colleagues [1] shows the diameter of the neo-sinuses as oversized, compared with a normal aortic root.
In contrast, there is a speculative hypothesis that the use of a cylindrical graft will cause accelerated valve degeneration due to "leaflet stress." This hypothesis is not supported by my clinical experience. I started implanting stentless composite grafts in 1998 [3] and, after a modification of the technique [4], I have successfully operated on 47 consecutive patients. In most cases valve prosthesis one size larger than the tube (oversizing) was used. However, considering the risk of potential dilatation, I have also used a valve prosthesis one size smaller (undersizing) in a few elderly patients. At discharge, as well as during the follow-up period of up to 3 years, all patients had very good hemodynamic results with normal motility of the aortic cusps showing no contact with the Dacron tube, low gradients across the valve, and no aortic regurgitation (Fig 1).
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Fig 1. Postoperative aortography after aortic root replacement with valved stentless composite graft using stentless porcine valve (Toronto SPV, St. Jude Medical, St. Paul, MN) and collagen-coated Dacron tube (InterGard, Intervascular, La Ciotat, France).
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Even though clinical and echocardiographic outcome between the undersizing and the oversizing of the valve do not differ, there is a technical problem in both groups. To avoid wrinkling or deviation of the aortic valve prosthesis, the difference in diameter of both devices has to be parted equally on the complete suture circumference. This increases the difficulty of the procedure. Based on the use of aortic root prosthesis as described by De Paulis and colleagues [1], the procedure can be even more complicated because of the necessity of positioning the tops of the commissures exactly at the level of sinotubular junction and modeling the valve prosthesis within the neo-sinuses.
The key to the lasting function of the stentless composite graft is the wrinkle-free position of the valve prosthesis in the vascular tube achieved by a correct implantation technique. This could be facilitated by the availability of identical diameters of tube grafts and valve prosthesis.
References
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De Paulis R., Nardi P., De Matteis G.M., Polisca P., Chiariello L. Bentall procedure with a stentless valve and a new aortic root prosthesis. Ann Thorac Surg 2001;71:1375-1376.[Abstract/Free Full Text]
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Franke U., Jarmann M.J., Uthoff K., et al. In vivo morphology of woven, collagen-sealed Dacron prosthesis in the thoracic aorta. Ann Thorac Surg 1997;64:1096-1098.[Abstract/Free Full Text]
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Urbanski P.P. Replacement of the ascending aorta and aortic valve with a valved stentless composite graft. Ann Thorac Surg 1999;67:966-971.[Abstract/Free Full Text]
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Urbanski P.P., Hacker R.W. Replacement of the aortic valve and ascending aorta with a valved stentless composite graft: technical considerations and early clinical results. Ann Thorac Surg 2000;70:17-20.[Abstract/Free Full Text]
