Ann Thorac Surg 2008;85:309. doi:10.1016/j.athoracsur.2007.07.099
© 2008 The Society of Thoracic Surgeons
New Technology
Invited commentary
Raymond Cartier, MD
Department of Surgery, Montreal Heart Institute, 5000 Belanger St E, Montreal, PQ H1T 1C8, Canada
(Email: rc2910{at}aol.com).
De Paulis and colleagues [1] have reported a new generation of composite Dacron graft (DuPont, Wilmington, DE) conduit with its corresponding tissue valve counterpart that could be preserved in glutaraldehyde without loosing its hemostatic properties. In an aging surgical population, surgeons are more frequently confronted with root replacement. Root replacement is generally necessary in cases of tissue loss such as endocarditis with abscess formation, aneurysmal degeneration with aortic stenosis or insufficiency, acute dissection, aortic stenosis with small root, and "porcelain" aorta.
Among currently available options are cryopreserved homografts, root allografts (Freestyle; Medtronic, Minneapolis, MN), and the "bio-Bentall," where the surgeon manually sutures the chosen tissue prosthesis to a Dacron conduit during the operation. Homografts are not always available when needed and always present the risk of transmitting prion diseases. The porcine root allograft is a good option but, unfortunately, has limited length and occasionally must be combined with a Dacron graft to cover extensive resection. Manually suturing an aortic bioprosthetic valve to a Dacron graft increases cross-clamping time, which generally does not help the surgeon’s disposition. The opportunity to use a preassembled Dacron graft-to-tissue prosthesis is an elegant option. The surgeon easily manipulates the prosthesis, experiences no surprises in sizing and fitting the valve, and does not expect calcification should reoperation be necessary.
Obviously, the new generation of Dacron grafts proposed by Dr De Paulis and his team provide a ready-to-use, composite, bioprosthetic graft. This conduit seems to preserve low porosity and pliability, which are desirable qualities during surgical implantation. The greater thickness of this graft may confer more stiffness, however, which is not ideal for an aortic root substitute. The biomechanical literature tells us that the ascending aorta is responsible for 50% of the impedance of the entire aorta [2]. Loss of the aortic wall expansion (normally about 16%) increases the cardiac workload [3]. How these affect long-term survival is not fully known. We do know that repeated microtraumas at the suture line interface (expansion of the native aorta vs nonexpansion of the Dacron) have the potential to generate pseudoaneurysm, with subsequent need for reoperation.
We have to remember that our heart beats a billion times every 25 years. Any minor "flaws" in the system over time are amplified and eventually cause problems. In our quest for improved quality of aortic root replacements, the next generation of conduits must address these issues if surgeons wish to optimize the quality of their work.
 |
References
|
|---|
- De Paulis R, Scaffa R, Maselli D, Salica A, Bellisario A, Weltert L. A third generation of ascending aorta Dacron graft: preliminary experience Ann Thorac Surg 2008;85:305-309.[Abstract/Free Full Text]
- Brewer RJ, Deck JD, Capati B, Nolan SP. The dynamic aortic rootIts role in aortic valve function. J Thorac Cardiovasc Surg 1976;72:413-417.[Abstract]
- Roman MJ, Ganau A, Saba PS, Pini R, Pickering TG, Devereux RB. Impact of arterial stiffening on left ventricular structure Hypertension 2000;36:489-494.[Abstract/Free Full Text]
Related Article
-
A Third Generation of Ascending Aorta Dacron Graft: Preliminary Experience
- Ruggero De Paulis, Raffaele Scaffa, Daniele Maselli, Andrea Salica, Alessandro Bellisario, and Luca Weltert
Ann. Thorac. Surg. 2008 85: 305-309.
[Abstract]
[Full Text]
[PDF]
Top
References