HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Walter B. Eichinger Ruediger Lange Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Eichinger, W. B. Articles by Lange, R. Search for Related Content PubMed PubMed Citation Articles by Eichinger, W. B. Articles by Lange, R. Related Collections Related Article

J Thorac Cardiovasc Surg 2006;132:1499-1500
© 2006 The American Association for Thoracic Surgery

Letter to the Editor

Small aortic annulus: The hydrodynamic performances of 5 commercially available tissue valves

German Heart Center Munich, Clinic of Cardiovascular Surgery, Munich, Germany

To the Editor:

We are writing to comment on the study by Gerosa and associates¹ published in a recent issue of the Journal.

This highly interesting report compared geometric dimensions and hemodynamic performance of 5 different stented tissue valves for aortic valve replacement. Three pericardial bioprostheses (Carpentier-Edwards Perimount Magna [Edwards Lifesciences, Irvine, Calif], Sorin Soprano, and Sorin Mitroflow [Sorin Biomedica Spa, Saluggio, Italy]) and 2 porcine bioprostheses (Medtronic Mosaic [Medtronic, Inc, Minneapolis, Minn] and St Jude Medical Epic Supra [St Jude Medical, Inc, St Paul, Minn]) were tested at cardiac outputs of 2, 4, 5, and 7 L/min. So that a meaningful comparison could be made, prostheses that could be fitted in a 21-mm pulse duplicator ring were used, regardless of industry-labeled valve size. This addresses a very important issue that we try to solve for in vivo comparisons of different valve types by calculating the "effective orifice fraction," which is the ratio of the intraoperatively measured aortic annulus area and the echocardiographically obtained effective orifice area of the prosthesis.^2,3

In our opinion, one of the most striking results of the study by Gerosa’s group was the finding that even some of the geometric dimensions given by the manufacturers could not be reproduced by direct measurements, such as the internal or the tissue annulus diameter of certain bioprostheses.

The authors state that there are some discrepant findings compared with in vivo results published by our group: We found that in some patients the implantation of a Medtronic Mosaic valve labeled one size bigger than the Carpentier-Edwards Perimount valve was possible because of the smaller geometric dimensions of this valve.⁴ In the described in vitro setting, upsizing of the Medtronic Mosaic compared with the Carpentier-Edwards Perimount Magna was not possible. This corresponds to our in vivo findings, because the Carpentier-Edwards Perimount Magna has a 3-mm smaller sewing ring diameter than the Carpentier-Edwards Perimount for the identical labeled valve size. Thus, the hemodynamic benefit of the Carpentier-Edwards Perimount Magna valve results from the possibility of upsizing.⁵

The second cited manuscript from our group³ is a prospective, nonrandomized comparison of 3 completely supra-annular prostheses (Carpentier-Edwards Perimount Magna, Medtronic Mosaic, and Sorin Soprano) with one intrasupra-annular valve (Carpentier-Edwards Perimount). These again were in vivo comparisons in which the sewing ring dimensions and the aortic root anatomy played a decisive role in the selection of a certain valve size. The basic findings of this work were that in patients with an aortic annulus of 18 to 20 mm in diameter (intraoperative direct measurements with a Hegar dilator), no significant hemodynamic differences between the investigated prostheses were present, whereas in patients with an annulus diameter between 21 and 23 mm, the Carpentier-Edwards Perimount Magna showed superior hemodynamic results compared with the other prostheses because of the beneficial ratio of sewing ring and internal orifice diameters. We disagree with the statement of Gerosa’s group that these conclusions would clash with their in vitro data. In our opinion, the decision that leads to the selection of a certain valve size in a complex anatomic structure, such as the aortic annulus in combination with prosthesis dimensions including stent height, sewing ring diameter, complete supra-annular position, and anatomic relation to the coronary ostia, is responsible for the different findings (Figure 1).

View larger version (19K): [in this window] [in a new window]   Figure 1. The schematic drawing shows two aortic root anatomies with an identical tissue annulus diameter (TAD). The right figure shows a more bulbar-shaped root. This is the ideal situation for complete supra-annular placement, in which the TAD corresponds to the internal orifice diameter (IOD) of the prosthesis (TAD = IOD). The left figure shows a narrow aortic root. Despite the same TAD, a completely supra-annular valve of the same size (gray) would not fit in. Thus a smaller valve (white) has to be chosen with the consequence that, despite implanting a completely supra-annular prosthesis, stent and sewing ring material impair the bloodstream. Thus the shape of the aortic root does not allow the implantation of a valve large enough to ensure that the IOD corresponds to the TAD. This illustrates the hypothesis that hemodynamic benefit cannot be achieved in every aortic root because of a completely supra-annular placement of the prosthesis. ESRD, External sewing ring diameter.

Footnotes

Walter Eichinger reports lecture fees from Edwards Lifesciences and St Jude Medical. Ruediger Lange reports lecture fees from Edwards Lifesciences and the Sorin Group.

References

1. Gerosa G, Tarzia V, Rizzoli G, Bottio T. Small aortic annulus: the hydrodynamic performances of 5 commercially available tissue valves. J Thorac Cardiovasc Surg 2006;131:1058-1064.[Abstract/Free Full Text]
   
2. Eichinger WB, Botzenhardt F, Guenzinger R, Bleiziffer S, Keithahn A, Bauernschmitt R, et al. The effective orifice area/patient aortic annulus area ratio: a better way to compare different bioprostheses? A prospective randomized comparison of the Mosaic and Perimount bioprostheses in the aortic position. J Heart Valve Dis 2004;13:382-388discussion 388-9.[Medline]
   
3. Botzenhardt F, Eichinger WB, Bleiziffer S, Guenzinger R, Wagner IM, Bauernschmitt R, et al. Hemodynamic comparison of bioprostheses for complete supra-annular position in patients with small aortic annulus. J Am Coll Cardiol 2005;45:2054-2060.[Abstract/Free Full Text]
   
4. Eichinger WB, Botzenhardt F, Keithahn A, Guenzinger R, Bleiziffer S, Wagner I, et al. Exercise hemodynamics of bovine versus porcine bioprostheses: a prospective randomized comparison of the Mosaic and Perimount aortic valves. J Thorac Cardiovasc Surg 2005;129:1056-1063.[Abstract/Free Full Text]
   
5. Botzenhardt F, Eichinger WB, Guenzinger R, Bleiziffer S, Wagner I, Bauernschmitt R, et al. Hemodynamic performance and incidence of patient-prosthesis mismatch of the complete supraannular Perimount Magna bioprosthesis in the aortic position. Thorac Cardiovasc Surg 2005;53:226-230.[Medline]
   

This article has been cited by other articles:

				T. Bottio, V. Tarzia, G. Rizzoli, and G. Gerosa The changing spectrum of bioprostheses hydrodynamic performance: considerations on in-vitro tests Interact CardioVasc Thorac Surg, October 1, 2008; 7(5): 750 - 754. [Abstract] [Full Text] [PDF]

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Walter B. Eichinger Ruediger Lange Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Eichinger, W. B. Articles by Lange, R. Search for Related Content PubMed PubMed Citation Articles by Eichinger, W. B. Articles by Lange, R. Related Collections Related Article