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Eur J Cardiothorac Surg 2003;24:335-336
© 2003 Elsevier Science NL

Letter to the Editor

Reply to Walther and Falk

Department of Thoracic and Cardiovascular Surgery, J.W. Goethe University, Theodor Stern Kai 7, 60599 Frankfurt am Main, Germany

Received 13 April 2003; accepted 15 April 2003.

^* Tel.: +49-69-6301-6141; fax: +49-69-6301-5849
e-mail: mirkodoss{at}aol.com

Key Words: Aortic valve replacement • Stentless bioprosthesis

We appreciate the attention that Walther et al. showed in our recent article and would like to point out the following issues in response to their comments.

Walther and colleagues suggest that our patient cohort is to small to allow for a meaningful analysis. We disagree! Without employing any statistical tests, any clinician will agree, that there is no clinically relevant difference between a mean gradient of 6.5 mmHg and one of 7.4 mmHg, or an ejection fraction of 64.6% and one of 66.6%. Also, a posterior wall thickness of 1.32 cm or one of 1.26 cm has no clinical relevance for the patient. Medically speaking, we would expect to need at least 15–20% differences between the groups to get a clinical relevance. The differences between the groups however, are in the region of 1–2%. Based on the relatively small sample size, after consulting our statisticians and the statisticians from Edwards Life Sciences, who have helped us design and evaluate our study, we can expect to pick up differences of 20% under this constellation.

With regard to intraoperatively measured annular diameters, we found no relevant differences between the groups (21.6 versus 22.4 mm). The subsequently implanted valve sizes are shown in Table 2 of our article [1].

Walther et al. imply that our article lacks information on indexed differences of left ventricular (LV) mass. We would like to call to their attention that we have separately reported all measurements that run into the equation of determining LV-mass index in Tables 1 and 3 of our article for both groups [1].We feel that the reader can thus better understand that there were no significant differences in the single components, rather than just seeing that the indexed end product did not differ.

Walther et al. go on to cite their article in which they report a significantly enhanced LV-mass regression after stentless aortic valve replacement [2]. They compared two different types of stentless valves with one stented valve, in groups that were of different sizes (n=49+n=57 versus n=74). Looking at the gradients that they report it appears that a reduction in transvalvular gradient by 1.4 mmHg (from postop 18.1 mmHg to 16.7 mmHg for stentless valves, with the stented valve gradients remaining at 20.1 mmHg) is statistically significant.

Furthermore, it appears that a pressure difference of 3.4 mmHg is enough to cause a significant reduction in LV-mass hypertrophy.

In our experience these minimal changes in pressure gradients cannot be held accountable for a more complete or faster regression of LV-mass. Our findings were similar to the findings of Cohen et al. from the Cleveland Clinic, who also conducted a prospectively randomized trial comparing stentless with stented aortic valves, and who also found no significant differences in hemodynamic performance or reduction in LV-mass between the groups [3].

In the current environment of science it is, however, not uncommon that different groups, investigating similar projects, come to different conclusions.

References

1. Doss M., Martens S., Wood P., Aybek T., Kleine P., Wimmer-Greinecker G., Moritz A. Performance of stentless versus stented aortic valve bioprostheses in the elderly patient: a prospective randomized trial. Eur J Cardiothorac Surg 2003;23:299-304.[Abstract/Free Full Text]
2. Walther T., Falk V., Langebartels G., Krüger M., Bernhardt U., Diegeler A., Gummert J., Autschbach R., Mohr F.W. Prospectively randomized evaluation of stentless versus conventional biological aortic valves: impact on early regression of left ventricular hypertrophy. Circulation 1999;100(19 Suppl):II6-II10.
3. Cohen G., Christakis G.T., Joyner C.D., Morgan C.D., Tamariz M., Hanayama N., Mallidi H., Szalai J.P., Katic M., Rao V., Fremes S.E., Goldman B.S. Are stentless valves hemodynamically superior to stented valves? A prospective randomized trial. Ann Thorac Surg 2002;73:767-778.[Abstract/Free Full Text]

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 Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Mirko Doss Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Doss, M. Search for Related Content PubMed Articles by Doss, M. Related Collections Valve disease