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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): Gary L. Grunkemeier YingXing Wu Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Grunkemeier, G. L. Articles by Wu, Y. Search for Related Content PubMed Articles by Grunkemeier, G. L. Articles by Wu, Y. Related Collections Valve disease Related Articles

J Thorac Cardiovasc Surg 2003;126:1661
© 2003 The American Association for Thoracic Surgery

Letters to the editor

Reply to the editor

^a Providence Health System, 9155 SW Barnes, Suite 33, Portland, OR 97225, USA

Reply to the Editor:

We thank Dr Shuhaiber and colleagues for their comments on our study comparing two heart valve models on the basis of reports from the literature. In describing the limitations of such comparisons, they give us another opportunity to stress the main purpose of our report, which was to point out precisely these limitations.

The ideal way to compare valve performance across multiple studies is to use risk-adjustment techniques with individual, patient-level data. But only summary, study-level information is available from published reports. We emphasized also that the simple, weighted-average pooling of results within valve types is not appropriate if these results are statistically heterogeneous.

A regression approach that does allow for heterogeneity was used to adjust for some series-level risk factors: the mean, maximum, and completeness of follow-up; bleeding rate, as a surrogate for anticoagulation intensity; mean age; percentage of male patients; year of publication; number of valves; and journal impact factor. Three of the risk factors that Dr Shuhaiber mentions, etiology, surgical technique and atrial fibrillation, were generally not available in these reports.

It can be seen from the plots of linearized rates that by arbitrarily selecting groups of studies, the superiority of either valve in either position for any of the three outcomes studied can be supported. Because there is a tendency to perform these literature comparisons despite the described limitations, we used statistical techniques that can account for some of these limitations. We also stressed the "cautious interpretation" of even the most carefully done comparisons.

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J. Thorac. Cardiovasc. Surg. 2003 126: 1660-1661. [Extract] [Full Text] [PDF]

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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): Gary L. Grunkemeier YingXing Wu Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Grunkemeier, G. L. Articles by Wu, Y. Search for Related Content PubMed Articles by Grunkemeier, G. L. Articles by Wu, Y. Related Collections Valve disease Related Articles