Paclitaxel and Arterial Smooth Muscle Cell Proliferation
To the Editor:
I have recently completed reading “Paclitaxel Inhibits Arterial Smooth Muscle Cell Proliferation and Migration In Vitro and In Vivo Using Local Drug Delivery,” published in the July 15, 1997, issue of Circulation. My questions concerning this study are related to the claimed statistical significance of the in vivo data. According to the published methodology, the data were analyzed by a two-tailed unpaired t test. Having applied this test to verify the significance between the reported means, I find that none of the presented in vivo data have any statistical significance, and I am curious whether Axel et al, in error, might have used a paired t test.
We thank Dr Heller for his comments on our article. After reviewing of the original data, we must admit that some statistical data of the in vivo part of the study were reported incorrectly. This was due to a misunderstanding between the statistician and the authors of the manuscript with regard to the probability values. Unfortunately, this error leads to statistical significance that does not exist in reality. However, we want to emphasize that the in vitro data were not affected by this error. The original data, the mean values, and the correct probability values are reported as follows in the Table⇑. The correct probability values are P=.18 for mean intimal wall area, P=.45 for intimal wall thickness, and P=.31 for degree of stenosis. Therefore, paclitaxel applied with the microporous balloon was not able to inhibit intimal growth in this preliminary in vivo study. However, concerning the conclusion of our study, we have completed comprehensive experiments with the double-balloon catheter and paclitaxel in which we could show in vivo efficacy. The results have been submitted for publication. We sincerely apologize for the errors.
- Copyright © 1998 by American Heart Association