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(Stroke. 2007;38:1141.)
© 2007 American Heart Association, Inc.

Letters to the Editor

Response to Letter by Barili et al

Johns Hopkins Medical Institutions, Baltimore, Md

Paul M. Sherman, MD

Wilford Hall Medical Center, San Antonio, Tex

Maura A. Grega, RN, MSN; David M. Yousem, MD, MBS; Louis M. Borowicz, Jr, MS; Ola A. Selnes, PhD William A. Baumgartner, MD

Johns Hopkins Medical Institutions, Baltimore, Md

Guy M. McKhann, MD

Zanvyl Krieger Institute, Johns Hopkins University, Baltimore, Md

An extract of the first 250 words of the full text is provided, because this article has no abstract.

Response:

We appreciate the comments by Dr Barili et al regarding our recent article on watershed strokes after cardiac surgery.¹

They point out that we did not study patients who did not have strokes after cardiac surgery, and therefore cannot comment on risk of stroke, in general, in patients exposed to a decrease in mean arterial pressure. We agree and would like to emphasize that the increased risk of bilateral watershed strokes in patients exposed to a drop in mean arterial pressure of at least 10 mm Hg is compared with other stroke patients. We are in the process of conducting other studies to determine the role of this drop in mean arterial pressure in the development of stroke, in general.

In addition, the inclusion of unilateral watershed strokes in the "control" group was questioned. We do not necessarily agree that the mechanism is exactly the same in patients with unilateral and bilateral watershed strokes. The latter group is more likely to have been exposed to a global decrease in hypoperfusion, causing equivalent hypoperfusion to both sides of the brain, whereas patients with unilateral watershed infarcts are more likely to have carotid or intracranial disease leading to selective hypoperfusion of one particular hemisphere.²

Finally, we do acknowledge that the 2 patient groups were not homogeneous at univariate analysis, both with regards to procedure and cardiopulmonary bypass time. Multivariate adjustment for procedure made minimal to no difference in the point estimates or levels of significance of the other covariates and thus . . . [Full Text of this Article]