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(Stroke. 2007;38:1140.)
© 2007 American Heart Association, Inc.

Letters to the Editor

Multifactorial Bases of Stroke After Cardiac Surgery

Fabio Barili, MD; Luca Dainese, MD; Gianluca Polvani, MD Paolo Biglioli, MD

Department of Cardiovascular Surgery, Centro Cardiologico Monzino, University of Milan, Milan, Italy

To the Editor:

We read with great interest the article by Gottesman et al¹ dealing with one of the most devasting complications of cardiac surgery, perioperative stroke. The article analyzed the impact on outcomes of watershed stroke and the role of intraoperative hypoperfusion on its onset. Nevertheless, their report raises some concerns.

The authors pointed out that hypoperfusion is an independent predictor of bilateral watershed strokes, a drop in mean arterial pressure of at least 10 mm Hg being associated with a 4-time increased adjusted risk of watershed strokes. The study group was composed of patients who developed postoperative stroke whereas patients who underwent cardiac surgery without developing stroke were not considered for statistical analysis. Moreover, only the relationship between bilateral watershed strokes and hypoperfusion was analyzed, whereas monolateral watershed strokes were considered together with other stroke patterns in group 2, despite the underlying mechanisms being more similar in monolateral and bilateral stroke than in other stroke patterns. Hence, by its nature this interesting study evaluated the impact of hypoperfusion on stroke severity whereas no conclusion can be given on the role of charges in blood pressure on stroke incidence and stroke patterns.

The 2 groups analyzed (bilateral watershed infarcts and other infarct patterns) were not homogeneous at univariate analysis. As underscored by the authors, patients with bilateral watershed infarcts were more likely to had undergone an aortic procedure. Aortic procedures are at higher risk of neurological events because they involve wide aortic manipulation² which is considered a major risk factor for embolization.³ Patients with aortic dissections were found to have strong dominance of bilateral cerebral infarct, which was different from the unilateral pattern of "cardiac-type" operations.⁴ Moreover, surgery of the ascending aorta is generally performed with a different pattern of cardiopulmonary bypass as ascending aortic cannulation is avoided⁵ and involves more frequently deep hypothermic circulatory arrest.²

Even the duration of cardiopulmonary bypass was significantly different between the 2 groups. Cardiopulmonary bypass machine produces systemic inflammatory response, destruction of blood cells, emboli, tissue edema and organ dysfunction.⁶ These effects lead to organ failure and poor outcomes if cardiopulmonary bypass time is increased.

In conclusion, the authors analyzed the effects of hypoperfusion on watershed strokes and gave new helpful information. However, the multifactorial bases of strokes still remain unclear and the relative role of hypoperfusion as well as embolization needs further study to be clarified.

Acknowledgments

Disclosures

None.

References

1. Gottesman RF, Sherman PM, Grega MA, Yousem DM, Borowicz LM Jr, Selnes OA, Baumgartner WA, McKhann GM. Watershed strokes after cardiac surgery: diagnosis, etiology, and outcome. Stroke. 2006; 37: 2306–2311.[Abstract/Free Full Text]
2. Goldstein LJ, Davies RR, Rizzo JA, Davila JJ, Cooperberg MR, Shaw RK, Kopf GS, Elefteriades JA. Stroke in surgery of the thoracic aorta: incidence, impact, etiology, and prevention. J Thorac Cardiovasc Surg. 2001; 122: 935–945.[Abstract/Free Full Text]
3. Abu-Omar Y, Balacumaraswami L, Pigott DW, Matthews PM, Taggart DP. Solid and gaseous cerebral microembolization during off-pump, on-pump, and open cardiac surgery procedures. J Thorac Cardiovasc Surg. 2004; 127: 1759–1765.[Abstract/Free Full Text]
4. Hedberg M, Boivie P, Edstrom C, Engstrom KG. Cerebrovascular accidents after cardiac surgery: an analysis of CT scans in relation to clinical symptoms. Scand Cardiovasc J. 2005; 39: 299–305.[CrossRef][Medline] [Order article via Infotrieve]
5. Fusco DS, Shaw RK, Tranquilli M, Kopf GS, Elefteriades JA. Femoral cannulation is safe for type A dissection repair. Ann Thorac Surg. 2004; 78: 1285–1289.[Abstract/Free Full Text]
6. Murphy GJ, Angelini GD. Side effects of cardiopulmonary bypass: what is the reality? J Card Surg. 2004; 19: 481–488.[CrossRef][Medline] [Order article via Infotrieve]

This Article Full Text (PDF) All Versions of this Article: 38/4/1140    most recent 01.STR.0000259825.90294.39v1 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 Download to citation manager Request Permissions Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Barili, F. Articles by Biglioli, P. Search for Related Content PubMed PubMed Citation Articles by Barili, F. Articles by Biglioli, P. Pubmed/NCBI databases Medline Plus Health Information Heart Surgery Stroke