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Ann Thorac Surg 2001;72:2181
© 2001 The Society of Thoracic Surgeons

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Correspondence

Left hemispheric stroke in CABG

^a Klinik für Herzchirurgie, Medizinische Universitaet zu Luebeck, Ratzeburger Allee 160, D-23538 Luebeck, Germany

e-mail: gerdes{at}medinf.mu-luebeck.de

To the Editor

We have read with great interest the recent report by Weinstein [1] that emphazises the strong preponderance of left-sided strokes after coronary artery bypass grafting (CABG). In this series of 2,217 consecutive patients undergoing CABG, there were a total of 51 strokes, and 18 of the 24 major (75%) perioperative strokes involved the left hemisphere. The author concluded that manipulative actions such as aortic clamping or cannulation are more likely to result in right-sided insults, as the brachiocephalic trunk is closest to the origin of such emboli. As a possible explanation for the large incidence of perioperative stroke, he suggested the fact that high-velocity jets from end-hole cannulas reach the left carotid orifice.

We agree that aortic cannula tip design is a very important factor influencing hydrodynamic characteristics of aortic cannulas. We [2] demonstrated in in vitro studies that most of the single-stream cannulas tested generate a pressure peak in the left carotid artery that is caused by jet streaming. Therefore, hyperperfusion of the left hemisphere and plaque dislodgment at the origin of the left common carotid artery may be initiated by high jet-stream velocity.

With reference to the multiple-stream Sarns Soft-flow aortic cannula, our investigations showed a balanced pressure and flow distribution between the aortic arch vessels. This supports the lower incidence of cerebral insults observed by Weinstein using this particular type of cannula.

The author concluded that the use of side-hole cannulas may reduce the incidence of perioperative strokes. Concerning this point, Parker [3], using an open-tip cannula with side-holes, described 95% of the fluid leaving the cannula through the open tip and only 5% passing through the side holes. For this reason, well-distributed aortic arch perfusion is not achieved by integration of side holes but by closure of the tip of the cannula.

As knowledge concerning the relationship between jet streaming and plaque dislodgment in vivo is scarce, further research is desirable to define the influence of cannula-derived flow characteristics on clinical outcome.

References

1. Weinstein G.S. Left hemispheric strokes in coronary surgery: implications for end-hole aortic cannulas. Ann Thorac Surg 2001;71:128-132.[Abstract/Free Full Text]
2. Joubert-Hübner E., Gerdes A., Klapproth P., et al. An in-vitro evaluation of aortic arch vessel perfusion characteristics comparing single versus multiple stream aortic cannulae. Eur J Cardiothorac Surg 1999;15:359-364.[Abstract/Free Full Text]
3. Parker R. Aortic cannulation. Thorax 1969;24:742-745.[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 Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Gerdes, A. Articles by Sievers, H.-H. Search for Related Content PubMed PubMed Citation Articles by Gerdes, A. Articles by Sievers, H.-H. Related Collections Coronary disease Related Article