Ann Thorac Surg 2004;77:1464
© 2004 The Society of Thoracic Surgeons
Images in cardiothoracic surgery
Dissociated brain blood flow during cardiac surgery
Vladimir Birjiniuk, MDa,
Patrick R. Treanor, CCPa,
Val Pochayb,
Michael D. Crittenden, MDa,
Viken L. Babikian, MDb*
a Department of Cardiothoracic Surgery, Harvard Medical School, Boston, Massachusetts, USA
b Department of Neurology, Boston University School of Medicine, Boston, Massachusetts, USA
* Address reprint requests to Dr Babikian, Department of Neurology, Boston University School of Medicine, Boston VAMC, 150 South Huntington Ave, Boston, MA 02130, USA.
e-mail: babikian{at}bu.edu
This 55-year-old man presented with a chief complaint of shortness of breath and fatigue during exertion. The past medical history was significant for hypertension, hyperlipidemia, and myocardial infarction. Coronary artery catheterization showed three-vessel disease, and an elective coronary bypass graft surgery was recommended. The coronary bypass grafting was performed with bilateral middle cerebral artery continuous monitoring using transcranial Doppler ultrasound (Nicolet/EME Pioneer TC-2020, Madison, WI). Flow velocities were symmetrical before the operation and after anesthesia was instituted (Fig 1A).
When pulsatile flow was initiated with a SARNS centrifugal pump, after cross-clamping of the ascending aorta and cannulation with a directional flow arterial cannula (Medtronic DLP 20F, Minneapolis, MN), a dissociation of the flow pattern was observed between the left and right middle cerebral arteries. As seen in Figure 1B, the flow is pulsatile in the left (top panel) and nonpulsatile in the right (bottom panel) middle cerebral arteries. This flow pattern continued throughout the duration of cross-clamping of approximately 72 minutes. The patient recovered from the surgery without a new neurologic deficit, and the clinical significance of this observation remains unknown.
This finding is not unique, however, as we have observed this phenomenon in approximately 20% of patients undergoing the same surgical procedure. Its cause remains unknown. It is not associated with extracranial internal carotid artery stenosis in this patient, as he had only minimal plaque formation on duplex ultrasound testing. We speculate it may be related to the position of the aortic cannula in the aortic arch during cross-clamping.
