Optical topography can predict occurrence of watershed infarction during carotid endarterectomy: technical case report.

BACKGROUND

The major risk of CEA is perioperative stroke. NIRS can detect ischemic changes during CEA; however, possible watershed-type perfusion defects may not be detected by single-channel NIRS occurring at some distance from the light source. In the present case, we tested the usefulness of optical topography (ie, multichannel NIRS, OT) for this purpose.

CASE DESCRIPTION

The patient (64-year-old man) exhibited nonsymptomatic 80% stenosis of the right ICA with normal cerebral perfusion. CEA was performed to prevent cerebral infarction. We used single-channel NIRS and OT for monitoring of perfusion changes during CEA. The optodes of OT were placed on the skull to cover the frontal and parietal lobes on the right side, whereas the sensor of the single-channel NIRS was placed on the right forehead. The single-channel NIRS detected no significant perfusion changes during surgery. However, the OT revealed occurrence of watershed-type perfusion defects in the border region between the right middle and posterior cerebral artery supply areas during cross-clamping of the right internal carotid artery. Postoperative MRI showed an ischemic region which corresponded to the area associated with the perfusion defects.

CONCLUSION

OT could detect watershed-type posterior perfusion defects which the single-channel NIRS failed to detect. OT may represent a useful tool for intraoperative monitoring during CEA.