Ultramicroscopic ulcerations and thrombi of the carotid bifurcation
N. R. Hertzer, E. G. Beven and S. P. Benjamin
It is widely accepted that transient cerebral ischemia and permanent stroke
frequently are caused by platelet and thrombotic cerebral emboli that
originate from lesions at the carotid bifurcation. Microembolization from
ulcerated atheroma during carotid dissection also offers a logical
explanation for the incidence of intraoperative neurologic deficits during
carotid endarterectomy. The risk of intraoperative embolization is obvious
when ulcers are macroscopic; but focal cerebral ischemia associated with
atheroma that appear smooth and nonulcerated usually has been attributed to
decreased regional cerebral blood flow. Several endarterectomy specimens
were submitted for scanning electron microscopic evaluation using X20
through X4,000 malignification. Results indicate that carotid atheroma may
contain superficial ulcerations and thrombi that are not appreciated by
direct inspection or conventional microscopic techniques. Electron
microscopic ulcerations and intraluminal thrombi may be responsible for
embolic transient ischemic attacks, spontaneous strokes, and intraoperative
neurologic deficits in patients in whom gross ulcerations are absent.
