Resolving siphon stenosis following endarterectomy.

Tandem arteriosclerotic lesions of the carotid sinus and siphon increase the risks of carotid endarterectomy; when the siphon is severely stenotic, a microvascular bypass may be the preferable procedure. Two patients, each with severe siphon stenosis and significant sinus lesions, however, were subjected to carotid endarterectomy as their initial surgical procedure. The postoperative arteriogram showed resolution of the siphon stenosis in both patients. The identification of an associated extracranial lesion, or the presence of a lesion located more distal in the siphon than atheroma usually occur, should alert the surgeon that the intracranial obstruction may be due to embolism. In patients with these tandem lesions, therefore, a repeat arteriogram, performed several weeks after endarterectomy of sufficient medial treatment interval, may show resolution of the intracranial lesion, and may avoid an unnecessary bypass procedure.