Patency Of Internal Carotid Artery Research Articles

Re-evaluation of Radioisotope Angiography as a Screening Test for Ischemic Cerebral Diseases

Old patients need a non-invasive screening test instead of conventional angiography for diagnosis of cerebrovascular diseases (CVD). The availability of radioisotope (RI) angiography as a screening test was studied on ischemic cerebral diseases, and compared with computed tomography findings or conventional angiographic findings. RI angiography was performed with a bolus injection of 20 mCi 99mTcO4- via a cephalic vein using a scintillation camera and an on-line computer system. One hundred images were obtained during 50 seconds. RI angiography was found useful for detecting occluded major arteries and perfusion through collateral circulations in acute stage of the ischemic CVD. Sequential examinations of RI angiography were performed without complications even in old patients. Recanalization of the major arteries was also detected without the help of conventional angiography. Occlusion of an internal carotid artery with no cross circulation indicated a poor prognosis, whereas good collateral circulation such as the presence of the flip-flop sign indicated a good recovery. A patent extracranial-intracranial (EC-IC) bypass after an operation and a patent internal carotid artery after a carotid endarterectomy were well detected. Increased perfusion of the distal middle cerebral arteries from the EC-IC bypass was revealed. The intracranial non-filling phenomenon in patients with brain death was also well detected. RI angiography is suitable for screening of ischemic cerebral diseases, especially in old patients, reconstructive vascular surgery, and brain death.

External Carotid Occlusion as a Cause of Recurrent Ischemia after Carotid Endarterectomy

Our experiences with a patient who developed recurrent hemispheric transient ischemic attacks 3 1/2 years after ipsilateral carotid endarterectomy are described. Although repeat arteriography demonstrated smooth and unobstructed common and internal carotid arteries and a normal intracranial circulation, there was complete occlusion of the external carotid artery at its origin, which appeared as a stump or diverticulum at the origin of the internal carotid artery. This stump was filled with atherothrombotic debris and served as a source of emboli to the adjacent and patent internal carotid artery. Excision of the stump effected complete relief of the recurrent ischemic symptoms. The pernicious potential of an external carotid obstruction when adjacent to a patent internal carotid artery should be recognized. To prevent this avoidable complication of carotid endarterectomy, we recommend that the origin of the external carotid artery be treated with the same standards of technical perfection as those customarily applied to the internal and common carotid arteries during this procedure.

External carotid occlusion as a cause of recurrent ischemia after carotid endarterectomy

Our experiences with a patient who developed recurrent hemispheric transient ischemic attacks 3 1/2 years after ipsilateral carotid endarterectomy are described. Although repeat arteriography demonstrated smooth and unobstructed common and internal carotid arteries and a normal intracranial circulation, there was complete occlusion of the external carotid artery at its origin, which appeared as a stump or diverticulum at the origin of the internal carotid artery. This stump was filled with atherothrombotic debris and served as a source of emboli to the adjacent and patent internal carotid artery. Excision of the stump effected complete relief of the recurrent ischemic symptoms. The pernicious potential of an external carotid obstruction when adjacent to a patent internal carotid artery should be recognized. To prevent this avoidable complication of carotid endarterectomy, we recommend that the origin of the external carotid artery be treated with the same standards of technical perfection as those customarily applied to the internal and common carotid arteries during this procedure. (Neurosurgery 11:518-521, 1982)

Artificial embolization of carotid-cavernous fistula with post-operative patency of internal carotid artery.

This report deals with a patient of 86 who developed a carotid-cavernous fistula. Artificial embolization alone was considered the safest treatment for this patient and proved to be adequate. Post-operative preservation of the patency of the internal carotid artery was demonstrated by angiography. We believe this method is particularly appropriate for carotid-cavernous fistulas if it is demonstrated by angiography that the major blood flow of the carotid artery pours into the fistula. A soft-iron clip attached to the muscle can be used for external and forceful guidance of the embolus into the fistula with the help of an electromagnet, hence the patency of the internal carotid artery can be preserved. The embolus should be introduced through the external carotid artery. This is the only case known to us in which patency of the internal carotid artery was post-operatively maintained. We have reviewed 545 reported cases of surgically treated carotid-cavernous fistulas and analysed the results from simple cervical carotid ligation to the more sophisticated methods of artificial embolizations. The results obtained by artificial embolization have been consistently good, while the other techniques have failed in large percentages. Artificial embolization should be used as the primary treatment for carotid-cavernous fistula, since ligation of the internal carotid artery precludes its embolization at a later date.