Occlusion of internal carotid artery. Further clinical angiographic, and therapeutic considerations

Symptomatic carotid artery occlusion. A reappraisal of hemodynamic factors

BACKGROUND

Over the last several years evidence has accumulated that in addition to embolism, a compromised cerebral blood flow may play an important role in causing transient ischemic attacks and ischemic stroke in patients with occlusion of the internal carotid artery. This evidence is found in both clinical features and ancillary investigations, particularly measurements of cerebral blood flow.

SUMMARY OF REVIEW

On the basis of 20 follow-up studies in patients with transient ischemic attacks or minor ischemic stroke associated with an occluded carotid artery, the annual risk of stroke was 5.5% (95% confidence interval [CI], 5.0% to 6.0%), and that of ipsilateral stroke (distinguished in 11 of the 20 studies) was 2.1% (95% CI, 1.6% to 2.8%). Patients with a compromised cerebral blood flow as measured by positron emission tomography, single-photon emission CT, transcranial Doppler, or stable xenon CT (six studies) have an even higher annual risk of stroke (all strokes: 12.5%; 95% CI, 8.9% to 17.6%; ipsilateral stroke: 9.5%; 95% CI, 6.4% to 14.0%).

CONCLUSIONS

Because a compromised cerebral blood flow may be an important causal factor in patients with symptomatic carotid artery occlusion, medical and surgical options for treatment are reviewed in this light.

Spontaneous history of asymptomatic internal carotid occlusion

Forty-nine patients with ICA occlusion, who presented without any neurological signs or symptoms, were prospectively followed for an average of 31.2 months. Eight patients (16%) suffered a stroke during follow-up, of which five were within the vascular territory of the occluded artery--5 patients (10%) developed TIAs 4 of which were ipsilateral to the occluded artery. Non-invasive vascular follow-up did not reveal a progression of extracranial arterial disease in the majority of later symptomatic patients. Twenty-three patients (46.9%) died during follow-up, coexisting coronary artery disease being the major cause of death.