Spontaneous history of asymptomatic internal carotid occlusion.

Abstract

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.

Increased Oxygen Extraction Fraction Is Associated With Prior Ischemic Events in Patients With Carotid Occlusion

“…Additional arterial samples were drawn at intervals during the examination for determination of PaCO 2 stability, hematocrit level, and carboxyhemoglobin content. CBF was measured using a bolus intravenous injection of 15 Olabeled water. 21,22 CBV was measured by inhalation of air containing trace amounts of CO labeled with 15 O.…”

“…CBF was measured using a bolus intravenous injection of 15 Olabeled water. 21,22 CBV was measured by inhalation of air containing trace amounts of CO labeled with 15 O. 23 OEF was measured after one or two breaths of 15 O-labeled O 2 in combination with data from the CBV and CBF measurements.…”

“…24 CMRO 2 was calculated as the product of OEF, CBF, and PaO 2 content. 24 The entire PET examination could be performed within 1 hour because of the short half-life (123 seconds) of 15 O. All radionuclides were produced in the Washington University cyclotron facility.…”

“…Hankey and coworkers 14 found a 5.9% annual risk of ipsilateral stroke in a review of 12 prospective follow-up studies of 1261 patients with angiographically confirmed symptomatic occlusion. Hennerici et al, 15 on the other hand, followed 49 asymptomatic patients for a mean follow-up of 31.2 months and observed only 5 ipsilateral strokes (3.9% annual risk). Some studies of stroke risk and cerebral hemodynamics have not distinguished between symptomatic and asymptomatic patients.…”

Outcome of Carotid Artery Occlusion Is Predicted by Cerebrovascular Reactivity

“…Moreover, other studies have demonstrated a lower annual stroke risk in asymptomatic patients with ICA occlusion than in symptomatic patients. 9,10 Recently, Derdeyn et al 11 demonstrated that compromised CBF in patients with ICA occlusion is associated with the presence of previous ischemic symptoms and with no other risk factors; consequently, they remarked on the importance of distinguishing between symptomatic and asymptomatic patients in further investigations of the relationship between hemodynamic compromise and stroke risk.…”