Revascularization procedures in internal carotid artery pseudo-occlusion

Surgical treatment of patients with suspected internal carotid artery (ICA) pseudo-occlusion and reduced cerebrovascular reactivity (CVR) is still uncertain regarding the diagnostic procedures, the risks and the optimal timing as well as performance of revascularization.

From 1983-2001, 781 patients with symptomatic ICA stenosis were treated surgically. In 53 patients, a final diagnosis of extracranial ICA pseudo-occlusion was established by repeating Digital Subtraction Angiography (DSA). Angiographical findings were anterograde "string-like" filling of ICA beyond the carotid bifurcation or retrograde filling of the proximal, so called "occluded" extracranial ICA, extending up to the skull base. The CVR was reduced. All patients underwent direct surgery of extracranial carotid artery. Diagnostic parameters, peri-operative risks and postoperative course of these patients were evaluated.

In 40 patients (75.5%) a successful revascularization of ICA was possible. ICA pseudo-occlusion was in all cases of atheromatous origin, moreover in 8 patients combined with a floating thrombus, distal to the stenosis. Thrombectomy was done by means of Fogarty catheter. In 13 patients (24.5%), a surgical re-opening of the ICA lumen was not possible. Five of these patients showed in DSA an anterograde "string sign", eight presented retrograde filling of ICA reaching the skull base. Peri-operative mortality was 1.9%, peri-operative morbidity was 7.5%. After a 4 years (mean) follow-up, 95% of the reopened ICA remained patent.

In patients with explicit carotid artery occlusion signs, careful selective DSA should be compulsory with a late series to detect ICA pseudo-occlusion. There is a chance for extracranial reopening ICA, even with compromised CVR, if anterograde "string like" or retrograde filling of proximal so called "occluded" ICA as far as the skull base is angiographically identified.