Endovascular treatment of distally located giant aneurysms

OBJECTIVE: Because giant aneurysms (GAs) can be technically difficult to clip, the endovascular approach is becoming increasingly popular. Endovascular treatment of distally located GAs, which often requires parent vessel occlusion, is particularly challenging because limited pathways are available for collateral flow. We aimed to determine the outcomes of endovascular attempts to treat GAs downstream from the circle of Willis. METHODS: Between 1991 and 1998, 27 patients with 27 distally located very large aneurysms or GAs were evaluated for possible endovascular treatment. Ten underwent selective embolization and 9 were treated with primary parent vessel occlusion, with or without distal bypass. Eight patients could not be treated endovascularly. RESULTS: Selective embolization resulted in only one cure. Two patients died as a result of subarachnoid hemorrhage during the follow-up period. One coil-treated patient, who underwent subsequent spontaneous parent vessel occlusion, and all nine patients treated primarily with parent vessel occlusion were considered cured after their treatments. Only two patients treated with parent vessel occlusion experienced periprocedural ischemia, which did not result in a major deficit in either case. Of the eight patients who could not be treated endovascularly, one succumbed to surgery, four died while being treated conservatively, and three were lost to follow-up monitoring. CONCLUSION: Selective aneurysm embolization is usually not curative in these situations. For selected patients, however, endovascular parent vessel occlusion is usually safe and effective in preventing the progression of symptoms and bleeding.