Treatment strategy for aneurysms of the posterior cerebral artery

Abstract

The authors carried out a retrospective review of the records of 12 patients with aneurysms of the posterior cerebral artery (PCA). Four were asymptomatic, 1 presented with a mass effect, and 7 with a subarachnoid haemorrhage (SAH). Of the 7 ruptured aneurysms, 3 were embolized and 2 were clipped. However, 2 patients died from rebleeding before any treatment. Of the 5 unruptured aneurysms, 1 was embolized with coils but the remaining 4 have been conservatively observed. No aneurysms have ruptured during the follow-up period, and 3 have thrombosed spontaneously. According to our results, the PCA aneurysms should be treated aggressively in the early phase. Although the preservation of the anatomical integrity of the PCA should naturally be one of the prime objectives, PCA occlusion may sometimes be inevitable when treating large or fusiform aneurysms. On the other hand, conservative therapy is one of the options for the treatment of incidentally encountered unruptured ones, because these have the possibility of spontaneous thrombosis.

Figure 1

Case 4: A large dissecting aneurysm of right P2 presented with SAH. A) The vertebral angiogram shows a multilobular aneurysm at right P2 thought to be a dissecting aneurysm. B) The vertebral angiogram obtained after TAE with parent artery occlusion reveals that the lumen of the aneurysm and the parent artery were completely occluded. C) Late phase of the right internal carotid angiogram obtained after parent artery occlusion demonstrates a collateral flow from leptomeningial anastomosis (arrows). However, transient hemiparesis and dysesthesia developed after parent artery occlusion.

Figure 2

Case 10: A large unruptured aneurysm at left Pl-P2 in a 44-year-old female presenting with headache. A) The initial vertebral angiogram shows a large, irregular-shaped aneurysm arising at right Pl-P2. B) The second vertebral angiogram taken a week later reveals shrinkage of the aneurysm, suggesting the progression of thrombosis. C,D) Repeated angiograms obtained three weeks and a year after the initial angiogram, respectively, demonstrate the progression of thrombosis (C) and, finally, the aneurysm and the parent artery are seen to be completely occluded (D).