Endovascular treatment of posterior cerebral artery aneurysms

Abstract

Background and purpose: The purpose of this study was to report the incidence, clinical presentation, endovascular treatment, and outcome of aneurysms of the posterior cerebral artery (PCA).

Patients and methods: Among 1880 aneurysms treated between January 1995 and January 2005, 22 aneurysms (1.2%) in 22 patients were located on the PCA. Ten patients presented with subarachnoid hemorrhage (SAH) from the PCA aneurysm: 2 of these patients had additional visual field deficits and 2 had additional occulomotor palsy. One patient presented with acute occulomotor palsy only. Eleven PCA aneurysms were unruptured: 9 were additional to another ruptured aneurysm and 2 were incidentally discovered. Three aneurysms were >15 mm and the other 19 aneurysms were < or = 8 mm. Eighteen aneurysms were saccular, 2 were fusiform, one was dissecting, and one was mycotic.

Results: All aneurysms were successfully treated, 17 with selective occlusion of the aneurysm with coils and 5 with simultaneous occlusion of the aneurysm and parent PCA with coils. There were no complications of treatment. Two patients died of sequelae of SAH shortly after treatment. One patient died 2 months after coiling of an unruptured P1 aneurysm with intramural thrombus of SAH from the same aneurysm. One patient had persistent hemianopsia. In 2 patients with intact visual field in which the parent PCA was occluded, no hemianopsia developed due to sufficient leptomeningeal collateral circulation.

Conclusion: Aneurysms of the PCA are rare with an incidence in our practice of 1.2% of all types of aneurysms. Clinical presentation is variable with SAH, occulomotor palsy, visual field deficit or a combination. Endovascular treatment with either selective occlusion of the aneurysm or occlusion of the aneurysm together with the parent artery with coils is safe and effective with good clinical results.

Fig 1.

Patient 11, a 43-year-old woman with an incidentally discovered fusiform P2 aneurysm. A, Lateral projection of vertebral aneurysm shows an 8-mm fusiform P2 aneurysm. B, Simultaneous angiogram of vertebral artery and right internal carotid artery shows complete occlusion of the aneurysm including the parent PCA and good filling of distal PCA branches through leptomeningeal collateral vessels. C, MR imaging 6 weeks after PCA occlusion shows no infarction in PCA territory.

Fig 2.

Patient 20, a 32-year-old man presenting with HH grade III SAH and hemianopsia. A, CT scan on the day of admission shows SAH and aneurysm in the left ambient cistern (arrow). B, Vertebral angiogram shows occluded left PCA beyond the P2, presumably by a dissecting aneurysm. Endovascular therapy was judged not necessary. C, CT scan after sudden clinical detoriation 4 days after admission shows enlargement of the aneurysm, recurrent SAH with thalamic hematoma and hemorrhagic infarction in the PCA territory. D, Angiogram after recurrent SAH shows filling of large dissecting aneurysm. E, Occlusion of the aneurysm with coils including the afferent P2. The patient died 3 days later.

Fig 3.

Patient 13, a 64-year-old man presenting with HH grade I SAH and right occulomotor palsy. A and B, MR imaging and angiography show dissecting fusiform P2 aneurysm with intramural thrombus. C and D, Vertebral (C) and right internal carotid (D) angiogram after occlusion of the aneurysm including the parent PCA show good collateral supply to the occipital lobe through leptomeningeal collaterals. E, MR imaging 6 weeks after PCA occlusion demonstrates no infarction in right PCA territory.

Fig 4.

Patient 22, a 64-year-old woman presenting with HH grade I SAH and hemianopsia. A, CT scan showing subarachnoid and intraventricular blood and a hematoma in the medial occipital lobe. B, Lateral vertebral angiogram showing a small aneurysm on the P4 (arrow). C, Superselective angiogram, which better demonstrates the small aneurysm. D, Occlusion of the aneurysm including the parent artery with coils.

Fig 5.

Patient 12, a 35-year-old man presenting with acute left occulomotor palsy. A and B, MR imaging and angiography show a left P1–P2 aneurysm pointing downward with an intramural thrombus. C and D, Coiling of the aneurysm with the aid of a supporting balloon results in complete occlusion of the lumen. E, CT scan 2 months later shows SAH from the coiled aneurysm. The patient died the next day.