Procedural Morbidity and Mortality of Elective Coil Treatment of Unruptured Intracranial Aneurysms

Patients and Aneurysms

Between January 1, 1995, and July 17, 2005, 906 aneurysms were selectively occluded with detachable coils. Of these 906 aneurysms, 687 had ruptured and 219 had not. Of the 219 unruptured aneurysms, 43 (in 42 patients) were treated in the same session as another recently ruptured aneurysm, and the remaining 176 aneurysms in 149 patients were treated electively. Of the 149 patients, 20 had more than 1 unruptured aneurysm coiled in a single session (17 patients with 2 unruptured aneurysms, 1 patient with 3 unruptured aneurysms, and 2 patients with 5 unruptured aneurysms).

Indication for coiling was assessed in a weekly joint meeting with neurosurgeons, neurologists, and neuroradiologists. In general, coiling was offered as a first treatment option in all large and giant aneurysms, all posterior circulation aneurysms, and all carotid artery aneurysms. Patients with aneurysms on the middle cerebral artery and anterior communicating artery were offered coiling when a defined neck was present.

The 149 patients with 176 electively coiled unruptured aneurysms are the subject of the present study. There were 132 women (88.6%) and 17 men (11.4%) with a mean age of 51.8 years (median, 52 years; range, 26–81 years). Forty-two patients (28%) were older than 60 years of age.

Of 176 aneurysms, 79 were additional to another ruptured aneurysm but were coiled more than 3 months after SAH. Fifty-nine aneurysms were incidentally discovered on imaging studies performed for clinical reasons unrelated to the presence of the aneurysm. Thirty-eight aneurysms presented with symptoms of mass effect: ophthalmoplegia, 18; visual disturbances, 6; brain stem compression, 4; hemiparesis, 3; frontal syndrome, 3; headache, 2; and trigeminal neuralgia, 2.

Fifty of 176 (28.4%) aneurysms were located in the posterior circulation: basilar tip, 31; posterior cerebral artery, 9; posterior inferior cerebellar artery, 5; and superior cerebellar artery, 5. One hundred twenty-six (71.6%) aneurysms were located in the anterior circulation: ophthalmic artery, 27; posterior communicating artery, 26; anterior communicating artery, 19; carotid tip, 17; middle cerebral artery, 12; cavernous sinus, 11; pericallosal artery, 6; carotid hypophyseal artery, 4; and anterior choroidal artery, 3.

Mean size of the 176 unruptured aneurysms was 10.6 mm (median, 8 mm; range, 2–55 mm). One hundred thirteen aneurysms (64%) were small (<10 mm), 44 aneurysms (25%) were large (10–25 mm), and 19 aneurysms (11%) were giant (25–55 mm).

Coiling Procedure

Coiling of aneurysms was performed on a biplane angiographic unit (Integris BN 3000 Neuro, Philips Medical Systems, Best, the Netherlands) with the patient under general anesthesia and systemic heparinization. Heparin was continued intravenously or subcutaneously for 48 hours after the procedure, followed by low-dose oral aspirin for 3 months. Coiling was performed with Guglielmi Detachable Coils (GDC; Boston Scientific, Fremont, Calif) or TruFill DCS coils (Cordis, Miami Lakes, Fla). Some large aneurysms were coiled with very long mechanically detachable coils (Detach 18; Cook Inc, Copenhagen, Denmark). The aim of coiling was to pack the aneurysm as densely as possible, until not a single additional coil could be placed. Complications of coiling were recorded.

Initial angiographic results of coiling were classified as complete occlusion (100%), nearly complete occlusion (90%–100%), and incomplete occlusion (<90%).

Supporting Devices

Twenty-seven wide-necked aneurysms were coiled with a temporary supporting balloon (Sentry; Boston Scientific), 2 wide-necked aneurysms were coiled after placement of a permanent supporting device (TriSpan; Boston Scientific), and one wide-necked aneurysm was coiled after placement of a stent (Neuroform; Boston Scientific).

Clinical and Angiographic Follow-Up

Patients were scheduled for a follow-up visit in the outpatient clinic 6 weeks after coiling and for follow-up angiography after 6 months. On both occasions, neurologic status was evaluated. The effect of coiling on symptoms of mass effect was categorized as cured, improved, unchanged, or worsened. Results of follow-up angiography were classified in the same way as for initial angiographic results.

Complications

Complications of coiling occurred in 6 patients, leading to death in 2 and permanent neurologic deficit in 4 (Table 1). Mortality of coiling was 1.3% (2 of 149; 95% confidence interval [CI], 0.7–5.1%) and morbidity was 2.6% (4 of 149; 95% CI, 0.8–7.0%). The 4 patients with permanent morbidity were independent (GOS 4).

Effect of Coiling on Symptoms of Mass Effect

Clinical follow-up was available in all 149 patients, including the 38 patients with aneurysms presenting with symptoms of mass effect. One of these 38 patients died immediately after coiling. Of the remaining 37 patients, the effect of coiling on symptoms of mass effect was as follows: cured, 13; improved, 14; unchanged, 7; and worsened, 3.

Angiographic Results, Follow-Up, and Additional Treatments

Initial aneurysm occlusion was complete (100%) in 132 aneurysms, nearly complete (90%–100%) in 36 aneurysms, and incomplete (<90%) in 8 aneurysms.

Six-month follow-up angiography was performed in 132 patients with 154 coiled aneurysms (87.5%). Follow-up angiography was not available in 17 patients with 22 coiled aneurysms. Seven patients with 11 aneurysms had died during the 6-month follow-up interval: 2 patients with 2 coiled aneurysms died of procedural complications of coiling; 2 patients with 2 coiled aneurysms died of pneumonia; 1 patient with 1 coiled aneurysm died of subarachnoid hemorrhage of another untreated aneurysm; 1 patient with 5 coiled aneurysms died of complications of surgery of an additional aneurysm; and 1 patient with 1 coiled aneurysm died of subarachnoid hemorrhage from the same aneurysm. Three patients with 4 coiled aneurysms refused follow-up angiography, and 7 patients with 7 coiled aneurysms are scheduled for follow-up angiography.

Partial reopening of the coiled aneurysm occurred in 25 of 154 aneurysms (16.2%) in 25 patients. Mean size of these reopened aneurysms was 22.6 mm (median, 20.5; range, 5–55 mm), and 16 of 25 (64%) reopened aneurysms were large or giant. Additional coiling was performed in 22 aneurysms and additional parent vessel occlusion in 1 aneurysm. Two partially reopened aneurysms were left untreated because the anatomy precluded additional coiling. There were no complications of additional treatments.