NASHVILLE, TENN. – The 10-year outcome for most giant intracranial aneurysms is rather dismal even if the lesions are initially successfully treated, according to findings from the International Study of Unruptured Intracranial Aneurysms.
Most patients lived through the first 2 years after diagnosis, but by 10 years, 37% of treated patients had died. Untreated patients had significantly higher mortality at 57%, Dr. James C. Torner said at the International Stroke Conference, which was sponsored by the American Heart Association.
“Compared to small aneurysms, the risk of all-cause mortality for these giant aneurysms is seven times greater in the first year, and the risk of hemorrhage or procedure-related death is 15 times higher. The risk does decrease over time, but it’s still elevated. It’s twice as high for death from hemorrhage and six times more likely from death due to rupture or a procedure by 10 years.”
Dr. Torner of the University of Iowa, Iowa City, presented 10-year outcomes from the International Study of Unruptured Intracranial Aneurysms (ISUIA), which followed 4,059 patients, of whom 187 had a giant unruptured intracranial aneurysm.
The mean lesion size was about 30 mm, but ranged from 25 to 63 mm. A third involved the internal carotid, and another third were cavernous. The remainder were either vestibular, posterior communicating, anterior cerebral, or middle cerebral.
Most were irregular; about 40% were a single sac. Daughter sacs were present in the rest. The volume ranged from 1,100 to 38,000 mm3, with about 10% having a volume of greater than 20,000 mm3.
Most of the patients were women (91%). Age was not related to occurrence; patients ranged from 25 to 82 years. There were some common risk factors, including smoking (in 70%), a family history of aneurysm (in 10%), a family history of coronary artery disease (in up to 45%, depending on patient age), hypertension (in up to 40%), and vascular headache. Patients aged 50 years or older were most likely to present with vascular headache (75%).
The baseline score on the modified Rankin Scale (mRS) was 1 in about 93% of the group. But 80% presented with some symptoms, including cranial nerve deficit (47%; commonly in cranial nerves III and IV), mass effect (16%), headache (44%), orbital pain (21%), and partial vision loss (25%).
Surgery was performed in 39% and endovascular treatment in 27%; the rest of the patients were initially untreated, although 3% later received endovascular treatment and 5% underwent surgical treatment during the follow-up period.
By 10 years, many of the lesions had ruptured. Posterior aneurysms were most likely to rupture (53%), while cavernous aneurysms were least likely to rupture (5%). About a third of the posterior communicating and 36% of the anterior lesions were unruptured.
The risk of rupture increased over the first 5 years, rising from almost 0% in year 1 to 20% by year 5. “Hemorrhage risk is huge over the first 5 years, even with the cavernous aneurysms – even they can rupture,” Dr. Torner said. “In those with smaller aneurysms, the risk of rupture may be high in the first 2 years, but then it subsides somewhat.”
Among the 59% of the overall group who survived, the mRS score remained excellent (1 or 2) by 10 years. Of the remainder who died, 23% died of a cranial or subarachnoid hemorrhage, and 11% of a cerebral infarct. Coronary disease, respiratory disease, and cancer were the other causes.
Treated patients generally fared better than untreated, although mortality varied significantly by lesion location. For anterior lesions, the death rate was 25% in untreated patients , 32% for surgical patients, and 19% in endovascular patients. Death rates for those with posterior communicating lesions were 90% for untreated and 50% for surgically treated patients; all of those with endovascular treatment died. For those with posterior lesions, death rates approached 100% for all groups.
Dr. Torner cautioned that because the study outcomes were collected during the 1990s, most treated patients underwent only coiling or clipping; better outcomes may be seen with more advanced therapies.
He said he had no relevant financial disclosures.