1 out of 25 patients of Intracranial Aneurysm Growth have rupture with in one year: JAMA

Unruptured intracranial aneurysms not undergoing preventive endovascular or neurosurgical treatment are often monitored radiologically to detect aneurysm growth, which is associated with an increase in the risk of rupture. However, the absolute risk of aneurysm rupture after detection of growth remains unclear.

A study was conducted by Kamp L et. al to determine the absolute risk of rupture of an aneurysm after detection of growth during follow-up and to develop a prediction model for rupture.

Individual patient data were obtained from 15 international cohorts. Patients 18 years and older who had follow-up imaging for at least 1 untreated unruptured intracranial aneurysm with growth detected at follow-up imaging and with 1 day or longer of follow-up after growth were included. Fusiform or arteriovenous malformation-related aneurysms were excluded. Of the 5166 eligible patients who had follow-up imaging for intracranial aneurysms, 4827 were excluded because no aneurysm growth was detected, and 27 were excluded because they had less than 1 day follow-up after detection of growth.

The primary outcome was aneurysm rupture. The absolute risk of rupture was measured with the Kaplan-Meier estimate at 3-time points (6 months, 1 year, and 2 years) after initial growth. Cox proportional hazards regression was used to identify predictors of rupture after growth detection.

The results of the study are as follows:

• A total of 312 patients were with 329 aneurysms with growth.
• During 864 aneurysm-years of follow-up, 25 of these aneurysms ruptured.
• The absolute risk of rupture after growth was 2.9% at 6 months, 4.3% at 1 year, and 6.0% at 2 years.
• In multivariable analyses, predictors of rupture were size, shape, and site.
• In the triple-S (size, site, shape) prediction model, the 1-year risk of rupture ranged from 2.1% to 10.6%.

Thus, the researchers concluded that within 1 year after growth detection, a rupture occurred in approximately 1 of 25 aneurysms. The triple-S risk prediction model can be used to estimate absolute risk of rupture for the initial period after detection of growth.

Reference:

Risk of Rupture After Intracranial Aneurysm Growth JAMA Neurol by Kamp L et. al published in the JAMA Neurol.

DOI: 10.1001/jamaneurol.2021.2915