RISK OF RUPTURE OF AN INTRACRANIAL ANEURYSM WITH GROWTH DETECTED DURING FOLLOW-UP: A MULTICENTRE COHORT STUDY
- Laura T. Van der Kamp (Netherlands)
Abstract
Background And Aims
Unruptured intracranial aneurysms (UIAs) not undergoing preventive treatment are often followed radiologically to detect aneurysm growth, which is associated with an increased risk of rupture. We aimed to determine the absolute risk of aneurysm rupture after detection of growth.
Methods
In this observational study, we included patients ≥18 years from 15 international cohorts with ≥1 UIA with growth. Growth was defined as ≥1 mm increase in at least one direction. We calculated the absolute risk of rupture at six months, one year, and two years. Hazard ratios (HRs) with 95% CIs were generated. A prediction model was built to estimate an individualized risk of rupture after detection of growth.
Results
We screened 5166 patients who had follow-up imaging for 6928 UIAs, and included 312 patients with 329 aneurysms with growth during follow-up. During 864 aneurysm-years of follow-up after detection of growth, 25 (7.6%) aneurysms ruptured. The absolute risk of rupture after growth was 2.9% [95%CI:0.9-4.9%] at six months, 4.3% [95%CI:1.9-6.7%] at one year, and 6.0% [95%CI:2.9-9.1] at two years. In multivariable analyses, predictors of rupture were size (≥7 mm: HR 4.3 [95%CI:4.1-13.0]), shape (irregular: HR 2.9 [95%CI:1.3-6.4]) and site (middle cerebral artery: HR 3.6 [95%CI:0.7-16.3]; anterior cerebral artery/posterior communicating artery/posterior circulation: HR 2.8 [95%CI:0.6-13.0])). In the triple-S (size, site, shape) prediction model, the one-year risk of rupture ranged from 2.1% to 10.6%.
Conclusions
Our newly developed triple-S prediction model can be used by physicians to estimate absolute risks of rupture for the initial period after detection of aneurysm growth.