The Unruptured Intracranial Aneurysm Treatment Score as a Predictor of Aneurysm Growth or Rupture.

BACKGROUND The Unruptured Intracranial Aneurysm Treatment Score (UIATS) was built to harmonize the treatment decision making on unruptured intracranial aneurysms. Therefore, it may also function as a predictor of aneurysm progression. In this study, we aim to assess the validity of the UIATS-model to identify aneurysms at risk of growth or rupture during follow-up. METHODS We calculated UIATS-scores for a consecutive series of conservatively treated unruptured intracranial aneurysms, included in our prospectively kept neurovascular database. CTA- and/or MRA-imaging at baseline and during follow-up was analyzed to detect aneurysm growth. We defined rupture as a CSF or CT proven subarachnoid hemorrhage. We calculated the area under the receiver operator curve, sensitivity, and specificity, to determine the performance of the UIATS-model. RESULTS We included 214 consecutive patients with 277 unruptured intracranial aneurysms. Aneurysms were followed for a median period of 1.3 years (range 0.3-11.7 years). During follow-up, 17 aneurysms enlarged (6.1%) and 2 aneurysms ruptured (0.7%). The UIATS model showed a sensitivity of 80% and a specificity of 44%. The area under the receiver operator curve was 0.62 (95% CI 0.46-0.79). CONCLUSION Our observational study involving consecutive patients with an unruptured intracranial aneurysm showed poor performance of the UIATS-model to predict aneurysm growth or rupture during follow-up.