Sensitivity of the Unruptured Intracranial Aneurysm Treatment Score (UIATS) to detect aneurysms at high-risk of rupture: Retrospective analysis in a cohort of 346 patients with a proven subarachnoid hemorrhage.

Introduction: The aim of this study was to assess the capability of the Unruptured Intracranial Aneurysm Treatment Score (UIATS) to discriminate unruptured intracranial aneurysms (UIAs) at high risk for subarachnoid hemorrhage (aSAH).

Material And Method: During the period from January 2012 to December 2022, we included all consecutive adult patients admitted to our institution for an aSAH caused by the rupture of a saccular IA. The patient-related, aneurysm-related and treatment-related risk factors considered by UIATS were retrieved from medical records. After UIATS calculation for all ruptured IAs in the cohort, patients were categorized as "true positives (TP)" if UIATS would have (appropriately) oriented the management toward treatment, whereas patients for whom the UIATS would have (inappropriately) recommended observation were categorized as "false negatives (FN)". Patients for whom UIATS was inconclusive were categorized as "undetermined (UND)". Sensitivity of the UIATS (Se ) was calculated by using the following formula: TP/(TP + FN).

Results: A total of 346 patients (253 women, 73%; mean age = 56 ± 1.45 years) were incorporated into the final analysis. There were 140 T P (40%), 79 F N (23%) and 127 UND (37%), leading to a Se of 63.9% (CI 58.3-69.5). Cumulatively, the UIATS failed to provide an appropriate recommendation in 60% of the entire cohort.

Conclusion: By retrospectively applying the UIATS in a cohort of ruptured IAs, our study emphasizes how vulnerable the UIATS can be. Even if the UIATS suggests conservative management, clinicians should inform patients that there is still a small risk of rupture.