Natural Course of Ruptured but Untreated Intracranial Aneurysms: A Multicenter 2-Year Follow-Up Study

The current understanding of untreated ruptured intracranial aneurysms has been limited by study design and inaccurate patient data. Multicenter clinical registry studies on untreated ruptured intracranial aneurysms in Chinese patients are scarce. We aimed to calculate the mortality of patients with untreated ruptured intracranial aneurysms in a current, clearly defined hospital cohort in China, with emphasis on mortality predictors over a 2-year period.

Patients with saccular untreated ruptured intracranial aneurysms were identified from the Chinese Multicenter Cerebral Aneurysm Database, a multicenter, prospective, observational database registered in China, which involved 32 tertiary medical centers covering 4 northern Chinese provincial regions. Patients with intracranial aneurysms, regardless of ruptured status, shape, age, or comorbidities, were consecutively included in 12 of 32 medical centers between 2017 and 2020. Survival probabilities were computed using the Kaplan-Meier method. Univariate and multivariate Cox regression analyses were conducted to determine the risk factors for the cumulative 2-year mortality. We analyzed the reasons for treatment decisions stratified by demographic characteristics and clinical features.

For 941 enrolled patients, 58.6% of patients died within 1 month of symptom onset; and 68.1% within 2 years. 98 patients underwent surgical repair during follow-up. Multivariate Cox regression analysis identified Hunt and Hess grades 3 to 5 (hazard ratio, 1.54 [95% CI, 1.01-2.35]; P=0.047), loss of consciousness at symptom onset (hazard ratio, 1.56 [95% CI, 1.18-2.07]; P=0.002), and largest aneurysm size of ≥5 mm (hazard ratio, 1.29 [95% CI, 1.05-1.59]; P=0.014) as mortality predictors during the 2-year follow-up. Among patients who were successfully followed up, 42.6% (280) of them refused surgical treatment.

Patients with poor Hunt and Hess grades, loss of consciousness at symptom onset, or largest aneurysms ≥5 mm in size showed a high mortality rate. A high number of treatment refusals was present in this study. These findings have implications for medical insurance policy, doctor-patient communication, and popular science education.