With the widespread application of neurovascular imaging techniques, the detection rate of unruptured intracranial aneurysms (UIAs) has significantly increased. [1] Previous studies have indicated that the prevalence of UIAs can be as high as 7 % in the population aged 35–75 in China. [2] Although the risk of an intracranial aneurysm rupturing over a lifetime is relatively low, estimated at about 1 % per year, [1], [3], [4] the consequences of rupture leading to subarachnoid hemorrhage (SAH) can be catastrophic, with mortality rates as high as 35 %-50 %. [5], [6] Microsurgical treatment (MST) and endovascular treatment (EVT) are the two most common approaches to prevent rupture. While a prior randomized trial suggested that EVT has better outcomes than MST for treating UIAs, it remains unclear whether this conclusion is applicable in developing countries. [7] Only a few single-center studies in China have investigated MST and EVT for UIAs. [8] However, these studies are limited by small sample sizes, lack multicenter data, do not use propensity score–matched analyses, and generally lack long-term follow-up.

EVT has rapidly advanced, with significant improvements in coil characteristics, supportive devices, and interventional techniques. [9] Although previous studies have indicated no difference in mortality between MST and EVT, [10], [11], [12], [13], [14], [15], [16] the data are relatively outdated and primarily focused on developed countries, lacking long-term follow-up for these patients (Table S1). Furthermore, few studies have analyzed in-hospital complications and their impact on long-term outcomes. Severe in-hospital complications can adversely affect patient prognosis and contribute to the healthcare burden on society. [12], [13] Therefore, there is an urgent need for a more updated and comprehensive study to compare the outcomes of MST and EVT in the treatment of UIAs.

To dynamically compare the impact of two treatment modalities on patient outcomes, we conducted a multicenter cohort study on UIAs in China. The aim was to elucidate the incidence of in-hospital complications associated with MST and EVT for UIAs in recent years, as well as to identify adverse risk factors for prognosis.