Contemporary Endovascular Techniques for Cerebral Aneurysms: Germany-wide In-hospital Outcomes vs. Coiling (2013-2022)

Background: Clinical and administrative studies suggest better functional outcomes after endovascular treatment (EVT) of intracranial aneurysms (IAs) compared to neurosurgical clipping (NSC). However, it remains unclear whether this applies to modern EVT techniques, such as balloon-assisted coiling (BAC), stent-assisted coiling (SAC), flow diversion (FD), or intrasaccular flow disruption (IFD). This study compares nationwide in-hospital outcomes of modern EVT methods and NSC with standard coiling (SC). Methods: Administrative data from all German hospitals (2013-2022) were analyzed using billing codes for SC, BAC, SAC, FD, IFD, and NSC in ruptured and unruptured IAs. Primary outcomes included functional independence (discharge type), poor outcomes (US Nationwide Inpatient Sample-Subarachnoid Hemorrhage Outcome Measure [NIS-SOM]), and in-hospital mortality. Propensity score weighting was used for comparisons. Results: A total of 77,684 procedures were analyzed (46.8% ruptured, 53.2% unruptured). In ruptured IAs, SAC, FD, and NSC were associated with lower functional independence (p=0.001, p=0.007, p<0.001) and higher mortality (p<0.001, p=0.001, p=0.032). Poor outcomes were more frequent after SAC (p=0.001) and NSC (p<0.001). In unruptured IAs, functional independence improved with BAC (p=0.036), SAC (p=0.045), and IFD (p<0.001), but decreased with NSC (p=0.017). Poor outcomes were less frequent with IFD (p<0.001), and mortality was lower with NSC (p=0.020) and IFD (p=0.003). Conclusions: Nationwide data from Germany reveal significant differences between EVT techniques and NSC for IA treatment. In ruptured IAs, SAC, FD, and NSC were associated with worse outcomes compared to SC. In unruptured IAs, BAC, SAC, and IFD improved functional outcomes, while NSC was linked to decreased functional outcomes. Notably, IFD consistently demonstrated superior functional outcomes despite limited utilization. Given the limitations of billing data, these findings suggest a potential shift favoring IFD as a safer treatment option in unruptured IAs.