Has a fast treatment transition from surgical to endovascular operations improved the survival of aneurysmal subarachnoid hemorrhage?

BackgroundSeveral studies have attributed decreasing case fatality rates (CFRs) of aneurysmal subarachnoid hemorrhage (aSAH) to the gradually increasing use of endovascular treatment without considering improvements in other outcome-affecting factors. To assess the independent effect of a treatment modality on CFRs, we investigated CFR changes in a high-volume center rapidly transitioning from surgical to endovascular operations as the first-line treatment for all aSAH patients except those with middle cerebral artery (MCA) aneurysms.MethodsWe identified all surgically/endovascularly treated aSAH patients in Helsinki University Hospital (HUH) during 2012-2017. As the treatment shift occurred in 2015, we defined two treatment eras: surgical (2012-2014) and endovascular (2015-2017). We compared time-dependent changes in 1-year CFRs between non-MCA and MCA patients using a Poisson regression model. To analyze consistency in operation rates, we also identified sudden-death and conservatively treated aSAHs in the HUH catchment area via two externally validated registers.ResultsOf all 665 hospitalized aSAH cases in the HUH catchment area, 557 (84%) received operative treatment; 367 (66%) underwent surgical and 190 (34%) endovascular operations. Between the treatment eras, endovascular treatment for non-MCA cases increased from 21 to 79%, whereas 99% of the MCA cases were treated surgically during the whole study-period. Among the operatively treated patients, the 1-year CFRs decreased similarly in patients with non-MCA (42%; from 14 to 8%; adjusted risk ratio (aRR) = 0.66 (95% CI 0.37-1.19)) and MCA aneurysms (42%; from 15 to 9%; aRR = 0.66 (0.16-1.60)). The proportion of operatively treated patients, their clinical condition on admission, and amount of bleeding on the first CT-scan remained unchanged over time.ConclusionsWe found similar CFR decreases in aSAH groups with and without undergoing a fast transition from surgery to endovascular operations, providing real-world evidence on the small independent effect of endovascular treatment on the decreasing CFRs in high-volume centers.