Abstract Body: Background: In mechanical thrombectomy (MT) for large vessel occlusions (LVO), approximately 10-20% of patients die within 90 days, with pneumonia and stroke due to cerebral infarction being the primary causes of death. This study compared the factors associated with pneumonia and stroke deaths using data from the K-NET registry, which records cases of MT in Kanagawa, Japan.

Methods: This prospective observational study included 3,187 patients registered in the K-NET registry from 2018 to 2021. Deaths occurring within 90 days due to pneumonia were classified as the pneumonia death group, while deaths due to cerebral infarction, any intracranial hemorrhage (ICH), or subarachnoid hemorrhage were classified as the stroke death group. Comparative analyses were conducted between these two groups.

Results: The median age of patients was 78 years. A total of 359 patients (11.3%) died within 90 days, including 83 (2.6%) in the pneumonia death group and 132 (4.1%) in the stroke death group. Compared to the stroke death group, the pneumonia death group was significantly older (83 vs. 81 years), had a higher proportion of males (67.5% vs. 47.0%), had more patients with a pre-stroke modified Rankin Scale (mRS) score of 3-5 (32.5% vs. 19.7%), had a higher ASPECTS score (7 vs. 5), and had a higher incidence of first-pass effect (FPE) (45.8% vs. 28.0%). However, there were significantly fewer cases of any ICH in the pneumonia death group (7.2% vs. 31.1%). The time from disease onset to death was significantly longer in the pneumonia death group (28 days vs. 3 days). Multivariate analysis revealed that stroke deaths were significantly associated with occlusion sites, low ASPECTS, subarachnoid hemorrhage, any ICH, and high baseline NIHSS scores. In contrast, pneumonia deaths were significantly associated with older age, male sex, and high baseline NIHSS scores.

Conclusion: Compared with the stroke death group, the pneumonia death group in patients undergoing MT for LVO had a significantly higher incidence of older age, male sex, and pre-stroke functional dependence, along with fewer hemorrhagic cases and a higher incidence of FPE. Older age and male sex were significant factors specifically associated with pneumonia death.