Abstract WP327: Development of a Predictive Index for Pneumonia-related Death after Mechanical Thrombectomy: A sub analysis of the K-NET registry

Background and Purpose: Pneumonia is a leading cause of death after mechanical thrombectomy (MT) for acute ischemic stroke, alongside stroke-related causes. Early risk assessment of pneumonia-related death could improve management and outcomes. However, risk factors specific to pneumonia-related death remain underexplored, and studies properly accounting for competing risks are limited. We aimed to identify independent predictors and develop a simple predictive index. Methods: We analyzed 3,187 consecutive patients who underwent MT between April 2018 and December 2021 in the K-NET registry, a prospective multicenter registry in comprehensive stroke centers across Kanagawa, Japan. Pneumonia-related death was defined as death from pneumonia within 90 days after stroke onset. It was considered the event of interest, while other causes of death were treated as competing events. Independent predictors were identified using multivariable Fine–Gray competing risk analysis. Based on the identified predictors, we developed a predictive index and evaluated its discriminative ability using bootstrap internal validation. Results: Median age was 78 years, and 45.1% were women. Pneumonia-related death occurred in 83 patients (2.6%), with a median age of 83 years. Independent predictors were male sex (HR 2.85), baseline NIHSS score (HR 1.07), age (HR 1.07), and puncture-to-recanalization time (P2R, HR 1.01). Based on these predictors, we developed a predictive index. The index was calculated as: sex (male: 15, female: 0) + NIHSS + age + 0.1 × P2R (min). The model showed good discrimination, with a C-index of 0.80 and a 90-day time-dependent AUC of 0.81. Conclusions: We developed a simple and accurate predictive index for pneumonia-related death within 90 days after MT. By enabling early identification of high-risk patients and guiding preventive strategies, this index may contribute to improved outcomes and serve as a practical tool in daily stroke care.