Table 1_Predicting prolonged mechanical ventilation after endovascular treatment for acute vertebrobasilar artery occlusion: AIRFLOW score.docx

Background and purposeVertebrobasilar artery occlusion (VBAO) is a rare yet severe type of ischemic stroke, often leading to respiratory failure that necessitates invasive mechanical ventilation and is associated with high mortality rates. While endovascular treatment (EVT) has improved outcomes for VBAO, many patients still require prolonged mechanical ventilation (PMV) post-EVT, further increasing mortality and posing challenging decisions for families. Currently, no predictive model exists to identify VBAO patients at risk of needing PMV after EVT. This study aims to develop and validate a predictive score for PMV in this patient population following EVT.
Materials and methodsThe derivation cohort prospectively recruited VBAO patients undergoing EVT from four comprehensive stroke centers (CSCs) in China. PMV was defined as continuous mechanical ventilation lasting for ≥7 days. Multivariable logistic regression was conducted to develop a scoring system. The performance of the model was evaluated for discrimination, calibration, and clinical utility. Four hundred and fourteen patients from acute Posterior circulation ischemic Stroke registry were enrolled to externally validate the model. Sensitivity analysis redefined PMV as using mechanical ventilation last for ≥ 14 days to further validate the model.
ResultsThe derivation cohort consisted of 419 patients from four CSCs, among whom 113 (27.0%) required PMV. The presence of malignant cerebellar edema, posterior circulation collateral status, symptomatic intracranial hemorrhage post-EVT, atrial fibrillation, intravenous thrombolsis, vasopressor therapy and Glasgow coma score classification are found to be independent predictors of PMV in logistic regression, then ‘AIRFLOW’ scoring system was created. The AIRFLOW score demonstrated good discrimination in derivation cohort (C-index, 0.85, 95% CI 0.81 to 0.89), as well as the validation cohort (C-index, 0.82, 95% CI 0.77 to 0.86). Calibration plots and decision curve analysis for AIRFLOW score indicated that the model accurately predicted the risk of PMV and had satisfactory net benefit across various thresholds. Similar results were found in sensitivity analysis.
ConclusionThe AIRFLOW score may help predict PMV in VBAO patients after EVT.

背景与目的
椎基底动脉闭塞（Vertebrobasilar artery occlusion, VBAO）是一种罕见却危重的缺血性卒中亚型，常引发呼吸衰竭，需实施有创机械通气，且伴随较高的死亡率。尽管血管内治疗（Endovascular treatment, EVT）改善了VBAO患者的预后，但仍有诸多患者在EVT术后需要长时间机械通气（Prolonged mechanical ventilation, PMV），这进一步提升了患者的死亡风险，同时也为患者家属带来了艰难的临床决策困境。目前尚无预测模型可用于识别EVT术后需接受PMV的VBAO高危患者。本研究旨在开发并验证一款针对该人群EVT术后PMV风险的预测评分系统。

材料与方法
本研究的推导队列前瞻性招募了来自中国4家综合卒中中心（Comprehensive stroke centers, CSCs）的接受EVT治疗的VBAO患者。本研究将PMV定义为持续时间≥7天的机械通气。采用多变量logistic回归分析构建评分系统，并从区分度、校准度及临床实用性三个维度评估模型性能。本研究纳入了来自急性后循环缺血性卒中注册研究的414例患者，用于对该模型进行外部验证。此外，本研究开展敏感性分析，将PMV重新定义为机械通气持续时间≥14天，以进一步验证模型的稳定性。

结果
本研究的推导队列共纳入来自4家综合卒中中心的419例患者，其中113例（27.0%）患者需要接受PMV。经logistic回归分析显示，恶性小脑水肿、后循环侧支循环状态、EVT术后症状性颅内出血、心房颤动、静脉溶栓、血管活性药物治疗以及格拉斯哥昏迷评分分级均为PMV的独立预测因素，据此构建了AIRFLOW评分系统。AIRFLOW评分在推导队列中展现出良好的区分度（C指数为0.85，95%置信区间0.81~0.89），在外部验证队列中同样表现优异（C指数为0.82，95%置信区间0.77~0.86）。校准曲线与决策曲线分析结果表明，该评分系统可准确预测PMV风险，且在不同风险阈值下均具有令人满意的净获益。敏感性分析也得到了相似的结果。

结论
AIRFLOW评分可用于预测VBAO患者EVT术后发生PMV的风险。