Objective <p>Massive haemoptysis due to central pulmonary artery (CPA) rupture in patients with advanced lung cancer is a fatal complication with limited early diagnostic tools. This study aimed to identify risk factors associated with pulmonary artery rupture and to propose a grading model to facilitate early diagnosis and timely endovascular intervention.</p> Materials and methods <p>This retrospective study included patients with advanced lung cancer who experienced in-hospital sudden haemoptysis-related death and received endovascular treatment for CPA abnormalities. Propensity score matching (PSM; 1:2) balanced covariates between haemoptysis-related and other in-hospital deaths. Following PSM, multivariable logistic regression was performed to identify independent risk factors. Patients were categorised into two cohorts: Group A (2012–2018) and Group B (2019–2024), the latter reflecting the implementation of early detection and endovascular management. Overall survival (OS) was compared using Kaplan–Meier analysis and log-rank testing.</p> Results <p>Among 886 in-hospital deaths, sudden haemoptysis accounted for 4.63% (41/886), with 90.24% (37/41) exhibiting CPA abnormalities. CPA abnormalities, tumour necrosis, cavitation, and progressive bloody or malodorous sputum were identified as significant risk factors (<i>p</i> &lt; 0.05). The haemoptysis group had significantly shorter OS than controls (<i>p</i> &lt; 0.001). A three-tier grading system for pulmonary arterial blowout syndrome (PABS) was developed, with acute PABS being the most prevalent (67.26%). Patients in Group B demonstrated significantly improved OS compared with Group A (<i>p</i> &lt; 0.001).</p> Conclusion <p>The PABS grading model enables risk stratification of life-threatening haemoptysis secondary to CPA rupture. Early identification and endovascular intervention may significantly improve clinical outcomes in advanced lung cancer.</p> Key Points <p><Emphasis Type="BoldItalic">Question</Emphasis><i> What are the clinical characteristics and risk stratification criteria for life-threatening haemoptysis arising from CPA rupture in advanced lung cancer?</i></p> <p><Emphasis Type="BoldItalic">Findings</Emphasis><i> In-hospital sudden haemoptysis mortality was 4.63% and strongly associated with CPA abnormalities. A PABS grading model characterises this fatal condition</i>.</p> <p><Emphasis Type="BoldItalic">Clinical relevance</Emphasis><i> The PABS grading system enables early recognition of high-risk CPA rupture in advanced lung cancer. Prompt identification and endovascular intervention may substantially improve patient outcomes</i>.</p> Graphical Abstract <p></p>