BACKGROUND: Acute decompensated pulmonary arterial hypertension (ADPH) is characterized by right heart failure due to elevated afterload and inadequate cardiac output, and it presents a significant mortality risk. Understanding mortality proportions and the impact of life-sustaining therapies is crucial for informing clinical practice and patient prognosis. OBJECTIVES: To assess mortality proportions in ADPH across different clinical settings and to assess how they vary depending on the type of life-sustaining interventions used. METHODS: A systematic review and meta-analysis of proportions were conducted, examining mortality in ADPH focusing on three primary outcomes: ICU mortality, hospital mortality, and hospital mortality in patients requiring extracorporeal membrane oxygenation (ECMO). Common and random-effects meta-analyses were performed to calculate pooled mortality proportions with 95% confidence intervals (CI95%). Temporal trends were analyzed using meta-regression. RESULTS: Twenty-five observational studies conducted between 2003 and 2023, involving 1,249 ADPH patients, were included. The random-effect analysis revealed an ICU pooled mortality proportion of 29% (CI95% 25-34, I CONCLUSIONS: Variation in ADPH mortality across hospital settings and life-sustaining therapies underscores the complexity of managing ADPH. These findings inform clinical practice and support prognostic discussions with patients and families.