Prediction and Risk Stratification for 30-Day Mortality in Stable Acute Pulmonary Embolism: Recalibration of the Multimarker Calculator and Evaluation of the AHA/ACC Classification

BACKGROUND: Risk stratification in haemodynamically stable acute pulmonary embolism (PE) remains challenging. The multimarker calculator (MMC) provides individualized 30-day mortality estimates, whereas the 2026 AHA/ACC Acute PE Clinical Categories (AHA/ACC classification) provide a phenotype-based framework incorporating clinical severity, right ventricular dysfunction, cardiac biomarker elevation, and respiratory compromise. We evaluated these approaches and recalibrated the original MMC in a Chinese multicentre cohort. METHODS: We included adults with haemodynamically stable acute PE from the prospective, multicentre China pUlmonary thromboembolism REgistry Study (2012-2021). The primary outcome was 30-day all-cause mortality. The MMC, 2019 European Society of Cardiology (ESC) model, and AHA/ACC classification were assessed using discrimination, decision-curve analysis, risk classification, and subgroup analyses. Logistic recalibration updated the original MMC linear predictor. The AHA/ACC classification was evaluated using 7-, 4-, and simplified phenotype-based 3-category schemes. RESULTS: Among 11,568 patients, 331 died within 30 days (2.9%). The MMC and 7-category AHA/ACC classification showed better discrimination than the ESC model (AUC, 0.704 and 0.680 vs. 0.606). The original MMC overestimated intermediate-high-risk mortality (mean predicted risk, 16.2%; observed risk, 9.4%). Recalibration improved calibration and identified a smaller intermediate-high-risk subgroup comprising 2.2% of patients, with 13.2% observed mortality. In the 3-category AHA/ACC classification, mortality increased stepwise across category B, partial phenotype involvement, and dual cardiopulmonary phenotype involvement (0.7%, 2.7%, and 6.7%). CONCLUSIONS: The recalibrated MMC may be useful for individualized 30-day mortality risk estimation, whereas the AHA/ACC classification may offer a simple framework for phenotype-based risk grouping.