Hemodynamic Correlates and Prognostic Value of the RISA‐PE Staging System in Acute Pulmonary Embolism

ABSTRACT Background Emerging therapies for acute PE highlight the need for a more granular risk classification. Aims The objective of this study was to validate a novel risk model—the RIsk claSsification Adapted to SCAI shock stages in acute PE (RISA‐PE), which applies the SCAI shock staging framework to right ventricular failure due to acute PE. Methods We retrospectively analyzed consecutive patients with acute intermediate‐ or high‐risk PE treated with LBMT at a tertiary academic center (October 2020 to May 2025). Patients were stratified by RISA‐PE stage (A–E) as previously described. Clinical data, including invasive pulmonary artery catheter hemodynamics and clinical outcomes were compared across stages. The primary endpoint was a composite of 30‐day PE‐related death, resuscitated cardiac arrest, or hemodynamic instability. Results Among the 181 patients (median age 59 years, 45% women) included in the study, advancing RISA‐PE stage was associated with progressive tachycardia, higher shock index, worse biomarker derangements (lactate and high‐sensitivity troponin) and increasing severity of RV dysfunction on imaging (lower TAPSE, higher RV/LV diameter ratio). Pre‐procedural pulmonary artery catheterization confirmed stage‐dependent declines in cardiac index, with the prevalence of low CI (≤2.2 L/min/m 2 ) rising from 25% in Stage A to 75% in Stage C ( p < 0.001). Clinical outcomes paralleled stage severity. Median hospital length‐of‐stay increased from 5 to 6 days (Stages A/B) to 19.9 days (Stage E, p < 0.001), and ICU stay from 2.5 to 3 days to 9.5 days, respectively ( p < 0.001). The primary composite outcome occurred in 0% of Stage A, 5% of Stage B, 12% of Stage C, 15% of Stage D, and 50% of Stage E patients ( p < 0.001). Conclusions The RISA‐PE staging system demonstrates strong correlation with RV dysfunction severity, invasive hemodynamics, and adverse outcomes in patients with acute PE treated with LBMT. RISA‐PE provides a graded framework for identifying patients at highest risk of deterioration and may guide escalation of therapy.