Risk stratification using the SCAI SHOCK classification in patients with acute pulmonary embolism

Pulmonary embolism (PE) is a leading cause of cardiovascular mortality, with high-risk cases exhibiting significant heterogeneity in treatment and outcomes. Existing classification systems fail to differentiate PE patients requiring vasopressor support from those experiencing cardiac arrest. This study applies the Society for Cardiovascular Angiography and Interventions (SCAI) shock classification to stratify high-risk PE patients and assess mortality differences.

Utilizing the Nationwide Inpatient Sample (NIS) database (2017-2020), we identified adult PE hospitalizations classified by SCAI shock stages: Stage A/B (hemodynamically stable or hypotensive without vasopressors), Stage C/D (requiring vasopressors and/or mechanical circulatory support [MCS]), and Stage E (out-of-hospital cardiac arrest [OHCA]). Outcomes included mortality, treatment modality, and complications. Multivariate logistic regression models were used to adjust for confounders.

Among 853,160 PE admissions, 5770 (0.68 %) were Stage C/D and 15,825 (1.86 %) were Stage E. Mortality increased with shock severity: 2.13 % (Stage A/B), 39.90 % (Stage C/D), and 65.95 % (Stage E) (p < 0.05). Mortality was lowest with surgical thrombectomy (17.24 % Stage C/D; 48.28 % Stage E) and highest with systemic thrombolysis (42.57 % Stage C/D; 70.62 % Stage E) (p < 0.05). Adjusted odds of mortality were 13.9 (95 % CI: 11.9-16.2, p < 0.05) for Stage C/D and 54.8 (95 % CI: 49.3-61.0, p < 0.05) for Stage E.

Applying the SCAI shock classification to high-risk PE stratifies mortality risk more precisely. Patients with cardiac arrest exhibit significantly higher mortality than those requiring vasopressors alone. Future studies should explore refined risk stratification integrating hemodynamic parameters and biomarkers to optimize treatment selection.