Serum Endothelin-1 in Suspected Acute Pulmonary Embolism: A Prospective Study

Background: We evaluated the diagnostic discrimination of serum endothelin-1 (ET-1), copeptin, and chemerin in adults evaluated for acute pulmonary embolism (PE). Methods: This prospective, single-center diagnostic study included 65 adults with CTPA-confirmed PE and 64 CTPA-negative controls recruited from the same emergency-department source population of patients evaluated for suspected PE. Controls were consecutively enrolled among dyspneic patients in whom CTPA excluded PE; no individual matching was used. Biomarkers were compared with D-dimer and the Wells score. Results: ET-1 was higher in the PE group (median, 12.96 vs. 6.41 pg/mL; p < 0.001) and showed moderate discrimination (AUROC, 0.731; 95% CI, 0.644–0.818), but was inferior to D-dimer (AUROC, 0.905; 95% CI, 0.852–0.958). Adding ET-1 to D-dimer changed the AUROC from 0.905 to 0.923 (DeLong p = 0.128), and adding ET-1 to Wells plus D-dimer changed it from 0.966 to 0.971 (DeLong p = 0.224). An age-adjusted D-dimer threshold preserved sensitivity (96.9%) and increased specificity from 48.4% to 56.3% relative to 0.50 mg/L FEU. Conclusions: ET-1 was associated with acute PE in this selected sample but did not materially improve discrimination beyond established comparators. Because the near-ceiling Wells–D-dimer model and selected sampling frame limit inference, external validation in an unselected diagnostic cohort is required.