title: The association between the proximal extension of the clot and the severity of pulmonary embolism (PE): a proposal for a new radiological score for PE.
abstract: BACKGROUND
  The aim of the study was to investigate the association between the proximal level of the clot and the severity of pulmonary embolism (PE).
  
  
  METHODS
  The cohort consisted of 99 consecutive patients with PE diagnosed by multi-detector computed tomography. A new score was constructed by calculating the mean value of the largest affected vessel [sub-segmental = 1, segmental = 2, lobar = 3, main pulmonary artery (MPA) = 4] in each lung.
  
  
  RESULTS
  A significant association was found between the most proximal level of PE and pulmonary artery obstruction index (PAOI) (P < 0.0001), right ventricular (RV)/left ventricular (LV) ratio (P < 0.0001), and PaO(2) (P = 0.004). No significant association was found between systolic blood pressure and the level of PE. Troponin-T was elevated in none of the sub-segmental, 5% of segmental, 20% of lobar, and in 56% of PEs in the MPA (P = 0.001). Significant association was found between the proposed score and PAOI (P < 0.0001), RV/LV ratio (P < 0.0001), PaO(2) (P < 0.008). Troponin-T was elevated in 10% of level 1, 0% of level 2, 43% level of 3, 66% of level 4 PE (P < 0.0001). Cut-off level score 4 yielded a sensitivity of 84% and a specificity of 74% for the detection of elevated troponin-T.
  
  
  CONCLUSIONS
  In conclusion, the study indicates that both the most proximal level of PE and the proposed score are related to the severity of PE as determined by blood oxygenation, biochemical and radiological parameters and could therefore be of value for rapid risk stratification of PE. However, the prognostic value of these classifications and their clinical significance needs to be evaluated in properly designed studies.
authors.affiliation: Department of Medicine, Østfold Hospital Trust, Fredrikstad, Norway. waleed.ghanima@so-hf.no
authors.forename: W
authors.initials: W
authors.lastname: Ghanima
authors.forename: M
authors.initials: M
authors.lastname: Abdelnoor
authors.forename: L O
authors.initials: LO
authors.lastname: Holmen
authors.forename: B E
authors.initials: BE
authors.lastname: Nielssen
authors.forename: P M
authors.initials: PM
authors.lastname: Sandset
mesh_terms: D002245:Carbon Dioxide / Q000097:blood; D016001:Confidence Intervals; D005500:Follow-Up Studies; D006801:Humans; D008168:Lung / Q000000981:diagnostic imaging / Q000503:physiopathology; D010100:Oxygen / Q000097:blood; D011446:Prospective Studies; D011651:Pulmonary Artery / Q000000981:diagnostic imaging*; D011655:Pulmonary Embolism / Q000000981:diagnostic imaging* / Q000503:physiopathology; D018570:Risk Assessment; D018709:Statistics, Nonparametric; D014057:Tomography, X-Ray Computed / Q000379:methods*; D020107:Troponin T / Q000097:blood; D018497:Ventricular Dysfunction, Right / Q000503:physiopathology
chemical_list: D020107:Troponin T; D002245:Carbon Dioxide; D010100:Oxygen