The mean bilateral proximal extension of the clot is associated with pulmonary embolism severity parameters and management-associated outcomes.

BACKGROUND The value of the proximal extension of the clot in risk stratification of pulmonary embolism (PE) has not been established. The mean bilateral proximal extension of the clot (MBPEC) is a computed tomography (CT) radiological score, where initial evaluation showed promising results considering its ability in predicting the severity of PE. PURPOSE To explore the possible associations between MBPEC and PE-severity parameters, short- and long-term outcomes of PE, and inter-observer agreement. MATERIAL AND METHODS Patients diagnosed with PE at Ostfold Hospital, Norway during 2003-2011 were identified. MBPEC was calculated by calculating the mean of a score in the range of 1-4 assigned for the most proximal extension of the clot in each lung: sub-segmental; segmental; lobar; and main pulmonary arteries. Medical records were reviewed to capture clinical, biochemical, and management-associated data (thrombolysis, admission to ICU). RESULTS The mean age of 245 included patients was 55 ± 16 years; 42% were women. Patients with higher MBPEC scores had a significantly higher pulse rate and lower oxygen saturation. MBPEC score <4 predicted a negative troponin value with a negative predictive value of 90% (95% confidence interval [CI] 81-95). Patients with MBPEC 4 were 5.3 times more likely to have elevated troponin (odds ratio [OR] 5.3, 95% CI 2.0-14.3). MBPEC score of 4 was independently associated with admission to ICU (OR 3.8, 95% CI 1.8-7.9). The inter-observer agreement was excellent; weighted kappa 0.82. CONCLUSION MBPEC is associated with PE-severity parameters and can predict short-term adverse outcomes.