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 Østfold 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.