OBJECTIVETo identify the risk factors associated with the severity of pulmonary embolism among patients with deep venous thrombosis of lower extremities.

METHODSThis prospective study enrolled 208 patients with acute deep venous thrombosis to screen for pulmonary embolism between July 2010 and July 2012 in Beijing Shijitan Hospital. There were 101 male and 107 female patients, with a mean age of (59 ± 16) years. Gender, age, extension, side of lower extremities of deep venous thrombosis was analyzed by χ² test. Ordinal Logistic regression was used to determine risk factors associated with severity of pulmonary embolism.

RESULTSThere were 83 patients with iliofemoral deep venous thrombosis, 102 patients with femoropopliteal and 23 patients with calf deep venous thrombosis. Pulmonary embolism was detected in 70 patients with the incidence of 33.7%. Pulmonary embolism was significantly correlated with extension (χ² = 17.286, P = 0.004) and sides (χ² = 15.602, P = 0.008) of deep venous thrombosis, not with age (χ² = 7.099, P = 0.260), gender (χ² = 7.014, P = 0.067), thrombotic risk factors (χ² = 3.335, P = 0.345) in univariate analysis. Results of multivariate ordinal logistic regression showed that iliofemoral vein thrombosis (OR = 6.172, 95% CI: 1.590 to 23.975, P = 0.009) and bilateral venous thrombosis (OR = 7.140, 95% CI: 2.406 to 24.730, P = 0.001) are associated with more serious pulmonary embolism.

CONCLUSIONSIncidence of pulmonary embolism is still high in patients with deep venous thrombosis. Extensive iliofemoral and bilateral vein thrombosis may increase risk of severity of pulmonary embolism. Clinicians should pay more attention to these high-risk patients.