Prevalence and Predictor of Pulmonary Embolism in a Cohort of Chinese Patients with Acute Proximal Deep Vein Thrombosis

Background: The aim of this study is to investigate the incidence of pulmonary embolism (PE) in a cohort of Chinese patients with acute (<14 days) proximal (above-knee) deep vein thrombosis (DVT) in the lower limbs, and to evaluate whether the location of thrombosis is associated with the existence of PE. Methods: A retrospective review of patients diagnosed with acute proximal DVT from January 2014 to June 2018 at a single center was performed. Helical computed tomography angiography was performed to screen PE within 48 hr after admission. Multiple factors associated with PE were compared between the PE group and the non-PE group. Results: A total of 100 patients with acute proximal DVT were screened for PE. The mean age was 56.9 +/- 18.1 (range 21-88) years, and 55% were male. The most common risk factors of DVT were immobilization (38%), malignancy (27%), and trauma or surgery (21%). Majority of the patients' thrombosis was located at the left leg (66%) and 8 patients had bilateral lower limb DVT. Femoral vein was involved in 52 patients (52%), while iliofemoral thrombosis was identified in 48 patients (48%). PE was identified in 58 patients (58%), including 3 massive and 55 nonmassive PE. There was no statistical difference between the PE group and the non-PE group in terms of age, sex, and risk factors. The D-dimer level was associated with the existence of PE (P = 0.038). Patients with iliofemoral thrombosis had a similar incidence of PE compared with those with femoral thrombosis alone (P = 1.000). Conclusions: PE occurred in more than half of patients with acute proximal DVT, despite the fact that most of them were asymptomatic. In this study, existence of PE did not correlate with pelvic thrombosis. Increasing D-dimer level was statistically associated with the presence of PE.