Prevalence and clinical characteristics of pulmonary thromboembolism in hospitalized patients with hypoxemia

Abstract

Objective To observe the prevalence and clinical characteristics of pulmonary thromboembolism (PTE) in patients with hypoxemia at department of respiratory medicine. Methods The clinical data of inpatients with hypoxemia at department of respiratory medicine in Beijing Tongren Hospital from May 2009 to May 2016 were retrospectively analyzed to investigate the prevalence and clinical characteristics of PTE, which included general information, PaO2, serum level of D-dimer, deep venous ultrasonography, computer tomography pulmonary angiography (CTPA) and ventilation-perfusion scanning. Results The incidence rate of PTE in patients with hypoxemia was 41.48% (73/176).141 patients were found to be combined with pulmonary underlying diseases.There was no difference in clinical manifestations such as hemoptysis, chest pain and dyspnea between PTE group and non-PTE group.The incidence rate of PTE in patients with lung cancer, asthma, bronchiectasis and chronic obstructive pulmonary disease was 38.89% (7/18), 33.33% (7/21), 33.33% (4/12) and 30.30% (10/33), respectively.D-dimer≥1 000 μg/L (OR=3.070, 95%CI: 1.436-6.563), deep vein thrombosis (OR=3.915, 95%CI: 1.481-10.349) and body mass index≥24.00 kg/m2 (OR=2.760, 95%CI: 1.214-6.278) were found to be risk factors of PTE in patients with hypoxemia.Patients with PTE were further divided into normal group (n=28) and abnormal group (n=45) according to serum level of D-dimer.Logistic regression analysis showed that subsegmental PTE (OR=5.557, 95%CI: 1.508-20.482) and age<70 years old (OR=4.126, 95%CI: 1.414-12.037) were associated with normal serum level of D-dimer.The patients were also divided into PTE without pulmonary underlying diseases (n=35) and PTE with pulmonary underlying diseases (n=38). Compared with the former, the latter demonstrated increased proportion of males (57.89% vs 31.43%), higher prevalence of symptoms including cough/expectoration (55.26% vs 14.29%) and fever (18.42% vs 2.86%), higher prevalence of D-dimer≥500 μg/L (81.58% vs 54.29%) and deep vein thrombosis (44.74% vs 17.14%) (all P<0.05). The patients with PTE combined with pulmonary underlying diseases also showed the decreased proportion of body mass index≥24 kg/m2 (65.71% vs 91.30%) and immobilization time≥three days (8.57% vs 34.29%), the lower incidence of syncope (0.00% vs 22.86%), and lower level of PaO2 [(61.88±10.55) mmHg vs (67.06±8.04) mmHg] when compared with those without pulmonary underlying diseases (all P<0.05). Conclusions There is a high prevalence of PTE in patients with hypoxemia hospitalized at department of respiratory medicine.D-dimer≥1 000 μg/L, deep vein thrombosis and body mass index≥24.00 kg/m2 are the risk factors of PTE in patients with hypoxemia.The serum level of D-dimer is more likely to be normal in patients with subsegmental PTE or younger age.Pulmonary underlying diseases may increase the risk of venous thromboembolism.Since PTE would further worsen the respiratory function of patients with pulmonary underlying diseases, prompt diagnosis and treatment of PTE may be more necessary for these patients. Key words: Hypoxemia; Pulmonary thromboembolism; Prevalence; Clinical characteristics; Risk factor