FROM CHEST
About 16% of patients with unexplained chronic obstructive pulmonary disease (COPD) acute exacerbations (AE-COPD) had an accompanying pulmonary embolism (PE), usually in regions that could be targeted with anticoagulants, according to a new systematic review and meta-analysis,
About 70% of the time an AE is a response to infection, but about 30% of the time, an AE has no clear cause, the authors said in a report on their research ( CHEST. 2017 March;151[3]:544-54 ). There is a known biological link between inflammation and coagulation, which suggests that patients experiencing AE-COPD may be at increased risk of PE.
The researchers reviewed and analyzed seven studies, comprising 880 patients. Among the authors’ reasons for conducting this research was to update the pooled prevalence of PE in AE-COPD from a previous systematic review published in CHEST in 2009.
The meta-analysis revealed that 16.1% of patients with AE-COPD were also diagnosed with PE (95% confidence interval 8.3%-25.8%). There was a wide range of variation between individual studies (prevalence 3.3%-29.1%). In six studies that reported on deep vein thrombosis, the pooled prevalence of DVT was 10.5% (95% CI 4.3%-19.0%).
Five of the studies identified the PE location. An analysis of those studies showed that 35.0% were in the main pulmonary artery, and 31.7% were in the lobar and inter-lobar arteries. Such findings “[suggest] that the majority of these embolisms have important clinical consequences,” the authors wrote.
The researchers also looked at clinical markers that accompanied AE-COPD and found a potential signal with respect to pleuritic chest pain. One study found a strong association between pleuritic chest pain and AE-COPD patients with PE (81.0% versus 40.0% in those without PE). A second study showed a similar association (24.0% in PE versus 11.5% in non-PE patients), and a third study found no significant difference.
The presence of PE was also linked to hypotension, syncope, and acute right failure on ultrasonography, suggesting that PE may be associated with heart failure.
Patients with PE were less likely to have symptoms consistent with a respiratory tract infection. They also tended to have higher mortality rates and longer hospitalization rates compared with those without PE.
The meta-analysis had some limitations, including the heterogeneity of findings in the included studies, as well as the potential for publication bias, since reports showing unusually low or high rates may be more likely to be published, the researchers noted. There was also a high proportion of male subjects in the included studies.
Overall, the researchers concluded that PE is more likely in patients with pleuritic chest pain and signs of heart failure, and less likely in patients with signs of a respiratory infection. That information “might add to the clinical decision-making in patients with an AE-COPD, because it would be undesirable to perform [computed tomography pulmonary angiography] in every patient with an AE-COPD,” the researchers wrote.
