Prevalence and Prognostic Relevance of Central Pulmonary Embolism: Systematic Review and Meta-Analysis

In patients with acute symptomatic pulmonary embolism (PE), embolic burden has an uncertain prognostic significance.

We performed a meta-analysis of studies including patients with PE to assess the prevalence and prognostic relevance of central PE (i.e., saddle or main pulmonary emboli) for short-term death and other adverse outcome events. A random-effects model was used to pool study results, and I² testing was used to test for heterogeneity.

Data from 28 studies (205,877 patients) were included in the analysis. Of the 26 studies with 205,410 participants that enrolled consecutive patients with PE, 7748 (3.8%) had central PE. Though there was no statistically significant difference between central and noncentral PE for odds of short-term all-cause mortality (odds ratio [OR] 1.19; 95% confidence interval [CI], 0.91-1.55), central PE had a significant association with short-term PE-related deterioration or death (OR, 2.47; 95% CI, 1.44-4.25). Results from 9 studies with 4325 PE patients that had available data showed that central PE had a significant association with the odds of short-term PE-related mortality (OR, 1.77; 95% CI, 1.22-2.55). Results were consistent for prospective (OR, 1.67; 95% CI, 1.21-2.32), and studies that only enrolled stable patients (OR, 1.42; 95% CI, 1.06-1.92).

Central PE was an uncommon finding in unselected patients diagnosed with PE. While central thrombus did not have an association with increased risk of all-cause mortality, it was significantly associated with an increased risk of PE-related deterioration and death short after diagnosis.