Multidetector CT scan for acute pulmonary embolism: embolic burden and clinical outcome.

Background: In patients with acute pulmonary embolism (PE), the correlation between the embolic burden assessed by multidetector CT (MDCT) scan and clinical outcomes remains unclear. Patients with symptomatic acute PE diagnosed based on MDCT angiography were included in a multicenter study aimed at assessing the prognostic role of the embolic burden evaluated with MDCT scan.

Methods: Embolic burden was assessed as (1) localization of the emboli as central (saddle or at least one main pulmonary artery), lobar, or distal (segmental or subsegmental arteries) and (2) the obstruction index by the scoring system of Qanadli. The primary outcome was 30-day all-cause death or clinical deterioration. Predictors of all-cause death or clinical deterioration were identified by Cox regression statistics.

Results: Overall, 579 patients were included in the study; 60 (10.4%) died or had clinical deterioration at 30 days. Central localization of emboli was not associated with all-cause death or clinical deterioration (hazard ratio [HR], 2.42; 95% CI, 0.77-7.59; P 5 .13). However, in 516 hemodynamically stable patients, central localization of emboli (HR, 8.3; 95% CI, 1.0-67; P 5 .047) was an independent predictor of all-cause death or clinical deterioration, whereas distal emboli were inversely associated with these outcome events (HR, 0.12; 95% CI, 0.015-0.97; P 5 .047). No correlation was found between obstruction index (evaluated in 448 patients) and all-cause death or clinical deterioration in the overall study population and in the hemodynamically stable patients.

Conclusions: In hemodynamically stable patients with acute PE, central emboli are associated with an increased risk for all-cause death or clinical deterioration. This risk is low in patients with segmental or subsegmental PE.