Prevalence and significance of clinically unsuspected pulmonary embolism: detection using coronary computed tomography angiography.

Abstract

Clinically unsuspected pulmonary embolism can be detected using coronary computed tomography (CT), but the clinical significance of unsuspected pulmonary embolism remains unclear. Pulmonary embolism was assessed using consecutive coronary CT from March 2003 to June 2007 to assess 1077 patients. Coronary CT was performed using a 16-row multidetector CT (MDCT) scanner with ECG-gating. A radiologist and a cardiologist retrospectively assessed the images of pulmonary arteries to arrive at a consensus diagnosis. Unsuspected pulmonary embolism was detected in 32/1,077 (3.0%) patients. No significant difference was observed with regard to death and acute pulmonary embolism between patients with and without unsuspected pulmonary embolism at five years (6.7% vs. 4.1%, p = 0.61). Prior cardiac surgery within three months of diagnosis of pulmonary embolism was an independent risk factor for unsuspected pulmonary embolism, which was detected in 10/89 (11%) of such patients. The absence of anticoagulant therapy was a risk factor (p = 0.015) for unsuspected pulmonary embolism post-cardiac surgery. Although only one out of 10 patients received anticoagulant therapy, none of the 10 experienced critical events. Five of the 10 patients underwent repeated coronary CT, and the embolus disappeared regardless of its size and location in four of the five patients who did not receive anticoagulant therapy. The prevalence of unsuspected pulmonary embolism detected using coronary CT was 3.0%. Prior cardiac surgery within three months of diagnosing pulmonary embolism was an independent risk factor for unsuspected pulmonary embolism. The long-term clinical outcomes of patients with unsuspected pulmonary embolism were favorable.