Differential diagnosis of acute pulmonary embolism using contrast echocardiography

Acute pulmonary embolism (aPE) leads to a significant decrease in antegrade pulmonary blood volume (PBV), which can be measured by contrast echocardiography at the bedside. The aim of this work was to evaluate the feasibility and performance of PBV differentiating between patients with and without aPE.

A total of 89 patients underwent computed tomography pulmonary angiography (CTPA) for suspected aPE were enrolled in the study. Their clinical and conventional echocardiographic characteristics were collected. Contrast echocardiography with measurements of PBV were performed.

There were 57 patients with aPE, with a mean Mastora pulmonary artery obstruction index (PAOI) of 56.14%. Pulmonary transit time (PTT), normalized PTT (nPTT) and PBV in patients with aPE was less than one half of those in patients without PE (p<0.05). There was significant negative correlation between PBV and Mastora PAOI (r=-0.897, p<0.01). None of the conventional echocardiographic parameters had an area under the receiver operating characteristic curve of >0.5, while it was 0.997(0.984~1.010) for PBV in differentiating between patients with aPE or not. The optimal cutoff valueof PBV was 370ml, with a sensitivity of 100%, a specificity of 95.45% and an accuracy of 96.55%.

PBV had a powerful performance in differentiating between patients with aPE or not, and a PBV of <370ml indicated aPE. Contrast echocardiography is enormously useful in the recognition and differentiation of PE and can assess the severity of the PE and the patient's response to therapy.