Computed tomography for the detection of free-floating thrombi in the right heart in acute pulmonary embolism.

Objectives: The aim of this study was to assess the prevalence of free-floating thrombi in the right heart (FFT) and the accuracy of computed tomography (CT) for their detection in pulmonary embolism (PE).

Methods: We studied 340 consecutive patients presenting with PE. All patients underwent CT and echocardiography.

Results: The prevalence of FFT was 3.5% in the global population of PE and 22% in high-risk PE. Dyspnoea, cardiogenic shock, cardiac arrest and tachycardia were more frequently found in patients with FFT (p = 0.04, p < 0.0001, p = 0.0003 and p = 0.01, respectively). Sensitivity and specificity of CT for the detection of FFT were 100% (95% confidence interval: 74%-100%) and 97% (95%-99%), whereas positive and negative predictive values were 57% (34%-78%) and 100% (99%-100%). Among patients with FFT, right ventricular dilation was always detected by CT, whereas no right ventricular dilation was found among patients with a false diagnosis of FFT performed by CT (p < 0.0001).

Conclusion: Prevalence of FFT is 3.5% and differs according to the clinical presentation. Detection of FFT by CT is feasible and should lead to echocardiography being promptly performed for the confirmation of FFT.