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).

CONCLUSIONS: 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. 

PMID: 20809126

Posted in Computed Tomography and tagged , , , , , .

One Comment

  1. I have to admit hat I have never seen a case of free floating right-sided thrombi… and I look for them!

    The reported prevalence from previous estimates ranges from 3.6% to 18%, and in this specific paper is at 3.5%. This seems a bit high.

    In my experience, since the ROI for triggering is placed at the MPA, there is still a fair amount of mixing of dense contrast in the RA and that usually makes assessing that region a bit more difficult. The authors mention this as well and do measure the PPV of CT at only 57%.

    Interesting concept and potentially useful information as FFT seem to be associated with a worse prognosis.

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