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Novel aspects in management of acute pulmonary embolism, Imaging
Session number: 978000
Session title: Novel aspects in the management of acute pulmonary embolism
Authors: Perrier. Geneva, Switzerland
The remarkable breakthrough in image quality by multidetector CT (MDCT) angiography has made it a heavy contender for investigating suspected pulmonary embolism (PE), both for diagnosis and risk stratification. Indeed, recent studies report a low, 1 to 2%, risk of unfavourable outcome in patients left untreated based on a negative MDCT. Therefore, at least in patients with a “non-high” clinical probability, MDCT may be used as a stand-alone test for suspected PE. But the story does not end there.
There is still no definitive answer to the question of whether or not to thrombolyse patients with right ventricular strain but no arterial hypotension (so-called submassive PE). But there soon will be, as a major European trial addressing this question is scheduled to begin in early 2007. If the results are positive, risk stratification will be mandatory and recent data in the field show that echocardiography is not sufficient: a right ventricular/left ventricular telediastolic (RV/LV) diameter above 0.9 is associated with a higher probability of death or recurrence, but has a low positive predictive value.
Elevated biomarkers (troponin and NT-proBNP), singly or in combination, are also associated with a poorer prognosis, with a similar low positive predictive value. In contrast, the predictive value for an adverse outcome in a patient with both right ventricular strain and elevated biomarkers is higher, around 40% (compared with less than 4% in a population with neither of those characteristics). So where does CT fit in?
New 64-slice CT machines with ECG-gated image acquisition provide accurate measurements of the heart chambers including, of course, the RV/LV diameter and the RV ejection fraction. Although the technique is not yet well-standardised, the results seem promising enough for CT to become a “test for all seasons”. Finally, anticoagulant treatment is still the mainstay of PE management and, there again, current research focuses on risk stratification, i.e. the identification of patients at high risk of recurrence after the initial 3-6 months anticoagulant course, who might benefit from prolonged anticoagulant treatment.
Conclusion
Diagnosing PE has become increasingly simple with the advent of multidetector CT. Risk stratification may become mandatory if a planned randomised trial shows that patients with submassive PE benefit from thrombolysis. For that purpose, biomarkers could serve as a screening test, followed by echocardiographic or CT evaluation of right ventricular function, if elevated.
Finally, better identification of patients at risk of recurrence of venous thromboembolism after the initial 3-6 months treatment phase, is required to target those who will benefit from prolonged anticoagulation.
The content of this article reflects the personal opinion of the
author/s and is not necessarily the official position of the
European Society of Cardiology.
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