Authors: Jeff Kline, MD // D Mark Courtney, MD
Citation: [Peer-Reviewed, Web Publication] Kline J , Courtney DM (2016, December 9). The PESIT Trial: Not all first time syncope needs testing for PE [NUEM Blog]. Retrieved from http://www.nuemblog.com/blog/the-pesit-trial
NEJM (rejected) Letter to Editor
Prevalence of syncope among patients tested for PE
The article by Prandoni et al “Prevalence of Pulmonary Embolism among Patients Hospitalized for Syncope” raises important questions regarding evaluation of patients for possible pulmonary embolism (PE). First is the degree to which clinicians should pursue testing for PE among patients with syncope. There is a potential to overgeneralize these findings beyond this sample. We explored this with re-examination of a data set of 7940 patients from 12 US emergency departments with symptoms prompting testing for PE [2]. Among 466 PE positive patients, 6.6% reported syncope, while among 7474 PE negative patients 6.0% did. (95% CI for difference, -1.7 - 3.0), suggesting syncope was not a predictor of PE. We also noted a mean age of 75 and a high prevalence of main pulmonary artery clot in the Prandoni study (42%), something we have not found in US studies of undifferentiated PE patients where median percent obstruction was 9% [3]. We do not doubt that PE can be a factor in syncope, but we have concerns over possible over testing for PE among undifferentiated syncope patients.
Additional Commentary
We have additional observations about this study which we were prevented from including due to space limitations in our – now rejected - letter submission.
Overall the US emergency department (ED) experience with syncope is likely different than the Italian setting:
Of the 2584 ED syncope patients, 1867 were discharged. Are we discharging 72% of our syncope patients? Whether or not we should be is another question, but it is likely that the US ED environment has a much lower threshold for admission for syncope than the Italian setting, no different than the US ED environment has a much lower threshold for testing for PE than the European setting. So it is highly likely that to some extent these Italian syncope patients are more ill than the average US ED syncope patient. This is supported by the elderly median age in the Prandoni study of 80….meaning half of all their patients were over 80 years of age! Also note that of the 717 remaining patients not discharged, a further 157 were excluded. So this sample really is a unique selected group…..making it such that the typical ED practitioner should not interpret this study as being instantaneously generalizable to their run of the mill syncope patient.
There are important messages in the Prandoni report that though perhaps while not novel bear some reflection. They did find a statistically increased proportion of PE+ patients with tachycardia, tachypnea, hypotension (by their definition systolic less than 110 mm Hg), signs of DVT and active cancer relative to their syncope patients who did not end up having PE. These findings are in no way surprising or novel as these have been previously seen as predictor variables for PE [2]. They also found a higher prevalence of PE among those with syncope of “undetermined origin.”
Bottom line
In elderly syncope patients with some combination of: tachycardia, tachypnea, hypotension, active cancer, and perhaps especially those without a clear suspected cause of syncope, PE should be a consideration that warrants testing. Perhaps this should be considered even when patients do not have the more traditional symptoms of PE such as dyspnea or chest pain. However, we would caution clinicians NOT to interpret this study as rationale for widespread testing on all or nearly all US ED syncope patients. The outcome of such a simplistic interpretation of this study would undoubtedly result in further radiation and contrast burden and harms for our patients.
Jeff A. Kline MD; Indiana University Departments of Emergency Medicine and Physiology
D. Mark Courtney MD MSCI; Northwestern University Department of Emergency Medicine
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References
- Prandoni P, Lensing AWA, Prins MH, et al. Prevalence of Pulmonary Embolism among Patients Hospitalized for Syncope. N Engl J Med 2016;375(16):1524–31.
- Courtney DM, Kline JA, Kabrhel C, et al. Clinical features from the history and physical examination that predict the presence or absence of pulmonary embolism in symptomatic emergency department patients: results of a prospective, multicenter study. Annals of Emergency Medicine 2010;55(4):307–315.e1.
- Courtney DM, Miller C, Smithline H, Klekowski N, Hogg M, Kline JA. Prospective multicenter assessment of interobserver agreement for radiologist interpretation of multidetector computerized tomographic angiography for pulmonary embolism. J Thromb Haemost 2010;8(3):533–9.