Short Attention Span Summary
PESIT down and shut up.
OK, everybody who doesn’t live under a rock has heard about this study’s conclusions: 1 in 6 patients admitted for syncope were found to have PE. This was a prospective study of patients presenting with first time syncope. Regardless of cause, all patients were considered and scored with Wells. Low Wells and negative d-dimer was considered ruled out for PE. All others had CT pulmonary angiogram (CTPA). Of 560 patients, PE prevalence was 17.3%, or roughly 1 in 6 patients.
Wait…what? Can this be right? Does this mean we have to rule out PE in every patient who presents with syncope? There are several concerns. First, patients had workup for PE up to 48 hours into the hospitalization for syncope. Hospitalization is a known PE risk factor in itself. Next, some of the clots were small (though 42% were in main pulmonary arteries) and may not have been clots at all, as it is known that smaller thrombi can be false positives. The other issue is the denominator. The authors use 560, but these were patients admitted to the hospital for syncope. The total number of patients who presented to the ED with syncope during this study was 2584. That makes the percentage with PE 3.8% (97/2584). Most patients were discharged home. The final major issue is overdiagnosis. The study looked for PE in patients who did not have symptoms to indicate PE, and they found them. EM Nerd called his critique of this study The Case of the Incidental Bystander. He writes, “Previous data has consistently demonstrated the majority of patients admitted to the hospital for syncope do not undergo evaluation for pulmonary embolism and do well. In these cohorts, patients were not subjected to universal screenings for pulmonary embolism, and experienced minimal adverse events.”
You will hear about this study and may be asked to consider PE workup more often in syncope patients you admit. I think the best way to think about this is to work up patients for PE who have symptoms that concern you that they may have a PE and not to feel obligated to perform universal PE screening on all patients admitted for syncope.
The FOAM world has blown up about this article. Here are some good reads:
- EM Nerd – The Case of the Incidental Bystander
- St. Emlyns
- EM Lit of Note – The Impending PE Apocalypse
- REBEL EM
- Journal Watch had a surprisingly uncritical review
- EM:RAP for a great audio summary with Rory Spiegel (aka EM Nerd)
N Engl J Med. 2016 Oct 20;375(16):1524-1531.
1From the Department of Cardiovascular Sciences, Vascular Medicine Unit, University of Padua, Padua (P.P., A.W.A.L.), the Department of Internal and Emergency Medicine, San Giovanni Addolorata Hospital, Rome (M.C.), the Department of Internal and Emergency Medicine, Civic Hospital of Camposampiero, Camposampiero (M.P., S.B.), the Department of Internal Medicine, Civic Hospital of Livorno, Livorno (N.M.), the Angiology Unit, Civic Hospital of Ravenna, Ravenna (E.B.), the Angiology Unit, Civic Hospital of Castelfranco Veneto, Castelfranco Veneto (A.V.), the Department of Internal Medicine, Civic Hospital of Cosenza, Cosenza (C.B.), the Department of Internal Medicine, Civic Hospital of Piacenza, Piacenza (D.I.), and the Department of Economics, Ca’ Foscari University of Venice, Venice (S.C.) – all in Italy; and the Department of Clinical Epidemiology and Technology Assessment, University of Maastricht, Maastricht, the Netherlands (M.H.P.).
The prevalence of pulmonary embolism among patients hospitalized for syncope is not well documented, and current guidelines pay little attention to a diagnostic workup for pulmonary embolism in these patients.
We performed a systematic workup for pulmonary embolism in patients admitted to 11 hospitals in Italy for a first episode of syncope, regardless of whether there were alternative explanations for the syncope. The diagnosis of pulmonary embolism was ruled out in patients who had a low pretest clinical probability, which was defined according to the Wells score, in combination with a negative d-dimer assay. In all other patients, computed tomographic pulmonary angiography or ventilation-perfusion lung scanning was performed.
A total of 560 patients (mean age, 76 years) were included in the study. A diagnosis of pulmonary embolism was ruled out in 330 of the 560 patients (58.9%) on the basis of the combination of a low pretest clinical probability of pulmonary embolism and negative d-dimer assay. Among the remaining 230 patients, pulmonary embolism was identified in 97 (42.2%). In the entire cohort, the prevalence of pulmonary embolism was 17.3% (95% confidence interval, 14.2 to 20.5). Evidence of an embolus in a main pulmonary or lobar artery or evidence of perfusion defects larger than 25% of the total area of both lungs was found in 61 patients. Pulmonary embolism was identified in 45 of the 355 patients (12.7%) who had an alternative explanation for syncope and in 52 of the 205 patients (25.4%) who did not.
PMID: 27797317 [PubMed – in process]