For about the zillionth time – the Prandoni observations of 16% prevalence of pulmonary embolism in syncope are not not generalizable.
This is the BASEL IX study (BAsel Syncope EvaLuation Study) whose primary purpose is to gather observational data regarding the outcomes of patients with syncope. These authors pulled a chunk of their data to address the question of whether PE was highly prevalent among those with syncope, as well as to describe the timing of such any downstream “missed” diagnoses.
The data presented comes from 1,895 patients enrolled in the main study, 1,397 of whom were eligible via being clinically stable enough to provide informed consent, and in whom a D-dimer result was available. Patients underwent clinical assessment by treating physicians without influence by the study.
Overall, only 14% underwent imaging for PE, with PE ultimately found in 1.4% of the cohort at initial presentation. About half the remaining patients who did not undergo imaging had normal D-dimer results and were retrospectively calculated to have low pre-test probability. By logical conclusion, however, that means half the remaining cohort was either non-low pretest or had elevated D-dimer – but still did not undergo imaging.
The follow-up period was up to two years in 83% of this cohort, and only 12 events occurred in follow-up, all in the non-low/elevated D-dimer group not undergoing initial imaging evaluation. Eight of these were PEs and 4 were cardiovascular deaths. The good news: the earliest subsequent PE diagnosis was 55 days, and earliest death was almost a year later.
So, no, again, no – no need to pursue PE in syncope unless otherwise clinically indicated, even if the patient may be at incidentally elevated risk.
“Prevalence of Pulmonary Embolism in Patients With Syncope”
http://www.onlinejacc.org/content/74/6/744.full