Pulmonary Embolism Rule-out Criteria non-inferior to usual care for patients at low-risk for pulmonary embolism

1. In this multicenter, randomized controlled study, the Pulmonary Embolism Rule-out Criteria (PERC) was not associated with an inferior rate of diagnosing thromboembolic events in low risk patients compared to care as usual.

2. The PERC strategy resulted in significantly fewer uses of CT pulmonary angiography, reduced ED length of stay, and fewer hospital admissions than usual care.

Evidence Rating Level: 2 (Excellent)

Study Rundown: The diagnostic strategy for Pulmonary Embolisms (PEs) is well established in the ED, consisting of D-dimer and subsequent CT Pulmonary Angiography (CTPA) as usual care. However, in patients who are determined to be of low-risk by clinicians, it is unclear if these diagnostic tests are over utilized. In this French, multicenter, randomized controlled trial, patients who were deemed by clinicians to have low probability of PE were worked-up for the presence of PE according to usual care or the clinical rule PE Rule-out Criteria (PERC). PERC did not result in an inferior rate of PE diagnosis compared to care as usual. In addition, PERC resulted in significantly fewer uses of CTPA, reduced ED length of stay, and fewer hospital admissions than care as usual. There was no significant difference in all-cause mortality between groups.

This trial supports the hypothesis that among patients with a low risk of PE, clinical rule out criteria may be just as effective as usual care but may result in fewer resources utilized. In addition, PEs that may be present even in these low risk patients tended to be segmental, which rarely need intervention. Though these results support use of such a clinical rule for this patient population, the economic benefit of this approach should be assessed, and the study should be repeated in other populations to increase its generalizability.

Click to read the study, published in JAMA

Relevant Reading: Prospective multicenter evaluation of the pulmonary embolism rule-out criteria

In-Depth [randomized controlled trial]: A total of 1749 patients with low-risk of PE (15% by clinical gestalt) were included from 14 French EDs for this non-inferiority, crossover clustered-randomized controlled trial. For 6 months of the trial, patients received care as usual for work-up of PE, involving D-dimer followed by CTPA. For the other 6 months, patients were evaluated with the PERC rule and were only followed up with usual care if PERC score was >0. A two-month washout period was present between the two study periods, and each ED was randomized to start with PERC or usual care before switching to the opposite strategy during the second half of the trial. PE was diagnosed at 1.5% in the PERC group and 2.7% in the usual care group for a difference of 1.3% (CI₉₅ -0.1 to 2.7%), though total thromboembolic events in the subsequent 3 months was non-inferior with a difference between groups of 0.1% (CI₉₅ -∞ to 0.8%). Patients in the PERC group were less likely to undergo CTPA (difference 9.7%; CI₉₅ 6.1 to 13.2%), had reduced ED stays (p < 0.001), and fewer hospital admissions (difference 3.3%; CI₉₅ 0.1 to 6.6%) than the usual care group. Post-hoc sensitivity analyses revealed similar results.

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