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Original Investigation
February 13, 2018

Effect of the Pulmonary Embolism Rule-Out Criteria on Subsequent Thromboembolic Events Among Low-Risk Emergency Department Patients: The PROPER Randomized Clinical Trial

Author Affiliations
  • 1Sorbonne Université, INSERM UMRS 1166, IHU ICAN, Paris, France
  • 2Emergency Department, Hôpital Universitaire Pitié-Salpêtrière, Assistance Publique-Hôpitaux de Paris (AP-HP), Paris, France
  • 3Clinical Research Platform (URC-CRC-CRB), AP-HP Hôpital Saint-Antoine, Paris, France
  • 4Emergency Department, Hôpital Avicenne, APHP, Bobigny, France
  • 5Emergency Department, Hôpital Saint-Antoine, APHP, Paris, France
  • 6Emergency Department, Hôpital Européen Georges Pompidou, APHP, Paris, France
  • 7Université Toulouse III Paul Sabatier, INSERM UMR 1027, CHU Toulouse, Toulouse, Emergency Department, Toulouse, France
  • 8Université Paris Descartes, INSERM UMR970, APHP, Emergency Department, Hôpital Cochin, Paris, France
  • 9Emergency Department, Hôpital Tenon, APHP, Paris, France
  • 10Emergency Department, Hôpital Lariboisière, APHP, Paris, France
  • 11Université Bourgogne Franche-Comté, Emergency Department, CHRU Minjoz, Besançon, France
  • 12Université Claude Bernard Lyon1, HESPER EA 7425, Hospices Civils de Lyon, Emergency Department, Hôpital Edouard Herriot, Lyon, France
  • 13Emergency Department, Hôpital Ambroise-Paré, APHP, Boulogne, France
  • 14Emergency Department, Hôpital Bichat, APHP, Paris, France
  • 15Université Paris Est, INSERM U955, APHP, Emergency Department, Hôpital Henri Mondor, Créteil, France
  • 16Emergency Department, Hôpital Saint Camille, Bry sur Marne, France
  • 17Emergency Department, Barts Health NHS Trust, London, United Kingdom
JAMA. 2018;319(6):559-566. doi:10.1001/jama.2017.21904
Key Points

Question  Does use of the pulmonary embolism rule-out criteria (PERC) in emergency department patients with low clinical probability of pulmonary embolism (PE) safely exclude the diagnosis of PE?

Findings  In this cluster-randomized crossover noninferiority trial that included 1916 patients with very low clinical probability of PE, the 3-month risk of a thromboembolic event when using a PERC strategy compared with a conventional strategy was 0.1% vs 0%, a difference that met the noninferiority criterion of 1.5%.

Meaning  In emergency department patients at very low risk of PE, the use of a PERC-based strategy did not lead to an inferior rate of subsequent thromboembolic events.


Importance  The safety of the pulmonary embolism rule-out criteria (PERC), an 8-item block of clinical criteria aimed at ruling out pulmonary embolism (PE), has not been assessed in a randomized clinical trial.

Objective  To prospectively validate the safety of a PERC-based strategy to rule out PE.

Design, Setting, and Patients  A crossover cluster–randomized clinical noninferiority trial in 14 emergency departments in France. Patients with a low gestalt clinical probability of PE were included from August 2015 to September 2016, and followed up until December 2016.

Interventions  Each center was randomized for the sequence of intervention periods. In the PERC period, the diagnosis of PE was excluded with no further testing if all 8 items of the PERC rule were negative.

Main Outcomes and Measures  The primary end point was the occurrence of a thromboembolic event during the 3-month follow-up period that was not initially diagnosed. The noninferiority margin was set at 1.5%. Secondary end points included the rate of computed tomographic pulmonary angiography (CTPA), median length of stay in the emergency department, and rate of hospital admission.

Results  Among 1916 patients who were cluster-randomized (mean age 44 years, 980 [51%] women), 962 were assigned to the PERC group and 954 were assigned to the control group. A total of 1749 patients completed the trial. A PE was diagnosed at initial presentation in 26 patients in the control group (2.7%) vs 14 (1.5%) in the PERC group (difference, 1.3% [95% CI, −0.1% to 2.7%]; P = .052). One PE (0.1%) was diagnosed during follow-up in the PERC group vs none in the control group (difference, 0.1% [95% CI, −∞ to 0.8%]). The proportion of patients undergoing CTPA in the PERC group vs control group was 13% vs 23% (difference, −10% [95% CI, −13% to −6%]; P < .001). In the PERC group, rates were significantly reduced for the median length of emergency department stay (mean reduction, 36 minutes [95% CI, 4 to 68]) and hospital admission (difference, 3.3% [95% CI, 0.1% to 6.6%]).

Conclusions and Relevance  Among very low-risk patients with suspected PE, randomization to a PERC strategy vs conventional strategy did not result in an inferior rate of thromboembolic events over 3 months. These findings support the safety of PERC for very low-risk patients presenting to the emergency department.

Trial Registration  clinicaltrials.gov Identifier: NCT02375919