• Yonathan Freund, Marine Cachanado, Adeline Aubry, Charlotte Orsini, Pierre-Alexis Raynal, Anne-Laure Féral-Pierssens, Sandrine Charpentier, Florence Dumas, Nacera Baarir, Jennifer Truchot, Thibaut Desmettre, Karim Tazarourte, Sebastien Beaune, Agathe Leleu, Mehdi Khellaf, Mathias Wargon, Ben Bloom, Alexandra Rousseau, Tabassome Simon, Bruno Riou, and PROPER Investigator Group.
• Sorbonne Université, INSERM UMRS 1166, IHU ICAN, Paris, France.
• JAMA. 2018 Feb 13; 319 (6): 559-566.

ImportanceThe 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.ObjectiveTo prospectively validate the safety of a PERC-based strategy to rule out PE.Design, Setting, And PatientsA 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.InterventionsEach 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 MeasuresThe 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.ResultsAmong 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 RelevanceAmong 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 Registrationclinicaltrials.gov Identifier: NCT02375919.

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