Does a PERC-based strategy safely rule out pulmonary embolism without increasing missed thromboembolic events in low-risk emergency department patients compared to a conventional strategy?
A PERC-based strategy is safe for ruling out pulmonary embolism in very low-risk emergency department patients, significantly reducing CTPA use and length of stay without increasing missed 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 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.
Freund et al. (Mon,) studied this question.