Pulmonary Embolism Rule-out Criteria Rule Research Articles

Computed tomography pulmonary angiogram ordering, adherence to decision rules and yield in the emergency department: An observational study.

Pulmonary embolism (PE) frequently requires diagnosis through CT pulmonary angiogram (CTPA). Appropriate application of evidence-based clinical decision tools can reduce unnecessary CTPAs. This study assessed adherence to and the efficacy of various aspects of the Queensland Health suspected PE diagnostic pathway, including Wells score, PE rule out criteria (PERC) and age-adjusted D-dimer interpretation. Retrospective study of CTPAs ordered from 1 January to 30 April 2023 in a tertiary and urban ED in Southeast Queensland. Data on clinical variables, D-dimer and CTPA results were collected through medical record and radiology database review. Descriptive analyses were used to determine adherence to Queensland guidelines and performance of D-dimer interpretation tools (including comparison of age-adjusted PE with a new pre-test probability [PTP]-based model using D-dimer cut-off <1000 ng/mL for Wells score ≤4 and 500 ng/mL for Wells score 4.5-6). A total of 573 CTPAs were available for analysis with a 12.4% (95% confidence interval 10.0-15.4) diagnostic yield. Stratification by Wells score showed yields of 4.0%, 18.5% and 41% for low-, moderate- and high-risk patients, respectively. Twenty-five patients with low-PTP who received CTPA could have been excluded with the PERC rule. Age-adjusted D-dimer interpretation may have prevented 26 CTPAs with no false negatives, whereas PTP approach may have prevented 128 CTPAs with four false negatives. Guideline adherence can be improved, and adherence to existing clinical decision tools may reduce unnecessary CTPA ordering and increase diagnostic yield. The use of the age-adjusted D-dimer had good sensitivity, whereas the new PTP approach will require further prospective research.

Safety of the Pulmonary Embolism Rule-Out Criteria Rule: Findings from the Registro Informatizado de la Enfermedad TromboEmbolica venosa (RIETE) Registry.

The diagnostic strategy for pulmonary embolism (PE) includes a D-dimer test when PE probability is low or intermediate, but false positive D-dimer results are frequent and can result in an unnecessary computed tomography pulmonary angiogram. The PE rule-out criteria (PERC) rule excludes PE without D-dimer testing when pre-test probability is <15%. The aim of this study was to assess the safety of the PERC rule strategy in patients included in the Registro Informatizado de la Enfermedad TromboEmbolica venosa (RIETE) registry. This retrospective cohort study used data from the RIETE registry, an ongoing, international prospective registry of patients with objectively confirmed venous thromboembolism. The primary outcome was the failure rate of the PERC strategy, represented by the proportion of PERC-negative (PERC-N) patients with a PE included in the registry. Secondary outcomes were a comparison of the clinical characteristics, treatment strategy, and outcome of PERC-N versus PERC-positive (PERC-P) patients at 3 months. From 2001 to 2021, 49,793 patients with acute PE were enrolled in the RIETE registry. We included 48,903 in the final analysis after exclusion of 890 patients with an undetermined PERC status. Only 346 patients were PERC-N with a failure rate of 0.7% (95% confidence interval 0.6-0.8%). PERC-N patients presented more frequently with chest pain, but less often with dyspnea, syncope or hypotension. They had also sub-segmental or segmental PE more frequently, were more often treated with direct oral anticoagulants, and received mechanical or pharmacological thrombolysis less often. In addition, PERC-N patients had a lower incidence of recurrent deep vein thrombosis, major bleeding, and death attributed to PE during the 3-month follow-up. A low failure rate of the PERC rule was observed in the RIETE registry, thus supporting its use to safely identify patients with an unlikely probability of PE.

Bedside exclusion of pulmonary embolism in children without radiation (BEEPER): a national study of the Pediatric Emergency Care Applied Research Network—Study protocol

BackgroundThe Pulmonary Embolism Rule Out Criteria (PERC) Peds rule, derived from the PERC rule, was derived to estimate a low pretest probability for pulmonary embolism (PE) in children but has not been prospectively validated. ObjectiveThe objective of this study was to present a protocol for an ongoing multicenter prospective observational study that evaluates the diagnostic accuracy of the PERC-Peds rule. MethodsThis protocol is identified by the acronym, BEdside Exclusion of Pulmonary Embolism without Radiation in children. The study aims were designed to prospectively validate, or if necessary, refine, the accuracy of PERC-Peds and D-dimer in excluding PE among children with clinical suspicion or testing for PE. Multiple ancillary studies will examine clinical characteristics and epidemiology of the participants. Children aged 4 through 17 years were being enrolled at 21 sites through the Pediatric Emergency Care Applied Research Network (PECARN). Patients taking anticoagulant therapy are excluded. PERC-Peds criteria data, clinical gestalt, and demographic information are collected in real time. The criterion standard outcome is image-confirmed venous thromboembolism within 45 days, determined from independent expert adjudication. We assessed interrater reliability of the PERC-Peds, frequency of PERC-Peds use in routine clinical care, and descriptive characteristics of missed eligible and missed patients with PE. ResultsEnrollment is currently 60% complete with an anticipated data lock in 2025. ConclusionsThis prospective multicenter observational study will not only test whether a set of simple criteria can safely exclude PE without need for imaging but also provide a resource to fill a critical knowledge gap about clinical characteristics of children with suspected and diagnosed PE.

The utility of risk assessment tools for acute pulmonary embolism in children.

The study consisted of patients under 18 years of age who were consulted to the Pediatric Pulmonology Clinic for the evaluation of PE. Patients were divided into two groups based on the confirmation of PE. The group with the presence of PE (n = 20) consisted of children who were diagnosed with PE. The group with the absence of PE (n = 28) consisted of children with clinically suspected PE but negative diagnostic imaging. Adult validated clinical decision PERC rule and Pediatric PE Model were retrospectively applied to the patients. In the study, PERC demonstrated a sensitivity of 60%and a specificity of 46% for the diagnosis of PE in children. When PE Model was evaluated for the children, it was found a 50% sensitivity and 75% specificity. Combining PE Model and PERC rule with D-dimer did not increase the specificity and sensitivity. Smoking was found to be relevant for PE in the childhood. Twenty-five percent of the patients had a genetic tendency for PE. All of the patients had an underlying disease as well. None of the current risk assessment tools (PE Model, PERC, D-dimer) were found to be accurate in predicting PE. Further larger population studies are still required to develop a better diagnostic approach.

Clinical predictors of pulmonary embolism for inpatients: are computed tomography pulmonary angiograms being requested appropriately?

The heterogeneity of inpatient pulmonary embolism (PE) presentations may lead to computed tomography pulmonary angiograms (CTPA) being over-requested. Current clinical predictors for PE, including Wells criteria and Pulmonary Embolism Rule-out Criteria (PERC), have predominantly focussed on outpatient and emergency department populations. To determine the clinical indicators for ordering inpatient CTPA and the predictors of positive scans for PE. Consecutive inpatient CTPA (performed >24 h after admission) from January 2017 to December 2017 were retrospectively reviewed. Variables including baseline characteristics, vital signs and risk factors for PE were extracted. A total of 312 CTPA was reviewed (average patient age 67 years; 46% male) and 36 CTPA were positive for PE (11.5%). The average time to inpatient CTPA request was 7 days. Clinical indicators associated with positive scans were hypoxia (odds ratio (OR) 2.4; 95% confidence interval (CI) 1.1-5.6), tachypnoea (OR 2.5; 95% CI 1.2-6.0), recent surgery or immobilisation (OR 2.7; 95% CI 1.2-6.4), S1Q3T3 pattern on electrocardiogram (ECG; OR 7.2; 95% CI 1.4-35.7) and right bundle branch block pattern on ECG (OR 4.7; 95% CI 1.6-13.1). Hypotension, fever and malignancy were not significant. Both PERC and Wells criteria had poor positive predictive value (12% and 27% respectively), but the negative predictive value for PERC and Wells was 100% and 95.8% respectively. Inpatient CTPA appear to be over-requested and can potentially be rationalised based on a combination of clinical predictors and Wells criteria and/or PERC rule. Further prospective studies are needed to develop accurate clinical decision tools targeted towards inpatients.

Effect of a Diagnostic Strategy Using an Elevated and Age-Adjusted D-Dimer Threshold on Thromboembolic Events in Emergency Department Patients With Suspected Pulmonary Embolism

Uncontrolled studies suggest that pulmonary embolism (PE) can be safely ruled out using the YEARS rule, a diagnostic strategy that uses varying D-dimer thresholds. To prospectively validate the safety of a strategy that combines the YEARS rule with the pulmonary embolism rule-out criteria (PERC) rule and an age-adjusted D-dimer threshold. A cluster-randomized, crossover, noninferiority trial in 18 emergency departments (EDs) in France and Spain. Patients (N = 1414) who had a low clinical risk of PE not excluded by the PERC rule or a subjective clinical intermediate risk of PE were included from October 2019 to June 2020, and followed up until October 2020. Each center was randomized for the sequence of intervention periods. In the intervention period (726 patients), PE was excluded without chest imaging in patients with no YEARS criteria and a D-dimer level less than 1000 ng/mL and in patients with 1 or more YEARS criteria and a D-dimer level less than the age-adjusted threshold (500 ng/mL if age <50 years or age in years × 10 in patients ≥50 years). In the control period (688 patients), PE was excluded without chest imaging if the D-dimer level was less than the age-adjusted threshold. The primary end point was venous thromboembolism (VTE) at 3 months. The noninferiority margin was set at 1.35%. There were 8 secondary end points, including chest imaging, ED length of stay, hospital admission, nonindicated anticoagulation treatment, all-cause death, and all-cause readmission at 3 months. Of the 1414 included patients (mean age, 55 years; 58% female), 1217 (86%) were analyzed in the per-protocol analysis. PE was diagnosed in the ED in 100 patients (7.1%). At 3 months, VTE was diagnosed in 1 patient in the intervention group (0.15% [95% CI, 0.0% to 0.86%]) vs 5 patients in the control group (0.80% [95% CI, 0.26% to 1.86%]) (adjusted difference, -0.64% [1-sided 97.5% CI, -∞ to 0.21%], within the noninferiority margin). Of the 6 analyzed secondary end points, only 2 showed a statistically significant difference in the intervention group compared with the control group: chest imaging (30.4% vs 40.0%; adjusted difference, -8.7% [95% CI, -13.8% to -3.5%]) and ED median length of stay (6 hours [IQR, 4 to 8 hours] vs 6 hours [IQR, 5 to 9 hours]; adjusted difference, -1.6 hours [95% CI, -2.3 to -0.9]). Among ED patients with suspected PE, the use of the YEARS rule combined with the age-adjusted D-dimer threshold in PERC-positive patients, compared with a conventional diagnostic strategy, did not result in an inferior rate of thromboembolic events. ClinicalTrials.gov Identifier: NCT04032769.

Case Report: A Near Miss of Pulmonary Embolism in a Division 1 Collegiate Basketball Player.

IntroductionThe clinical presentation of pulmonary embolism (PE) is often associated with classic vital instability such as tachycardia, hypoxia, and tachypnea. This critical diagnosis is often less likely if a patient is negative by Pulmonary Embolism Rule-Out Criteria (PERC) standards with a low pre-test probability of disease. Caution must be used when evaluating elite athletes with the PERC rule due to low resting heart rate and certain risk factors, which are inherent to athletics.Case ReportWe report the case of a 20-year-old male Division 1 collegiate athlete with pleuritic chest pain diagnosed with PE despite being PERC negative. His presenting heart rate (HR) of 79 beats per minute was correctly determined to be tachycardic relative to his resting HR of 47–60 beats per minute. Despite his PERC negative status, PE was found after an elevated D-dimer and subsequent computed tomography angiography.ConclusionSpecial consideration should be used when evaluating elite athletes for PE, as their resting physiology may differ from the general population. Additionally, certain risk factors for thromboembolic disease are inherent in competitive athletics and should be considered during an initial risk assessment. The presented patient was successfully treated with oral anticoagulation for three months and was able to return to play.

Retrospective validation of the pulmonary embolism rule-out criteria rule in 'PE unlikely' patients with suspected pulmonary embolism.

Patients presenting to emergency departments (EDs) with suspected pulmonary embolism (PE) can be risk stratified and those who are deemed to be at low risk for PE usually undergo D-dimer testing. A negative D-dimer in this low-risk group rules out PE with a high degree of certainty because of its high sensitivity. The D-dimer is, however, a poorly specific test and positive results often lead to unnecessary radiological imaging (notably computed tomography pulmonary angiography). The Pulmonary Embolism Rule-Out Criteria (PERC) rule has been suggested as an alternative to D-dimer testing in these patients. This study looked at whether the PERC rule could safely replace the use of D-dimer in patients suspected of PE, but deemed 'PE unlikely' by the dichotomized Wells score in a UK ED setting. This was a retrospective review of 986 patients with suspected PE who had a blood sample for D-dimer level taken. In patients deemed 'PE unlikely' (using the dichotomized Wells score), the diagnostic performance of the PERC rule was compared with a standard D-dimer level in the detection of PE at index presentation and up to 3 months afterwards. Of the 986 patients, 940 patients were deemed 'PE unlikely' using the dichotomized Wells score. Three patients with confirmed PE would have been missed by the PERC rule compared with only one missed by the D-dimer test. In these patients, the sensitivity of the PERC rule for detecting PE was 91.4% [95% confidence interval (CI): 76.9-98.2%], with a negative likelihood ratio of 0.25 (95% CI: 0.08-0.73). However, the negative predictive value of the PERC rule was 99.1% (95% CI: 97.3-99.8%). In comparison, the sensitivity for the standard D-dimer test was 97.1% (95% CI: 85.1-99.9%), with a negative likelihood ratio of 0.04 (95% CI: 0.01-0.27). The negative predictive value for the standard D-dimer test was 99.8% (95% CI: 99.2-100%). The PERC rule has a high negative predictive value for excluding PE in patients presenting with suspected PE to the ED. However, the PERC rule may still miss around 8% of confirmed PE in patients who are deemed 'PE unlikely' by a dichotomized Wells score. Caution is advised in using the PERC rule as a substitute for the standard D-dimer test in all these patients.

Evaluation of the pulmonary embolism rule out criteria (PERC rule) in children evaluated for suspected pulmonary embolism

BackgroundThe pulmonary embolism rule out criteria (PERC) reliably predicts a low probability of PE in adults. We examine the diagnostic accuracy of the objective components of the PERC rule in children previously tested for PE. MethodsChildren aged 5–17 who had a D-dimer or pulmonary vascular imaging ordered from 2004 to 2014 in a large multicenter hospital network were identified by query of administrative databases. Using explicit, predefined methods, trained abstracters selected charts of children clearly tested for PE, collected the 8 objective variables for PERC, and determined PE criterion standard status (image or autopsy confirmed PE or deep vein thrombosis within 30 days by query of the Indiana Network for Patient Care (INPC)). ResultsWe identified 543 patients, including 56 (10.3%, 95% CI: 7.8–13.1%) who were PE+, with a mean and median age of 15 years. All 8 objective criteria from PERC were negative in 170 patients (31%), including one with PE (false negative rate 0.6%, 0–3.2%). Diagnostic sensitivity and specificity were 98.2% (90.5–100%), and 34.7 (30.5–39.1%), respectively, leading to a likelihood ratio negative = 0.05 (0.1–0.27). When treated as a diagnostic test based upon sum of criteria positive, PERC had good discrimination between PE+ vs PE− with an area under receiver operating characteristic curve 0.81 (0.75–0.86). ConclusionsIn this sample of children and teenagers with suspected PE, the PERC rule was negative in 31%, and demonstrated good overall diagnostic accuracy, including a low false negative rate. These data support the need for a large, prospective diagnostic validation study of PERC in children.

Impact of altitude-adjusted hypoxia on the Pulmonary Embolism Rule-out Criteria

BackgroundThe Pulmonary Embolism Rule-out Criteria (PERC) defines hypoxia as an oxygen saturation (O2 sat) < 95%. Utilizing this threshold for hypoxia at a significant elevation above sea level may lead to an inflated number of PERC-positive patients and unnecessary testing. The aim of this study was to determine the effect of an altitude-adjusted O2 sat on PERC's sensitivity and the potential impact on testing rates. MethodsAt the University of Utah Emergency Department (ED) (elevation: 4980 ft/1518 m), we prospectively enrolled a convenience sample of patients presenting with chest pain and/or shortness of breath. We calculated PERC utilizing triage vital signs and baseline clinical variables and noted the diagnosis of acute PE during the ED visit. We adjusted the PERC O2 sat threshold to <90% to account for altitude to determine the potential impact on outcomes and decision tool performance. ResultsOf 3024 study patients, 1.9% received the diagnosis of an acute PE in the ED, resulting in a sensitivity of 96.6% for the traditional PERC (95% CI: 88.1%–99.6%). Utilizing a definition of hypoxia of <90%, the sensitivity of the altitude-adjusted PERC rule was 94.8% (95% CI: 85.6%–98.9%). Assuming that imaging would not have been pursued for PERC-negative patients, the altitude-adjusted PERC rule would have reduced the overall rate of advanced imaging by 2.7% (95% CI: 1.8%–4.1%). ConclusionAdjusting the PERC O2 sat threshold for altitude may result in decreased rates of advanced imaging for PE without a substantial change in the sensitivity of the PERC rule.

P104: Evaluating the use of the pulmonary embolism rule-out criteria in the emergency department

Introduction: Diagnosing pulmonary embolism (PE) can be challenging because the signs and symptoms are often non-specific. Studies have shown that evidence-based algorithms are not always adhered to in the Emergency Department (ED), which leads to unnecessary CT scanning. The pulmonary embolism rule-out criteria (PERC) can identify patients who can be safely discharged from the ED without further investigation for PE. The purpose of this study is to evaluate the use of the PERC rule in the ED and to compare the rates of testing for PE if the PERC rule was used. Methods: This was a health records review of ED patients investigated for PE at two emergency departments over a two-year period (April 2013-March 2015). Inclusion criteria were ED physician ordered CT pulmonary angiogram, ventilation-perfusion scan, or D-dimer for investigation of PE. Patients under the age of 18 were excluded. PE was considered to be present during the emergency department visit if PE was diagnosed on CT or VQ (subsegmental level or above), or if the patient was subsequently found to have PE or deep vein thrombosis during the next 30 days. Trained researchers extracted anonymized data. The rate of CT/VQ imaging and the negative predictive value was calculated. Results: There were 1,163 patients that were tested for PE and 1,097 patients were eligible for our analysis. Of the total, 330/1,097 (30.1%; 95%CI 27.4-32.3%) had CT/VQ imaging for PE, and 48/1,097 (4.4%; 95%CI 3.3-5.8%) patients were diagnosed with PE. 806/1,097 (73.5%; 95%CI 70.8-76.0%) were PERC positive, and of these, 44 patients had a PE (5.5%; 95%CI 4.1-7.3%). Conversely, 291/1,097 (26.5%; 95%CI 24.0-29.2%) patients were PERC negative, and of these, 4 patients had a PE (1.4%; 95%CI 0.5-3.5%). Of the PERC negative patients, 291/291 (100.0%; 95%CI 98.7-100.0%) had a D-dimer test done, and 33/291 (11.3%; 95%CI 8.2-15.5%) had a CT angiogram. If PERC was used, CT/VQ imaging would have been avoided in 33/1,097 (3%; 95%CI 2.2-4.2%) patients and the D-dimer would have been avoided in 291/1,097 (26.5%; 95%CI 24.0-29.2%) patients. Conclusion: If the PERC rule was used in all patients with suspected PE, fewer patients would have further testing. The false negative rate for the PERC rule was low.

Effect of the Pulmonary Embolism Rule-Out Criteria on Subsequent Thromboembolic Events Among Low-Risk Emergency Department Patients

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. To prospectively validate the safety of a PERC-based strategy to rule out PE. 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. 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. 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. 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%]). 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. clinicaltrials.gov Identifier: NCT02375919.

Combination of Pulmonary Embolism Rule-out Criteria and YEARS Algorithm in a European Cohort of Patients with Suspected Pulmonary Embolism.

Both the YEARS algorithm and the pulmonary embolism (PE) rule-out criteria (PERC) were created to exclude PE with limited diagnostic tests. A diagnostic strategy combining both scores might save additional computed tomography pulmonary angiography (CTPA) scans, but they have never been evaluated in conjunction. The aim of this study was to determine the safety and efficiency of combining YEARS and PERC in a single diagnostic strategy for suspected PE. The PERC rule was assessed in 1,316 consecutive patients with suspected PE who were managed according to YEARS. We calculated the absolute difference (with 95% confidence interval [CI]) in failure rate and the number of 'saved' CTPAs for the scenario that PE would have been ruled out without CTPA in the absence of all PERC items. Using the YEARS algorithm, PE was diagnosed in 189 patients (14%), 680 patients (52%) were managed without CTPA and the 3-month rate of venous thromboembolism in patients in whom PE was ruled out was 0.44% (95% CI: 0.19-1.0). Only 6 of 154 patients (3.9%; 95% CI: 1.4-8.2) with no YEARS items who were referred for CTPA would have been PERC negative, of whom none were diagnosed with PE at baseline or during follow-up (0%; 95% CI: 0-64). Applying PERC before YEARS in all patients would have led to a failure rate of 1.42% (95% CI: 0.87-2.3%), 0.98% (95% CI: 0.17-1.9) more than shown in patients managed by YEARS. Combining YEARS with PERC would have yielded only a modest improvement of efficiency in patients without a YEARS item and an unacceptable failure rate in patients with ≥ 1 YEARS item.

Pulmonary embolism rule-out criteria (PERC) rule in European patients with low implicit clinical probability (PERCEPIC): a multicentre, prospective, observational study

The ability of the pulmonary embolism rule-out criteria (PERC) to exclude pulmonary embolism without further testing remains debated outside the USA, especially in the population with suspected pulmonary embolism who have a high prevalence of the condition. Our main objective was to prospectively assess the predictive value of negative PERC to rule out pulmonary embolism among European patients with low implicit clinical probability. We did a multicentre, prospective, observational study in 12 emergency departments in France and Belgium. We included consecutive patients aged 18 years or older with suspected pulmonary embolism. Patients were excluded if they had already been hospitalised for more than 2 days, had curative anticoagulant therapy in progress for more than 48 h, or had a diagnosis of thromboembolic disease documented before admission to emergency department. Physicians completed a standardised case report form comprising implicit clinical probability assessment (low, moderate, or high) and a list of risk factors including criteria of the PERC rule. They were asked to follow international recommendations for diagnostic strategy, masked to PERC assessment. The primary endpoint was the proportion of patients with low implicit clinical probability and negative PERC who had venous thromboembolic events, diagnosed during initial diagnostic work-up or during 3-month follow-up, as externally adjudicated by an independent committee masked to the PERC and clinical probability assessment. The upper limit of the 95% CI around the 3-month thromboembolic risk was set at 3%. We did all analyses by intention to treat, including all patients with complete follow-up. This trial is registered with ClinicalTrials.gov, number NCT02360540. Between May 1, 2015, and April 30, 2016, 1773 consecutive patients with suspected pulmonary embolism were prospectively assessed for inclusion, of whom 1757 were included. 1052 (60%) patients were classed as having low clinical probability, 49 (4·7%, 95% CI 3·5-6·1) of whom had a venous thromboembolic event. In patients with a low implicit clinical probability, 337 (32%) patients had negative PERC, of whom four (1·2%; 95% CI 0·4-2·9) went on to have a pulmonary embolism. In European patients with low implicit clinical probability, PERC can exclude pulmonary embolism with a low percentage of false-negative results. The results of our prospective, observational study allow and justify an implementation study of the PERC rule in Europe. French Ministry of Health.

Knowledge Translation of the PERC Rule for Suspected Pulmonary Embolism: A Blueprint for Reducing the Number of CT Pulmonary Angiograms.

IntroductionComputerized decision support decreases the number of computed tomography pulmonary angiograms (CTPA) for pulmonary embolism (PE) ordered in emergency departments, but it is not always well accepted by emergency physicians. We studied a department-endorsed, evidence-based clinical protocol that included the PE rule-out criteria (PERC) rule, multi-modal education using principles of knowledge translation (KT), and clinical decision support embedded in our order entry system, to decrease the number of unnecessary CTPA ordered.MethodsWe performed a historically controlled observational before-after study for one year pre- and post-implementation of a departmentally-endorsed protocol. We included patients > 18 in whom providers suspected PE and who did not have a contraindication to CTPA. Providers entered clinical information into a diagnostic pathway via computerized order entry. Prior to protocol implementation, we provided education to ordering providers. The primary outcome measure was the number of CTPA ordered per 1,000 visits one year before vs. after implementation.ResultsCTPA declined from 1,033 scans for 98,028 annual visits (10.53 per 1,000 patient visits (95% CI [9.9–11.2]) to 892 scans for 101,172 annual visits (8.81 per 1,000 patient visits (95% CI [8.3–9.4]) p<0.001. The absolute reduction in PACT ordered was 1.72 per 1,000 visits (a 16% reduction). Patient characteristics were similar for both periods.ConclusionKnowledge translation clinical decision support using the PERC rule significantly reduced the number of CTPA ordered.

Detection of Pulmonary Embolism in High-Risk Children

To evaluate 2 commonly used adult-based pulmonary embolism (PE) algorithms in pediatric patients and to derive a pediatric-specific clinical decision rule to evaluate children at risk for PE, given the paucity of data to guide diagnostic imaging in children for whom PE is suspected. We performed a single-center retrospective study among 561 children <22 years of age undergoing either D-dimer testing or radiologic evaluation (computed tomography or ventilation-perfusion scan) in the emergency department setting for concern of PE. A diagnosis of PE required radiologic confirmation and anticoagulant treatment. We evaluated the test characteristics of the Wells criteria and Pulmonary Embolism Rule-out Criteria (PERC) low-risk rule and used recursive partition analysis to derive a clinical decision rule. Among the 561 patients included in the study, 36 (6.4%) were diagnosed with PE. The Wells criteria demonstrated a sensitivity and specificity of 86% and 60%, respectively. The sensitivity and specificity of the PERC were 100% and 24%, respectively. A clinical decision rule including the presence of oral contraceptive use, tachycardia, and oxygen saturation <95% demonstrated a sensitivity and specificity of 90% and 56%, respectively, a positive and negative likelihood ratio of 2.0 and 0.2, and a positive and negative predictive value of 0.12 and 0.99, respectively. The risk of PE is low among children not receiving estrogen therapy and without tachycardia and hypoxia in those with an initial suspicion of PE. Application of the PERC rule and Wells criteria should be used cautiously in the pediatric population.

A retrospective analysis of the combined use of PERC rule and Wells score to exclude pulmonary embolism in the Emergency Department

BackgroundThe pulmonary embolism rule-out criteria (PERC) rule is an eight-factor decision rule to support the decision not to order a diagnostic test when the gestalt-based clinical suspicion on pulmonary embolism...

PERC rule to exclude the diagnosis of pulmonary embolism in emergency low-risk patients: study protocol for the PROPER randomized controlled study.

BackgroundThe diagnosis of Pulmonary Embolism (PE) in the emergency department (ED) is crucial. As emergency physicians fear missing this potential life-threatening condition, PE tends to be over-investigated, exposing patients to unnecessary risks and uncertain benefit in terms of outcome. The Pulmonary Embolism Rule-out Criteria (PERC) is an eight-item block of clinical criteria that can identify patients who can safely be discharged from the ED without further investigation for PE. The endorsement of this rule could markedly reduce the number of irradiative imaging studies, ED length of stay, and rate of adverse events resulting from both diagnostic and therapeutic interventions. Several retrospective and prospective studies have shown the safety and benefits of the PERC rule for PE diagnosis in low-risk patients, but the validity of this rule is still controversial. We hypothesize that in European patients with a low gestalt clinical probability and who are PERC-negative, PE can be safely ruled out and the patient discharged without further testing.Methods/DesignThis is a controlled, cluster randomized trial, in 15 centers in France. Each center will be randomized for the sequence of intervention periods: a 6-month intervention period (PERC-based strategy) followed by a 6-month control period (usual care), or in reverse order, with 2 months of “wash-out” between the 2 periods. Adult patients presenting to the ED with a suspicion of PE and a low pre test probability estimated by clinical gestalt will be eligible. The primary outcome is the percentage of failure resulting from the diagnostic strategy, defined as diagnosed venous thromboembolic events at 3-month follow-up, among patients for whom PE has been initially ruled out.DiscussionThe PERC rule has the potential to decrease the number of irradiative imaging studies in the ED, and is reported to be safe. However, no randomized study has ever validated the safety of PERC. Furthermore, some studies have challenged the safety of a PERC-based strategy to rule-out PE, especially in Europe where the prevalence of PE diagnosed in the ED is high. The PROPER study should provide high-quality evidence to settle this issue. If it confirms the safety of the PERC rule, physicians will be able to reduce the number of investigations, associated subsequent adverse events, costs, and ED length of stay for patients with a low clinical probability of PE.Trial registrationNCT02375919.

Age and sex-dependent trends in pulmonary embolism testing and derivation of a clinical decision rule for young patients

ImportanceDespite low prevalence of pulmonary embolism (PE) in young adults, they are frequently imaged for PE, which involves radiation exposure and substantial financial cost.ObjectiveDetermine the use and positive proportions for...

Pulmonary Embolism in the Pediatric Emergency Department

To describe patients who present to the pediatric emergency department (PED) and are subsequently diagnosed with pulmonary embolism (PE). Electronic medical records from 2003 to 2011 of a tertiary care pediatric health care system was retrospectively reviewed to identify patients <21 years who had a final International Classification of Diseases, Ninth Revision diagnosis of PE. Patient demographics, and hospital course were recorded. Adult validated clinical decision rules Wells criteria and Pulmonary Embolism Rule-out Criteria (PERC) were retrospectively applied. PERC identified 8 clinical criteria for adult patients using logistic regression modeling to exclude PE without additional diagnostic evaluation. If all criteria are met, further evaluation is not indicated. Of 1 185 794 PED visits, 105 patients had an ultimate diagnosis of PE. Twenty-five met study criteria, and all were admitted. Forty percent of these patients had PE diagnosed in the PED. The most common risk factors were BMI ≥25 (50%, 10 of 20), oral contraceptive use (38% 5 of 13 female patients), and history of previous thrombus without PE (28%, 7 of 25). When the PERC rule was applied retrospectively, 84% of patients could not be ruled out, indicating additional evaluation for PE was needed. Pulmonary embolism is rare in children but does occur. This study emphasizes risk factors among children that should raise the suspicion of PE. Additional studies are needed to further evaluate risk factors and signs and symptoms of PE to develop pediatric specific clinical decision rules to provide reliable and reproducible means of determining pretest probability of PE.