Pulmonary Embolism Rule-out Criteria Research Articles

Pulmonary Embolism Workup in Five Steps

A workup for pulmonary embolism (PE) is complex, with multiple clinical decision rules to remember. A proper diagnostic workup can safely rule out PE without the use of computed tomography, which is both expensive and exposes patients to radiation and intravenous contrast. However, once PE has been diagnosed, it is important to risk stratify patients according to severity to both treat and disposition them correctly. PQRsTU is a simple, easy-to-remember mnemonic for the workup of PE that considers five phases: PERC phase (PE rule-out criteria), Quantify gestalt phase (to determine proper use of D-dimer or direct to imaging), Risk stratification phase (once PE has been diagnosed), Treatment phase, and Unit or floor (patient disposition). This structured method for evaluating PE will help clinicians develop a systematic, evidence-based approach to this complex and potentially lethal disease. Video is available at https://vimeo.com/91406117 Password: perls.

The arithmetic of gestalt

It has been said that we are the sum of all we have met. As a learner in the emergency department, I have a lot of meeting to do. Take Sandy, a 35-year-old single mother. Her triage note reads that she came to the hospital after losing her breath bathing her 3-year-old daughter. If you had read it. If you had asked her, she would have told you that she’s been sweating through her clothing during the day, causing her colleagues in the university administrative office to stare awkwardly. She says no to your list of Pulmonary Embolism Rule-Out Criteria (PERC) criteria queries, uses a copper intrauterine device (IUD) as birth control (it was the cheapest option), and is healthy, as far as she knows. If you had asked her. If you had listened, she would have described a difficult social situation that had left her the sole provider for her young daughter. She walks the local drag once or twice a month, selling sex to whomever will buy as her current job does not pay enough to make rent every 30 days.

Wells score and Pulmonary Embolism Rule Out Criteria in preventing over investigation of pulmonary embolism in emergency departments.

Unnecessary diagnostic tests are usually ordered to most of the patients with dyspnea or pleuritic chest pain, because of the worse outcomes of missed diagnosis of pulmonary embolism (PE). To identify rates and causes of over investigation for PE and to search whether it was possible to reduce this over investigation by using Wells score and Pulmonary Embolism Rule Out Criteria (PERC). A retrospective observational cohort study performed in an emergency department of a tertiary care university hospital. All patients who were ordered diagnostic with the suspicion of PE were included in the study. They were grouped into two as PE (+) and PE (-) and compared. Among 108 patients, 53 (49%) were diagnosed as PE (+) and overdiagnosis was present in 55 (51%) patients i.e., PE (-). The sensitivity of high Wells score was 43%, specificity 78%, positive predictive value 66% and negative predictive value 59%. PERC criteria found to be negative (when all of the eight criteria were fulfilled) in only five patients. The sensitivity of the test was 98%, specificity 7%, positive predictive value 50%, negative predictive value 80%. When individual parameters of PERC were evaluated solely for the exclusion of PE; "no leg swelling" and "no previous deep venous thrombosis or PE history" were found significantly negatively correlated with PE diagnosis (p= 0.001, r= -0.325 and p= 0.013, r= -0.214 respectively). Over investigation of PE in emergency departments still remains as an important problem. In order to prevent this, the clinical prediction rules must be developed further and their use in combination should be searched in future studies.

Pulmonary Embolism Rule-out Criteria vs D-dimer testing in low-risk patients for pulmonary embolism: a retrospective study

Study objectivesThe Pulmonary Embolism Rule-out Criteria (PERC) score has shown excellent negative predictive value; however, its use in the European population with high prevalence of PE is controversial. In Europe, PERC is not part of routine practice. For low-risk patients, guidelines recommend D-dimer testing, followed if positive by imaging study. We aimed to study the rate of diagnosis of PE after D-dimer testing in PERC-negative patients that could have been discharged if PERC was applied. MethodThis was a multicenter retrospective study in Paris, France. We included all patients with a suspicion of PE who had D-dimer testing in the emergency department, low pre-test probability, and a negative PERC score (that was retrospectively calculated). Patients with insufficient record to calculate PERC score were excluded. The primary end point was the rate of PE diagnosis before discharge in this population. Secondary end points included rate of invasive imaging studies and subsequent adverse events. ResultsWe screened 4301 patients who had D-dimer testing, 1070 of whom were PERC negative and could be analyzed. The mean age was 35 years and 46% were men. D-dimer was positive (>500 ng/L) in 167 (16%) of them; CTPA or V/Q scan was performed in 153 (14%) cases. PE was confirmed in 5 cases (total rate 0.5%, 95% confidence interval 0.1%-1.1%). Fifteen patients (1%) experienced non-severe adverse events. ConclusionD-dimer testing in PERC-negative patients led to a diagnosis of PE in 0.5% of them, with 15% of patients undergoing unnecessary irradiative imaging studies.

P152 Pulmonary Embolism Rule-out Criteria in Clinical Practice

Suspected pulmonary embolism (PE) is a common reason for referral to the medical team on call. The pulmonary embolism rule-out criteria (PERC) is a validated scoring system to identify patients...

Evaluation of the pulmonary embolism rule-out criteria in a retrospective cohort at an urban academic hospital

BackgroundThe pulmonary embolism rule-out criteria (PERC) is an 8-variable clinical decision rule that identifies patients at low risk for pulmonary embolism (PE) to prevent unnecessary diagnostic testing in the evaluation of suspected PE in the emergency department (ED). The objective of this study was to determine PERC's safety and diagnostic use in our institution's ED population. MethodsWe performed a retrospective analysis on consecutive adult patients evaluated with computed tomographic angiography (CTA) for suspicion of PE at our ED during the dates January 1, 2011, to December 31, 2011. Patients negative for all 8 PERC criteria (ie, “PERC [−]”) were considered to be at low risk for PE. All data were analyzed using SPSS-20 (SPSS Inc, Chicago, IL) to calculate the variables of interest and their respective 95% confidence intervals (95% CIs). ResultsDuring the 12-month study period, 729 subjects were evaluated with CTA for suspicion of PE. Ten subjects were excluded because of nondiagnostic imaging studies. After exclusion, 719 subjects were available for analysis. Prevalence of PE was 4.5%. PERC (−) had a sensitivity of 96.9% (95% CI, 84.3%-99.4%), a negative predictive value of 98.8% (95% CI, 93.5%-99.8%), and a negative likelihood ratio of 0.26 (95% CI, 0.04-1.82) when used as an independent diagnostic test to exclude PE. ConclusionsUse of PERC could have safely avoided 11.5% of CTAs, reducing potential patient harm, health care costs, and unnecessary diagnostic testing. Consistent with prior studies, PERC can be safely used to identify low-risk patients for whom further testing can be deferred.

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.

Retrospective Evaluation of the Pulmonary Embolism Rule-Out Criteria Rule at an Urban Academic Hospital

Retrospective Evaluation of the Pulmonary Embolism Rule-Out Criteria Rule at an Urban Academic Hospital

Sixteen-Year-old Athlete with Chest Pain and Shortness of Breath due to Pulmonary Emboli

BackgroundPulmonary embolism (PE) is a life-threatening condition that is extremely uncommon in the healthy pediatric population. ObjectiveBecause pediatric PE is rarely on the Emergency Physician's differential diagnosis, with this case we hope to increase the clinical suspicion for PE in children who present to the Emergency Department (ED). Case ReportThis is a case of bilateral pulmonary embolism in a 16-year-old basketball player whose only risk factor is oral contraceptive medication. Initial vital signs demonstrated a temperature of 37.1°C (98.8°F), blood pressure 124/74 mm Hg, heart rate 74 beats/min, respiratory rate 16 breaths/min, and oxygen saturation 100% on room air. Subsequent vital signs, physical examination, chest radiograph, electrocardiogram, and laboratory assessments were all within normal limits. Using clinician gestalt in combination with the patient's Wells score of 0, a D-dimer was obtained and returned at 1916 ng/mL. The computed tomography scan with PE protocol detected a total of seven pulmonary emboli bilaterally. The patient was anticoagulated with Lovenox (Sanofi US, Bridgewater, NJ) in the ED and admitted to the pediatric intensive care unit. Complete thrombophilia work-up was negative. The patient was discharged with Lovenox and was transitioned to warfarin. ConclusionsEmergency Physicians may be inclined to discharge a pediatric patient at low pre-test probability for PE with outpatient follow-up if the work-up is non-contributory. But the current adult PE clinical criteria are not as sensitive or specific in the pediatric population. This case demonstrates that the clinician's gestalt should play a major role in combination with the Wells score and PERC (pulmonary embolism rule-out criteria) rule to exclude PE until clinical decision rules specific for the pediatric population are established.

Overuse of Computed Tomography Pulmonary Angiography in the Evaluation of Patients with Suspected Pulmonary Embolism in the Emergency Department

Clinical decision rules have been developed and validated for the evaluation of patients presenting with suspected pulmonary embolism (PE) to the emergency department (ED). The objective was to assess the percentage of computed tomographic pulmonary angiography (CT-PA) procedures that could have been avoided by use of the Wells score coupled with D-dimer testing (Wells/D-dimer) or pulmonary embolism rule-out criteria (PERC) in ED patients with suspected PE. The authors conducted a prospective cohort study of adult ED patients undergoing CT-PA for suspected PE. Wells score and PERC were calculated. A research blood sample was obtained for D-dimer testing for subjects who did not undergo testing as part of their ED evaluation. The primary outcome was PE by CT-PA or 90-day follow-up. Secondary outcomes were ED length of stay (LOS) and CT-PA time as defined by time from order to initial radiologist interpretation. Of 152 suspected PE subjects available for analysis (mean ± SD age = 46.3 ± 15.6 years, 74% female, 59% black or African American, 11.8% diagnosed with PE), 14 (9.2%) met PERC, none of whom were diagnosed with PE. A low-risk Wells score (≤4) was assigned to 110 (72%) subjects, of whom only 38 (35%) underwent clinical D-dimer testing (elevated in 33/38). Of the 72 subjects with low-risk Wells scores who did not have D-dimers performed in the ED, archived research samples were negative in 16 (22%). All 21 subjects with low-risk Wells scores and negative D-dimers were PE-negative. CT-PA time (median = 160 minutes) accounted for more than half of total ED LOS (median = 295 minutes). In total, 9.2 and 13.8% of CT-PA procedures could have been avoided by use of PERC and Wells/D-dimer, respectively.

60 Can We Reduce the Use of Computed Tomography Pulmonary Angiography in Young Female Patients Being Evaluated for Pulmonary Embolism?

Study Objectives: Computed tomography pulmonary angiography is frequently used to evaluate for pulmonary embolism in the emergency department (ED). Though the use of computed tomography pulmonary angiography is increasing exponentially, concerns remain regarding breast radiation exposure, particularly in young female patients. We aimed to determine how often computed tomography pulmonary angiography was performed on females <50 years, and to describe the use of adjunctive testing (D-dimer, chest radiography) and validated screening tools such as the Pulmonary Embolism Rule-out Criteria (PERC) and Revised Geneva score (RGS) in this population.

Is “PERC Negative” Adequate to Rule Out Pulmonary Embolism in the Emergency Department? Evaluating Meta-analysis for Studies of Clinical Prediction Models

Editor’s Capsule Summary for Singh et al:2What is already known on this topic: The pulmonary embolism rule-out criteria (PERC) are commonly used to identify patients for whom D-dimer or other testing can be deferred.What question this study addressed: Are the PERC reliable?What this study adds to our knowledge: In this meta-analysis of 11 studies from 6 countries, the PERC were highly sensitive (97%) in excluding pulmonary embolism but were nonspecific (23%).How this is relevant to clinical practice: This pooled analysis strongly corroborates the safety of using PERC to defer D-dimer testing.

Performance of the Pulmonary Embolism Rule-out Criteria (the PERC rule) combined with low clinical probability in high prevalence population

IntroductionPERC rule was created to rule out pulmonary embolism (PE) without further exams, with residual PE risk<2%. Its safety is currently not confirmed in high PE prevalence populations even when combined with low clinical probability assessed by revised Geneva score (RGS). As PERC rule and RGS are 2 similar explicit rules with many redundant criteria, we hypothesized that the combination of PERC rule with gestalt clinical probability could resolve this limitation. MethodsWe collected prospectively documented clinical gestalt assessments and retrospectively calculated PERC rules and RGS from a prospective study of PE suspected patients. We analyzed performance of combinations of negative PERC with low clinical probability assessed by both methods in high overall PE prevalence population. ResultsAmong the final study population (n=959), the overall PE prevalence was 29.8%. Seventy-four patients (7.7%) were classified as PERC negative and among them, 4 patients (5.4%) had final diagnosis of PE. When negative PERC was combined with low pretest probability assessed by RGS or gestalt assessment, PE prevalence was respectively 6.2% and 0%. This last combination reaches threshold target of 2% and unnecessary exams could easily have been avoided in this subgroup (6%). However, it confidence interval was still wide (0%; CI 0–5). ConclusionsPERC rule combined with low gestalt probability seems to identify a group of patients for whom PE could easily be ruled out without additional test.A larger study is needed to confirm this result and to ensure safety.

Reducing CT-PA Ordering for Suspected Pulmonary Embolism

The pulmonary embolism rule-out criteria (PERC) (see table) and Wells score (see table) coupled with d-dimer testing (Wells/d-dimer) are validated decision rules that safely eliminate the need for computed tomography pulmonary angiography (CT-PA) in patients with suspected PE. …

Diagnostic Accuracy of Pulmonary Embolism Rule-Out Criteria: A Systematic Review and Meta-analysis

To perform a systematic review and meta-analysis to define the diagnostic performance of pulmonary embolism rule-out criteria (PERC) in deferring the need for D-dimer testing to rule out pulmonary embolism in the emergency department (ED). We searched EMBASE, MEDLINE, Scopus, Web of Knowledge, and all the evidence-based medicine reviews that included the Cochrane Database of Systematic Reviews through August 14, 2011, and hand searched references in potentially eligible articles and conference proceedings of major emergency medicine organizations for the previous 2 years. We selected studies that reported diagnostic performance of PERC, reported original research, and were conducted in the ED, with no language restrictions. Two investigators independently identified eligible studies and extracted data. We used contingency tables to calculate sensitivity, specificity, and likelihood ratios. We found 12 qualifying cohorts (studying 13,885 patients with 1,391 pulmonary embolism diagnoses), 10 prospective and 2 retrospective, from 6 countries. Pooled sensitivity, specificity, positive likelihood ratios, and negative likelihood ratios for 10 included studies were 0.97 (95% confidence interval [CI] 0.96 to 0.98), 0.23 (95% CI 0.22 to 0.24), 1.24 (95% CI 1.18 to 1.30), and 0.17 (95% CI 0.13 to 0.23), respectively. Significant heterogeneity was observed in specificity (I(2)=97.2%) and positive likelihood ratio (I(2)=84.2%). The existing literature suggests consistently high sensitivity and low but acceptable specificity of the PERC to rule out pulmonary embolism in patients with low pretest probability.

6 Prognostic Accuracy of Pulmonary Embolism Rule-out Criteria: A Systematic Review and Meta-Analysis

6 Prognostic Accuracy of Pulmonary Embolism Rule-out Criteria: A Systematic Review and Meta-Analysis

Performance of the Pulmonary Embolism Rule-out Criteria (the PERC Rule) Combined with Low Clinical Probability in High Prevalence Population

article Introduction: PERC rule was created to rule out pulmonary embolism (PE) without further exams, with resid- ual PE riskb2%. Its safety is currently not con! rmed in high PE prevalence populations even when combined with low clinical probability assessed by revised Geneva score (RGS). As PERC rule and RGS are 2 similar ex- plicit rules with many redundant criteria, we hypothesized that the combination of PERC rule with gestalt clinical probability could resolve this limitation. Methods: We collected prospectively documented clinical gestalt assessments and retrospectively calculated PERC rules and RGS from a prospective study of PE suspected patients. We analyzed performance of combi- nations of negative PERC with low clinical probability assessed by both methods in high overall PE prevalence

Utilization and Yield of Chest Computed Tomographic Angiography Associated with Low Positive D-dimer Levels

BackgroundIt is unclear to what degree broadly applied D-dimer testing combined with a low threshold for imaging with even minimally positive results may be contributing to the utilization of chest computed tomographic angiography (CTA). Study ObjectivesTo determine what proportion of chest CTAs for suspected pulmonary embolism (PE) were performed in the setting of minimally elevated D-dimer levels, and to determine the prevalence of PE in those patients when stratified by clinical risk. MethodsRetrospective chart review of all patients who had chest CTA for the evaluation of suspected PE during the years 2002–2006 in a suburban community teaching hospital emergency department. ResultsThere were 1136 eligible patient visits, of which 353 (31.1%) were found to have D-dimer levels in the low positive range (0.5–0.99 μg/mL). Of these 353 patients, 9 (2.6%; 95% confidence interval [CI] 0.9–4.2%) were diagnosed with PE. There were also 109 patients (9.6%) who had normal D-dimer levels (<0.5 μg/mL). Two of these 109 (1.8%; 95% CI 0–4.2%) were diagnosed with PE. When stratified by the Pulmonary Embolism Rule-out Criteria, 99 of 353 patients with low positive D-dimer levels (28.0%; 95% CI 23.4–32.7%), and 14 of 109 with normal D-dimer levels (12.8%; 95% CI 6.6–19.1%) were classified as low risk, none of whom had PE. ConclusionsNearly one-third of all chest CTAs were done for patients with minimally elevated D-dimer levels, and another 9.6% for patients with normal D-dimer levels with very low yield. Further research to define clinical criteria identifying patients with minimal risk of PE despite low positive D-dimer levels represents an opportunity to improve both patient safety and utilization efficiency of chest CTA.

The pulmonary embolism rule‐out criteria (PERC) rule does not safely exclude pulmonary embolism

The Pulmonary Embolism Rule-out Criteria (PERC) rule is a clinical diagnostic rule designed to exclude pulmonary embolism (PE) without further testing. We sought to externally validate the diagnostic performance of the PERC rule alone and combined with clinical probability assessment based on the revised Geneva score. The PERC rule was applied retrospectively to consecutive patients who presented with a clinical suspicion of PE to six emergency departments, and who were enrolled in a randomized trial of PE diagnosis. Patients who met all eight PERC criteria [PERC((-))] were considered to be at a very low risk for PE. We calculated the prevalence of PE among PERC((-)) patients according to their clinical pretest probability of PE. We estimated the negative likelihood ratio of the PERC rule to predict PE. Among 1675 patients, the prevalence of PE was 21.3%. Overall, 13.2% of patients were PERC((-)). The prevalence of PE was 5.4% [95% confidence interval (CI): 3.1-9.3%] among PERC((-)) patients overall and 6.4% (95% CI: 3.7-10.8%) among those PERC((-)) patients with a low clinical pretest probability of PE. The PERC rule had a negative likelihood ratio of 0.21 (95% CI: 0.12-0.38) [corrected] for predicting PE overall, and 0.63 (95% CI: 0.38-1.06) in low-risk patients. Our results suggest that the PERC rule alone or even when combined with the revised Geneva score cannot safely identify very low risk patients in whom PE can be ruled out without additional testing, at least in populations with a relatively high prevalence of PE.

442: Do Emergency Physicians Appropriately Select Patients for CT to Diagnose Pulmonary Embolus?

Pulmonary embolus (PE) is a challenging disease that carries the potential for poor outcome and, if missed, is often the subject of medical malpractice litigation. Physicians in emergency departments (ED) may be overusing the computed tomography (CT) to diagnose pulmonary embolus in a defensive fashion. Clinical decision tools have been developed and validated regarding the utility of further diagnostic testing for PE. We sought to evaluate if the emergency physician decision to perform a CT conforms to the validated clinical decision algorithms for pulmonary embolus. This study is a retrospective chart review performed in a level 1, urban, tertiary care ED from October 24, 2008 to October 24, 2009. Inclusion criteria were patients aged 18 years or older who underwent chest CT imaging. We excluded subjects whose imaging was not specifically performed for PE or those with charts documenting the use of a validated PE diagnostic algorithm as part of the workup. Data collected included diagnostic predictors used in each of the rules: Pulmonary Embolism Rule-Out Criteria (PERC), Wells Criteria (Wells), and Revised Geneva Criteria (RGC), D-dimer, and the presence of PE on CT. Each score from the diagnostic algorithms was dichotomized into low/high probability for pulmonary embolism. High probability in this study indicates that the CT scan was indicated. The data were entered into the REDCap database and analyzed by SAS using Fisher, Chi-square, and logistic regression as appropriate. Of 565 ED visits that included imaging of the chest, there were 330 enrolled. The prevalence of PE in the study cohort was 11.5% (38/330) (95%CI: 0.08,0.15). The D-dimer assay was performed in 72.7% (240/330) of subjects with a mean of 2007 (95%CI 1639;2374); 64.6% of subjects had values >500. Of the patients who were ultimately diagnosed with PE on CT, 28.9% (11/38) did not have a D-dimer assay performed prior to CT imaging, and 2.6% (1/38) had a D-Dimer <500. The following odds ratios were observed in the positive PE cohort: admission status OR 7.58 (p500 and hypoxia were not significantly associated with PE (OR 1.47 p=0.37; OR 0.81 p=0.66). (Table 1) Utilizing the algorithms, according to PERC 95% (314/330), Wells 88% (291/330), and RGC 81% (269/330) of subjects met criteria for moderate or high pre-test probability for PE. The sensitivities of each test in predicting PE in this cohort were PERC 100% (95%CI 91;100), Wells 100% (95%CI 91;100), RGC 89% (95%CI 80;99). The specificities for each test were PERC 5% (95%CI 3;8), Wells 13% (95%CI 1;18), RGC 19% (95%CI 15;24).Tabled 1 In this retrospective study, the emergency physician's high clinical suspicion had a high predictive value for pulmonary embolus when compared to any single variable used in the 3 clinical scoring methods including D-Dimer >500. Most CT studies performed in the ED to diagnose pulmonary embolus are clinically indicated by validated prediction algorithms even when performed based on physician gestalt alone.