Impact of a rapid rule-out protocol for pulmonary embolism on the rate of screening, missed cases, and pulmonary vascular imaging in an urban US emergency department

Triple Threat: A Case Presentation of Pulmonary Embolism With Diabetic Ketoacidosis and Lower Respiratory Tract Infection

This case report details the diagnostic challenges and management of a middle-aged man who presented with complaints of fever and breathlessness. He was initially suspected of lower respiratory tract infection and diabetic ketoacidosis on clinical examination and treated with intravenous fluids, antibiotics, and insulin infusion. The point of care ultrasound (POCUS), as part of the primary survey, showed right atrium (RA)-right ventricle (RV) dilation and a D-shaped left ventricle, which was highly suspicious of pulmonary embolism and was later confirmed with computed tomography pulmonary angiogram (CTPA). The patient was successfully managed for pulmonary embolism, diabetic ketoacidosis, and lower respiratory tract infection.

POCUS for Thrombus: Emphasizing the Importance of Initial Point-of-Care Ultrasound in the Management of Pulmonary Thromboembolism

Pulmonary embolism (PE) constitutes a substantial health burden among individuals in the United States. It ranks as the third most common cause of cardiovascular death aside from stroke and myocardial infarction. Diagnostic errors are common with PE as patients can present with non-specific symptoms or could be completely asymptomatic with PE being an incidental finding. Diagnostic errors can result in missed or late diagnosis of PE, which, in turn, increases health care costs, morbidity, and mortality rates. Hence, early diagnosis is crucial. Computed tomography pulmonary angiography (CTPA) remains the gold standard in PE diagnosis, despite exposure to high doses of radiation. Point-of-care ultrasound (POCUS) is an underutilized, non-invasive technique that aids in the early diagnosis of PE and can safely reduce the radiation from CTPA in cases where contraindication exists. POCUS has been shown to have a high sensitivity and specificity for early diagnosis of PE.

Adherence to Best Practice Advice for Diagnosis of Pulmonary Embolism

PURPOSE

This study evaluated clinician adherence to the American College of Physicians Best Practice Advice for diagnosis of pulmonary embolism.

DESIGN

A prospective, single-center, descriptive design was utilized.

METHODS

A heterogeneous sample of 111 hemodynamically stable adult inpatients with a computed tomography pulmonary angiogram ordered was consented. Electronic medical records were reviewed for demographic and clinical variables to determine adherence. The 6 individual best practice statements and the overall adherence were evaluated by taking the sum of "yes" answers divided by the sample size.

RESULTS

Overall adherence was 0%. Partial adherence was observed with clinician-recorded clinical decisions rules and obtaining d-dimer (3.6% [4/111] and 10.2% [9/88], respectively) of low/intermediate probability scorers. Age adjustment of d-dimer was not recorded. Computed tomography pulmonary angiogram was the first diagnostic test in 89.7% (79/88) in low/intermediate probability patients.

CONCLUSION

In hemodynamically stable, hospitalized adults, adherence to best practice guidelines for diagnosis of pulmonary embolism was minimal. Clinical utility of the guidelines in hospitalized adults needs further evaluation. Systems problems (eg, lack of standardized orders, age-adjusted d-dimer values, information technology support) likely contributed to poor guideline adherence.

Pulmonary embolism prevalence among emergency department cohorts: A systematic review and meta-analysis by country of study

Essentials The threshold to test for pulmonary embolism (PE) might be lower in North America than Europe. We compared the PE prevalence and positive yield of imaging in Europe and North America. More patients tested in Europe are diagnosed with PE, and imaging is more often positive. Our systematic review supports the hypothesis of overtesting for PE in North America. ABSTRACT: Background There is an impression that North American emergency department (ED) patients tested for pulmonary embolism (PE) differ from European ones. Objectives We compared the PE prevalence, frequency of use, and positive yield of imaging among ED patients tested for PE in Europe and North America. Methods We searched for studies reporting consecutive ED patients tested for PE. Two authors screened full texts, performed risk of bias assessment, and data extraction. We conducted a meta-analysis of proportions for each outcome and a multiple meta-regression. Results From 3109 publications, 44 were included in the systematic review. The prevalence of PE in Europe was 23% (95% confidence interval [CI], 21-26) and in North America 8% (95% CI, 6-9). The adjusted mean difference (aMD) in the prevalence of PE in the European compared with North American studies, was 15% (95% CI, 10-20). Computed tomography pulmonary angiography (CTPA) was used in 60% (95% CI, 52%-68) of European and 38% (95% CI, 24-51) of North American patients tested for PE (aMD, 23% [95% CI, 7-39]). The CTPA diagnostic yield was 29% (95% CI, 26-32) in Europe and 13% (95% CI, 9-17) in North America (aMD, 15% [95% CI, 8-21]). Conclusion Compared with North America, European ED studies have a higher prevalence of PE and diagnostic yield from CTPA, despite a higher frequency of CTPA use among patients tested for PE. This supports the hypothesis that those tested for PE in North American EDs have a lower risk of PE compared with Europe.

Short and long-term mortality in elderly patients with suspected not confirmed pulmonary embolism

INTRODUCTION

Most patients evaluated for suspected pulmonary embolism(PE) conclude the Emergency Department(ED) work-up with a diagnosis of PE not confirmed(PE excluded;PE-E). We aimed to investigate the clinical features, short and long-term mortality, and prognostic factors for death in elderly with PE-E, and to compare these figures with those of patients with PE confirmed(PE-C).

METHODS

Consecutive patients ≥65 years old evaluated in the ED for clinically suspected hemodynamically stable acute PE were included in this retrospective cohort study.

RESULTS

Study population: 657 patients with suspected PE, PE-C:162(24.65%). When compared with PE-C, patients with PE-E presented a higher prevalence of chronic cardiopulmonary disease (17.37% vs 8.02%, p = 0.003), a lower prevalence of pulse rate >110 (13.13% vs 25.93%; p<0.001), of arterial oxygen saturation <90% (16.16% vs. 25.93%; p = 0.007) and of hospitalized patients (52.93% vs 98.15%; p < 0.001). Thirty-day, 90-day, 1-year, 2-year and 5-year overall mortality was 8.83%, 15.98%, 23.59%, 29.68%, and 51.09%, respectively, differences between PE-E and PE-C non statistically significant. Among patients with PE-E, multivariate analysis showed that simplified Pulmonary Embolism Severity Index score>0 was associated with higher short and long-term mortality (30-day:HR:5.31,p = 0.029; 5 year:HR:2.18, p < 0.001), meanwhile comorbidity (Charlson Comorbidity Index>0) only with higher long-term mortality (30-day: HR:1.60, p = 0.342; 5 year: HR:1.41, p = 0.038).

CONCLUSION

In real world haemodinamically stable elderly patients evaluated in the ED for suspected PE, short and long-term mortality was markedly high regardless whether PE was confirmed or excluded. At the time to set management and follow up strategies, elderly patients with PE excluded should not be considered a low-risk population.

Evaluation of Cancer Patients With Suspected Pulmonary Embolism: Performance of the American College of Physicians Guideline

BACKGROUND

Accurate risk stratification of pulmonary embolism (PE) can reduce unnecessary imaging. We investigated the extent to which the American College of Physicians (ACP) guideline for evaluation of patients with suspected PE could be applied to cancer patients in the emergency department of a comprehensive cancer center.

MATERIALS AND METHODS

Data from cancer patients who underwent CT pulmonary angiography (CTPA) between August 1, 2015, and October 31, 2015, were collected. We assessed each patient's diagnostic workup for its adherence to the ACP guideline in terms of clinical risk stratification and age-adjusted d-dimer level and the degree to which these factors were associated with PE.

RESULTS

Of the 380 patients identified, 213 (56%) underwent CTPA indicated per the ACP guideline, and 78 (21%) underwent CTPA not indicated per the guideline. Only one of the patients who underwent nonindicated CTPA had a PE. Fifty-seven patients underwent unnecessary d-dimer evaluation, and 71 patients with negative d-dimer test results underwent nonindicated CTPA. PEs were found in 6 of 108 (6%) low-risk patients, 22 of 219 (10%) intermediate-risk patients, and 13 of 53 (25%) high-risk patients. The ACP guideline had negative predictive value of 99% (95% confidence interval: 93%-100%) and sensitivity of 97% (95% confidence interval: 86%-100%) in predicting PE.

CONCLUSION

The ACP guideline has good sensitivity for detecting PE in cancer patients and thus can be applied in this population. Compliance with the ACP guideline when evaluating cancer patients with suspected PE could reduce the use of unnecessary imaging and laboratory studies.

Predictive value of the urinary dipstick test in the management of patients with urinary tract infection-associated symptoms in primary care in Indonesia: a cross-sectional study

OBJECTIVE

To assess the test characteristics of a urine dipstick test in predicting a positive urine culture in an outpatient setting in Indonesia.

DESIGN

Cross-sectional study.

SETTING

Two outpatient clinics in Medan, Indonesia.

PARTICIPANTS

616 consecutively enrolled participants suspected of having a urinary tract infection.

OUTCOME MEASURES

The primary outcome is the estimates of accuracy (sensitivity, specificity, predictive values) where urine culture is the reference test. The secondary outcome is the post-test probability of a positive urine culture.

RESULTS

The optimal test characteristics were obtained when index test positivity was defined as any leucocyte esterase reaction and/or a nitrite reaction and reference test positivity was defined as a urine culture with a growth of at least 103 colony-forming units/mL (sensitivity: 88.2% (95% CI 81.6 to 93.1), negative predictive value: 93.0% (95% CI 88.9 to 95.9)). The post-test probability of a positive urine culture after a negative urinary dipstick test was 7% in the obstetric/gynaecology clinic and 8% in the internal medicine clinic.

CONCLUSION

The use of a urine dipstick test in a rule-out strategy can reduce the need for urine culture and avoid the prescription of (ineffective) antibiotics in a non-urology outpatient setting.

Interventions to Reduce the Overuse of Imaging for Pulmonary Embolism: A Systematic Review

BACKGROUND

Imaging use in the diagnostic workup of pulmonary embolism (PE) has increased markedly in the last 2 decades. Low PE prevalence and diagnostic yields suggest a significant problem of overuse.

PURPOSE

The purpose of this systematic review is to summarize the evidence associated with the interventions aimed at reducing the overuse of imaging in the diagnostic workup of PE in the emergency department and hospital wards.

DATA SOURCES

PubMed, MEDLINE, Embase, and EBM Reviews from 1998 to March 28, 2017.

STUDY SELECTION

Experimental and observational studies were included. The types of interventions, their efficacy and safety, the impact on healthcare costs, the facilitators, and barriers to their implementation were assessed.

DATA SYNTHESIS

Seventeen studies were included assessing clinical decision support (CDS), educational interventions, performance and feedback reports (PFRs), and institutional policy. CDS impact was most comprehensively documented. It was associated with a reduction in imaging use, ranging from 8.3% to 25.4%, and an increase in diagnostic yield, ranging from 3.4% to 4.4%. The combined implementation of a CDS and PFR resulted in a modest but significant increase in the adherence to guidelines. Few studies appraised the safety of interventions. There was a lack of evidence concerning economic aspects, facilitators, and barriers.

CONCLUSIONS

A combined implementation of an electronic CDS and PFRs is more effective than purely educational or policy interventions, although evidence is limited. Future studies of high-methodological quality would strengthen the evidence concerning their efficacy, safety, facilitators, and barriers.

Thrombosis, Hypercoagulable States, and Anticoagulants

Patients with derangements of secondary hemostasis resulting from inherited or acquired thrombophilias are at increased risk of venous thromboemboli (VTE). Evaluation of a patient with suspected VTE proceeds via evidence-based algorithms that involve computing a pretest probability based on the history and physical examination; this guides subsequent work-up, which can include D dimer and/or imaging. Testing for hypercoagulable disorders should be pursued only in patients with VTE with an increased risk for an underlying thrombophilia. Direct oral anticoagulants are first-line VTE therapies, but they should be avoided in patients who are pregnant, have active cancer, antiphospholipid antibody syndrome, severe renal insufficiency, or prosthetic heart valves.

RESPECT-ED: Rates of Pulmonary Emboli (PE) and Sub-Segmental PE with Modern Computed Tomographic Pulmonary Angiograms in Emergency Departments: A Multi-Center Observational Study Finds Significant Yield Variation, Uncorrelated with Use or Small PE Rates

INTRODUCTION

Overuse of CT Pulmonary Angiograms (CTPA) for diagnosing pulmonary embolism (PE), particularly in Emergency Departments (ED), is considered problematic. Marked variations in positive CTPA rates are reported, with American 4-10% yields driving most concerns. Higher resolution CTPA may increase sub-segmental PE (SSPE) diagnoses, which may be up to 40% false positive. Excessive use and false positives could increase harm vs. benefit. These issues have not been systematically examined outside America.

AIMS

To describe current yield variation and CTPA utilisation in Australasian ED, exploring potential factors correlated with variation.

METHODS

A retrospective multi-centre review of consecutive ED-ordered CTPA using standard radiology reports. ED CTPA report data were inputted onto preformatted data-sheets. The primary outcome was site level yield, analysed both intra-site and against a nominated 15.3% yield. Factors potentially associated with yield were assessed for correlation.

RESULTS

Fourteen radiology departments (15 ED) provided 7077 CTPA data (94% ≥64-slice CT); PE were reported in 1028 (yield 14.6% (95%CI 13.8-15.4%; range 9.3-25.3%; site variation p <0.0001) with four sites significantly below and one above the 15.3% target. Admissions, CTPA usage, PE diagnosis rates and size of PE were uncorrelated with yield. Large PE (≥lobar) were 55% (CI: 52.1-58.2%) and SSPE 8.8% (CI: 7.1-10.5%) of positive scans. CTPA usage (0.2-1.5% adult attendances) was correlated (p<0.006) with PE diagnosis but not SSPE: large PE proportions.

DISCUSSION/ CONCLUSIONS

We found significant intra-site CTPA yield variation within Australasia. Yield was not clearly correlated with CTPA usage or increased small PE rates. Both SSPE and large PE rates were similar to higher yield historical cohorts. CTPA use was considerably below USA 2.5-3% rates. Higher CTPA utilisation was positively correlated with PE diagnoses, but without evidence of increased proportions of small PE. This suggests that increased diagnoses seem to be of clinically relevant sized PE.

Guidance for the treatment of deep vein thrombosis and pulmonary embolism

This guidance document focuses on the diagnosis and treatment of venous thromboembolism (VTE). Efficient, cost effective diagnosis of VTE is facilitated by combining medical history and physical examination with pre-test probability models, D dimer testing and selective use of confirmatory imaging. Clinical prediction rules, biomarkers and imaging can be used to tailor therapy to disease severity. Anticoagulation options for acute VTE include unfractionated heparin, low molecular weight heparin, fondaparinux and the direct oral anticoagulants (DOACs). DOACs are as effective as conventional therapy with LMWH and vitamin K antagonists. Thrombolytic therapy is reserved for massive pulmonary embolism (PE) or extensive deep vein thrombosis (DVT). Inferior vena cava filters are reserved for patients with acute VTE and contraindications to anticoagulation. Retrievable filters are strongly preferred. The possibility of thoracic outlet syndrome and May-Thurner syndrome should be considered in patients with subclavian/axillary and left common iliac vein DVT, respectively in absence of identifiable triggers. The optimal duration of therapy is dictated by the presence of modifiable thrombotic risk factors. Long term anticoagulation should be considered in patients with unprovoked VTE as well as persistent prothrombotic risk factors such as cancer. Short-term therapy is sufficient for most patients with VTE associated with transient situational triggers such as major surgery. Biomarkers such as D dimer and risk assessment models such the Vienna risk prediction model offer the potential to customize VTE therapy for the individual patient. Insufficient data exist to support the integration of bleeding risk models into duration of therapy planning.

Incidence of pulmonary emboli on chest computed tomography angiography based upon referral patterns

Pulmonary embolism (PE) is a potentially lethal condition, and the diagnosis of PE can be difficult. The purpose of this study is to evaluate the incidence of PE on chest computed tomography angiography (CTA) studies ordered in the inpatient, outpatient, and emergency department (ED) settings and further segregated based on the adult and pediatric populations, and by the ordering clinician (attending physicians, resident physicians, or physician extenders). A retrospective review of chest CTA examinations performed between July 1,2009 and June 30, 2010 was performed. Of 5848 adult CTA studies, PE was diagnosed in 594 (10.1 %). Of these positive studies, 315 (53 %) were inpatient, 234 (39.4 %) were ED patients, and 45 (7.6 %) were outpatient. Four hundred sixty-four of 4445 (10.4 %) CTA examinations ordered by attending physicians were positive for PE. Seventy-four of the 801 (9.2 %) CTA examinations ordered by resident physicians were positive for PE. Fifty-six of the 608 CTA examinations ordered by physician extenders were positive for PE. Thirty-three pediatric CTA studies for PE met criteria and none of them indicated PE. There is no significant difference in the incidence of PE in chest CTA based on setting or ordering clinician.

Evaluation of Patients With Suspected Acute Pulmonary Embolism: Best Practice Advice From the Clinical Guidelines Committee of the American College of Physicians

DESCRIPTION

Pulmonary embolism (PE) can be a severe disease and is difficult to diagnose, given its nonspecific signs and symptoms. Because of this, testing patients with suspected acute PE has increased dramatically. However, the overuse of some tests, particularly computed tomography (CT) and plasma d-dimer measurement, may not improve care while potentially leading to patient harm and unnecessary expense.

METHODS

The literature search encompassed studies indexed by MEDLINE (1966-2014; English-language only) and included all clinical trials and meta-analyses on diagnostic strategies, decision rules, laboratory tests, and imaging studies for the diagnosis of PE. This document is not based on a formal systematic review, but instead seeks to provide practical advice based on the best available evidence and recent guidelines. The target audience for this paper is all clinicians; the target patient population is all adults, both inpatient and outpatient, suspected of having acute PE.

BEST PRACTICE ADVICE 1

Clinicians should use validated clinical prediction rules to estimate pretest probability in patients in whom acute PE is being considered.

BEST PRACTICE ADVICE 2

Clinicians should not obtain d-dimer measurements or imaging studies in patients with a low pretest probability of PE and who meet all Pulmonary Embolism Rule-Out Criteria.

BEST PRACTICE ADVICE 3

Clinicians should obtain a high-sensitivity d-dimer measurement as the initial diagnostic test in patients who have an intermediate pretest probability of PE or in patients with low pretest probability of PE who do not meet all Pulmonary Embolism Rule-Out Criteria. Clinicians should not use imaging studies as the initial test in patients who have a low or intermediate pretest probability of PE.

BEST PRACTICE ADVICE 4

Clinicians should use age-adjusted d-dimer thresholds (age × 10 ng/mL rather than a generic 500 ng/mL) in patients older than 50 years to determine whether imaging is warranted.

BEST PRACTICE ADVICE 5

Clinicians should not obtain any imaging studies in patients with a d-dimer level below the age-adjusted cutoff.

BEST PRACTICE ADVICE 6

Clinicians should obtain imaging with CT pulmonary angiography (CTPA) in patients with high pretest probability of PE. Clinicians should reserve ventilation-perfusion scans for patients who have a contraindication to CTPA or if CTPA is not available. Clinicians should not obtain a d-dimer measurement in patients with a high pretest probability of PE.

Could the number of CT angiograms be reduced in emergency department patients suspected of pulmonary embolism?

BACKGROUND

This study was undertaken to identify the prevalence of pulmonary embolism (PE) in the emergency department (ED) of an urban teaching hospital and also to test a Bayesian model in estimating the number of CT pulmonary angiography (CTA) expected to be performed in an emergency department.

METHODS

The data for this study was obtained through a retrospective review of electronic medical records for all ED patients suspected of PE who underwent chest CTA or ventilation perfusion scanning (V/Q) between 2009 and 2010. The data is presented as means and standard deviation for continuous variables and percentages with 95% confidence intervals (95%CI) for proportions. The prevalence of PE was used as pre-test probability in the Bayesian model. Post-test probability was obtained using a Fagan nomogram and likelihood ratios for CTA.

RESULTS

A total of 778 patients (560 females) with mean age of 50 years (range 18-98 years) were enrolled (98.3% underwent chest CTA and 1.7% underwent V/Q scan). A total of 69 patients had PE, rendering an overall prevalence of 8.9% (95%CI, 7.1% to 11.1%) for PE. We calculated that 132 CTA's per year could be avoided in our institution, without compromising safe exclusions of PE (keeping post-test probability of PE below 2%).

CONCLUSIONS

Despite differences in our patient populations and /or study designs, the prevalence of PE in our institution is about average compared to other institutions. Our proposed model for calculating redundant chest CTA is simple and can be used by institutions to identify overuse of CTA.

Systematic review and meta-analysis of pregnant patients investigated for suspected pulmonary embolism in the emergency department

OBJECTIVES

Pregnancy causes a small increase in risk of venous thromboembolism (VTE), but a large increase in concern upon presentation to an emergency department (ED) with symptoms of pulmonary embolism (PE), which may cause physicians to employ a low test threshold. This was a systematic review with the hypothesis that symptomatic pregnant patients in the ED have a low relative risk (RR) for VTE outcome.

METHODS

Studies in all languages were identified by structured search of PubMed, EMBASE, the Cochrane library, and bibliographies in February 2014. Papers with ED patients evaluated for possible PE that included pregnancy status, and had adequate reference standards, were included. An outcome of VTE (either deep venous thrombosis [DVT] or PE) was considered disease-positive (VTE+). Papers were assessed for selection and publication bias, and heterogeneity (I(2) ). The random effects model was used if I(2)  > 24%.

RESULTS

Seventeen full-length studies of 25,339 patients were analyzed. Pooled data showed I² = 0% with a symmetrical funnel plot. Two small studies with less than 1% of all patients had evidence of selection bias. The frequency of VTE+ rate among the 506 pregnant patients was 4.1% (95% confidence interval [CI] = 2.6% to 6.0%), compared with 12.4% (95% CI = 9.0% to 16.3%) among nonpregnant patients. The pooled RR of pregnancy for VTE+ diagnosis was 0.60 (95% CI = 0.41 to 0.87). Patients in the third trimester had a RR of 0.85 (95% CI = 0.40 to 1.77), and patients of childbearing age (≤45 years) had a RR of 0.56 (95% CI = 0.34 to 0.93).

CONCLUSIONS

In the ED setting, physicians test for PE in pregnant patients at a low threshold, resulting in a low rate of VTE diagnosis and a RR of VTE that is lower than that for nonpregnant women of childbearing age who are tested for PE in the ED setting.

Developing an international register of clinical prediction rules for use in primary care: a descriptive analysis

PURPOSE

We describe the methodology used to create a register of clinical prediction rules relevant to primary care. We also summarize the rules included in the register according to various characteristics.

METHODS

To identify relevant articles, we searched the MEDLINE database (PubMed) for the years 1980 to 2009 and supplemented the results with searches of secondary sources (books on clinical prediction rules) and personal resources (eg, experts in the field). The rules described in relevant articles were classified according to their clinical domain, the stage of development, and the clinical setting in which they were studied.

RESULTS

Our search identified clinical prediction rules reported between 1965 and 2009. The largest share of rules (37.2%) were retrieved from PubMed. The number of published rules increased substantially over the study decades. We included 745 articles in the register; many contained more than 1 clinical prediction rule study (eg, both a derivation study and a validation study), resulting in 989 individual studies. In all, 434 unique rules had gone through derivation; however, only 54.8% had been validated and merely 2.8% had undergone analysis of their impact on either the process or outcome of clinical care. The rules most commonly pertained to cardiovascular disease, respiratory, and musculoskeletal conditions. They had most often been studied in the primary care or emergency department settings.

CONCLUSIONS

Many clinical prediction rules have been derived, but only about half have been validated and few have been assessed for clinical impact. This lack of thorough evaluation for many rules makes it difficult to retrieve and identify those that are ready for use at the point of patient care. We plan to develop an international web-based register of clinical prediction rules and computer-based clinical decision support systems.

Rationale and methodology for a multicentre randomised trial of fibrinolysis for pulmonary embolism that includes quality of life outcomes

BACKGROUND

Submassive pulmonary embolism (PE) has a low mortality rate but can degrade functional capacity.

OBJECTIVE

The present study aims to provide rationale, methodology, and initial findings of a multicentre, randomised trial of fibrinolysis for PE that used a composite end-point, including quality of life measures.

METHODS

This investigator-initiated study was funded by a contract between a corporate partner and the investigator's hospital (the prime site). The investigator was the Food and Drug Administration (FDA) sponsor. The prime site subcontracted, indemnified, and trained consortia members. Consenting, normotensive patients with PE and right ventricular strain (by echocardiography or biomarkers) received low-molecular-weight heparin and random assignment to a single bolus of tenecteplase or placebo in double-blinded fashion. The outcomes were: (i) in-hospital rate of intubation, vasopressor support, and major haemorrhage, or (ii) at 90 days, death, recurrent PE, or composite that defined poor quality of life (echocardiography, 6 min walk test and surveys). The planned sample size was n = 200.

RESULTS

Eight sites enrolled 87 patients over 5 years. The ratio of patients screened for each enrolled was 7.4 to 1, equating to 11 h screening time per patient enrolled. Primary barrier to enrolment was the cost of screening. Two patients died (2.5%, 95%CI [0-8%]), one developed shock, but 18 (22%, 95%CI: [13-30%]) had a poor quality of life.

CONCLUSIONS

An investigator-initiated, FDA-regulated, multicentre trial of fibrinolysis for submassive PE was conducted, but was limited by screening costs and a low mortality rate. Quality of life measurements might represent a more important patient-centred end-point.

D-dimer threshold increase with pretest probability unlikely for pulmonary embolism to decrease unnecessary computerized tomographic pulmonary angiography

BACKGROUND

Increasing the threshold to define a positive D-dimer could reduce unnecessary computed tomographic pulmonary angiography (CTPA) for a suspected pulmonary embolism (PE) but might increase rates of a missed PE and missed pneumonia, the most common non-thromboembolic diagnosis seen on CTPA.

OBJECTIVE

Measure the effect of doubling the standard D-dimer threshold for 'PE unlikely' Revised Geneva (RGS) or Wells' scores on the exclusion rate, frequency and size of a missed PE and missed pneumonia.

METHODS

Patients evaluated for a suspected PE with 64-channel CTPA were prospectively enrolled from emergency departments (EDs) and inpatient units of four hospitals. Pretest probability data were collected in real time and the D-dimer was measured in a central laboratory. Criterion standard was CPTA interpretation by two independent radiologists combined with clinical outcome at 30 days.

RESULTS

Of 678 patients enrolled, 126 (19%) were PE+ and 93 (14%) had pneumonia. Use of either Wells' ≤ 4 or RGS ≤ 6 produced similar results. For example, with RGS ≤ 6 and standard threshold (< 500 ng mL(-1)), D-dimer was negative in 110/678 (16%), and 4/110 were PE+ (posterior probability 3.8%) and 9/110 (8.2%) had pneumonia. With RGS ≤ 6 and a threshold < 1000 ng mL(-1) , D-dimer was negative in 208/678 (31%) and 11/208 (5.3%) were PE+, but 10/11 missed PEs were subsegmental and none had concomitant DVT. Pneumonia was found in 12/208 (5.4%) with RGS ≤ 6 and D-dimer < 1000 ng mL(-1).

CONCLUSIONS

Doubling the threshold for a positive D-dimer with a PE unlikely pretest probability could reduce CTPA scanning with a slightly increased risk of missed isolated subsegmental PE, and no increase in rate of missed pneumonia.

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

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Clinical prediction rules for pulmonary embolism: a systematic review and meta-analysis

SUMMARY BACKGROUND

Pretest probability assessment is necessary to identify patients in whom pulmonary embolism (PE) can be safely ruled out by a negative D-dimer without further investigations.

OBJECTIVE

Review and compare the performance of available clinical prediction rules (CPRs) for PE probability assessment.

PATIENTS/METHODS

We identified studies that evaluated a CPR in patients with suspected PE from Embase, Medline and the Cochrane database. We determined the 95% confidence intervals (CIs) of prevalence of PE in the various clinical probability categories of each CPR. Statistical heterogeneity was tested.

RESULTS

We identified 9 CPR and included 29 studies representing 31215 patients. Pooled prevalence of PE for three-level scores (low, intermediate or high clinical probability) was: low, 6% (95% CI, 4-8), intermediate, 23% (95% CI, 18-28) and high, 49% (95% CI, 43-56) for the Wells score; low, 13% (95% CI, 8-19), intermediate, 35% (95% CI, 31-38) and high, 71% (95% CI, 50-89) for the Geneva score; low, 9% (95% CI, 8-11), intermediate, 26% (95% CI, 24-28) and high, 76% (95% CI, 69-82) for the revised Geneva score. Pooled prevalence for two-level scores (PE likely or PE unlikely) was 8% (95% CI,6-11) and 34% (95% CI,29-40) for the Wells score, and 6% (95% CI, 3-9) and 23% (95% CI, 11-36) for the Charlotte rule.

CONCLUSION

Available CPR for assessing clinical probability of PE show similar accuracy. Existing scores are, however, not equivalent and the choice among various prediction rules and classification schemes (three- versus two-level) must be guided by local prevalence of PE, type of patients considered (outpatients or inpatients) and type of D-dimer assay applied.

Prospective evaluation of right ventricular function and functional status 6 months after acute submassive pulmonary embolism: frequency of persistent or subsequent elevation in estimated pulmonary artery pressure

BACKGROUND

No published data have systematically documented pulmonary artery pressure over an intermediate time period after submassive pulmonary embolism (PE). The aim of this work was to document the rate of pulmonary hypertension, as assessed noninvasively by estimated right ventricular systolic pressure (RVSP) of >or= 40 mm Hg 6 months after the diagnosis of submassive PE.

METHODS

We enrolled 200 normotensive patients with CT angiography-proven PE and a baseline echocardiogram to estimate RVSP. All patients received therapy with unfractionated heparin initially, but 21 patients later received alteplase in response to circulatory shock or respiratory failure. Patients returned at 6 months for repeat RVSP measurement, and assessments of the New York Heart Association (NYHA) score and 6-min walk distance (6MWD).

RESULTS

Six months after receiving a diagnosis, 162 of 180 survivors (90%) returned for follow-up, including 144 patients who had been treated with heparin (heparin-only group) and 18 patients who had been treated with heparin plus alteplase (heparin-plus-alteplase group). Among the heparin-only patients, the RVSP at diagnosis was >or= 40 mm Hg in 50 of 144 patients (35%; 95% CI, 27% to 43%), compared with 10 of 144 patients at follow-up (7%; 95% CI, 3% to 12%). However, the RVSP at follow-up was higher than the baseline RVSP in 39 of 144 patients (27%; 95% CI, 9% to 35%), and 18 of these 39 patients had a NYHA score of >or= 3 or exercise intolerance (6MWD, < 330 m). Among heparin-plus-alteplase patients, the RVSP was >or= 40 mm Hg in 11 of 18 patients at diagnosis (61%; 95% CI, 36% to 83%), compared with 2 of 18 patients at follow-up (11%; 95% CI, 1% to 35%). The RVSP at follow-up was not higher than at the time of diagnosis in any of the heparin-plus-alteplase patients (95% CI, 0% to 18%).

CONCLUSIONS

Six months after experiencing submassive PE, a significant proportion of patients had echocardiographic and functional evidence of pulmonary hypertension.

Prospective diagnostic accuracy assessment of the HemosIL HS D-dimer to exclude pulmonary embolism in emergency department patients

INTRODUCTION

Chest pain and shortness of breath are among the most common symptoms requiring immediate evaluation. Testing for pulmonary embolism (PE) has become easier and widespread due to D-dimer blood tests. Safe use of these tests is only possible if sensitivity is high and they are used in non-high probability patients. We evaluated diagnostic performance of the HemosIL HS D-dimer, which despite FDA approval in 2005, has been minimally reported in prospective standard clinical care.

MATERIALS AND METHODS

We used a prospective observational study design to follow patients in a single center with the HemosIL HS ordered for symptoms of possible PE with positive test result if >243 ng/ml. The outcome was PE or deep venous thrombosis (DVT) at the time of presentation or subsequent 45 days determined by structured evaluation of imaging tests, phone, or medical record follow-up in all patients.

RESULTS

529 patients received a D-dimer and 4.7% were ultimately diagnosed with PE or DVT. The sensitivity of the HemosIL HS was 96.0% (95% CI; 79.6 to 99.9%) specificity was 65.7% (95% CI; 61.4 to 69.8%) and likelihood ratio negative was 0.06 (95% CI; 0.01 to 0.42). The probability of PE in patients with a negative D-dimer was 1/332 or 0.3% (95% CI; 0.01% to 1.67%). The receiver operator curve had an area under the curve of 0.87 and supported the current cut-point as optimal.

CONCLUSIONS

The HemosIL HS D-dimer had high sensitivity, very low negative post-test probability and is useful in excluding PE in the acute care setting.

Randomized trial of computerized quantitative pretest probability in low-risk chest pain patients: effect on safety and resource use

STUDY OBJECTIVE

We hypothesize that the presentation of a quantitative pretest probability of acute coronary syndrome would safely reduce unnecessary resource use in low-risk emergency department (ED) chest pain patients.

METHODS

Randomized controlled trial of adult patients with chest pain paired with their clinicians. Patients had neither obvious evidence of acute coronary syndrome nor obvious other reason for admission. Clinicans provided their unstructured point estimate for pretest probability before randomization. Clinicans and patients in the intervention group received a printout of pretest probability of acute coronary syndrome result displayed numerically and graphically. Controls received no printout. Patients were followed for 45 days for predefined criteria of acute coronary syndrome and efficacy endpoints. Endpoints were compared between groups, with 95% confidence intervals (CIs) for differences.

RESULTS

Four hundred were enrolled, and 31 were excluded for cocaine use or elopement from care. The mean pretest probability estimates of acute coronary syndrome were 4 (SD 5%) from clinicians and 4 (SD 6%) from the computer. Safety and efficacy endpoints for controls (n=185) versus intervention patients (n=184) were as follows: (1) delayed or missed diagnosis of acute coronary syndrome: 1 of 185 versus 0 of 184 (95% CI for difference -2.8% to 15.0%); (2) hospital admission with no significant cardiovascular diagnosis, 11% versus 5% (-0.2% to 11%); (3) thoracic imaging imparting greater than 5 mSv radiation with a negative result, 20% versus 9% (95% CI for difference = 3.8% to 18.0%); (4) median length of stay, 11.4 hours versus 9.2 hours (95% CI for difference = -2.9 to 7.6 hours); (5) reported feeling "very satisfied" with clinician explanation of problem on follow-up survey, 38% versus 49% (95% CI for difference = 0.9% to 21.0%); (6) readmitted within 7 days, 11% versus 4% (95% CI for difference = 2.5% to 13.2%).

CONCLUSION

Presentation of a quantitative estimate of the pretest probability of acute coronary syndrome to clinicians and low-risk ED chest pain patients was associated with reduced resource use, without evidence of increased rate of premature discharge of patients with acute coronary syndrome.

Venothromboembolism

This article focuses on the clinical presentation, diagnosis, and management of veno-thromboembolism, including deep venous thrombosis (DVT) and pulmonary embolism (PE), from the perspective of the emergency physician. The discussion is divided into two sections: DVT and PE. Because veno-thromboembolism is a continuum, certain aspects, such as background, incidence, the use of D dimer, and anticoagulation of both DVT and PE, are discussed together. Heavier emphasis is placed on topics germane to the emergency physician, and considerations for special populations are reviewed.

Tandem measurement of D-dimer and myeloperoxidase or C-reactive protein to effectively screen for pulmonary embolism in the emergency department

OBJECTIVES

The hypothesis was that the tandem measurement of D-dimer and myeloperoxidase (MPO) or C-reactive protein (CRP) could significantly decrease unnecessary pulmonary vascular imaging in emergency department (ED) patients evaluated for pulmonary embolism (PE) compared to D-dimer alone.

METHODS

The authors measured the sequential combinations of D-dimer and MPO and D-dimer and CRP in a prospective sample of ED patients evaluated for PE at two centers. Patients were followed for 90 days for venous thromboembolism (VTE, either PE or deep venous thrombosis [DVT]), which required the consensus of two of three blinded physician reviewers.

RESULTS

The authors enrolled 304 patients, 22 with VTE (7%; 95% confidence interval [CI] = 5% to 10%). The sensitivity and specificity of a D-dimer alone (cutoff > or = 500 ng/mL) were 100% (95% CI = 85% to 100%) and 59% (95% CI = 53% to 65%), respectively, and was followed by pulmonary vascular imaging negative for PE in 38% (115/304; 95% CI = 32% to 44%). The combination of either a negative D-dimer, or MPO < 22 mg/dL, had a sensitivity of 100% and specificity of 73% (95% CI = 67% to 78%). Thus, tandem measurement of D-dimer and MPO would have decreased the frequency of subsequent negative pulmonary vascular imaging from 38% to 25% (95% CI of the difference of -13% = -5% to -20%). The combination of CRP and D-dimer would not have significantly improved the rate of negative imaging.

CONCLUSIONS

The tandem measurement of D-dimer and MPO would have significantly decreased negative pulmonary vascular imaging compared with D-dimer alone and should be validated prospectively.

Guidelines on the diagnosis and management of acute pulmonary embolism: the Task Force for the Diagnosis and Management of Acute Pulmonary Embolism of the European Society of Cardiology (ESC)

Non-thrombotic PE does not represent a distinct clinical syndrome. It may be due to a variety of embolic materials and result in a wide spectrum of clinical presentations, making the diagnosis difficult. With the exception of severe air and fat embolism, the haemodynamic consequences of non-thrombotic emboli are usually mild. Treatment is mostly supportive but may differ according to the type of embolic material and clinical severity.

Integrated strategies for the diagnosis of venous thromboembolism

Diagnosis of deep vein thrombosis (DVT) and pulmonary embolism (PE) is an important medical problem because of the high fatality rate from PE and the large number of cases not diagnosed before causing death. Over the last decade, there has been considerable research into the diagnostic process. It is widely accepted that venous ultrasound imaging is an accurate test for the diagnosis of DVT and is the imaging test of choice. For PE, computer tomographic pulmonary angiography (CTPA) is replacing ventilation perfusion lung scanning. Technology for CTPA is rapidly evolving and multi-row detector scans have quite reasonable sensitivity and specificity. Despite the accuracy of imaging tests, the post-test probability of disease is highly dependent on pretest probability. Clinical evaluation tools have developed that enable us to accurately categorize patients' risk prior to diagnostic imaging. One advantage of this characterization is an ability to exclude the diagnosis of DVT or PE if clinical probability is sufficiently low and when the D-dimer is negative. There are now a number of D-dimer assays that have well-defined specificities and sensitivities, which enable use in conjunction with clinical probability. A careful combination of clinical assessment, D-dimer and imaging enables safe PE rule out protocols without imaging, an ability to suspect false positive imaging results, and more accurate determination of true positive imaging. These integration strategies result in safer, more convenient and cost-effective care for patients.

Examination of hospital referral practices for CT pulmonary angiography

Guidelines for the evaluation of venous thromboembolism (VTE) include a history and physical examination in conjunction with computed tomographic pulmonary angiography (CTPA), Doppler ultrasonography, and D-dimer measurements. We performed a retrospective analysis to evaluate the diagnostic yield of CTPA at our facility. Patients between the ages of 18 and 100 with a CTPA completed through the emergency department and/or any inpatient service over a 6-month period were reviewed and a retrospective Simplified Wells Score was calculated. Three hundred and three patients underwent CTPA for acute VTE. A Simplified Wells Score was calculated for 279 subjects, with a mean score of 1.6 +/- 1.6. Twenty CTPA procedures demonstrated VTE, a positive rate of 7.2%, which was lower than expected. This result likely reflects lack of adherence to a clinical algorithm for assessment of VTE and an overly cautious approach to symptom evaluation.

Imaging of pulmonary embolism and t-PA therapy effects using MDCT and liposomal iohexol blood pool agent: preliminary results in a rabbit model

RATIONALE AND OBJECTIVES

Polyethylene glycol-coated liposomal blood pool contrast agents maintain contrast enhancement over several hours. This study aimed to evaluate (long-term) imaging of pulmonary arteries, comparing conventional iodinated contrast with a liposomal blood pool contrast agent. Also, visualization of the (real-time) therapeutic effects of tissue plasminogen activator (t-PA) on pulmonary embolism (PE) was attempted.

MATERIALS AND METHODS

Six rabbits (weight approximately 4 kg) had autologous blood clots injected through the superior vena cava. Imaging was performed using conventional contrast (iohexol, 350 mg I/ml; GE HealthCare, Princeton, NJ) at a dose of 1400 mg I per animal, and after wash-out, animals were imaged using an iodinated liposomal blood pool agent (88 mg I/mL, dose 900 mg I/animal). Subsequently, five animals were injected with 2 mg of t-PA and imaging continued for up to 4(1/2) hours.

RESULTS

Both contrast agents identified PE in the pulmonary trunk and main pulmonary arteries in all rabbits. Liposomal blood pool agent yielded uniform enhancement, which remained relatively constant throughout the experiments. Conventional agents exhibited nonuniform opacification and rapid clearance postinjection. Three of six rabbits had mistimed bolus injections, requiring repeat injections. Following t-PA, pulmonary embolus volume (central to segmental) decreased in four of five treated rabbits (range 10-57%, mean 42%). One animal showed no response to t-PA.

CONCLUSIONS

Liposomal blood pool agents effectively identified acute PE without need for reinjection. PE resolution following t-PA was quantifiable over several hours. Blood pool agents offer the potential for repeated imaging procedures without need for repeated (nephrotoxic) contrast injections.

Contrast nephropathy following computed tomography angiography of the chest for pulmonary embolism in the emergency department

OBJECTIVE

To estimate the frequency of contrast nephropathy after computed tomography angiography (CTA) to rule out pulmonary embolism (PE) in the emergency department (ED) setting.

METHODS

We prospectively followed patients undergoing CTA for PE, while in the ED, for 45 days. Patients who refused follow-up or were receiving hemodialysis were excluded. Severe renal failure was defined as an increase in creatinine > or = 3.0 mg dL(-1) or a need for hemodialysis within the follow-up period. Patients were also followed for laboratory-defined contrast nephropathy, defined as an increase in creatinine of > 0.5 mg dL(-1) or > 25%, within seven days following CTA.

RESULTS

A total of 1224 patients were followed, and 354 [29%, 95% confidence interval (CI): 26-32%] patients had paired (preCTA and post-CTA) creatinine measurements. None developed renal failure (0/1224; 0%, CI: 0-0.3%). 44 patients developed laboratory-defined contrast nephropathy, corresponding to an overall frequency of 4% (44/1224; CI: 3-5%) and 12% (44/354; 95% CI: 9-16%) among those with paired creatinine measurements.

CONCLUSIONS

Following CTA for PE, the incidence of severe renal failure was very low, but the incidence of laboratory-defined contrast nephropathy (4% overall and 12% of those with paired measurements) was higher than expected.

Emergency medicine practitioner knowledge and use of decision rules for the evaluation of patients with suspected pulmonary embolism: variations by practice setting and training level

BACKGROUND

Several clinical decision rules (CDRs) have been validated for pretest probability assessment of pulmonary embolism (PE), but the authors are unaware of any data quantifying and characterizing their use in emergency departments.

OBJECTIVES

To characterize clinicians' knowledge of and attitudes toward two commonly used CDRs for PE.

METHODS

By using a modified Delphi approach, the authors developed a two-page paper survey including 15 multiple-choice questions. The questions were designed to determine the respondents' familiarity, frequency of use, and comprehension of the Canadian and Charlotte rules. The survey also queried the frequency of use of unstructured (gestalt) pretest probability assessment and reasons why physicians choose not to use decision rules. The surveys were sent to physicians, physician assistants, and medical students at 32 academic and community hospitals in the United States and the United Kingdom.

RESULTS

Respondents included 555 clinicians; 443 (80%) work in academic practice, and 112 (20%) are community based. Significantly more academic practitioners (73%) than community practitioners (49%) indicated familiarity with at least one of the two decision rules. Among all respondents familiar with a rule, 50% reported using it in more than half of applicable cases. A significant number of these respondents could not correctly identify a key component of the rule (23% for the Charlotte rule and 43% for the Canadian rule). Fifty-seven percent of all respondents indicated use of gestalt rather than a decision rule in more than half of cases.

CONCLUSIONS

Academic clinicians were more likely to report familiarity with either of these two specific decision rules. Only one half of all clinicians reporting familiarity with the rules use them in more than 50% of applicable cases. Spontaneous recall of the specific elements of the rules was low to moderate. Future work should consider clinical gestalt in the evaluation of patients with possible PE.

Prospective study of the diagnostic accuracy of the simplify D-dimer assay for pulmonary embolism in emergency department patients

OBJECTIVE

To determine if a d-dimer assay (Simplify D-dimer; Agen Biomedical; Brisbane, Australia) can reliably exclude pulmonary embolism (PE) by producing a posttest probability of PE < 1% in low-risk, symptomatic emergency department (ED) patients.

METHODS

Hemodynamically stable patients were evaluated for PE using a structured d-dimer-centered protocol; d-dimer testing was performed prior to imaging. Prior to testing, physicians completed an electronic data form that included their unstructured clinical estimate for the pretest probability of PE (< 15%, 15 to 40%, or > 40%) and the elements of the Charlotte rule and Canadian score for PE. Criterion standard was selective use of pulmonary vascular imaging and 90-day follow-up.

RESULTS

We enrolled 2,302 patients (mean age, 45 +/- 16 years [+/- SD]; 31% male); 108 patients received a diagnosis of PE (4.7%; 95% confidence interval [CI], 3.6 to 5.6%). The overall sensitivity and specificity of the d-dimer assay were 80.6% (95% CI, 71.8 to 87.5%) and 72.5% (95% CI, 70.6 to 74.4%), respectively. The negative likelihood ratio and negative predictive value were 0.27 (95% CI, 0.18 to 0.39) and 98.7% (95% CI, 98.0 to 99.1%), respectively. The posttest prevalence of PE among low-risk patients with negative d-dimer results was 0.7% (95% CI, 0.3 to 1.4%) for the unstructured estimate, 1.2% (95% CI, 0.7 to 2.0%) for the Canadian score, and 1.1% (95% CI, 0.6 to 1.7%) for the Charlotte rule.

CONCLUSIONS

The Simplify D-dimer assay had moderate sensitivity and relatively high specificity for PE in low-risk ED patients. The combination of a physician's unstructured estimate of pretest probability of PE of < 15% and a negative d-dimer result produced a posttest probability of PE of 0.7% (95% CI, 0.3 to 1.4%).

A highly sensitive ELISA D-dimer increases testing but not diagnosis of pulmonary embolism

OBJECTIVES

To determine the effect of introducing a rapid enzyme-linked immunosorbent assay (ELISA) D-dimer on the percentage of emergency department (ED) patients evaluated for pulmonary embolism (PE), the use of associated laboratory testing, pulmonary vascular imaging, and the diagnoses of PE.

METHODS

Patients evaluated for PE during three 120-day periods were enrolled: immediately before (period 1), immediately after (period 2), and one year after the introduction of a rapid ELISA D-dimer in the hospital. The frequency of ED patients evaluated for PE with any test, with D-dimer testing, and with pulmonary vascular imaging and the frequency of PE diagnosis during each time period were determined.

RESULTS

The percentage of patients evaluated for PE nearly doubled; from 1.36% (328/24,101) in period 1 to 2.58% (654/25,318) in period 2 and 2.42% (583/24,093) in period 3. The percentage of patients who underwent D-dimer testing increased more than fourfold; from 0.39% (93/24,101) in period 1 to 1.83% (464/25,318) in period 2 and 1.77% (427/24,093) in period 3. The percentage of patients who underwent pulmonary vascular imaging increased from 1.02% (247/24,101) in period 1 to 1.36% (344/25,318) in period 2 and to 1.39% (334/24,093) in period 3. There was no difference in the percentage of patients diagnosed as having PE in period 1 (0.20% [47/24,101]), period 2 (0.27% [69/25,318]), and period 3 (0.24% [58/24,093]).

CONCLUSIONS

In the study's academic ED, introduction of ELISA D-dimer testing was accompanied by an increase in PE evaluations, D-dimer testing, and pulmonary vascular imaging; there was no observed change in the rate of PE diagnosis.

The probability of pulmonary embolism is a function of the diagnoses considered most likely before testing

OBJECTIVES

To determine the frequency of pulmonary embolism (PE) diagnosis when different alternative diagnoses were considered most likely before testing, because the relationship between specific alternative diagnoses and the diagnosis of PE has not been explored.

METHODS

This study was a preplanned secondary analysis of a prospective study of the diagnosis of pulmonary embolism conducted in the emergency department (ED) of an urban university hospital. Physicians were queried as to their most likely pretest diagnosis when they ordered any of the following tests to evaluate possible PE: D-dimer, contrast-enhanced computed tomography of the chest, ventilation-perfusion lung scan, or pulmonary angiogram. To compare the frequency of PE diagnosis across alternative diagnoses, risk ratios, 95% confidence intervals (CI), and p-values using Fisher's exact test were calculated.

RESULTS

Six hundred seven patients were enrolled, and 61 had PE. Physicians thought PE was the most likely pretest diagnosis in 162 (26.7%) patients, and 20.4% (95% CI = 14.4% to 27.4%) of these patients had PE. For four alternative diagnoses, PE was diagnosed less frequently than when PE was considered most likely: musculoskeletal pain (2.2%, 95% CI = 0.4% to 6.2%), anxiety (1.7%, 95% CI = 0.0 to 9.2%), asthma or chronic obstructive pulmonary disease (0, 95% CI = 0.0 to 10.9%), and viral syndrome (0, 95% CI = 0.0 to 14.3%).

CONCLUSIONS

The frequency of PE is related to the most likely pretest alternative diagnosis. PE is diagnosed infrequently when anxiety, asthma or chronic obstructive pulmonary disease, musculoskeletal pain, or viral syndrome is the most likely alternative diagnosis.

Frequency of thrombophilia-related genetic variations in patients with idiopathic pulmonary embolism in an urban emergency department

BACKGROUND

The frequency of the thrombophilic genetic variants factor V Leiden (FVL) G1691A, prothrombin G20210A, and methylenetetrahydrofolate reductase (MTHFR) C677T in acutely symptomatic ambulatory patients with idiopathic pulmonary embolism (PE) has not been measured.

METHODS

This prospective case-control study included patients presenting to urban emergency departments (EDs) with chest pain or shortness of breath. Cases were classified as idiopathic PE (49 patients with PE, but without overt risk factors for thrombosis). Control groups included (a) patients with nonidiopathic PE (152 patients with PE and risk factors); (b) patients in whom PE was excluded (91 patients who had PE ruled out with a structured protocol, including follow-up); and (c) patients in whom PE was not suspected (193 patients without a workup for PE, who were free of PE on follow-up). Blood DNA extracts were analyzed by PCR and restriction fragment length polymorphism analysis for the FVL, prothrombin, and MTHFR sequence variations.

RESULTS

Either the FVL or prothrombin variant was found in 10% (95% confidence interval, 3%-22%) of patients with idiopathic PE compared with 13% (8%-20%) of nonidiopathic PE, 2% (5%-14%) of PE excluded, and 9% (5%-14%) of PE not suspected patients. Patients with idiopathic PE tended to have a higher frequency of homozygous MTHFR sequence variants, but mean (SD) plasma homocysteine concentrations were not increased [15.6 (5.4) micromol/L vs 12.8 (4.6) micromol/L for homozygous, and wild-type, respectively; P = 0.40].

CONCLUSIONS

The frequency of either the FVL or prothrombin sequence variant was not increased in idiopathic PE patients compared with nonidiopathic PE patients or patients who had PE excluded. These data suggest that genotyping to detect idiopathic PE would have limited clinical utility in the urban ED setting.