A prospective reassessment of the utility of the Wells score in identifying pulmonary embolism

Applying Wells score to inconclusive perfusion only modified PIOPED II (Prospective Investigation of Pulmonary Embolism Diagnosis II) readings in order to optimize the lung scintigraphy diagnostic yield in acute pulmonary embolism detection

OBJECTIVE

When using perfusion only modified PIOPED II criteria for PE detection, generated non-diagnostic scans are found to be the main diagnostic restriction. The objective of current study is to identify the role of Wells criteria added to inconclusive readings with the intent of enhancing the lung scintigraphy diagnostic yield.

METHODS

CTPA was performed in 34 suspected PE patients with inconclusive lung scintigraphy. They also were evaluated by Wells score and classified as low, intermediate and high probability. Overall prevalence and the rate of PE for each probability were calculated. Furthermore, NPV for scores < 2 and PPV for scores > 6 were computed.

RESULTS

Having a mean age of 59.75 ± 17.38 years, 7 (20.6%), 23 (67.6%) and 4 (11.8%) of cases had total criteria point count < 2, 2-6 and > 6, respectively. Using CTPA, 5 patients (14.7%) were diagnosed with PE. None of the patients with scores < 2 had PE with an associated NVP of 100%. Patients with scores 2-6 had a PE rate of 4.3% and 100% of patients with scores > 6 were diagnosed with PE, implying that the PPV of scores > 6 was 100%.

CONCLUSION

Adding Wells score to non-diagnostic scans allowed identification of PE to be done reliably, and provided further insight into how lung scintigraphy in conjunction with clinical assessment is a practical strategy not only for the patients unfit for performing CTPA but also in all the patients referred for PE evaluation.

Use of a three-tiered clinical decision rule to quantify unnecessary radiological investigation of suspected pulmonary embolism

BACKGROUND

Clinical decision rules for suspected pulmonary embolism are proposed to identify patients suitable for discharge without radiological investigation. Their use varies between institutions.

AIMS

To quantify unnecessary radiological investigations for suspected pulmonary embolism (PE) as defined by a newly proposed three-tiered clinical decision rule incorporating the revised Geneva score, Pulmonary Embolism Rule-Out Criteria and D-dimer. To quantify missed diagnosis of PE if the proposed clinical decision rule were followed.

METHODS

A retrospective audit was conducted; applying the proposed clinical decision rule to 584 emergency department (ED)-based encounters at the Royal Adelaide Hospital from May to November 2015. Encounters were confined to emergency presentations where suspected acute PE was investigated with computed tomography pulmonary angiography or ventilation-perfusion scanning; inpatient and follow-up studies were excluded. Sensitivity, specificity, positive predictive value and negative predictive value of the proposed clinical decision rule within the studied population were calculated.

RESULTS

Data were obtained for 584 patient encounters where suspected PE was investigated radiologically. Applied retrospectively, the proposed clinical decision rule had a negative predictive value of 97.7% and a sensitivity of 98.5% for radiologically proven PE; 9.2% of scans could have been avoided. One case of PE would have been missed; a false-negative rate of 1.5%.

CONCLUSION

Retrospective application of the proposed clinical decision rule to the studied cohort indicates at least 9% of radiological investigations were unnecessary. A prospective study is needed to assess the safety and cost-effectiveness of applying such a pathway to all patients presenting to ED with suspected PE.

Triage for suspected acute Pulmonary Embolism: Think before opening Pandora's Box

This is a review of the current strengths and weaknesses of the various imaging modalities available for the diagnosis of suspected non-massive Pulmonary Embolism (PE). Without careful consideration for the clinical presentation, and the timely application of clinical decision support (CDS) methodology, the current overutilization of imaging resources for this disease will continue. For a patient with a low clinical risk profile and a negative D-dimer there is no reason to consider further workup with imaging; as the negative predictive value in this scenario is the same as imaging. While the current efficacy and effectiveness data support the continued use of Computed Tomographic angiography (CTA) as the imaging golden standard for the diagnosis of PE; this test does have the unintended consequences of radiation exposure, possible overdiagnosis and overuse. There is a persistent lack of appreciation on the part of ordering physicians for the effectiveness of the alternatives to CTA (ventilation-perfusion imaging and contrast enhanced magnetic resonance angiography) in these patients. Careful use of standardized protocols for patient triage and the application of CDS will allow for a better use of imaging resources.

Pulmonary embolism: current and new treatment options

BACKGROUND

Pulmonary embolism (PE) can be a life-threatening emergency. Accurate diagnostic techniques and patient-specific management strategies are necessary to ensure favorable clinical outcomes.

METHODS

Relevant guidelines, articles, reviews, and abstracts were identified using a narrative approach in PubMed/MEDLINE, Google Scholar, clinicaltrials.gov and nice.org.uk. English-language articles published in 2000-2014 were initially identified using the search terms: novel OAC, pulmonary embolism, venous thromboembolism, diagnosis, treatment, rivaroxaban, apixaban, dabigatran, and edoxaban. The initial literature search was supported by a 'snowballing' style literature search, and relevant articles were included based on a professional judgment of relevance.

SCOPE

We discuss the diagnosis of PE and the categorization of risk for subgroups, which may assist with making treatment decisions. We review current guidance on acute and long-term treatment, possible limitations of traditional anticoagulant therapy, and the development of direct oral anticoagulants, which may significantly alter the management of patients with PE. Finally, we discuss special considerations in high-risk and hard-to-treat subpopulations that may benefit from the improved benefit-risk profile offered by these newer agents.

CONCLUSIONS

The direct oral anticoagulants may overcome several of the limitations associated with traditional anticoagulant therapy, potentially improving the standard of care for PE patients, including high-risk and hard-to-manage subgroups.

Heightened clinical suspicion of pulmonary embolism and disregard of the D-dimer assay: a contemporary trend in an era of increased access to computed tomography pulmonary angiogram?

BACKGROUND

Prospective studies have shown that utilising qualitative D-dimers in those with a low Wells pre-test probability (PTP) of pulmonary embolism (PE) have significantly reduced the number of computed tomography pulmonary angiograms (CTPA) being performed. These studies have been based on a PE prevalence of approximately 6% in the low PTP group.

AIM

This study compares the diagnostic approach to PE in the study institution to well-established guidelines. The study also re-examines the cost-benefit analyses of qualitative d-dimers and CTPA in the low PTP group.

METHODS

A retrospective study of 169 consecutive CTPA requested in the emergency department of a major teaching hospital during a 12-month period.

RESULTS

The prevalence of PE was 0% (0/65), 11.7% (9/77) and 0% (0/2) in the low, moderate and high Wells PTP groups respectively, and 6.3% (9/144) overall. PTP was documented in 10 (6.9%) cases, and the qualitative Clearview Simplify D-dimer was only ordered in 33.8% (22/65) of low PTP subjects. The false positive D-dimer rate was 90.2% (37/41). Cost-benefit analysis and assay performance defines a narrow range of low PTP PE prevalence between 1% and 5% for the utilisation of the qualitative D-dimer assay.

CONCLUSIONS

The overall prevalence of PE in subjects undergoing CTPA was significantly lower compared with data in the literature. The authors recommend warranted clinical suspicion of PE should be confirmed by a senior physician prior to placing a patient in the PE work-up pathway. In such patients, the qualitative D-dimer assay should be utilised if PTP is low, and the exclusionary efficiency of the D-dimer will be improved in the setting of higher PE prevalence in this subgroup. Hospitals should audit local PE prevalence, as cost-benefit analyses raises questions about the effectiveness of D-dimers when PE prevalence is very low in the low PTP subgroup.

Critical issues in the evaluation and management of adult patients presenting to the emergency department with suspected pulmonary embolism

This clinical policy from the American College of Emergency Physicians is the revision of a 2003 clinical policy on the evaluation and management of adult patients presenting with suspected pulmonary embolism (PE).(1) A writing subcommittee reviewed the literature to derive evidence-based recommendations to help clinicians answer the following critical questions: (1) Do objective criteria provide improved risk stratification over gestalt clinical assessment in the evaluation of patients with possible PE? (2) What is the utility of the Pulmonary Embolism Rule-out Criteria (PERC) in the evaluation of patients with suspected PE? (3)What is the role of quantitative D-dimer testing in the exclusion of PE? (4) What is the role of computed tomography pulmonary angiogram of the chest as the sole diagnostic test in the exclusion of PE? (5) What is the role of venous imaging in the evaluation of patients with suspected PE? (6) What are the indications for thrombolytic therapy in patients with PE? Evidence was graded and recommendations were given based on the strength of the available data in the medical literature.

The modified Wells score accurately excludes pulmonary embolus in hospitalized patients receiving heparin prophylaxis

BACKGROUND

The usefulness of the Wells score has not been assessed in hospitalized patients receiving prophylactic heparin.

METHODS

Retrospective, observational study of hospitalized patients receiving prophylactic heparin who underwent contrast-enhanced chest computed tomography (CT) for a concern of pulmonary embolism (PE) more than 2 days after admission. Patients with contraindications to, or interruptions in, prophylactic heparin were excluded. The modified (eg, dichotomous) Wells score was retrospectively calculated by reviewing each patient's record. Requesting a D-dimer was taken to mean that alternate diagnoses were of equal or greater likelihood than acute PE.

RESULTS

From January 2006 through December 2007, 286 patients met inclusion criteria. Pulmonary embolus diagnosed by CT was present in 20 patients (7%). The sensitivity, specificity, positive and negative predictive values of a Wells score ≥4.0 were 95%, 27%, 9% and 99%, respectively. A D-dimer was ordered in 70 of the 74 PE-unlikely cases, was elevated in 67, and falsely positive in all but 1.

CONCLUSIONS

The prevalence of PE in hospitalized patients receiving prophylactic heparin is lower than in cohorts from which the Wells prediction criteria were derived and validated. A modified Wells score <4 safely excludes PE in such patients and reduces the need for CT. D-dimer testing adds nothing to the evaluation.

An algorithm for the diagnosis and management of chest pain in primary care

This article focuses on the key clinical and investigatory features that help differentiate the multiple causes of chest pain in adults in assessment of patients with undifferentiated chest pain in primary care using history, physical examination, and basic initial investigations. The initial treatment of many of the causes is discussed. Some treatments not only relieve symptoms but also provide further diagnostic information based on the response to treatment. Guidance for referral for specialist assessment and further investigations is provided, but the diagnostic usefulness of these measures is not discussed.

Underutilization of evidence-based strategies in the diagnosis and treatment of venous thromboembolism among trainees

BACKGROUND

The knowledge and attitude of trainees toward the use of prediction rules in the diagnosis of venous thromboembolism (VTE) is understudied. The extent of knowledge as far as imaging strategies in the setting of VTE and use of low molecular weight heparin (LMWH) among trainees is also understudied.

METHODS

This was a cross-sectional study; between October, 2006 and March, 2008, surveys were distributed at grand rounds and national medicine board review courses. Respondents returning completed surveys included 43 medicine attendings, 139 residents, and 134 medical students Emergency physicians were called at work and 46 completed an abbreviated version of the survey. Attending and trainee responses were compared.

RESULTS

Over 60% of students and 40% of residents did not use any prediction rules. Most attendings (>60%) did not use a prediction rule. Among attendings, 48% of emergency physicians and 30% of medicine attendings felt that prediction rules were too complex to use. Knowledge about imaging techniques and diagnostic protocols for VTE were worse for students than for residents. A substantial minority of all respondents (17% of students, 12% of residents and 13% of medicine attendings) would not use LMWH in the therapy of non-massive pulmonary embolism. In general, level of training did not translate into a greater proportion of correct responses to clinical scenarios or greater knowledge about imaging systems and strategies.

CONCLUSION

Trainees do not use a structured approach to VTE diagnosis. LMWH therapy is underutilized by a large minority of trainees and attendings. A top-down approach is needed to revitalize evidence-based management of VTE.