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PERCs of the Wells Score

Pulmonary embolism (PE) is one of the big “can’t miss” diagnoses in the emergency department. Unfortunately, presenting symptoms are often vague, and definitive diagnostic testing is expensive and comes with risks of radiation and contrast to the patient. In order to avoid missing a PE while mitigating the risks associated with overtesting, some clinical decision tools have been created to aid in the diagnostic process. We will focus on two of these commonly used decision tools: the PERC rule and the WELLS score for PE.

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 What are 3 pretest probability scoring systems used to evaluate patients with a suspected pulmonary thromboembolism?

Although it does help us in deciding who maybe at higher risk of PTE, I personally feel these scoring systems help us document who DOES NOT need work-up. There are quite a few patients who come in with non-specific chest pain or shortness of breath, and you should ALWAYS entertain the idea of PTE in these patients. But, not every single one of these patients need a d-dimer or CTA. Better yet, some of these patients can be discharged home without any investigation if they are low-risk and PERC negative.

Articles of Interest

Clinical criteria to prevent unnecessary diagnostic testing in emergency department patients with suspected pulmonary embolism

Overtesting for PE has long been recognized as a significant problem in the process of ruling out pulmonary embolism [8]. In particular, the D-dimer test frequently results in a false positive test result that demands expensive and timeconsuming radiological imaging.

Comparison of YEARS and Adjust-Unlikely D-dimer Testing for Pulmonary Embolism in the Emergency Department

The “Adjust-Unlikely” rule would modestly reduce imaging and identify all cases of PE. YEARS would substantially reduce imaging but miss 1 in 14 cases of PE.

PERC Rule for Pulmonary Embolism

The PERC (Pulmonary Embolism Rule-out Criteria) Rule is utilized by physicians to avoid further testing for pulmonary embolism in patients deemed to be at low risk.

Pulmonary Embolism Challenges in Diagnosis Part 1

There are a number of decision rules that are used as objective aids in the work up of PE. Wells and PERC (Pulmonary Embolism Rule out Criteria) are the two most commonly utilized tools in North American EDs. It is important to understand how the prevalence of PE in your population impacts decision making... Once you have decided to test for PE, our experts suggest starting with Wells to get an idea of the pre-test probability. 1. If <2, use PERC 2. If 2-4, send D-dimer 3. If >4, consider a CTPA

Pulmonary Embolism Rule-Out Criteria: A Clinical Decision Rule That Works

Is there a clinical prediction rule that can reliably exclude the presence of a pulmonary embolism (PE), and thus avoid the use of computed tomography (CT) in patients believed to be at very low risk?

Ruling Out Pulmonary Embolism in the Primary Care Setting

Many clinical decision rules exist to estimate the patient's risk level based on certain clinical characteristics and subsequently guide the evaluation of suspected PE. These include the Wells score, Geneva score, Pisa model, and Pulmonary Embolism Rule-out Criteria (PERC). Each of the rules has advantages and disadvantages...

The Legend score synthesizes Wells, PERC, Geneva, D-dimer and predicts acute pulmonary embolism prior to imaging tests

The prediction rules of acute pulmonary embolism(PE) before imaging tests recommended by the commonly used guidelines have low diagnostic efficiency if not combined with D-dimer, therefore it is necessary to seek for a prediction rule with higher diagnostic efficiency.

Values of the Wells and Revised Geneva Scores Combined with D-dimer in Diagnosing Elderly Pulmonary Embolism Patients

In conclusion, for elderly cases, the Wells score appeared to be a more accurate rule, with which could reduce the rate of misdiagnosis and avoid unnecessary tests; D-dimer is of greater value in excluding PE when combined with Wells score or revised Geneva score.

Resources

PERC rule

... aimed at assessing which patients with chest pain or shortness of breath could safely not undergo any testing (not even a D-dimer test).

Revised Geneva Score

Objectifies risk of PE, like Wells’ score. How do you use the Geneva Score (Revised) in your own clinical practice? Pretty much in all patients with a clinical suspicion of PE. I only do the score (and the D-dimer test if the score is non-high) in patients in whom I am ready to order a CTPA should the score be high probability or the D-dimer positive.

YEARS

Helps rule out pulmonary embolism; also validated in pregnant patients with clinically suspected PE.

Wells score

Objectifies risk of pulmonary embolism. The model should be applied only after a history and physical suggests that venous thromboembolism is a diagnostic possibility. it should not be applied to all patients with chest pain or dyspnea or to all patients with leg pain or swelling.