Well's Criteria for Pulmonary Embolism
Objectifies risk of pulmonary embolism
Jennifer Glen
Provided by
EVAL FoundationInstructions
Well's Criteria is not meant to diagnose Pulmonary Embolism (PE).
- The scoring system cannot completely rule our PE in patients with a low probability score or confirm PE with a high probability score.
A d-dimer can be falsely positive for many patients with non-VTE.
- There must first be clinical suspicion for PE in the patient, such as presentation of symptoms (chest pain, shortness of breath, etc.).
- A thorough history and physical must be completed first with findings that suggest venous thromboembolism (VTE) as a diagnostic possibility.
- Second to a history and physical is application of the Wells' Criteria.
- A common mistake made is applying the Wells' Criteria or ordering the d-dimer as the first order or operations. For example, by applying the model to or ordering a d-dimer on all patients with chest pain or shortness of breath or to all patients with leg pain or swelling without first obtaining a history and physical exam.
The score can guide your workup by
- Predicting pre-test probability of PE.
- Guide appropriate testing to rule out the diagnosis, such as d-dimer or CT angiogram.
- Inform interpretation of subsequent diagnostic tests.
- Reduce the need for invasive testing.
The Wells' Criteria risks stratifies for pulmonary embolism (PE). The criteria estimate pre-test probability and guides testing required for diagnosing a PE. The score is often used in conjunction with d-dimer testing. The Wells' Criteria has be validated in both inpatient and emergency department settings.
The intent of the Wells' score was to determine if the patient was low risk enough to rule out testing with a d-dimer. In clinical practice, the Well's score is often used to predict who is low-risk and then apply the PERC rule to stop workup for PE.
Well's Criteria is not meant to diagnose Pulmonary Embolism (PE). The scoring system cannot completely rule out PE in patients with a low probability score or confirm PE with a high probability score. A thorough history and physical must be completed first with findings that suggest venous thromboembolism (VTE) as a diagnostic possibility. Second to a history and physical is application of the Wells' Criteria. A common mistake made is applying the Wells' Criteria or ordering the d-dimer as the first order or operations. For example, by applying the model to or ordering a d-dimer on all patients with chest pain or shortness of breath or to all patients with leg pain or swelling without first obtaining a history and physical exam. A d-dimer can be falsely positive for many patients with non-VTE.
The score can guide your workup by
- Predicting pre-test probability of PE.
- Guide appropriate testing to rule out the diagnosis, such as d-dimer or CT angiogram.
- Inform interpretation of subsequent diagnostic tests.
- Reduce the need for invasive testing.
- There must first be clinical suspicion for PE in the patient, such as presentation of symptoms (chest pain, shortness of breath, etc.).
Summary
The Wells' Criteria can be applied in two ways, three tier model or the two tier model. The two tier model is preferred and supported by the American College of Emergency Physicians (ACEP) 2011 clinical policy of PE. The two tier model uses only the high sensitivity d-dimer and more conservative risk stratification. It is thought that "intermediate" risk patients, such as the three tier model, may be at too high risk to be evaluated without further risk stratification.
Wells' Criteria
| Clinical signs and symptoms of DVT | No (0 points) | Yes (3 points) |
| PE is #1 diagnosis OR equally likely | No (0 points) | Yes (3 points) |
| Heart rate > 100 | No (0 points) | Yes (1.5 points) |
| Immobilization at least 3 days OR surgery in the previous 4 weeks | No (0 points) | Yes (1.5 points) |
| Previously, objectively diagnosed PE or DVT | No (0 points) | Yes (1.5 points) |
| Hemoptysis | No (0 points) | Yes (1 points) |
| Malignancy w/ treatment within 6 months or palliative | No (0 points) | Yes (1 points) |
Three Tier Model
Low Risk: 1.3% incidence of PE in the ED population (<2 points)
- An alternative is to consider applying the PERC rule-out criteria to stop workup for PE
- Consider d-dimer testing to rule out pulmonary embolism
- If the dimer is negative consider stopping the workup
- If the dimer is positive consider CTA
Moderate Risk: 16.2% incidence of PE in the ED population (2-6 points)
- Consider high sensitivity d-dimer testing or CTA
- If the dimer is negative consider stopping the workup
- If the dimer is positive consider CTA
High risk: 40.6% incidence of PE in an ED population (> 6 points)
- Due to higher risk, consider CTA
- D-dimer testing is not recommended.
Two Tier Model
PE Unlikely: 3% incidence of PE (0-4 points)
- Consider high sensitivity d-dimer testing
- If the dimer is negative consider stopping the workup
- If the dimer is positive consider CTA
PE Likely: 28% incidence of PE (> 4 points)
- Due to higher risk, consider CTA testing.
All questions & possible results
GuidanceTitle not visible
Clinical signs and symptoms of DVT
Select one option:
- No
- Yes
PE is the primary diagnosis or equally likely
Select one option:
- No
- Yes
Heart rate > 100
Select one option:
- No
- Yes
Immobilization at least 3 days OR surgery in the previous 4 weeks
Select one option:
- No
- Yes
History of PE or DVT diagnosis
Select one option:
- No
- Yes
Hemoptysis
Select one option:
- No
- Yes
Malignancy with treatment within 6 months or palliative
Select one option:
- No
- Yes
Possible results
Moderate risk group: 16.2% incidence of PE in an ED population (2-6 points)
Result is based on a three tier model of low, moderate or high risk groups.
- Guidelines appear to favor the two tier model of "PE Unlikely" or "PE Likely" (see below result panel) which implements only the high sensitivity d-dimer and more conservative risk stratification. However, "intermediate" risk patients may be still too high risk to be evaluated without further risk stratification.
Management
- The original intent of the Well's score was to determine who was low risk enough to rule out testing with a d-dimer.
- Consider high sensitivity d-dimer testing or CTA
- If the dimer is negative consider stopping the workup
- If the dimer is positive consider CTA
Considerations
- Since the high sensitivity d-dimer has a low specificity (approximately 50%), patients who are considered high risk ought to be ruled out with CTA.
- Consider using age adjusted d-dimer cutoffs in low risk patients over 50 years (rGeneva "not high" or Wells' "low").
- Age (years) x 10 µg/L = cutoff (patients > 50 yrs)
High risk group: 40.6% incidence of PE in an ED population (> 6 points)
Result is based on a three tier model of low, moderate or high risk groups.
- Guidelines appear to favor the two tier model of "PE Unlikely" or "PE Likely" (see below result panel) which implements only the high sensitivity d-dimer and more conservative risk stratification. However, "intermediate" risk patients may be still too high risk to be evaluated without further risk stratification.
Management
- The original intent of the Well's score was to determine who was low risk enough to rule out testing with a d-dimer.
- Due to higher risk, consider CTA
- D-dimer testing is not recommended.
Considerations
- Since the high sensitivity d-dimer has a low specificity (approximately 50%), patients who are considered high risk ought to be ruled out with CTA.
Low risk group: 1.3% incidence of PE in an ED population (< 2 points)
Result is based on a three tier model of low, moderate or high risk groups.
- Guidelines appear to favor the two tier model of "PE Unlikely" or "PE Likely" (see below result panel) which implements only the high sensitivity d-dimer and more conservative risk stratification. However, "intermediate" risk patients may be still too high risk to be evaluated without further risk stratification.
Management
- The original intent of the Well's score was to determine who was low risk enough to rule out testing with a d-dimer.
- An alternative is to consider applying the PERC rule-out criteria to stop workup for PE
- Consider d-dimer testing to rule out pulmonary embolism
- If the dimer is negative consider stopping the workup
- If the dimer is positive consider CTA
Considerations
- Multiple d-dimer assays are available. Ensure that a proven high-sensitivity assay is available and that the test has been validated/audited.
- Since the high sensitivity d-dimer has a low specificity (approximately 50%), patients who are considered high risk ought to be ruled out with CTA.
- Consider using age adjusted d-dimer cutoffs in low risk patients over 50 years (rGeneva "not high" or Wells' "low").
- Age (years) x 10 µg/L = cutoff (patients > 50 yrs)
PE Unlikely: 3% incidence of PE (0-4 points)
Result is based on a two tier model of "PE Unlikely" or "PE Likely".
- Guidelines appear to favor the two tier model which implements only the high sensitivity d-dimer and more conservative risk stratification. However, "intermediate" risk patients may be still too high risk to be evaluated without further risk stratification.
Management
- The original intent of the Well's score was to determine who was low risk enough to rule out testing with a d-dimer.
- Consider high sensitivity d-dimer testing
- If the dimer is negative consider stopping the workup
- If the dimer is positive consider CTA
Considerations
- Since the high sensitivity d-dimer has a low specificity (approximately 50%), patients who are considered high risk ought to be ruled out with CTA.
- Consider using age adjusted d-dimer cutoffs in low risk patients over 50 years (rGeneva "not high" or Wells' "low").
- Age (years) x 10 µg/L = cutoff (patients > 50 yrs)
PE Likely: 28% incidence of PE (> 4 points)
Result is based on a two tier model of "PE Unlikely" or "PE Likely".
- Guidelines appear to favor the two tier model which implements only the high sensitivity d-dimer and more conservative risk stratification. However, "intermediate" risk patients may be still too high risk to be evaluated without further risk stratification.
Management
- The original intent of the Well's score was to determine who was low risk enough to rule out testing with a d-dimer.
- Due to higher risk, consider CTA testing.
Considerations
- Since the high sensitivity d-dimer has a low specificity (approximately 50%), patients who are considered high risk ought to be ruled out with CTA.
- Consider using age adjusted d-dimer cutoffs in low risk patients over 50 years (rGeneva "not high" or Wells' "low").
- Age (years) x 10 µg/L = cutoff (patients > 50 yrs)
Literature
- Excluding pulmonary embolism at the bedside without diagnostic imaging: management of patients with suspected pulmonary embolism presenting to the emergency department by using a simple clinical model and d-dimer. Ann Intern Med. 2001 Jul 17;135(2):98-107. — Wells PS, Anderson DR, Rodger M, Stiell I, Dreyer JF, Barnes D, Forgie M, Kovacs G, Ward J, Kovacs MJ.
- Prospective validation of Wells Criteria in the evaluation of patients with suspected pulmonary embolism. Ann Emerg Med. 2004 Nov;44(5):503-10. — Wolf SJ, McCubbin TR, Feldhaus KM, Faragher JP, Adcock DM.
- Effectiveness of managing suspected pulmonary embolism using an algorithm combining clinical probability, D-dimer testing, and computed tomography. JAMA. 2006 Jan 11;295(2):172-9. — van Belle A, Büller HR, Huisman MV, Huisman PM, Kaasjager K, Kamphuisen PW, Kramer MH, Kruip MJ, Kwakkel-van Erp JM, Leebeek FW, Nijkeuter M, Prins MH, Sohne M, Tick LW; Christopher Study Investigators.
