Wells score (pulmonary embolism)
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The Wells score is a clinical prediction rule used to classify patients suspected of having pulmonary embolism (PE) into risk groups by quantifying the pre-test probability. It is different than Wells score for DVT (deep vein thrombosis). It was originally described by Wells et al. in 1998,[1] using their experience from creating Wells score for DVT in 1995.[2] Today, there are multiple (revised or simplified) versions of the rule, which may lead to ambiguity.[1][3][4]
The purpose of the rule is to select the best method of investigation (e.g. D-dimer testing, CT angiography) for ruling in or ruling out the diagnosis of PE, and to improve the interpretation and accuracy of subsequent testing, based on a Bayesian framework for the probability of the diagnosis.
The rule is more objective than clinician gestalt, but still includes subjective opinion (unlike e.g. Geneva score).
Originally it was developed in 1998 to improve the low specificity of V/Q scan results (which then had a more important role in the workup of PE than now).
It categorized patients into 3 categories: low / moderate / high probability. It was formulated in the form of an algorithm, not a score.
Subsequent testing choices were V/Q scanning, pulmonary angiography, and serial compression ultrasound.
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The emergence of D-dimer assays prompted the revision of the rule.
This version was published as a score, and according to the final score, patients could be categorized in either 3 groups (low / intermediate / high risk) or 2 groups (low / high risk)
Subsequent testing choices included D-dimer testing for low risk cases, and V/Q scanning, pulmonary angiography, and compression ultrasonography for intermediate / high risk patients and low-risk patients with positive D-dimer results.
| Variable | Points |
|---|---|
| Clinical signs and symptoms of DVT | 3 |
| An alternate diagnosis is less likely than PE | 3 |
| Heart rate >100 | 1.5 |
| Immobilization or surgery in the previous 4 weeks | 1.5 |
| Previous DVT / PE | 1.5 |
| Hemoptysis | 1 |
| Malignancy (treatment currently, in the previous 6 months, or palliative) | 1 |
Risk of PE using 3 categories (data from the derivation group)
| Risk group | Points required | Risk of PE |
|---|---|---|
| Low risk | 0-1 | 3.6% |
| Moderate risk | 2-6 | 20.5% |
| High risk | >6 | 66.7% |
Risk of PE using 2 categories (data from the derivation group)
| Risk group | Points required | Risk of PE |
|---|---|---|
| Low | 0-4 | 5.1% |
| High | >4 | 39.1% |
References
[edit]- ^ a b c Wells, Philip S.; Ginsberg, Jeffrey S.; Anderson, David R.; Kearon, Clive; Gent, Michael; Turpie, Alexander G.; Bormanis, Janis; Weitz, Jeffrey; Chamberlain, Michael; Bowie, Dennis; Barnes, David; Hirsh, Jack (1998-12-15). "Use of a Clinical Model for Safe Management of Patients with Suspected Pulmonary Embolism". Annals of Internal Medicine. 129 (12): 997–1005. doi:10.7326/0003-4819-129-12-199812150-00002. ISSN 0003-4819. PMID 9867786. S2CID 41389736.
- ^ Wells, P. S.; Hirsh, J.; Anderson, D. R.; Lensing, A. W.; Foster, G.; Kearon, C.; Weitz, J.; D'Ovidio, R.; Cogo, A.; Prandoni, P. (1995-05-27). "Accuracy of clinical assessment of deep-vein thrombosis". Lancet. 345 (8961): 1326–1330. doi:10.1016/s0140-6736(95)92535-x. ISSN 0140-6736. PMID 7752753. S2CID 23107192.
- ^ a b c Wells, P. S.; Anderson, D. R.; Rodger, M.; Ginsberg, J. S.; Kearon, C.; Gent, M.; Turpie, A. G.; Bormanis, J.; Weitz, J.; Chamberlain, M.; Bowie, D.; Barnes, D.; Hirsh, J. (March 2000). "Derivation of a simple clinical model to categorize patients probability of pulmonary embolism: increasing the models utility with the SimpliRED D-dimer". Thrombosis and Haemostasis. 83 (3): 416–420. doi:10.1055/s-0037-1613830. ISSN 0340-6245. PMID 10744147. S2CID 10013631.
- ^ a b Wells, Philip S.; Anderson, David R.; Rodger, Marc; Stiell, Ian; Dreyer, Jonathan F.; Barnes, David; Forgie, Melissa; Kovacs, George; Ward, John; Kovacs, Michael J. (2001-07-17). "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". Annals of Internal Medicine. 135 (2): 98–107. doi:10.7326/0003-4819-135-2-200107170-00010. ISSN 0003-4819. PMID 11453709. S2CID 2708155.