Medicine:Wells score (pulmonary embolism)
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).
Original algorithm[1]
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.
Revised score [3][4]
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
- ↑ 1.0 1.1 1.2 Wells, Philip S.; Ginsberg, Jeffrey S.; Anderson, David R.; Kearon, Clive; Gent, Michael; Turpie, Alexander G.; Bormanis, Janis; Weitz, Jeffrey et al. (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. https://www.acpjournals.org/doi/10.7326/0003-4819-129-12-199812150-00002.
- ↑ Wells, P. S.; Hirsh, J.; Anderson, D. R.; Lensing, A. W.; Foster, G.; Kearon, C.; Weitz, J.; D'Ovidio, R. et al. (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. https://pubmed.ncbi.nlm.nih.gov/7752753/.
- ↑ 3.0 3.1 3.2 Wells, P. S.; Anderson, D. R.; Rodger, M.; Ginsberg, J. S.; Kearon, C.; Gent, M.; Turpie, A. G.; Bormanis, J. et al. (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. https://pubmed.ncbi.nlm.nih.gov/10744147/.
- ↑ 4.0 4.1 Wells, Philip S.; Anderson, David R.; Rodger, Marc; Stiell, Ian; Dreyer, Jonathan F.; Barnes, David; Forgie, Melissa; Kovacs, George et al. (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. https://www.acpjournals.org/doi/10.7326/0003-4819-135-2-200107170-00010.
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