Guideline Development Group

Summary of Evidence

The major signs and symptoms of LE DVT include pain, tenderness, swelling, warmth, or redness/discoloration (Table 7). Presence of these signs and symptoms should raise the suspicion of a LE DVT, but they cannot be used alone in the diagnostic process.^{30, 59} The likelihood of LE DVT should be established through use of a standardized tool. This recommendation is supported by numerous CPGs^{25, 35, 59, 60} and a meta-analysis.⁶¹ A standardized tool uses the presence of clinical features of a LE DVT to determine the likelihood that a LE DVT is present and guides the selection of the most appropriate test to diagnose a LE DVT. Physical therapists should use a standardized tool as part of their examination process when signs and symptoms of LE DVT are present. The results of the assessment should then be communicated with the medical team.

The Wells’ Criteria for LE DVT is the most commonly used tool to determine likelihood of LE DVT (Table 8). ^{20, 62} Originally, the Wells’ Criteria for LE DVT used a three tier risk stratification of low, moderate, and high. A score of 3 or greater was high risk, 1-2 was moderate and 0 or below was low risk. In a study of 593 patients, 16% had a LE DVT. When the rate of LE DVT was examined in each stratification level the rates were 3% (1.7-5.9% 95% CI), 16.6% (12%-23% 95% CI) and 74.6% (63-84% 95% CI) for low, moderate and high risk, respectively. Other studies have found a clear distinction in the rate of LE DVT between the three risk stratification levels.^{61, 63} A 2014 systematic review showed that as the score on the Well’s increased, so did the likelihood of a LE DVT.⁶⁴ This relationship has held up across multiple subgroups of patients including outpatient, inpatient, those with malignancy, gender, and previous history of a LE DVT.

In 2003, the Wells’ Criteria for LE DVT was modified to a two- stage stratification of 1. LE DVT likely; or, 2. LE DVT unlikely, and a history of previous LE DVT was added to the tool.⁶⁵ Reducing the model to two levels was easier to use and did not compromise patient safety when used in conjunction with a D-dimer test. Individuals with 2 or more points were categorized as likely and less than 2 were unlikely. In a study of 1082 outpatients, 27.9% (23.9-31.8% 95% CI) of those classified as likely had a proximal LE DVT or a PE. Of those patients classified as unlikely, 5.5% (3.8-7.6%) had a proximal LE DVT or a PE.

Beyond the Wells’ Criteria for LE DVT, other risk stratification tools have been developed, but there are limited comparison studies between the tools. One example is the Oudega Rule, developed for primary care providers. When compared to the Wells’ Criteria for LE DVT, it has similar effectiveness.^{66, 67}

The Wells’ Criteria for LE DVT has a long and well supported history of successfully stratifying risk or likelihood of LE DVT across patient populations and practice settings and is therefore the GDG recommends this tool for risk stratification. Physical therapists should advocate for its use with their interdisciplinary team and determine the best way to communicate the results and risks.