Diagnosis of Lower Limb Deep Venous Thrombosis
Diagnosis of Lower Limb Deep Venous Thrombosis
Abstract & Commentary
By John Shufeldt, MD, JD, MBA, FACEP, Chief Executive Officer, NextCare, Inc.; Attending Physician/Vice Chair, Department of Emergency Medicine, St. Joseph's Hospital and Medical Center, Mesa, AZ, is Editor for Urgent Care Alert.
Dr. Shufeldt reports no financial relationships relevant to this field of study.
Synopsis: An evaluation of the usefulness of scoring to predict the presence of lower limb deep venous thrombosis.
Source: Subramaniam RM, et al. Diagnosis of lower limb deep venous thrombosis in emergency department patients: Performance of Hamilton and modified Wells scores. Ann Emerg Med. 2006;48:678-685.
The diagnosis of deep venous thrombosis (DVT) by clinical indicators alone is often unreliable. Moreover, untreated DVT can lead to pulmonary embolism, a serious and sometimes fatal complication. The purpose of this study was to compare the sensitivity of 2 clinical grading classifications, the modified Wells score (10 less well-defined and somewhat overlapping components) and the Hamilton score (7 non-overlapping components). (See Table.)
Subramaniam and colleagues enrolled 317 patients suspected of having lower limb DVT. Eight patients were excluded from the study for the examiner's failure to order a d-dimer test. Of the 309 patients who met inclusion criteria, 67 (21.7%) had ultrasonic confirmation of a DVT.
Using the Hamilton score, 195 patients were placed in the likely category and 114 were placed in the unlikely category. Of the patients determined to be positive for DVT, 34% had a pretest probability of 'unlikely' using the Hamilton score. Sixty-six percent had a pretest probability of likely. Applying the modified Wells criteria, 25% had a pretest probability of unlikely, and 75% had a pretest probability of likely.
Of the 309 patients studied, 143 (46%) had a negative d-dimer result and 166 (54%) had a positive d-dimer result. Of the 143 patients in the study with a negative d-dimer result, 135 (94%) had a negative ultrasound finding.
Only one patient was determined to have a DVT who had a negative d-dimer result and an 'unlikely' classification. The authors concluded that combining either the Hamilton criteria or the modified Wells criteria with a negative d-dimer result led to an estimated sensitivity of 99%. Further, the Hamilton criteria were less cumbersome to use since there was less overlap and less operator subjectivity.
Commentary
This study is of particular use to urgent care centers that have the availability of d-dimer testing. In patients who the provider believes have low clinical suspicion for a DVT, it can be effectively ruled out by using the Hamilton or modified Wells score along with a negative d-dimer test, thus, saving the time and expense of ordering for a venous Doppler examination. One note of caution: This study enlists a fairly small sample size; consequently, its conclusions may not be representative of a larger patient population.
The Hamilton test, which is arguably easier to apply, performed just as well as the modified Wells score to risk stratify patients with suspected lower extremity venous thrombosis.
The diagnosis of deep venous thrombosis (DVT) by clinical indicators alone is often unreliable. Moreover, untreated DVT can lead to pulmonary embolism, a serious and sometimes fatal complication.Subscribe Now for Access
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