Evaluation of the Patient with Suspected Deep Vein Thrombosis

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Applied Evidence

Evaluation of the Patient with Suspected Deep Vein Thrombosis

J Fam Pract. 2001 February;50(2):167-171

References

1. US Department of Health and Human Services. National Ambulatory Medical Care Survey (1995). NCHS CD-ROM Series 13, No. 11, SETS Version 1.221. Washington, DC: US Department of Health and Human Services; 1997.

2. Anderson FA, Wheeler HB, Goldberg RJ, et al. A population-based perspective of the hospital incidence and case-fatality rates of deep vein thrombosis and pulmonary embolism: the Worcester DVT study. Arch Intern Med 1991;151:933-38.

3. Meignan M, Rosso J, Gauthier H, et al. Systematic lung scans reveal a high frequency of silent pulmonary embolism in patients with proximal deep venous thrombosis. Arch Intern Med 2000;160:159-65.

4. Lamberts H. In Het Huis van de huisarts. Verslag van het Transitieproject. Lelystad: Meditekst, 2nd edition, 1994.

5. Sandler DA, Duncan JS, Ward P, et al. Diagnosis of deep-vein thrombosis: comparison of clinical evaluation, ultrasound, plethysmography, and venoscan with x-ray venogram. Lancet 1984;2:716-18.

6. O’Donnell TF, Jr, Abbott WM, Athanasoulis CA, Millan VG, Callow AD. Diagnosis of deep venous thrombosis in the outpatient by venography. Surg Gynecol Obstet 1980;150:69-74.

7. McLachlan J, Richards T, Paterson JC. An evaluation of clinical signs in the diagnosis of venous thrombosis. Arch Surg 1962;85:738-44.

8. Wells PS, Hirsh J, Anderson DR, et al. Accuracy of clinical assessment of deep-vein thrombosis. Lancet 1995;345:1326-30.

9. Wells P, Anderson DR, Bormanis J, et al. Value of assessment of pretest probability of deep-vein thrombosis in clinical management. Lancet 1997;350:1795-98.

10. Wells PS, Hirsch J, Anderson DR, et al. A simple clinical model for the diagnosis of deep-vein thrombosis combined with impedance plethysmography: potential for an improvement in the diagnostic process. J Intern Med 1998;243:15-23.

11. Kearon C, Julian JA, Newman TE, Ginsberg JS. for the McMaster Diagnostic Imaging Practice Guidelines Initiative. Noninvasive diagnosis of deep venous thrombosis. Ann Intern Med 1998;128:663-77.

12. Anderson DR, Wells PS, Stiell I, et al. Management of patients with suspected deep vein thrombosis in the Emergency Department: combining use of a clinical diagnosis model with d-dimer testing. J Emerg Med 2000;19:225-30.

13. Wildberger JE, Vorwerk D, Kilbinger M, et al. Bedside testing (SimpliRED) in the diagnosis of deep vein thrombosis: evaluation of 250 patients. Invest Radiol 1998;33:232-35.

14. Spritzer CE, Sostman HD, Wilkes DC, Coleman RE. Deep venous thrombosis: experience with gradient-echo MR imaging in 66 patients. Radiology 1990;177:235-41.

15. Moody AR, Pollock JG, O’Connor AR, Bagnall M. Lower-limb deep venous thrombosis: direct MR imaging of the thrombus. Radiology 1998;209:349-55.

16. Vukov LF, Berquist TH, King BF. Magnetic resonance imaging for calf deep venous thrombophlebitis. Ann Emerg Med 1991;20:497-99.

17. Laissy JP, Cinqualbre A, Loshkajian A, et al. Assessment of deep venous thrombosis in the lower limbs and pelvis: MR venography versus duplex Doppler sonography. Am J Roentgenol 1996;167:971-75.

18. Erdman WA, Jayson HT, Redman HC, et al. Deep venous thrombosis of extremities: role of MR imaging in the diagnosis. Radiology 1990;174:425-31.

19. Spritzer CE, Norconk JJ, Sostman HD, Coleman RE. Detection of deep venous thrombosis by magnetic resonance imaging. Chest 1993;104:54-60.

20. ACCP Consensus Committee on Pulmonary Embolism. Opinions regarding the diagnosis and management of venous thromboembolic disease chest. 1998;113:499-504.

21. American Thoracic Society. The diagnostic approach to acute venous thromboembolism clinical practice guideline. Am J Respir Crit Care Med 1999;160:1043-66.

22. Cogo A, Lensing AW, Koopman MW, et al. Compression ultrasonography for diagnostic management of patients with clinically suspected deep vein thrombosis: prospective cohort study. BMJ 1998;316:17-20.

23. Birdwell BG, Raskob GE, Whitsett TL, et al. The clinical validity of normal compression ultrasonography in outpatients suspected of having deep venous thrombosis. Ann Intern Med 1998;128:1-7.

24. Heijboer H, Buller HR, Lensing AW, et al. A comparison of real-time compression ultrasonography with impedance plethysmography for the diagnosis of deep-vein thrombosis in symptomatic outpatients. N Engl J Med 1993;329:1365-69.

25. Bernardi F, Prandoni P, Lensing AWA, et al. D-dimer testing as an adjunct to ultrasonography in patients with clinically suspected deep vein thrombosis: prospective cohort study. BMJ 1998;317:1037-40.

Some physicians advocate repeating the duplex venous ultrasound in patients with an initial negative test result, if the suspicion for DVT remains. Two studies with a total of 2107 patients repeated the ultrasound 5 to 7 days later, if the first ultrasound result was normal; patients with 2 normal ultrasound results did not receive anticoagulation.^22,23 Only 0.6% of these patients had a thromboembolic complication (DVT or pulmonary embolism) during the next 3 months, and only 1 of these occurred during the week between ultrasounds. A third study repeated the ultrasound 1 day and again 6 days later in patients with a normal initial ultrasound results.²⁴ Of 390 patients with 3 normal ultrasound results, only 6 had a thromboembolic complication during the next 3 months. Thus, in patients with 2 normal results 1 week apart, the risk of a thromboembolic complication during the next 3 months is approximately 1%.

D-dimer is a fibrin degradation product, and elevated levels are associated with an increased risk of DVT. Different d-dimer assays vary considerably in their performance. Latex agglutination assays are fast and cheap but not very accurate; they are therefore not recommended. Microplate enzyme-linked immunoassays (ELISAs) are accurate but expensive; membrane ELISAs are less expensive and nearly as accurate. The accuracy of one of the most widely used d-dimer tests (SimpliRED) is shown in Table 3. Note that a negative d-dimer test rersult alone does not rule out DVT; 2% to 5% of patients with suspected DVT and a negative d-dimer result actually have DVT. This is similar to the performance of ultrasound alone in unselected patients with suspected DVT. Because of the differences between tests, clinicians should learn which test is used by their laboratory and should advocate for use of the most accurate available test.

The d-dimer test is most useful in a patient with a moderate risk of DVT and a normal duplex venous ultrasound result. In one study, only 1 of 598 patients with normal ultrasound and normal d-dimer test results (membrane ELISA; Instant-IA d-dimer kit, Stago, Asnieres, France) developed a DVT in the next 3 months. Of 88 patients with normal duplex venous ultrasound results but elevated d-dimer levels, 5 had a DVT detected 1 week later with a repeat ultrasound, and an additional 2 had venous thromboembolic complications during the next 3 months.²⁵

Approaching the patient

Evaluating all patients with suspected DVT in the same way risks overdiagnosing low-risk patients and underdiagnosing high-risk patients. The history and physical examination can guide the selection and interpretation of further diagnostic tests. Begin by using the Wells clinical decision rule Figure 1 to put the patient in the low-, moderate-, or high-risk group. Remember that this rule was developed in nonpregnant patients with a first DVT. For pregnant patients or those with a history of previous DVT, you should have a higher index of suspicion.

Next, use the algorithm in Figure 2 to guide your evaluation. DVT can be considered adequately ruled out in low-risk patients with a negative ultrasound result and in moderate-risk patients with normal d-dimer and normal ultrasound results. Moderate-risk patients with a normal initial result on ultrasound but an abnormal d-dimer level should have a repeat ultrasound in 1 week. Moderate- and high-risk patients with an abnormal ultrasound result should be treated for DVT. High-risk patients with a normal ultrasound result still have a fairly high probability of DVT and should have a venogram to establish the diagnosis. In high-risk patients normal ultrasound and normal d-dimer results do not adequately rule out DVT.

Of course, this algorithm should not be used inflexibly. Patients with new or progressive symptoms (eg, a person with suspected DVT who develops signs and symptoms of PE) should be evaluated immediately. Pregnant patients and patients with a history of DVT should be evaluated more aggressively, because their overall risk of DVT is higher.

All correspondence should be addressed to Mark H. Ebell, MD, MS, 330 Snapfinger Drive, Athens, GA 30605. E-mail: ebell@msu.edu.