Withholding Anticoagulation after a Negative Result on Duplex Ultrasonography for Suspected Symptomatic Deep Venous Thrombosis

15 June 2004 | Volume 140 Issue 12 | Pages 985-991

Background: Negative results on simplified compression ultrasonography cannot rule out symptomatic deep venous thrombosis (DVT) without further testing, such as repeated ultrasonography several days later. Repeated testing is costly and inconvenient, and patients are sometimes less likely to return for follow-up tests.

Objective: To determine the rate of venous thromboembolism when anticoagulation is withheld in patients with symptoms of DVT of the leg after negative results on a single examination with comprehensive duplex ultrasonography.

Design: Prospective clinical cohort study.

Setting: Peripheral vascular laboratory of a tertiary care academic hospital.

Patients: 445 consecutive patients in whom a first episode of symptomatic DVT was suspected.

Intervention: The researchers examined the entire leg with comprehensive duplex ultrasonography, using compression and Doppler techniques. Anticoagulation was withheld from the group with negative results. Patients were observed for thromboembolic events for 3 months.

Measurements: All patients who had new or progressive symptoms or signs of venous thromboembolism during follow-up underwent objective testing.

Results: Comprehensive duplex ultrasonography yielded normal results in 384 patients (86.3%) and showed DVT in 61 patients (13.7%). Nineteen cases of DVT (31.1%) were isolated to the deep veins of the calf. Nine patients in the negative cohort (2.3%) were excluded from analysis because they received anticoagulation for reasons unrelated to venous thromboembolism. Three of 375 patients (0.80% [95% CI, 0.16% to 2.33%]) in the normal cohort had symptomatic venous thrombosis during the 3-month follow-up. All 384 patients in the negative cohort completed follow-up.

Limitations: The study was conducted at a single tertiary care center by a peripheral vascular staff with substantial experience in duplex ultrasonography, which may limit the applicability of the results to other institutions. Pregnant patients were excluded.

Conclusions: It is safe to withhold anticoagulation after negative results on comprehensive duplex ultrasonography in nonpregnant patients with a suspected first episode of symptomatic DVT of the leg. New or progressive symptoms should prompt further testing.

Editors' Notes Context Simplified compression ultrasonography is useful in detecting deep venous thrombosis (DVT), but repeated testing is required 5 to 7 days later to detect proximal propagation from an unvisualized calf vein. Comprehensive duplex ultrasonography examines deep veins from the inguinal ligament to the malleolus. Contribution Consecutive patients with suspected symptomatic first episodes of DVT underwent comprehensive duplex ultrasonography. Anticoagulation was withheld if results were negative, regardless of symptoms or clinical signs. On 3-month follow-up, the overall rate of symptomatic venous thrombosis was 0.8%. Implications An acceptably low risk for false-negative results on comprehensive duplex ultrasonography may obviate the need for repeated testing in the vast majority of patients with suspected first episodes of DVT. –The Editors

 

Author and Article Information

From LDS Hospital and University of Utah, Salt Lake City, Utah; and Franklin Square Hospital Center, Baltimore, Maryland.

Acknowledgments: The authors thank Charles Laggore, MD; Elizabeth Underwood, MD; and Troy Chatwin, PA-C, for their work in patient enrollment and follow-up. They also thank Greg Goodman, MD; Steven Merrell, MD; Joni Boone, RVT; the staff of the LDS Hospital Peripheral Vascular Laboratory; Willis Layton, RVT; and Lawrence Porter for their work on preparation of multimedia materials and especially acknowledge Graham F. Pineo, MD; James George, MD; and Gary E. Raskob, PhD, for their service as independent adjudicators.

Grant Support: By the Deseret Foundation, Salt Lake City, Utah (grant no. 371).

Potential Financial Conflicts of Interest: None disclosed.

Requests for Single Reprints: Scott M. Stevens, MD, Department of Medicine, LDS Hospital, Eighth Avenue and C Street, Salt Lake City, UT 84143; e-mail, scott.stevens{at}ihc.com.

Current Author Addresses: Dr. Stevens: Department of Medicine, LDS Hospital, Eighth Avenue and C Street, Salt Lake City, UT 84143.

Dr. Elliott: Pulmonary/Critical Care Division, Department of Medicine, LDS Hospital, Eighth Avenue and C Street, Salt Lake City, UT 84143.

Ms. Chan: Statistical Data Center, LDS Hospital, Eighth Avenue and C Street, Salt Lake City, UT 84143.

Dr. Egger: Public Health Programs, Department of Family and Preventive Medicine, University of Utah, 50 North Medical Drive, Salt Lake City, UT 84132.

Dr. Ahmed: Franklin Square Hospital Center, 9105 Franklin Square Drive, Baltimore, MD 21237.

Author Contributions: Conception and design: S.M. Stevens, C.G. Elliott, K.J. Chan, M.J. Egger.

Analysis and interpretation of the data: S.M. Stevens, C.G. Elliott, K.J. Chan, M.J. Egger.

Drafting of the article: S.M. Stevens, C.G. Elliott, K.J. Chan, M.J. Egger.

Critical revision of the article for important intellectual content: S.M. Stevens, C.G. Elliott, K.J. Chan, M.J. Egger.

Final approval of the article: S.M. Stevens, C.G. Elliott, K.J. Chan, M.J. Egger, K.M. Ahmed.

Statistical expertise: K.J. Chan, M.J. Egger.

Obtaining of funding: S.M. Stevens, C.G. Elliott.

Administrative, technical, or logistic support: S.M. Stevens, K.M. Ahmed.

Collection and assembly of data: S.M. Stevens, K.M. Ahmed.

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