Normal whole-arm ultrasound rules out upper extremity deep venous thrombosis

By Will Boggs MD

A normal whole-arm ultrasound can rule out upper-extremity deep venous thrombosis (UE-DVT) and preclude the necessity of anticoagulation, researchers from Italy report.

"Outpatients are often seen in angiology or radiology clinics that often can rely only on clinical examination and ultrasonography," Dr. Michelangelo Sartori, from S. Orsola-Malpighi University Hospital, Bologna, Italy, told Reuters Health by email. "We show that, similarly to the lower extremity, a negative complete ultrasound assessment of the upper extremity can safely exclude DVT."

Only about 14% of all DVT cases involve the upper extremity, but prompt diagnosis is needed to identify patients who require anticoagulation to prevent pulmonary embolism.

"Contrast venography has been the accepted reference standard for suspected UE-DVT diagnosis," Dr. Sartori said, "but it is an invasive test requiring the use of ionizing radiation and with several potential adverse events such as contrast allergies and renal dysfunction. The non-feasibility of venography for a large number of patients compelled us to use the duplex ultrasonography in every day clinical practice."

Dr. Sartori and colleagues' letter online May 11 in JAMA Internal Medicine reports their experience using ultrasonography to screen for UE-DVT in 483 patients who presented for suspected symptomatic DVT or superficial venous thrombosis (SVT) of the upper extremity.

Two-thirds of patients had normal ultrasound findings, and 4.3% had inconclusive results requiring repeated testing. Two of these 21 patients with inconclusive results had DVT on repeat ultrasound, and one had SVT.

Of the 337 patients with normal ultrasound results, one (0.3%) developed ipsilateral DVT after one month and one (0.3%) developed SVT after peripheral vein infusion. No cases of pulmonary embolism occurred.

Overall, whole-arm ultrasound missed 1 diagnosis of DVT, for a failure rate of 0.3%.

"We found a three-month VTE rate of 0.6% after a negative ultrasound and such figure is not different from the three-month VTE incidence in management studies for lower limb DVT," Dr. Sartori said. "Thus, anticoagulant therapy can be withheld for clinically suspected UE-DVT after negative ultrasound examination without further testing in the ambulatory office setting. However, in case of lack of appropriate visualization of a portion of the subclavian vein, the ultrasonogram should be repeated."

Dr. Scott M. Stevens, from Intermountain Medical Center, Murray, Utah, cowrote an accompanying editorial. He told Reuters Health by email, "I would strongly consider ultrasound as the first-line test for suspected UE-DVT, and would reserve venography or (computed tomography) venography only for cases in which ultrasound is non-diagnostic, or in which it is strongly suspected that ultrasound may be false-negative. Clinicians might also consider using a clinical pre-test probability score, d-dimer, and ultrasound in a diagnostic algorithm, though it would be nice to see further outcome studies validating this approach."

"I would only initiate anticoagulation in a patient with normal ultrasound if I strongly suspected the test to be false negative (i.e., I thought proximal subclavian thrombosis likely, which might be undetected by ultrasound) while awaiting the results of venography - especially in a patient with limited cardiopulmonary reserve, for whom pulmonary embolism might have a high probability of being fatal," Dr. Stevens said.

Dr. Stevens added, "It is worth noting that the 9th ACCP (American College of Chest Physicians) antithrombotic guidelines suggest initial use of ultrasound for suspected UE-DVT, and this study would increase the level of evidence underlying that guideline. Also, unlike venography and CT venography, ultrasound does not carry the risks of radiation and contrast exposure."

No conflicts of interest were reported.

SOURCE: http://bit.ly/1dZMAzu and http://bit.ly/1zYyto6

JAMA Intern Med 2015.

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