The ability of real-time B-mode ultrasound to directly visualize arteries and veins and thereby give anatomic rather than physiologic information is unique among the currently available noninvasive methods of vascular evaluation. The usefulness of this technique for examination of the carotid arteries has been well proven. Little attention, however, has been given to its applicability for deep venous evaluation. Over the past 12 months the veins of 108 upper and 215 lower extremities have been studied with high-resolution real-time ultrasound. The technique and interpretive criteria are presented. Thirty extremities underwent confirmatory venography, and in this group the specificity and sensitivity of the ultrasound were 94% and 100%, respectively. In addition, the age of the thrombi detected was accurately predicted in 93% of this group. These preliminary results suggest that real-time B-mode venous ultrasound is an accurate, clinically useful noninvasive technique for the detection of deep venous thrombosis that complements the more widely used physiologic screening tests.
Venous duplex scanning (VDS) is sensitive and specific for proximal deep-vein thrombosis (DVT) but has poor sensitivity for isolated calf DVT, some of which can extend to the proximal veins and result in clinically significant pulmonary emboli. The intent of this study was to determine the long-term outcome of outpatients with negative VDS and to assess the accuracy of three biochemical markers of hypercoagulability for the detection of DVT. Consecutive ambulatory patients referred to our vascular laboratory with a question of lower extremity DVT had plasma determination of D-dimer, prothrombin fragment 1.2, and thrombin-antithrombin complex. Additionally, patients with a negative VDS were followed for 6 months to determine the frequency of subsequent venous thrombosis. Of 207 patients seen in our vascular laboratory, 171 had either a single negative VDS or two negative studies (done 24-72 h apart). Follow-up of 161 patients for 6 months showed no evidence of venous thromboembolism. The remaining 10 patients died from other causes or had alternative diagnoses made to explain their symptoms. The D-dimer and thrombinantithrombin complex had equal test accuracy for the diagnosis of DVT and were superior to the prothrombin fragment 1.2 levels. Symptomatic venous thromboembolism occurring after negative VDS is uncommon. D-dimer and thrombin-antithrombin levels have equal utility as diagnostic tests for DVT.
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