Does Repeat Duplex Ultrasound for Lower Extremity Deep Vein Thrombosis Influence Patient Management?

Abstract

The clinical significance of lower extremity deep vein thrombus (DVT) propagation in the setting of anticoagulation therapy remains unclear. The purpose of this study is to compare results of thrombus outcome found with repeat duplex ultrasonography to the incidence of pulmonary embolism and mortality. During a recent 18-month period, 457 patients were diagnosed with lower extremity DVT with duplex ultrasonography and their data were retrospectively analyzed. Repeat examinations were available for review in 118 patients (51 men, 67 women). Results of repeat duplex exams were divided into 4 groups: resolved, improved, unchanged, or extended proximally. All patients received heparin and warfarin therapy. Ventilation-perfusion (V/ Q) scans were obtained only for signs and symptoms of pulmonary embolism (n=30). Mortality, the prevalence of high-probability V/ Q scans, frequency of intracaval filter insertion, gender, mean age, mean prothrombin time (PT), mean partial thromboplastin time (PTT), mean number of repeat ultrasounds per patient, and mean time over which the repeat ultrasounds took place were compared among the 4 groups. Patients who had proximal extension of DVT (19%) on repeat duplex ultrasound had an increased prevalence of pulmonary embolism (p<0.05). Also, patients whose DVT resolved were younger (p<0.05). There was no difference among the 4 groups in mortality, placement of Greenfield filters, mean PT, mean PTT, mean number of ultrasound exams per patient, or mean follow-up time over which the exams took place. Proximal extension of DVT documented by repeat duplex ultrasound is a significant risk factor for pulmonary embolism. Repeat duplex ultrasound can identify a group of patients who may benefit from insertion of an intracaval filter device.

The safety of radiofrequency ablation of the great saphenous vein in patients with previous venous thrombosis

“…As others have suggested, 25 we have more recently tended to treat SFJ thrombus extension with antiplatelet therapy rather than anticoagulation until resolution. In the other patients, any further proximal extension of a DVT documented by repeat duplex ultrasound study is a significant risk factor for PE 12 and should be treated with standard anticoagulation.…”

“…Standardized criteria for the diagnosis of acute DVT included diminished or absent color Doppler signals with respiration or augmentation maneuvers, echogenic signals within the vein lumen either partially or completely occluding the vessel, inability to compress the vein by pressure on the transducer, and dilated veins where thrombus was suspected. 12 Once a DVT diagnosis was made, all vein segments involved were recorded. Post-thrombotic changes in examined veins were identified as obstructed or narrowed veins with thickened wall and reduced compressibility, intraluminal webs, hyperechoic material, multiple channels, and partly destroyed, thickened valves, as well as increased venous collaterals.…”

Early stroke-related deep venous thrombosis: risk factors and influence on outcome

“…We decided to search for distal DVT as it also poses an indirect but significant threat, as the thrombi propagates above the knee in even up to 20% of cases [15, 16]. Therefore, the risk of proximal extension and possibility of developing PE as a sequel should not be neglected [17].…”

Diagnostic tests and strategies in venous thromboembolism

“…Repeated ultrasound studies have also been evaluated. 22 In patients with lower extremity DVT, a further scan after a week can pick up proximal extension of DVT, which can occur in 19% of patients. An increased prevalence of PE of 2.5% is seen in patients if no further treatment is given after a single normal ultrasound scan, which can be reduced to 1% with a repeat ultrasound at 7–14 days.…”