Ortho-Preferred

Deep Venous Thrombosis (DVT) - Ultrasound

Discussion
  • allows assessment of DVT from the external iliac vein down to the popliteal veins
  • visualization distal to the popliteal veins is usually not possible
  • may be able to detect patency of major vessels, but it is not effective for smaller vessels
  • will not diagnose pelvic thrombi
  • note that clots seen on ultrasound comprise a spectrum from clots in the calf (usually not seen), to clots on the femoral valve cusps (non occlusive), to occlusive deep venous thrombosis which extends from the popliteal vessels to the proximal vessels (the latter is associated with higher risk of PE)
  • note that the reliability of the ultrasound study is very user dependent (more experienced technicians will give a more accurate study)
Diagnostic criteria
  • visualization of an intraluminal thrombus in a deep vein
  • lack of compressibility of the venous lumen
  • filling of the lumen w/ echoes
  • diminished Doppler waveforms
  • lack of augmentation of venous flow w/ compression of calf muscles
  • lack of effect of respiration on the Doppler wave form
False negative study
  • note that on occassion DVT distal to the popliteal veins will progress proximally
  • hence, when there is clinical indication of a DVT (such as a persistently swollen calf and/or a positive Homan's sign) despite negative findings on an initial ultrasound, then a repeat ultrasound should be considered
  • in the study by Ciccone, et al. (1998), venography and DVT were used to evaluate clot formation (total joint replacement patients)
    • venograms determine that over 90% of clots formed in the calf vessels
    • ultrasound was unreliable in diagnosing calf thrombi
References
B-mode ultrasound scanning in the detection of proximal venous thrombosis after total hip replacement.

Compression ultrasonography for the detection of deep venous thrombosis in patients who have a frx the hip. A prospective study.

Deep-vein thrombosis after fracture of the pelvis: assessment with serial duplex-ultrasound screening.

Duplex scanning versus venography as a screening examination in total hip arthroplasty patients.

Prospective ultrasound evaluation of venous thrombosis in high-risk trauma patients.

Ultrasound surveillance for asymptomatic deep venous thrombosis after total joint replacement.



Original Text by Clifford R. Wheeless, III, MD.

Last updated by Data Trace Staff on Monday, February 17, 2014 3:18 pm