title: Isolated Deep Venous Thrombosis: Implications for 2-Point Compression Ultrasonography of the Lower Extremity.
abstract: OBJECTIVE
  Two-point compression ultrasonography focuses on the evaluation of common femoral and popliteal veins for complete compressibility. The presence of isolated thrombi in proximal veins other than the common femoral and popliteal veins should prompt modification of 2-point compression technique. The objective of this study is to determine the prevalence and distribution of deep venous thrombi isolated to lower-extremity veins other than the common femoral and popliteal veins in emergency department (ED) patients with clinically suspected deep venous thrombosis.
  
  
  METHODS
  This was a retrospective study of all adult ED patients who received a lower-extremity venous duplex ultrasonographic examination for evaluation of deep venous thrombosis during a 6-year period. The ultrasonographic protocol included B-mode, color-flow, and spectral Doppler scanning of the common femoral, femoral, deep femoral, popliteal, and calf veins.
  
  
  RESULTS
  Deep venous thrombosis was detected in 362 of 2,451 patients (14.7%; 95% confidence interval [CI] 13.3% to 16.1%). Thrombus confined to the common femoral vein alone was found in 5 of 362 cases (1.4%; 95% CI 0.2% to 2.6%). Isolated femoral vein thrombus was identified in 20 of 362 patients (5.5%; 95% CI 3.2% to 7.9%). Isolated deep femoral vein thrombus was found in 3 of 362 cases (0.8%; 95% CI -0.1% to 1.8%). Thrombus in the popliteal vein alone was identified in 53 of 362 cases (14.6%; 95% CI 11% to 18.2%).
  
  
  CONCLUSIONS
  In our study, 6.3% of ED patients with suspected deep venous thrombosis had isolated thrombi in proximal veins other than common femoral and popliteal veins. Our study results support the addition of femoral and deep femoral vein evaluation to standard compression ultrasonography of the common femoral and popliteal vein, assuming that this does not have a deleterious effect on specificity.
authors.affiliation: Department of Emergency Medicine, the University of Arizona Medical Center, Tucson, AZ. Electronic address: sriadhikari@aol.com.
authors.forename: Srikar
authors.initials: S
authors.lastname: Adhikari
authors.affiliation: Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE.
authors.forename: Wes
authors.initials: W
authors.lastname: Zeger
authors.affiliation: Department of Emergency Medicine, Thomas Jefferson University, Philadelphia, PA.
authors.forename: Christopher
authors.initials: C
authors.lastname: Thom
authors.affiliation: Department of Emergency Medicine, Thomas Jefferson University, Philadelphia, PA.
authors.forename: J Matthew
authors.initials: JM
authors.lastname: Fields
mesh_terms: D004636:Emergency Service, Hospital; D005260:Female; D005268:Femoral Vein / Q000000981:diagnostic imaging*; D006801:Humans; D007866:Leg / Q000098:blood supply / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D019095:Point-of-Care Systems; D011152:Popliteal Vein / Q000000981:diagnostic imaging*; D012189:Retrospective Studies; D014463:Ultrasonography; D020246:Venous Thrombosis / Q000000981:diagnostic imaging*