The clinical validity of normal compression ultrasonography in outpatients suspected of having deep venous thrombosis.
BACKGROUND
Ultrasonography using vein compression accurately detects proximal deep venous thrombosis in symptomatic outpatients. Repeated testing is required for patients with normal results at presentation, but the optimal management of such patients is uncertain.


OBJECTIVE
To test the safety of withholding anticoagulation in outpatients suspected of having first-episode deep venous thrombosis who have normal results on simplified compression ultrasonography at presentation and on a single repeated test done 5 to 7 days later.


METHODS
Prospective cohort study.


METHODS
Noninvasive vascular laboratories at a university teaching hospital and a Veterans Administration medical center.


METHODS
405 consecutive outpatients suspected of having first-episode deep venous thrombosis.


METHODS
Ultrasonography was performed at presentation. The common femoral and popliteal veins were assessed for compressibility. If the result was normal, anti-coagulation was withheld and testing was repeated 5 to 7 days later. Anticoagulation was withheld from all patients whose results remained normal according to compression ultrasonography, regardless of their symptoms. The safety of this approach was tested by follow-up lasting 3 months.


METHODS
Objective testing was done during follow-up in all patients with symptoms or signs of venous thromboembolism. The outcome measure was symptomatic venous thrombosis or pulmonary embolism during follow-up, confirmed by objective testing.


RESULTS
Ultrasonography had normal results in 335 patients (83%) and abnormal results in 70 (17%). None of the patients with normal results died of pulmonary embolism. Venous thromboembolism occurred during follow-up in 2 patients with normal ultrasonographic results (0.6% [95% CI, 0.07% to 2.14%]) and in 4 patients with abnormal results (5.7% [CI, 1.58% to 13.99%]) (P = 0.009).


CONCLUSIONS
It is safe to withhold anticoagulation in outpatients suspected of having first-episode deep venous thrombosis if results of simplified compression ultrasonography are normal at presentation and on a single repeated test done 5 to 7 days later.
Birdwell
B G
BG
Veterans Administration Medical Center, Oklahoma City, OK 73104, USA.
Raskob
G E
GE
Whitsett
T L
TL
Durica
S S
SS
Comp
P C
PC
George
J N
JN
Tytle
T L
TL
McKee
P A
PA
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000627:therapeutic use; D002985:Clinical Protocols; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D015203:Reproducibility of Results; D013924:Thrombophlebitis / Q000000981:diagnostic imaging* / Q000188:drug therapy; D014463:Ultrasonography / Q000379:methods
D000925:Anticoagulants