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[Echo-Doppler for early diagnosis of deep venous thrombosis in orthopedic surgery and traumatology. A retrospective study of 1,647 patients].

UNLABELLED
The authors report the results of duplex ultrasound scanning investigation for the detection of deep venous thrombosis after orthopedic surgery and compare asymptomatic and symptomatic populations.


PURPOSE OF THE STUDY
To estimate the rate of deep venous thrombosis diagnosed by duplex scanning in those 2 populations and precise their features.


MATERIAL
A total of 1,647 in-patients all receiving low-molecular-weight heparin and investigated from 1989 to 1993. either for screening because of high risk of thrombosis (asymptomatic group: 930 patients, mean age +/- SD 63 +/- 17 years) or for clinical suspicion of deep vein thrombosis (symptomatic group; 717 patients, mean age +/- SD: 57 +/- 21 years). Difference between the two groups mean ages were significant (p < 10(-8).


METHODS
An Hitachi EUB 450 duplex and an Acuson colour duplex 128 XP, with 3.5 MHz and 7.5 MHz linear probes were used. Veins were tested for compressibility in transverse view from caval site to both ankles. Retrospective analysis of patients database results has been achieved.


RESULTS
There was no significant difference in deep vein thrombosis rate between screening asymptomatic group (356/930:38%) and symptomatic group (253/717: 35%). There was a linear relation, in the 2 groups, between age and deep vein thrombosis rate, from 10% before twenty to 45% after eighty years old. For a relative risk to have thrombosis detected before twenty definite at 1, it was 2.1 for 20-29, 4.9 for 40-49, 6.2 for 60-69 and 8.6 later than 80 years old. Proximal deep vein thrombosis was detected in only 5% (87/1,647) of patients. Distal muscular soleal veins were the most usual involved sites of thrombosis. Isolated soleal thrombosis were detected in 16% (270/1,647) of patients. There was non significant difference between the deep vein thrombosis rate after total knee or hip arthroplasty among selected patients for duplex scanning from 1989, and the true prevalence assessed among all the patients who have undergone total hip or knee arthroplaty during the last 6 months.


DISCUSSION
Pessimistic results previously reported for duplex screening among asymptomatic patients are not confirmed. Calf vein thrombosis rate assessed by duplex scanning exceeds by 15 a 20% usual rates assessed by contrast venography, among patients receiving low-molecular-weight heparins. That difference could be assigned to the isolated muscular soleal thrombosis usually missed at contrast venography.


CONCLUSION
Deep vein thrombosis rate among orthopedic surgical patients, is much higher when detected with Duplex ultrasound scanning than detected with contrast venography, and is related to patient age. Screening for deep venous thrombosis by duplex scanning in orthopedic surgery is as efficient among asymptomatic as among symptomatic patients and could become soon a systematic screening. Soleal vein thrombosis are the most usual. Mechanical calf venous pump stimulation in association with low molecular weight heparin, has to be evaluated in attempting to reduce those muscular soleal veins thrombosis.