Group

Case

Incidence of VTE (%)

Peak velocity

Mean velocity

Observation group

150

0.6

58.41 ± 8.25

31.14 ± 5.23

Control group

150

5.3

43.33 ± 8.05

23.02 ± 5.49

t

-

4.6

15.9

13.1

p

-

0.03

0.0001

0.0001