The risk of lower-limb superficial vein thrombosis relative to lower-limb venous thrombotic events is not increased in winter months.

Abstract

Ambient temperature (that impacts differently venous flow in superficial and deep veins) could have a different effect on the risk of superficial and deep venous thrombosis. We searched for a trimestral variation of the risk of superficial venous thrombosis among all lower-limb thrombotic events (lower-limb thrombotic events = superficial venous thrombosis + deep venous thrombosis). We retrospectively analyzed the results of venous ultrasound investigations performed among 11,739 patients (aged 67 ± 19 years old, 56.1% males) referred for suspected lower-limb thrombotic events over a 12-year period. Chi-square test was used to compare the superficial venous thrombosis/lower-limb thrombotic events ratio observed by trimesters to a homogeneous distribution. The proportion of lower-limb thrombotic events were 30.7%, 28.8%, 31.1%, and 31.4% (Chi2: 0.133; p = 0.987) of total investigations, while that of superficial venous thrombosis among all lower-limb venous thrombotic events were 27.2%, 30.0%, 31.4%, and 31.0%, for the first, second, third, and fourth trimesters respectively (Chi2: 0.357; p: 0.949). No trimestral variation of the superficial venous thrombosis/lower-limb venous thrombotic events ratio was observed.