Skin Temperature of the Lower Extremities in Patients with Varicose Veins Associated with Saphenous Vein Incompetence

Abstract

It is well known that the skin temperature of the lower limbs in patients with varicose veins is higher than that of normal limbs. This temperature increase is considered to be due to incompetent perforating veins and/or precapillary arterio-venous shunts. Several workers have shown that the temperature of venous blood in deep veins is higher than that in superficial veins. However, there are few reports on the difference of skin temperatures of the lower limbs in patients with varicose veins in the standing, supine or prone positions. The purpose of this study is to reveal these differences.

The subjects were 65 patients with unilateral or bilateral varicose veins associated with long saphenous vein incompetence detected by Doppler imaging. They consisted of 20 men and 45 women and their ages ranged from 35 to 81 years old, with a mean of 55.9 years old. Altogether, 92 affected limbs (16 right, 22 left and 27 bilateral) and 38 normal limbs were investigated The skin temperature of the healthy legs of patients were used for control. Skin temperatures were measured by thermography (NEC San-ei, TH3106ME). Patients were kept in a supine or prone position so that the most prominent varicossities were on the upper side in a quiet room at temperature of 23-25℃ for approximately 5 minutes. After these procedures patients were kept in a standing position for approximately 5 minutes and thermography was performed again. The histograms of the skin temperature of the lower limbs and the maximum temperature was calculated automatically. In the standing position the mean maximum skin temperatures (MMT) of the affected and normal limbs were 34.82±0.97℃ (n=91) and 33.92±1.05℃ (n=34), respectively. The former was statistically higher than the latter (p<0.001). In the lateral position MMT of the affected and normal limbs were 34.74±0.79℃ (n=48) and 33.96±0.79℃ (n=20), respectively. The former was statistically higher than the latter (p=0.004). MMT of normal limbs (n=20) showed no difference between the standing and lateral positions. MMT of the affected limbs (n=47) in the standing position was 0.12℃ higher than that in the lateral position, but there was no statistically significant difference. In both patients with (n=8) and without (n=39) congestive dermatitis, MMT in the standing position were 0.54℃ and 0.02℃, both higher than those in the lateral position but their differences were not statistically significant.

In this study there were not significant differences of the skin temperature of the leg between the standing and the supine or prone positions, but there was a tendency for the skin temperature to increase in the standing position, especially in patients with congestive dermatitis. These findings suggest the possibility that not only incompetent perforating veins and/or precapillary AV shunts but also saphenous vein incompetence plays a role in the increase of skin temperature of the legs of patients with varicose veins.