Is arteriovenous shunting involved in the development of varicosities? A study of the intraluminal pressure and oxygen content in varicose veins.

OBJECTIVES

Arteriovenous (AV) shunting has been postulated as the underlying cause of varicose veins. The aim of this study was to analyse pressure and oxygen content in primary varicose veins in order to determine evidence of arterial shunting.

METHODS

Thirty-nine patients with varicose veins underwent cannulation of varicosities. The pressure and the blood oxygen content within varicosities were measured in different positions and during exercise. Similar measurements were made in the long saphenous veins of 10 control subjects without venous disease.

RESULTS

Mean pressure in varicose veins in the supine position was 12.3 mmHg (Standard deviation [SD] 3.6 mmHg). Control subjects had similar pressures measured in the long saphenous vein. No pulsatile pressure tracings were obtained. Varicosity pressures in the erect position averaged 66 mmHg (SD 9 mmHg). In all cases, the pressure correlated with the distance of the varicosity from the heart. Pressure reduction in varicosities after exercise was significantly less than that in control subjects. Recovery time (RT 90) was also significantly shorter than in the control group. Mean venous pO2 in varicosities was 4.5 kPa (SD 1.0) in the supine position dropping to 3.9 kPa (SD 0.9) on standing; these values were not significantly different to samples from control subjects.

CONCLUSIONS

AV shunting is unlikely to be a causative factor in the development of primary varicose veins.