Factors affecting the risk of deep venous occlusion after ultrasound-guided sclerotherapy for varicose veins.

OBJECTIVE: To determine which covariates predisposed to deep venous occlusion (DVO) after ultrasound-guided sclerotherapy (UGS) for varicose veins.

DESIGN: Ultrasound scans before and at 3 to 7 days after UGS to detect post-procedure deep venous occlusion.

MATERIALS: A consecutive series of 1931 treatment sessions in 852 patients treated by a technique for UGS.

METHODS: Ultrasound examination of the full length of axial deep veins above and below knee before and soon after every procedure. Crude chi(2) analysis of all covariates allowed selection of those that showed apparent significant influence. Logistic regression analysis of these then determined which independently predisposed to post-procedure deep venous occlusion.

RESULTS: Deep venous occlusion was only observed after UGS using foamed sclerosant and occurred following 28 treatment sessions. No significant difference for risk of deep venous occlusion was observed for patient characteristics or which veins were treated. Logistic regression analysis showed significant independent increased risk in a limb from using highly diluted or undiluted sclerosant (OR 0.55; 95% CI 0.19 to 1.59 for 0.6-1.0% solution, OR 10.45; 95% CI 3.12 to 34.99 for 2-2.3% and OR 0.36; 95% CI 0.07 to 1.74 for 3% solution), treating veins >or=5mm diameter (OR 3.70; 95% CI 1.23 to 11.13) and injecting >or=10 ml of foamed sclerosant for a limb (OR 3.64; 95% CI 1.21 to 10.90).

CONCLUSIONS: The risk of deep venous occlusion after UGS in this series was lower when using highly diluted or undiluted sclerosant, when treating veins less than 5mm in diameter and when restricting the volume of foam injected to less than 10 ml.