Six studies of saphenous veins (four RCTs and two non-randomised comparative studies) and two studies of reticular veins and telangiectases (one RCT and one non-randomised comparative study) were included in the review. Follow-up in the saphenous vein studies ranged from six months to 10 years. Follow-up in the reticular veins and telangiectases studies ranged from five weeks to 75 days.
Saphenous veins: In studies of saphenous veins, all success rates were in favour of foam (lowest 67%, 95% CI 59% to 75% and highest 84%, 95% CI 74% to 94%) compared with liquid (lowest 17.5%, 95% CI 6% to 29% and highest 76%, 95% CI 69% to 83%). Four studies (three RCTs and one non-randomised comparative study) were combined in a meta-analysis. This meta-analysis did not report a comparative outcome measure for foam and liquid, but instead reported a separate outcome for each type of treatment. Success rate was statistically significantly greater with foam (76.38%, 95% CI 71% to 82%) compared with liquid (39.5%, 95% CI 33% to 43%). There was evidence of statistically significant heterogeneity (p≤0.0001).
Side effects were reported to be rare for all trials. One study reported that 2.5% of patients who received foam experienced visual disturbance that lasted less than two minutes compared with none in the liquid group. One study reported that 0.2% of patients in the foam group experienced unspecified side effects compared to 2.4% in the liquid group. One study reported that local reactions were rare and moderate with no statistical differences between groups. One study reported that there was no difference in adverse events (paraesthesia included) between the two groups.
Reticular veins and telangiectases: One of the two studies of reticular veins and telangiectases showed a higher patient and investigator satisfaction score for foam (80%) compared to liquid sclerotherapy (59.3%). The other study found no significant difference in median patient satisfaction score or in expert scores between the two groups. Both studies reported that local side effects (pigmentation, microthrombi, matting) were more common in the foam group than the liquid group, but this was not statistically significant.