The treatment of patients with varicose veins results in a considerable workload and financial burden to the NHS. Visible varicose veins occur in up to 40% of men and 32% of women.

Foam sclerotherapy (foam) and endovenous laser ablation (EVLA) have emerged as alternative treatments to surgery for patients with varicose veins, but uncertainty exists regarding their clinical and cost-effectiveness in the medium and long-term. This is important because if varicose veins recur, further treatments may be required.

CLASS was a national multi-centre NIHR HTA-funded trial designed primarily to assess the clinical and cost-effectiveness of three treatment modalities: a) foam; b) EVLA with subsequent foam to varicosities when required; and c) surgery. Primary outcome measures include disease-specific quality of life (QoL), measured by the Aberdeen Varicose Vein Questionnaire (AVVQ) and generic QoL, measured by EQ-5D, SF-36 at 6 months, and cost-effectiveness as cost per quality adjusted life year (QALY) gained.

A total of 798 adult patients with symptomatic primary varicose veins were recruited into the trial and randomised to one of the treatment options. At six weeks and six months after treatment, participants were reviewed at an outpatient clinic where the study outcomes are assessed. Participants were also followed up at five years. At five years, disease specific quality of life was better after laser ablation or surgery than after foam sclerotherapy.

CLaSS was led by Professor Julie Brittenden based at the University of Glasgow.





The five year clinical results were published in the New England Journal of Medicine 2019, volume 381, pages 912-922 (

The six month clinical results were published in the New England Journal of Medicine 2014, volume 371, pages 1218-1227 ( 

The six month cost effectiveness results were published in the British Journal of Surgery 2014, volume 101, pages 1532–1540 ( 

We have also published results relating to behavioural recovery after treatment for varicose veins in the British Journal of Surgery 2016, volume 103, pages 374-381 ( ( 

Full results from the six month follow-up have been published in Health Technology Assessment, volume 19, issue 27