Alcohol embolization versus non-invasive treatment for pain relief in peripheral venous malformations: a comparative study.

Background: Pain is one of the most important symptoms affecting quality of life in patients with venous malformations. Alcohol embolization is a common approach among other treatment modalities. However, the benefits and complications of this therapy require rigorous evaluation in the face of emerging alternative treatments. The aim of this study was to evaluate the efficacy of alcohol embolization in pain management compared with non-invasive treatment, and to explore associated complications. Methods: We performed a retrospective, comparative study at the Vascular Malformation Center, University Hospital of Bern, from 2008 to 2022. Consecutive patients with peripheral venous malformations were included, one group underwent alcohol embolization and the other group received non-invasive treatment including counseling for compression stockings, physical therapy and anticoagulation. Decision to treat was made jointly by the clinician and the patient, after discussing the potential harms and benefits. Pain levels were measured using the 0-10 Numerical Rating Scale on every scheduled visit. Inverse probability of treatment weights were used to adjust for confounders such as severity of malformation indicated by number of tissues affected, localization, presence of hypertrophic tissue, history of thrombophlebitis, age, and level of pain at the initial visit. The primary outcome was change in maximal pain level, and secondary outcomes included changes in mean and minimal pain levels within 1 year of follow-up. Results: A total of 227 patients were included in the analysis, 86 in the intervention group and 141 in the control group. Over the course of one year, both the control and alcohol embolization groups experienced reductions in pain. The control group showed a reduction in maximal pain from 4.42 by 0.95 points, with an additional non-significant reduction of 0.99 points in the alcohol embolization group [estimate: -0.0027 per day, 95% confidence interval (CI): -0.0061, 0.0007, P=0.12]. However, alcohol embolization led to a more pronounced and significant reduction in mean and minimal pain, with additional reductions of 1.06 (-0.0029 per day, 95% CI: -0.0055, -0.0003, P=0.02) and 0.69 points per year (-0.0019 per day, 95% CI: -0.0035, -0.0004, P=0.01), respectively. Seven minor and five major complications occurred in the alcohol embolization group. Conclusions: Non-invasive treatment helps patients with venous malformations to manage maximal pain effectively. Alcohol embolization results in a faster and more pronounced reduction in mean and minimal pain levels, but we found no statistical evidence of an advantage of alcohol embolization for reducing maximal pain. Treatment efficacy did not appear to be influenced by gender, age, or previous treatment history. To adequately assess the efficacy of new therapies, future trials should include both disease-specific, patient-reported outcome measures and a control group.