Diseases with vascular malformations are rare and often congenital, affecting patients of all ages. Depending on their extent and localization, they can cause discomfort and, especially if activity is restricted, lead to loss or reduced quality of life.

The therapy is usually reserved for a few specialized centers and includes interventional sclerotherapy as well as conservative therapy by compression with appropriate compression stockings. However, there are currently no study-based recommendations for this approach.

The aim of this study is to prove a therapeutic effect of compression therapy using flat-knitted compression stockings on venous malformations of the extremities and to derive from this a therapy recommendation in connection with an improvement in the health status and quality of life.

For this purpose, patients with a confirmed venous malformation of the upper or lower extremity independent of previous therapy will be included. We will investigate patients with epi- and/or subfascial localization of the venous malformation independent of the local extent (cross-articular or not).

Inclusion Criteria:

• Patients with a confirmed venous malformation of the upper/lower extremity independent of previous therapy with epi- and/or subfascial localization of the venous malformation independent of the local extent (cross-articular or not)
• Compression stocking can be put on independently or by the parents
• Written declaration of consent present

Exclusion Criteria:

• Lack of compliance, patient is not available for control appointments
• Additional drug therapy (anticoagulation) for extensive venous malformations with threatening thromboembolic complications
• Known allergic reaction/intolerance to components of flat-knitted compression stockings
• Pregnancy
• Rejection of the study participation by the patient
• Contraindications for the planned MRI examination (pacemakers, implants not suitable for MRI, claustrophobia)
• Occurrence of an emergency situation
• Severe heart failure as contraindication for compression therapy
• Peripheral arterial disease as contraindication for compression therapy

Adverse event data were collected for 18 months during the enrollment, inclusion and investigation period of participants.

During the whole Investigation period there were no participants at Risk for All-Cause Mortality because no potentially life-threatening diagnosis, treatment or therapy was performed. Especially there was no use of drugs, contrast agent or other potentially allergy triggering procedures. All procedures related to the study have been performed non-invasively. Nevertheless, all-cause mortality was monitored.

Double-blind study. Neither investigator nor patient knows the compression class (class I versus class II) of the compression stockings used in the different investigation periods in this patient.