[Problems posed by therapeutic trials in vascular acrosyndromes]

Vascular acrosyndromes are mainly subjective clinical phenomena that are difficult to classify, are related to the patient's background, and require a particularly strict protocol for the evaluation of their therapy. An essential criterion is the homogeneity of groups treated, the Raynaud's phenomenon having to be separated into idiopathic Raynaud's disease, digital arteritis and scleroderma. Functional subjective disturbances have to be rated by the patients themselves, while taking into account the conditions of daily life and of climate. Clinical trials must be double-blind against placebo after a pre-inclusion study. They must be conducted entirely during cold spells for Raynaud's phenomena. Static measurements are of limited value amongst functional exploratory techniques, dynamic tests (vascular reactivity to cold) providing more valid data on the action of medication.