[Sympathectomy and microcirculation: physiopathologic reflections].

Sympathectomy provokes vascular motor denervation, and drastically modifies the vasomotor equilibrium of the limbs which is also dependent on metabolic, humoral and myogenic factors. Therapeutic efficacy of sympathectomy is related to the state of activity and reactivity of these other factors. The fall in peripheral resistance resulting from the opening up of cutaneous arteriovenous anastomoses increases flow through a stenosis or bypass, with the tendency for development of the collateral circulation. Positive effects may be obtained also when trophic disorders exist, but there is the risk of a nutritional circulation steal in the presence of blood hyperviscosity, with the need for associated rheologic treatment. Indications are few in Raynaud's disease, except for digital arterial disease.