Microcirculatory Effects of Iloprost in Patients with Suspected Secondary Raynaud Phenomenon

Background: The clinical efficacy of iloprost, a stable analogue of prostacyclin, in patients with Raynaud's phenomenon (RP) has been widely reported. However, its mechanism of action is still unclear, and also unknown is why the benefit lasts for many weeks after therapy is discontinued. The aim of the present study was to learn what kind of microcirculatory changes occur in the skin of the affected hand one month after the end of iloprost treatment in patients with RP. Patients and Methods: Eleven subjects (8 women, 3 men, mean age forty-four years) with RP suspected to be secondary to a collagen disease entered the study and were infused with iloprost up to 2.0 ng/kg/minute for six hours on five consecutive days. At baseline and one month after treatment discontinuation, laser Doppler flowmetry, ther-mography, and computer-assisted video capillaroscopy of the affected hand were performed. Results: At the end of follow-up, the mean capillary density as recorded by video capillaroscopy was significantly increased as was the skin temperature in the different areas (fingertip, nailbed, tenar, hypotenar). In contrast, laser Doppler flowmetry revealed no significant changes after therapy. Comment: The improvement of vascularization of the skin and, therefore, the decrease in avascular areas in patients with RP suspected to be secondary to a connective tissue disease appear to be associated with enhancement of nutritional flow. Rather than rely on an angiogenetic effect of iloprost, these modifications may be related to the drug-induced normalization of the described dysfunctional arteriolar-venular anastomoses in the skin of RP patients through redistribution of flow