Practical interest of in vivo reflectance confocal microscopy quantification of cutaneous vascular flow during iloprost treatment

Introduction: iloprost is a recommended treatment for several vascular diseases such as severe Raynaud's syndrome and digital ulcers in Systemic Sclerosis (SS). In vivo reflectance confocal microscopy (RCM) is a non-invasive imaging tool that can evaluate cutaneous microcirculation. The goal of this study was to observe, in real time, the effect of iloprost on cutaneous microcirculation by using RCM. Material and method: Five patients with microvascular diseases that needed iloprost were included. Administration speed started at 0.5 ng/kg/min until the maximum tolerated dosage. Recordings of capillary flow were done using RCM before treatment and at each change in the drug dosage. Results: The blood flow of the five patients demonstrated a significant increase from the dosage of 0.5 ng/kg/min. This significant variation did not exist at higher dosage. Discussion: This study suggests a precocious effect of iloprost in increasing the cutaneous vascular flow; this effect was not enhanced at higher drug dosage. Monitoring cutaneous capillary flow by in vivo RCM could then be of interest in optimizing iloprost dosage. This procedure will likely reduce the side effects of iloprost that are dose-dependent.