Skin Perfusion of Fingers Shows a Negative Correlation with Capillaroscopic Damage in Patients with Systemic Sclerosis

To the Editor: Two variants of laser Doppler monitoring exist to evaluate digital blood flow: laser Doppler imaging (LDI) and laser Doppler flowmetry (LDF). The first technique uses a scanning method with a distant light source and detector, while the second uses optical fibers to carry the light to and from the tissue. As a result, LDF measures the microcirculatory blood flow through a very small volume of tissue, whereas LDI scans a larger tissue area. LDF continuously measures skin blood perfusion; because of the scanning time, LDI cannot measure it continuously1. We address the relationship between digital blood flow and capillaroscopic damage in patients with systemic sclerosis (SSc). Table 1 outlines the main studies. View this table: Table 1. Main studies of laser Doppler monitoring and capillaroscopy to evaluate microvascular damage in patients with systemic sclerosis (SSc). Using LDI, Correa, et al found lower digital blood flow in 44 patients with SSc compared with healthy controls at baseline and after cold stimulus2. No correlation was found between functional … Address correspondence to Prof. Salsano; E-mail: felice.salsano{at}uniroma1.it