Response to: Comparison of laser Doppler imaging, fingertip lacticemy test, and nailfold capillaroscopy for assessment of digital microcirculation in systemic sclerosis

[1] in a recent issue of Arthritis Research & Th erapy: 'Compari son of laser Doppler imaging, fi ngertip lacti-cemy test, and nailfold capillaroscopy for assessment of digital microcirculation in systemic sclerosis'. Using the laser Doppler imaging (LDI) technique, the authors found lower digital blood fl ow in systemic sclerosis (SSc) patients when compared with healthy controls. However, the authors did not discover any correlation between the functional (LDI) and morphological micro vascular abnormalities, evaluated by nailfold capillaro scopy (NFC), suggesting that these techniques are complementary tools for the evaluation of independent microangiopathy aspects in SSc patients. Th e conclusions of the article may be controversial since these fi ndings are in contrast with those of other recent reports that were not reported and considered in the authors' investigation. In particular, some recent studies described a correlation between fi ngertip blood perfusion (FBP), evaluated separately by LDI and laser Doppler fl owmetry (LDF) techniques, and the extent of nailfold microvascular damage, as evaluated by nailfold videocapillaroscopy (NVC) [2-4]. Th e paper from Cutolo and colleagues [2] demonstrated a signifi cantly lower FBP in SSc patients (P <0.05) compared with controls, and this FBP was found to be partially reversible (increasing) after heating of the LDF probe at 36°C (P <0.001), even if the slope of variation was signifi cantly lower in SSc patients com pared with controls (P <0.05). Interestingly, SSc patients showing the 'late' NVC pattern of micro angiopathy showed an FBP that was signifi cantly lower than that of patients with the 'active' or 'early' NVC patterns (P <0.05) [2,5]. In addition, a nega tive correlation between the FBP degree and the NVC rating (score) of the microvascular damage was observed (P <0.05) [2,6,7]. Similar results were found by Rosato and colleagues [3], who described signifi cantly lower mean blood perfusion in the hand/fi ngers of SSc patients characterized by the 'late' NVC pattern of microangiopathy when compared with patients showing the 'early' or 'active' NVC patterns. Th e authors concluded that the LDI and capillaroscopic images fully matched the defi nition of the various stages of the microvascular digital damage in SSc [3]. In the third study, again, SSc patients characterized by the 'active' or 'late' NVC patterns showed a red blood cell velocity that was more decreased (65.5% and 66.2% reduction, respectively) than that of patients sharing the 'early' pattern of micro angio pathy [4]. Th …