Laser Doppler-recorded venoarteriolar reflex in Raynaud's phenomenon

Abstract

The aim of the study was to assess whether Laser Doppler-recorded venoarteriolar reflex (VAR) response to hand lowering can contribute to differentiate primary from secondary Raynaud's phenomena. Materials and methods Skin fingerpulp perfusion (PU) of each hand of 60 persons was investigated: 15 healthy controls; 15 primary Raynaud's phenomenon (RP) patients; 15 patients with Raynaud's phenomenon secondary to systemic sclerosis (SSc); 15 patients with Raynaud's phenomenon secondary to vibration exposure. Blood perfusion was monitored by Laser Doppler flowmetry (LDF) as initial values and at a temperature of 32 °C with hands on the sternum (PUh) and in dependency (PUd). VAR indices were analyzed: delta VAR (ΔVAR) calculated as (PUd−PUh); percent change of perfusion—{(ΔVAR/PUh)×100}; and vasoconstriction response—(PUd/PUh). Results Initial mean superficial skin temperatures and perfusions in Raynaud's phenomenon groups were significantly lower compared to healthy controls but with wide overlap of the values in individual cases. Venoarteriolar indices were significantly different between secondary Raynaud's phenomenon groups and healthy controls and between secondary and primary Raynaud's phenomenon groups. Percent changes were significantly higher in control and primary RP groups compared to secondary RP groups. Vasoconstriction indices between primary and secondary RP patients ( p<0.0001) and between controls and secondary RP patients ( p<0.0001) also differed. A loss of venoarteriolar reflex (ΔPU≥0) was established in 10.0% of primary, 53.3% of sclerodermic, and 36.7% of vibration-induced Raynaud's phenomenon patients. The significantly higher prevalence rate of impaired venoarteriolar reflex in secondary Raynaud's phenomenon patients proves local vasomotor dysfunction and reflects either postganglionar sympathetic insufficiency with vascular tone failure or altered smooth muscle cells' responses. Conclusions Laser Doppler flowmetry is a valuable noninvasive method for investigation of the very early skin venoarteriolar dysfunctions, for evaluation of focal autonomic dysregulation and skin vasomotor abnormalities in RP patients. Laser Doppler-recorded venoarteriolar reflex testing is a simple procedure and an adequate additional diagnostic tool, which contributes to diagnose RP and differentiate primary from secondary RP.