THE VENOARTERIOLAR REFLEX IN CHRONIC VENOUS INSUFFICIENCY

The aim of this study was to evaluate the veno-arteriolar reflex in th e gaiter area and in the big toe of patients with chronic venous insuf ficiency (CVI). Twenty patients with lipodermatosclerosis and CVI comp rised the disease group, and twenty subjects without venous disease co mprised the control group. The activity of the veno-arteriolar reflex in the gaiter area and in the big toe in the affected and unaffected l imbs of patients with CVI, and in normal controls was assessed by calc ulating the percentage fall in skin blood flux on dependency as measur ed by Laser Doppler fluxmetry. The results showed that the veno-arteri olar reflex was normal in the gaiter area in both the affected limb an d the unaffected limb in patients with CVI compared to normal controls , [median percentage fall in flux and interquartile range for affected limb in patients with CVI = 49 (35-69), for the unaffected limb of pa tients with CVI = 41 (24-58), for normal controls = 49 (31-57), p valu e (Mann-Whitney) for patient groups compared to normals = 0.52, 0.60 r espectively]. However in the big toe the veno-arteriolar reflex was im paired in the affected limb of patients with CVI compared to both the unaffected limb and to normal controls, [median percentage fall in flu x and interquartile range for affected limb in patients with CVI = 52 (29-64), for the unaffected limb of patients with CVI = 69 (45-78), fo r normal controls = 75 (51-80), p value (Mann-Whitney) for patient gro ups compared to normals = 0.017, 0.92 respectively]. This study demons trates that there is an impairment of the veno-arteriolar reflex when measured in the big toe, but not when measured in the gaiter area in t he affected limb of patients with CVI, suggesting the presence of a sy mpathetic neuropathy in the affected limb of patients with CVI.