Primary Varicose Veins: Elevated Plasma Levels of the Soluble Isoform of the Vegf Receptor Flt-1 (S.Flt-1)

Objectives To examine plasma soluble flt-1 (s.flt-1) and its release in primary varicose (VVs) and normal veins. Methods Patients with primary VVs (n = 13, CEAP grade II or above) and control subjects (n=7) (all non-smokers, receiving no medications) rested supine for 15 min before cannulation of a foot vein. Following a further 10 min resting supine, blood was collected from an arm vein and foot vein. A below-knee cuff was applied and inflated to 90-95 mmHg for 10 min (to prompt a mild venous stasis). A further blood sample was collected from the foot vein. Plasma s.flt-1 was analysed by ELISA. Results Baseline plasma s.flt-1 from the arm was similar in normal subjects and patients with VVs (P>0.1). From the foot before cuff application, however, baseline plasma s.flt-1 was markedly elevated in VVs (P<0.001). Application of the cuff in control subjects resulted in a marked (54.2%) elevation in s.flt-1 by 10 min (P<0.015). In VVs, however, cuff application prompted little or no change, an increase of only 5.5% (P<0.1). Conclusions Elevated plasma levels of s.flt-1 may be important in the pathogenesis of primary VVs, by potentially mediating the action(s) of vascular endothelial growth factor.