Altered Vascular Function in Chronic Kidney Disease

Chronic kidney disease (CKD) is an independent risk factor for the development of cardiovascular disease, with both diseases characterized by reduced nitric oxide (NO) bioavailability and vascular dysfunction. Passive leg movement (PLM) has previously been shown to produce NO-mediated hyperemia in the lower extremity, however this technique has not yet been utilized to assess vascular function in patients with CKD. PURPOSE: To assess vascular function in patients with CKD using PLM, in addition to the traditional flow-mediated dilation (FMD) technique. METHODS: Assessment of vascular function via PLM and FMD was performed on 12 patients (CKD, 67±3 yrs) and 12 healthy controls (CON, 59±2 yrs). Hemodynamics and artery diameters during PLM and FMD were measured utilizing ultrasound Doppler of the femoral and brachial arteries, respectively. RESULTS: Patients with CKD had reduced peak leg blood flow (LBF) (CKD, 384±39 vs. CON, 626±93 mL/min, p<0.05) and a reduced change in LBF from baseline to peak (ΔpeakLBF) (CKD, 153±27 vs. CON, 274±41 mL/min, p<0.05) during PLM compared to CON. Additionally, ΔpeakLBF was significantly correlated with kidney function as assessed by estimated glomerular filtration rate for all participants (r=0.53, p<0.05). As anticipated, FMD was also significantly attenuated in CKD patients compared to CON. CONCLUSION: Vascular function as assessed by PLM and FMD is attenuated in patients with CKD compared to controls, supporting a reduction in NO bioavailability in this chronic disease state. Additionally, PLM appears to be a novel and feasible approach to assess NO-mediated vascular function in CKD and is associated with kidney function.