Lipid-apheresis improves microcirculation of the upper limbs

Lipid-apheresis (LA) is thought to improve microcirculation. However, limited data are available on the effects on peripheral microcirculation. We investigated upper limb microcirculation of 22 patients undergoing regular LA on a weekly basis before and after LA. Using standardized semiquantitative scales, we analyzed blood flow, vasomotor function, and erythrocyte aggregation by capillary microscopy. In addition, capillary blood flow in quiescence and under heat and cryo-stress was evaluated by photoplethysmographic and laser Doppler anemometry. Moreover, levels of vasoactive mediators adrenalin, noradrenalin, endothelin-1 (ET-1), atrial natriuretic peptide (ANP), asymmetrical dimethyl-arginine (ADMA), as well as total protein and fibrinogen were measured. We found a significant increase in blood flow, the number of perfused capillaries and an improvement of erythrocyte aggregation by capillary microscopy. Using laser Doppler anemometry, we were able to show that this increase was predominantly located in the superficial layer capillaries (Δ44.53 ± 135.81%, n.s.) and less so in deeper layer arterioles (Δ2.75 ± 24.84%, n.s.). Vascular response to heat and cryo stress was also improved after LA but failed to reach significance. LA significantly reduced levels of epinephrin (-33 ± 39.2%), ANP (-28.8 ± 20.2%), ADMA (-74.1 ± 23%), and fibrinogen (-45.4 ± 19.7%) when comparing before LA and after LA values. In summary, we found an improvement in the microcirculation of the upper limbs under LA, which may result from a decrease of vasoconstrictors, improvement of vasomotor function, and a decrease in blood viscosity or erythrocyte aggregation.