PLASMAPHERESIS FOR HYPERVISCOSITY SYNDROME IN MACROGLOBULINEMIA WALDENSTROM AND MULTIPLE-MYELOMA - INFLUENCE ON BLOOD RHEOLOGY AND THE MICROCIRCULATION

The efficacy of plasmapheresis in improving blood flow properties in patients with hyperviscosity syndrome was studied during 22 plasmapheresis treatments in four patients with hyperviscosity syndrome (three with macroglobulinemia Waldenstrom, one with multiple myeloma). Immediately before and after plasmapheresis (exchange volume 3 liters) the following parameters were determined: standard hematologic parameters, serum proteins, plasma viscosity, whole blood viscosity, and blood flow velocity in finger nalifold capillaries by video microscopy. The hematocrit remained unchanged. Paraprotein concentrations were markedly reduced by plasmapheresis (average 35%). Plasma viscosity fell from 5.0 +/- 3.3 cp to 2.1 +/- 1.0 cp (p < 0.0001, normal range 1.1 to 1.4 cp). Whole blood viscosity changed accordingly. The plasma viscosity before plasmapheresis (x) determined the drop in viscosity after plasmapheresis, according to the following regression: y = 0.97 - 0.77 x; r = 0.962, p < 0.001. The spontaneous capillary blood cell flow velocity increased from 0.33 +/- 0.44 mm/sec to 0.55 +/- 0.21 mm/sec (p < 0.01) and the change in spontaneous flow velocity (y) was correlated with the change in plasma viscosity (x): y = 0.02 - 0.05 x; r = 0.833, n = 7, p < 0.05. We conclude that plasma viscosity is a major determinant of capillary blood flow and that plasmapheresis is an efficient treatment of abnormal microcirculation caused by increased plasma viscosity. Our data make it possible to predict the benefit of plasmapheresis in a given situation and contribute to a better use of this valuable method.