Polycythemia vera (PV) commonly presents with @entity432 . Untreated @entity1 have a poor prognosis due to the occurrence of @entity715 . Treatment outcomes in PV and @entity715 events in other forms of @entity6582 and in primary @entity1148 lead to the conclusion that both raised packed cell volume ( @entity1485 ) values and quantitative/qualitative platelet changes play a role in the pathogenesis of these vascular occlusive events. In vitro blood viscosity values are predominantly affected by the @entity1485 , particularly at low shear rates and are thus high in untreated PV. Generally, under physiologic conditions blood flow is not governed by blood viscosity due to a number of factors, such as prevailing high shear rates, red cell axial migration, and adaptive vessel diameter changes. Peripheral blood flow is low in untreated PV. Whereas some untreated @entity1 maintain adequate @entity26 transport to the tissues, this may not apply in those with @entity299 . There is evidence that low flow rates predispose to occlusive events. Under pathologic low blood flow or static conditions, the rheologic blood changes of untreated PV, demonstrated in vitro, play a role in producing a more deleterious outcome of an occlusive event. Under blood flow conditions, red cell axial migration occurs. This leaves a plasmatic zone at the vessel wall into which platelets are dispersed and where shearing forces are maximal. These forces lead to platelet activation. Increased @entity1485 values reduce the width of the plasmatic zone and lead to an increased possibility of platelet activation, platelet-platelet contact and platelet-vessel wall interaction, particularly when the platelet count is raised as well. These effects increase the likelihood of the initiation of @entity715 formation in PV.

Hemorheologic considerations in the pathogenesis of vascular occlusive events in XXXX vera.

@entity1 :: ('9606', 'Species') :: ['patients'] @entity6582 :: ('MESH:D011086', 'Disease') :: ['polycythemia'] @entity1148 :: ('MESH:D013922', 'Disease') :: ['thrombocythemia'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity1485 :: ('158372', 'Species') :: ['PCV'] @entity299 :: ('MESH:D006331', 'Disease') :: ['cardiac or local vessel disease'] @entity432 :: ('MESH:D001157', 'Disease') :: ['vascular occlusion'] @entity715 :: ('MESH:D013927', 'Disease') :: ['thromboses', 'thrombus', 'thrombotic']
@entity6582 :: (MESH:D011086,Disease) :: ['polycythemia']
