Different effect of hydroxyurea and phlebotomy on prevention of arterial and venous thrombosis in Polycythemia Vera

In the present work we investigated more thoroughly the same cohort of PV patients to determine whether cytoreduction therapy with HU, in comparison with therapeutic PHL, was differently effective in protecting from arterial and venous thrombosis. The rationale of this analysis, approved by our IRB, is supported by the following considerations: (i) the two vascular complications are biologically different processes with distinct physiopathology supporting that arterial and venous events are separate entities with specific risk factors that require careful evaluation and management10. (ii) HU may predominantly exert its antithrombotic property by reducing the cellular components of thrombi formation, including leukocytes, and (iii) leukocytosis is associated more with arterial than venous thrombosis in PV1 .