Table 9. Thrombosis and PNH The... | American Society of Hematology

Table 9.

Thrombosis and PNH

The pathogenesis of the thrombophilia of PNH is speculative. Sites of thrombosis that are disproportionately represented in PNH Hepatic vein (Budd-Chiari syndrome) Mesenteric veins Portal vein Cerebral veins Dermal veins Propensity toward thrombosis appears roughly proportional to the size of the PNH clone.* The risk of thromboembolic disease appears higher in white and African-American patients than in patients of Asian/Pacific Island or Hispanic ancestry even when adjusted for clone size. White and African-American patients with greater than 50% GPI-AP-deficient granulocytes who have no contraindications are candidates for prophylactic anticoagulation with warfarin.† Patients with PNH who have experienced a thromboembolic event should remain anticoagulated indefinitely.‡

The size of the PNH clone is determined by flow cytometric analysis of expression of GPI-APs on peripheral blood granulocytes.

Standard-intensity warfarin therapy (INR 2.0-3.0) is recommended for chronic therapy.

Long-term anticoagulation should be reassessed in any patient who undergoes a spontaneous remission or in whom the PNH clone size falls to below 50%.