Table 4.

General therapeutic principles established by the 2015 revised IPSET model for thrombotic risk stratification in patients with essential thrombocythemia

Risk	Attributes	Management
Very low	Age ≤ 60 years, JAK2 wild type, no prior thrombosis	Observation or low-dose aspirin if vasomotor symptoms present
Low	Age ≤ 60 years, JAK2 V617F+, no prior thrombosis	Low-dose aspirin, unless contraindicated.a Twice-daily aspirin if cardiovascular risk factors present
Intermediate	Age > 60 years, JAK2 wild type, no prior thrombosis	Cytoreductive therapy plus low-dose aspirin, unless contraindicateda, or twice-daily aspirin without cytoreductive therapy if no cardiovascular risk factors present
High	Age > 60 years and JAK2 V617F+, or prior thrombosis history regardless of other factors	Cytoreductive therapy plus low-dose aspirin, unless contraindicateda

IPSET, International Prognostic Score of Thrombosis for Essential.

^aAspirin is generally contraindicated in the presence of acquired von Willebrand’s disease caused by extreme thrombocytosis.