New Scoring System Proposed for Risk of Thrombotic Events in MPN

By Dustin Samples - Last Updated: December 14, 2022

All myeloproliferative neoplasms (MPNs) come with the inherent risk of arterial and venous thrombotic events. Despite the serious outcomes these events have on morbidity and mortality in patients with MPN, their occurrence is hard to predict.

Researchers at the Hôpital Saint-Louis in Paris, France, recently decided to design a new scoring system for the stratification and prediction of arterial and venous thrombosis. Using data from their own MPN reference center, the team retrospectively reviewed the records of patients with MPN seen at their institution from 2011 to 2021.

A total of 1055 patients were reviewed, and diagnoses included essential thrombocytopenia (ET; n=494), polycythemia vera (PV; n=362), myelofibrosis (n=161), myelodysplastic syndrome (MDS)/MPN (n=9), and unclassified MPN (n=29). At the time of MPN diagnosis, 115 patients presented with arterial thrombotic events, and 146 patients presented with venous thrombotic events.

Mean follow-up for the study was 9.45 years. During the study, 72 patients experienced a total of 75 arterial thrombotic events, and 79 experienced 97 venous events. The events included acute myocardial infarction (32%), stroke (26.67%), transient ischemic attack (24%), splanchnic thrombosis (37.11%), and deep vein thrombosis (27.83%).

Reported incidence rates (patients/year) of arterial events by diagnosis were as follows: PV, 0.69%; ET, 0.75%; and myelofibrosis, 0.43%. Venous events by diagnosis were as follows: PV, 0.95%; ET, 0.78%; and myelofibrosis, 1.59%.

The researchers analyzed the association between these events and previous factors by hazard ratio and suggested this new point system, which they say performed similar to (venous events) or better than (arterial events) current risk stratification standard tests:

Arterial Risk Score: cardiovascular risk factors (including male sex, use of tobacco, hypertension, diabetes, or hypercholesterolemia), 1 point; TET2 or DNMT3A mutation, 1 point; age at diagnosis >60 years, 2 points; arterial thrombosis prior to or at diagnosis, 2 points. Low risk was defined as an overall score of 0-1, and high risk was an overall score of 2-6.

Venous Risk Score: venous thrombosis prior to or at diagnosis, 1 point; JAK2 V617F mutation, 1 point. Low risk was defined as an overall score of 0, and high risk was an overall score of 1-2.

Pasquer H, De Oliveira RD, Soret J, et al. Distinct clinico-molecular arterial and venous thrombotic scoring systems for MPN patients risk stratification. Abstract #341. Presented at the 64th ASH Annual Meeting and Exposition; December 10-13, 2022; New Orleans, Louisiana.