Formalised assessment of systemic thrombogenicity in patients with Polycythemia vera suffered an ischemic stroke

Introduction. Thrombosis diagnosis and prevention in patients with Polycythemia vera (PV) suffered an ischemic stroke (IS) are still open. The aim was to find the reasons for systemic thrombogenicity and to compare the applicability of the main scales assessing thrombosis risk in patients with PV suffered IS.
Materials and methods. We followed up 127 people (42-75 y.o.), of which 68 were patients with PV suffered IS (group I) and 59 non-PV-patients with ischemic stroke (group II). Clinical study included common blood analysis, rheological properties of erythrocytes, coagulation and endothelial parameters, cytokines, inflammation markers, angiogenesis markers, and testing for the V617F mutation in the JAK2 gene. The follow up included common and neurological examinations as well, and the assesment of thrombosis risk factors with both Caprini scale and CHA2DS2-VASc scale. All patients were examined twice as in the acute period of IS as well as in 16-18 months.
Results. Between the groups no significant differences were found for the NIHSS average score and for Bartel index as well.The Caprini score belonged to the “very high risk” (score > 6) in both groups in the acute period of IS. At the same time, the score “8-10 points” prevailed in group II (68%) whereas the score “11-12 points” prevailed in group I.In the acute time of IS the CHA2DS2-VASc score revealed 12% of patients from both groups who had a score of “3-4 points” (moderate risk of thrombosis).In group I thrombotic complications rate correlated significantly with the JAK2V617F gene allelicloading (r = 0.236; p < 0.05), and the development of recurrence cerebrovascular disorders correlated significantly with Caprini score (r = 0.241; p < 0.05), but not with CHA2DS2-VASc score.Aiming to predict thrombotic complications in PV-patients the threshold (cut off) points were established for those markers as factor VIII, factor VII, red blood cell deformability, thrombin activated fibrinolysis inhibitor (TAFI), red blood cell count, white blood cell count, t-PA, VEGF-A, p-thrombomodulin, and ADAMTS-13.This pattern of parameters showed the odds ratio of thrombotic complications 10.3 (95% CI 7.6-13.8) in PV-patients in thelong-term period.At the end of the follow up the Caprini score showed a trend towards a decreasing in total while the CHA2DS2-VASc score remained virtually unchanged.
Conclusion. We assume the accurate assessment of thrombotic risk in patients with Polycythemia vera suffered an ischemic stroke requires a proposed pattern of parameters including the test for JAK2V617F allelicloading and the calculation of Caprini score but not CHA2DS2-VASc score. Final results may provoke to change standard antithrombotic therapy in those patients towards its intensification due to pathogenetic featues of cancer-associated thrombosis.

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