Microvascular symptoms

Current understanding

Erythromelalgia, headaches, visual disturbances, paresthesias — typically responsive to low-dose aspirin in ET/PV.

Evidence log

• 2026-07-22 — Disease Burden, Inadequate Hematocrit Control, and Thromboembolic Events in Patients with Polycythemia Vera Despite Current Standard of Care Treatment: A Retrospective Claims Study.: 2026 — Retrospective US claims study in PV (n=11,311) found persistent symptom burden and thromboembolic events despite SoC, with the majority not maintaining HCT <45% — reinforcing inadequate hematocrit control as an unresolved driver of microvascular symptomatology in real-world practice. (novelty: 3)
• 2026-09-03 — Targeting Thrombopoietin/MPL Signaling to Mitigate JAK2V617F-Driven Cardiac Microvascular Disease.: Preclinical study identifies endocardial thrombopoietin/MPL signaling as a driver of JAK2V617F-mutant hematopoiesis-induced cardiac microvascular disease under cardiometabolic stress, reversible with anti-MPL neutralizing antibody — extending the JAK2 microvascular symptom axis from peripheral (erythromelalgia, headache) to a cardiac microcirculatory phenotype with a novel therapeutic handle. (novelty: 4)
• 2026-07-23 — Hyperviscosity encephalopathy in suspected polycythemia vera at high altitude: a case report.: Case report at extreme high altitude illustrates that severe hyperviscosity from erythrocytosis can escalate beyond typical microvascular manifestations to frank encephalopathy, underscoring altitude as a modifier of MPN microvascular/hyperviscosity symptomatology. (novelty: 3)
• 2026-03-20 — Association between JAK2 Mutations and Thoracic Aortic Aneurysms in Myeloproliferative Neoplasms: Scoping review (2024) flags a JAK2-MPN association with thoracic aortic aneurysm — a macrovascular complication distinct from the classic microvascular syndrome but worth noting when evaluating JAK2-driven vascular symptomatology. (novelty: 4)

Open questions

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