Potential Biological and Physiological Determinants for Exercice in Patients With Polycythemia Vera
For patients and families
In plain language
An automatic summary of structured registry data. It is an orientation aid, not a substitute for the official protocol or a physician assessment.
- What is being studied
- The protocol lists: Research samples blood viscosity and viscoelasticity:.
- Who it may be relevant to
- Registry conditions: Polycythemia, Polycythemia Vera (PV). Basic parameters: 18 years — 70 years · All.
- What needs checking
- Age, condition and sex are only basic indicators. Prior treatment, laboratory values and other mandatory requirements appear in the eligibility criteria below.
- Where it takes place
- France
- Next step
- Save the trial, show it to the treating physician, and confirm current recruitment with the study center. Costs, documents and travel →
Unsure about the terms? Read our patient guide →
Official title
Characterization of Exercise Intolerance in Patients With Polycythemia Vera: Study of Potential Biological and Physiological Determinants.
Overview
Polycythemia vera (PV) is a rare haematological disorder characterized by an excessive production of red blood cells, associated with the somatic JAK2 V617F mutation. Clinical manifestations are varied and often include exercise intolerance but the underlying mechanisms remain poorly understood. Physical activity is recommended in the management of chronic diseases, but it must be tailored to the physiological profile of the patient. A cardiopulmonary exercise test (CPET) is essential to ensure safety, detect possible contraindications, and assess maximal oxygen uptake (VO₂max), a key indicator of aerobic performance. This prospective, experimental, non-randomized study will include patients with PV followed at Lyon Sud University Hospital and for which a CPET is scheduled in their routine clinical follow-up. The primary objective is to compare VO₂max between two groups of patients: moderate (\<10%) versus marked (≥10%) extent of blood viscosity increase after the completion of the CPET. The main hypothesis is that a significant increase in blood viscosity during exercise (≥10%) is a major limiting factor in oxygen transport and leads to a reduced VO₂max, reflecting impaired exercise tolerance. Secondary analyses will focus on hemorheological parameters, tissue oxygenation, and cardiorespiratory and metabolic responses. The study aims to better understand the biological and physiological determinants of exercise intolerance in this population.
Interventions
- Biological Research samples blood viscosity and viscoelasticity:
Research samples: Blood rheology: hematocrit, blood viscosity, deformability and erythrocyte aggregation, viscoelasticity
Primary outcome measures
- Blood viscosity (Centipoise) at 6 shear rates. [Time frame: Measurements will be performed at baseline (pre-test), at 3 minutes post-CPET, and at 60 minutes post-CPET]
Secondary outcome measures (3)
- Rheological properties of blood: deformability and aggregation of erythrocytes [Time frame: Measurements will be performed at baseline (pre-test), at 3 minutes post-CPET, and at 60 minutes post-CPET.]
- Viscoelasticity of blood [Time frame: Measurements will be performed at baseline (pre-test), at 3 minutes post-CPET, and at 60 minutes post-CPET]
- Tissue and haemoglobin oxygenation with near-infrared spectroscopy (NIRS) [Time frame: Measurement will be performed during the CPET.]
Eligibility criteria
Inclusion criteria
- Patient aged at least 18 years and under 70.
- Patient followed for a diagnosis of Polycytemia vera (confirmed JAK2 V617F mutation) and who were prescribed a CPET because of their wish to resume regular physical activity.
- Patient affiliated with or benefiting from a social security scheme.
Exclusion criteria
- Any known history of heart disease or chronic respiratory illness likely to affect VO₂max independently of Polycytemia vera (e.g., asthma), according to the investigator's judgment.
- Any known history of major thromboembolic complication, according to the investigator's judgment.
- Body mass index (BMI) greater than 35, according to the investigator's judgment.
- Participation in another interventional research protocol that may interfere with the present study, according to the investigator's judgment.
- Adult subject under legal protection measures (guardianship, curatorship).
- Subject currently receiving psychiatric care.
- Subject deprived of liberty by judicial or administrative decision.
Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.
Healthy volunteers: No
Study design
- Allocation
- N/A
- Model
- Single group
- Masking
- Open label
- Primary purpose
- Basic science
Study locations
France · 1 center
- Department of Sports Medicine and Physical Activity. Pulmonary Function Testing. Croix Rou — Lyon
Identifiers
NCT: NCT07341048 · 69HCL25_0364 · 2025-A01032-47