Potential Biological and Physiological Determinants for Exercice in Patients With Polycythemia Vera (ACTIVAQ)

January 14, 2026 updated by: Hospices Civils de Lyon

Characterization of Exercise Intolerance in Patients With Polycythemia Vera: Study of Potential Biological and Physiological Determinants.

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.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

54

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • France
      • Lyon, France, 69001
        • Department of Sports Medicine and Physical Activity. Pulmonary Function Testing. Croix Rousse Hospital.
        • Contact:
        • Contact:
        • Principal Investigator:
          • Emeric Stauffer, Dr
        • Sub-Investigator:
          • Mael Heiblig, Dr

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

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.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Polycythemia vera
Patients diagnosed with polycythemia vera, with confirmed presence of the JAK2 V617F mutation, who wish to resume regular daily physical activity and have been prescribed an exercise test for this purpose as part of their follow-up at Lyon Sud Hospital
Biological: Research samples blood viscosity and viscoelasticity:
Research samples: Blood rheology: hematocrit, blood viscosity, deformability and erythrocyte aggregation, viscoelasticity
Other Names:
  • the level of tissue oxygenation and hemoglobin oxygenation that will be measured by near-infrared spectroscopy (NIRS).

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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
Blood viscosity will be measured using a cone-plate viscometer (Brookfield, model LVDVII+ PRO, cone CPE 40) on native hematocrit blood, at 7 different shear rates: 2.25, 4.5, 11.5, 22.5, 45, 90, and 225 s-¹, using an ascending ramp shear protocol.
Measurements will be performed at baseline (pre-test), at 3 minutes post-CPET, and at 60 minutes post-CPET

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
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.
Analyses will be performed on EDTA tubes. Erythrocyte deformability will be measured by ektacytometry at 9 shear stresses (0.3-30 Pa) under isotonic conditions. Maximal elongation index (EImax) and shear stress for 50% deformation (SS₁/₂) will be recorded. Aggregation/disaggregation will be assessed by syllectometry at 40% hematocrit. Parameters include aggregation index (AI) and minimal shear rate (γmin) for full disaggregation
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
Viscoelastic properties of blood will be assessed using rotational thromboelastometry (ROTEM delta) on citrated blood tubes. The following tests will be performed: NATEM, TEMACT, FIBTEM, and EXTEM. For each test, the following parameters will be measured: clotting time (CT, in seconds), clot amplitude at 5, 10, 20, and 30 minutes (A5, A10, A20, A30, in mm), alpha angle (indicating clot formation velocity, in degrees), maximum clot firmness (in mm), percentage of clot lysis at 30 minutes (LI30), as well as lysis onset time (LOT) and total lysis time (LT), both expressed in seconds
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.
Near-infrared spectroscopy (NIRS) will be performed using the Portamon MKIII system (Artinis) with a sampling rate of 100 Hz. This non-invasive technique involves placing surface electrodes on the skin over the vastus lateralis muscle, halfway between the anterior superior iliac spine and the patella. NIRS enables continuous monitoring of changes in oxyhemoglobin (HbO₂) and deoxyhemoglobin (HHb) concentrations, allowing for the calculation of the tissue oxygenation index (TOI)
Measurement will be performed during the CPET.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Hospices Civils de Lyon

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

January 1, 2026

Primary Completion (Estimated)

May 1, 2027

Study Completion (Estimated)

May 1, 2027

Study Registration Dates

First Submitted

January 5, 2026

First Submitted That Met QC Criteria

January 5, 2026

First Posted (Estimated)

January 14, 2026

Study Record Updates

Last Update Posted (Actual)

January 15, 2026

Last Update Submitted That Met QC Criteria

January 14, 2026

Last Verified

January 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 69HCL25_0364
  • 2025-A01032-47 (Other Identifier: ID-RCB)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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