Deciphering the Mechanisms of Central BP Regulation in Patients With PD Associated With Orthostatic Hypotension

Deciphering the Mechanisms of Central Blood Pressure Regulation in Patients With Parkinson Disease Associated With Orthostatic Hypotension: A 2-phase Observational Study With Healthy Participants and Patients With Parkinson's Disease

Status

Not yet recruiting

Phases

Unknown

Study type

Observational

Source

ClinicalTrials.gov

Registry ID

NCT07139756

Acronym

HYPOPARK

Enrollment

130

Registered

2025-08-24

Start date

2025-10-01

Completion date

2028-03-31

Last updated

2025-08-24

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Parkinson Disease, Orthostatic Hypotension

Keywords

lower body negative pressure, parkinson disease, orthostatic hypotension

Brief summary

Phase 1 objective: test the feasibility of using a 3Tesla MRI scanner instead of a 7Tesla MRI scanner to measure brainstem responses to LBNP in healthy participants. Phase 2 primary objective: compare the brainstem responses to LBNP in patients with PD associated with OH to PD patients without OH using BOLD fMRI

Detailed description

Phase 1 objective: test the feasibility of using a 3Tesla MRI scanner instead of a 7Tesla MRI scanner to measure brainstem responses to LBNP in healthy participants using BOLD fMRI Phase 2 primary objective: compare the brainstem responses to LBNP in patients with PD associated with OH to PD patients without OH using BOLD fMRI Phase 2 secondary objectives: * assess modulation of functional connectivity in response to LBNP (effective connectivity analysis by psycho-physiological interactions (PPI)) and determine differences between the two groups * assess functional connectivity in resting state and determine differences between the two groups * compare structural connectivity in both groups using tractography * compare renal response to LBNP in both groups using contrast-enhanced ultrasound * compare pre-cerebral flow response to LBNP in both groups

Interventions

DIAGNOSTIC_TESTLower body negative pressure

LBNP is a technique that redistributes blood from the upper body to the dependent regions of the legs, thus reducing central venous pressure and venous return and thereby activating the sympathetic nervous system (SNS). The subject is placed in a cylindrical airtight tank, which is sealed at the level of the iliac crests, and sub-atmospheric pressure is produced using a vacuum pump. It can be used to characterize the cardiovascular responses to orthostatic stress

Study design

Observational model

CASE_CONTROL

Time perspective

PROSPECTIVE

Eligibility

Sex/Gender

ALL

Age

18 Years to 75 Years

Healthy volunteers

Yes

Inclusion criteria

Phase 1: Inclusion Criteria: * Signed informed consent * Age ≥ 18 years and \<75 years * Normal office blood pressure (\<140/90 mmHg) * For women of childbearing potential: using or willing to use during the study a reliable contraception method compatible with MRI

Exclusion criteria

* Schellong test showing OH (drop of Systolic BP \>20 mmHg or Diastolic BP \>10 mmHg) * Pregnant or lactating women * Refusal to be informed of incidental findings * Any medication (acute or chronic prescription) except oral contraception * Clinical significant abnormal blood test as assessed by the investigator * Chronic or acute illness * Concomitant participation in a clinical trial * Blood donation in the 60 previous days * Contra-indications for MRI * Unable to follow study procedures * Having a hierarchical relationship with the investigator or being family of the investigator Phase 2: Inclusion Criteria: * Signed informed consent * Fulfilling Movement Disorder Society clinical criteria for clinically established PD * Age ≥18 years and \<75 years * PD treated by dopamine replacement therapy (DRT) * Willing and able to comply with the visit schedule and study procedures * Autonomous in daily life * Schellong test showing OH (drop of Systolic BP \>20 mmHg or Diastolic BP \>10 mmHg)(for study group with OH) or no OH (for studygroup without OH) * For women of childbearing potential: using or willing to use during the study a reliable contraception method compatible with MRI

Design outcomes

Primary

Measure	Time frame	Description
Differences and changes in BOLD fMRI signal intensity	1.5 hour	Changes in brain BOLD fMRI signal in the dorsolateral medulla of the brainstem in response to LBNP

Secondary

Measure	Time frame	Description
Functional connectivity	1.5 hour	Activation patterns in spatially separated brain regions tending to have synchronous activity in resting state and activation pattern change during LBNP
Structural connectivity	30 minutes	Map of anatomical (neural) connections within the brain in PD patients with and without OH
Contrast-enhanced renal ultrasound	1.5 hour	Changes in renal perfusion in response to LBNP
pre-cerebral blood flow	30 minutes	changes in pre-cerebral blood flow in response to LBNP

Countries

Switzerland

Contacts

Primary ContactGrégoire Wuerzner, Prof

Gregoire.Wuerzner@chuv.ch+41 79 556 1973

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026