Hemodynamic Mechanisms of Abdominal Compression in the Treatment of Orthostatic Hypotension in Autonomic Failure

Purpose

Compression garments have been shown to be effective in the treatment of orthostatic hypotension in autonomic failure patients. The purpose of this study is to determine the hemodynamic mechanisms by which abdominal compression (up to 40 mm Hg) improve the standing blood pressure and orthostatic tolerance in these patients, and to compare them with those of the standard of care midodrine. The investigators will test the hypothesis that abdominal compression will blunt the exaggerated fall in stroke volume and the increase in abdominal vascular volume during head up tilt.

Conditions

  • Orthostatic Hypotension
  • Pure Autonomic Failure
  • Multiple System Atrophy
  • Autonomic Failure

Eligibility

Eligible Ages
Between 18 Years and 80 Years
Eligible Genders
All
Accepts Healthy Volunteers
No

Inclusion Criteria

  • Male and female patients,
  • between 18-80 yrs.,
  • with neurogenic orthostatic hypotension associated with primary autonomic failure (Parkinson Disease, Multiple System Atrophy and Pure Autonomic Failure). Orthostatic hypotension will be defined as ≥20 mmHg decrease in systolic BP or ≥10 mmHg of diastolic BP within 3 minutes on standing associated with impaired autonomic reflexes determined by autonomic testing in the absence of other identifiable causes (Freeman et al., 2011).
  • Patients able and willing to provide informed consent.

Exclusion Criteria

  • Pregnancy.
  • Significant cardiac, renal or hepatic illness, or with contraindications to administration of pressor agents or external abdominal compression will be excluded.
  • Clinically unstable coronary artery disease, or major cardiovascular or neurological event in the past 6 months, and; other factors which in the investigator's opinion would prevent the subject from completing the protocol including clinically significant abnormalities in clinical, mental or laboratory testing

Study Design

Phase
Phase 1
Study Type
Interventional
Allocation
Randomized
Intervention Model
Crossover Assignment
Primary Purpose
Other
Masking
Single (Participant)

Arm Groups

ArmDescriptionAssigned Intervention
Experimental
Abdominal compression and placebo pill
Abdominal compression with an inflatable abdominal binder (up to 40 mmHg) during head up tilt, and placebo pill given 1 hour before the second head up tilt
  • Other: Abdominal compression
    Abdominal compression of 40 mmHg with a commercial inflatable cuff applied during head up tilt
    Other names:
    • abdominal binder
  • Drug: Placebo pill
    Placebo pill given 1 hour before the second heat up tilt
Sham Comparator
Sham abdominal compression and placebo
Sham abdominal compression with an inflatable abdominal binder (~5 mmHg) during head up tilt, and placebo pill given 1 hour before the second head up tilt
  • Other: Sham abdominal compression
    Sham abdominal compression of 5 mmHg with a commercial inflatable cuff applied during head up tilt
    Other names:
    • abdominal binder
  • Drug: Placebo pill
    Placebo pill given 1 hour before the second heat up tilt
Experimental
Abdominal compression and midodrine
Abdominal compression with an inflatable abdominal binder (up to 40 mmHg) during head up tilt, and midodrine 2.5-10 mg PO given 1 hour before the second head up tilt
  • Other: Abdominal compression
    Abdominal compression of 40 mmHg with a commercial inflatable cuff applied during head up tilt
    Other names:
    • abdominal binder
  • Drug: midodrine
    Midodrine single dose 2.5-10mg PO given 1 hour before the second head up tilt
    Other names:
    • ProAmatine
Active Comparator
Sham abdominal compression and midodrine
Sham abdominal compression with an inflatable abdominal binder (~5 mmHg) during head up tilt, and midodrine 2.5-10mg PO given 1 hour before the second head up tilt
  • Other: Sham abdominal compression
    Sham abdominal compression of 5 mmHg with a commercial inflatable cuff applied during head up tilt
    Other names:
    • abdominal binder
  • Drug: midodrine
    Midodrine single dose 2.5-10mg PO given 1 hour before the second head up tilt
    Other names:
    • ProAmatine

Recruiting Locations

Vanderbilt University
Nashville, Tennessee 37232
Contact:
Emily C Smith, RN
615-875-1516
autonomics@vumc.org

More Details

NCT ID
NCT02429557
Status
Recruiting
Sponsor
Vanderbilt University

Study Contact

Emily C Smith, RN
615.875.1516
autonomics@vumc.org

Detailed Description

Patients with autonomic failure are characterized by disabling orthostatic hypotension (low blood pressure on standing) due to severe impairment of the autonomic nervous system. Compression garments such as waist-high stockings and abdominal binders have been shown to improve orthostatic hypotension in these patients. The purpose of this study is to determine the hemodynamic mechanisms by which abdominal compression (up to 40 mm Hg) improve the standing blood pressure and orthostatic tolerance in these patients, and to compare them with those of the standard of care midodrine. The investigators will test the hypothesis that abdominal compression will blunt the exaggerated fall in stroke volume and the increase in abdominal vascular volume during head up tilt. This study will help us better understand the contribution of the abdominal veins to orthostatic hypotension and the mechanisms underlying this non-pharmacological therapeutic approach.

Participants will be studied in a tilt table in two separate days in a randomized, crossover fashion with sham abdominal compression (~5 mmHg) and active compression (~40 mmHg).