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NCT Number: NCT03854097

Effect of Intermittent Pressure in Patients With PAD

The study will evaluate the effect of intermittent negative pressure (INP) on peripheral arterial disease (PAD) patient vascular function and blood flow. Patients will be given either -40mmHg INP or -10mmHg INP which will act as a placebo. Healthy volunteers will be given -40mmHg INP to evaluate changes in vascular function and blood flow with INP in healthy physiology.

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Key information

Conditions

Peripheral Arterial Disease Arterial Occlusive Diseases Arteriosclerosis Atherosclerosis Cardiovascular Diseases Peripheral Vascular Diseases Vascular Diseases

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

School of Medicine, University of Dundee, Ninewells Hospital & Medical School

Dundee, United Kingdom

About this study

Atherosclerosis occurs when blood supply to the lower limbs is restricted upon accumulation of fat in the arteries. Atheroslerosis in the lower limbs is termed peripheral arterial disease (PAD). The initial symptom is pain in the lower limbs followed by ulceration and gangrene. The literature has indicated that intermittent negative pressure (INP) can be used to reduce pain and facilitate wound healing. INP is a non-invasive technique that aims to increase arterial and skin blood flow in lower limbs and foot. This study aims to investigate the underlying mechanisms that are involved in changes in blood flow following application of INP. The Flow-Ox 'boot' will be used to apply INP for periods ranging from 4-8 weeks, for an hour twice per day, to the lower limb to determine the effects of INP on vascular function and blood flow. Specifically, vascular tests such as assessments of endothelial function, arterial stiffness, ankle-brachial pressure index (ABPI) and blood borne metabolic and inflammatory markers will be performed before and after INP application. A pain chart will be employed before and after INP application to determine whether there is any change in perception of pain felt by individuals who suffer from pain associated with lower limb arterial disease.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

PAD Patients:

  • Age ≥ 18 years
  • Attending vascular outpatient clinics or admitted in ward with PAD.
  • ABPI <0.9

Healthy Volunteers:

  • Age ≥ 18 years
  • No current or previous significant cardiovascular illness
  • Able to give written informed consent

Exclusion criteria

PAD Patients:

  • Unable to give written informed consent
  • Patients with deep venous thrombosis
  • Pregnant women

Healthy Volunteers:

  • Positive medical history of: Vascular diseases such as PAD, stroke, IHD, hypertension... etc.
  • Haematological conditions such as hypercoagulability, deep venous thrombosis... etc.,
  • Alcohol excess
  • Unable to give written informed consent
  • Pregnant women

Treatment and study plan

Active Intermittent Negative Pressure (INP)

Device

Application of -40mmHg negative pressure on the lower limb

Placebo Intermittent Negative Pressure (INP)

Device

Application of -10mmHg negative pressure on the lower limb

Primary outcomes

  1. Change in microvascular blood flow

    Time frame: Baseline, 1 day and 4-8 weeks

    Microvascular blood flow measurement in foot using laser Dopper imaging.

  2. Change in microvascular endothelial function

    Time frame: Baseline, 1 day and 4-8 weeks

    Peak blood perfusion response to acetylcholine (ACh) delivered by iontophoresis will be measured using a laser Doppler imager.

  3. Change in arterial stiffness

    Time frame: Baseline, 1 day and 4-8 weeks

    Brachial pulse wave analysis (PWA) augmentation index (Ax) and carotid-femoral pulse wave velocity (m/s) (PWV) as an indication of arterial stiffness.

  4. Change in macrovascular endothelial function

    Time frame: Baseline, 1 day and 4-8 weeks

    Brachial endothelial function measured as change in brachial blood vessel diameter (%) upon shear stress.

Secondary outcomes

  1. Change in pain score

    Time frame: Baseline, 1 day and 4-8 weeks

    Self-scoring of pain felt by patient on a visual analogue scale with 0 being no pain at all to 10 being the worst pain ever felt.

  2. Change in concentration of blood borne inflammatory and oxidative stress biomarkers

    Time frame: Baseline, 1 day and 4-8 weeks

    Concentration of inflammatory and oxidative stress markers of endothelial activation/damage (including IL-1a, IL-6, IL-10, TNF-a, CRP, E-selectin and sICAM-1) measured in serum and plasma collected from patient blood samples.

  3. Change in Ankle-Brachial Pressure Index (ABPI)

    Time frame: Baseline, 1 day and 4-8 weeks

    Brachial systolic pressure and ankle (dorsalis pedis) systolic pressure (mmHg) measured using Doppler probe. ABPI calculated as ankle systolic pressure divided by brachial systolic pressure.

    ABPI <0.9 = PAD, ABPI =>1.0 Normal.

Sponsors and collaborators

Lead sponsor

University of Dundee

Other

Registry information

Official study title

Mechanistic Insights Into Changes in Blood Flow Following Application of Intermittent Negative Pressure

Important dates

Study start
2019
Primary completion
2021
Study completion
2021
First posted
Feb 26, 2019
Registry last updated
Aug 6, 2021

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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