Peripheral Arterial Disease
Conditions
Keywords
PAD
Brief summary
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.
Detailed description
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.
Interventions
DEVICEActive Intermittent Negative Pressure (INP)
Application of -40mmHg negative pressure on the lower limb
DEVICEPlacebo Intermittent Negative Pressure (INP)
Application of -10mmHg negative pressure on the lower limb
Sponsors
University of Dundee
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE
Masking
SINGLE (Subject)
Eligibility
Sex/Gender
ALL
Age
18 Years to No maximum
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in microvascular blood flow | Baseline, 1 day and 4-8 weeks | Microvascular blood flow measurement in foot using laser Dopper imaging. |
| Change in microvascular endothelial function | 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. |
| Change in arterial stiffness | 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. |
| Change in macrovascular endothelial function | Baseline, 1 day and 4-8 weeks | Brachial endothelial function measured as change in brachial blood vessel diameter (%) upon shear stress. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Ankle-Brachial Pressure Index (ABPI) | 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. |
| Change in pain score | 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. |
| Change in concentration of blood borne inflammatory and oxidative stress biomarkers | 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. |
Countries
United Kingdom
Outcome results
None listed