SMART Exercise for PAD

Trial statusRecruiting
Trial phasePhase 3
Trial typeInterventional
Biological sexAll
Age50+
SponsorNorthwestern University

About this trial

Supervised exercise therapy (SET), consisting of treadmill exercise conducted three times weekly at a center while supervised by healthcare personnel, is first line therapy for people disabled by lower extremity peripheral artery disease (PAD). However, travelling three times/week to a center for SET is burdensome. Compared to SET, home-based exercise is more accessible and less burdensome. Yet, evidence-based guidelines recommend SET over home-based exercise for PAD. Walking exercise is first line therapy to improve walking distance for PAD, but it does not eliminate ischemic leg symptoms in most people with PAD. The investigators' work and that of others showed that nitrate-rich beetroot juice, which increases plasma nitrite, limb perfusion, and skeletal muscle function, significantly improved exercise tolerance and reduced non-response to exercise in people with and without PAD. The investigators will use a 2 x 2 factorial design to address two major barriers to achieving benefits from exercise therapy for PAD: First, guideline recommendations for supervised exercise therapy (SET) as first line therapy for PAD. Second, the inability of exercise therapy to eliminate PAD-related disability in most people with PAD. Participants will be randomized to one of four groups for 12 weeks: Supervised treadmill exercise + nitrate rich beetroot juice; supervised treadmill exercise + placebo, home-based walking exercise + nitrate rich beetroot juice, home-based walking exercise + placebo.

Eligibility criteria

This trial does not accept healthy volunteers

Qualifiers

An ABI <= 0.90 at baseline.

Vascular lab evidence of PAD (such as a toe brachial pressure less than or equal to 0.70 or an ankle brachial index less than or equal to 0.90), or angiographic evidence of PAD defined as at least 70% stenosis of an artery supplying the lower extremities.

An ABI of >0.90 and <1.00 who experience a 20% or greater drop in ABI in either leg after the heel-rise test.

Disqualifiers

Above- or below-knee amputation

Limb-threatening ischemia defined as an ABI <0.40 with symptoms of rest pain

Wheelchair confinement or requiring a walker to ambulate

Walking is limited by a condition other than PAD

Trial design

Design model

Factorial

Treatments tested in this trial

  • Supervised Treadmill Exercise

    Behavioral

    This is a 12 week intervention where participants will walk for exercise 3 times a week on a treadmill at a center while being supervised by healthcare personnel.

  • Home-Based Exercise

    Behavioral

    This is a 12 week intervention where participants will walk at home for exercise with guidance from a study coach. They will have 4 in person visits in the first four weeks and then have weekly phone calls in the last 8 weeks of the intervention with their coach.

  • Nitrate-rich beetroot Juice

    Dietary supplement

    Participants will drink one shot of nitrate rich beet-root juice twice daily for 12 weeks.

Treatment groups

210 Participants
are divided into 4 treatment groups
Group A: Supervised treadmill exercise + nitrate rich beetroot juiceExperimental treatment 2 interventions
Group B: Supervised treadmill exercise + placeboPlacebo comparator 1 intervention
Group C: Home-based walking exercise + nitrate rich beetroot juiceExperimental treatment 2 interventions
Group D: Home-based walking exercise + placeboPlacebo comparator 1 intervention

Trial outcomes

Primary outcomes

1

Six-Minute Walk Distance

Change in six-minute walk distance

Time frame
Measured at baseline and 12 week follow-up

Secondary outcomes

1

Walking Impairment Questionnaire (WIQ) Distance Score

WIQ distance score - Range 0-100, 100 is best.

Time frame
measured at baseline and 12 weeks
2

PROMIS Mobility Questionnaire Score

PROMIS mobility score from administered PROMIS questionnaire. Score range is from zero to infinity and a higher score means a better outcome.

Time frame
measured at baseline and 12 weeks
3

20-meter Improvement in Six-Minute Walk Distance

Meaningful response to exercise interventions

Time frame
measured at 12 weeks
4

Step Count

Step count measured over seven days with the FITBIT

Time frame
measured at baseline and 12 weeks

Other outcomes

1

Physical Activity Step Count

Step count measured over seven days with FITBIT

Time frame
Measured at baseline and 24 weeks
2

Physical activity distance

Physical activity distance measured over seven days with FITBIT

Time frame
Measured at baseline and 24 weeks.
3

Short physical performance battery (SPPB)

SPPB range, range 0-12, 12-best

Time frame
measured at baseline and 12 weeks
4

Walking Impairment Questionnaire (WIQ) Stair Climbing Score

WIQ stair climbing score from administered WIQ, range 0-100, 100 is best.

Time frame
measured at baseline and 12 weeks

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