# IMProving mobility After revasCularizaTion in Peripheral Artery Disease: the IMPACT PAD Trial

> **NIH NIH UG3** · NORTHWESTERN UNIVERSITY · 2024 · $1,264,646

## Abstract

More than 300,000 surgical or endovascular lower extremity revascularization procedures are performed
annually for Medicare beneficiaries who have lower extremity peripheral artery disease (PAD) without limb
threatening ischemia, and rates of these procedures are increasing. In these patients, revascularization
typically improves, but does not eliminate, PAD related walking impairment. Lower extremity revascularization
combined with supervised exercise significantly improves walking performance compared to revascularization
alone in people who have PAD without limb threatening ischemia. However, supervised exercise is
inaccessible or burdensome for most PAD patients. We hypothesize that home-based exercise combined with
lower extremity revascularization will significantly improve walking performance compared to revascularization
alone in patients with PAD undergoing revascularization for disabling PAD.
 We further hypothesize that inorganic nitrate, a major source of nitric oxide (NO) abundant in beetroot juice,
will improve walking performance after lower extremity revascularization, compared to placebo. In preclinical
models, NO inhibits inflammation, neointimal hyperplasia, thrombosis, and vascular smooth muscle cell
migration at sites of revascularization. NO increases angiogenesis and perfusion, repairs skeletal muscle
damaged by ischemia, and stimulates mitochondrial activity. A large body of evidence, assembled over more
than 25 years, supports our hypothesis that inorganic nitrate (such as that in nitrate-rich beetroot juice) will
improve walking performance and other lower extremity outcomes after lower extremity revascularization.
 Effective, accessible, and safe therapies are needed to enhance the benefits and improve durability of
lower extremity revascularization. Therefore, in a randomized clinical trial with a 2 x 2 factorial design, we will
test the following two primary hypotheses in 386 patients randomized within three months of a successful lower
extremity revascularization for disabling PAD: First, that home-based exercise combined with lower extremity
revascularization will improve six-minute walk distance more than revascularization alone at 6-month follow-up
(Primary Aim #1). Second, that nitrate-rich beetroot juice combined with lower extremity revascularization will
improve six-minute walk, compared to placebo combined with revascularization at 6-month follow-up (Primary
Aim #2). In Secondary Aims, we will establish whether home-based exercise, compared to control, and
whether nitrate-rich beetroot juice, compared to placebo, improve the Walking Impairment Questionnaire and
the PROMIS Mobility Questionnaire and prevent hemodynamic failure of the revascularized vessel. In
exploratory aims, we will test the effects of the interventions on plasma nitric oxide bioavailability and on
gastrocnemius muscle biopsy measures of capillary density, myofiber size, and mitochondrial activity. If our
hypotheses are correct, results of t...

## Key facts

- **NIH application ID:** 10885321
- **Project number:** 1UG3HL169565-01A1
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** Mary McGrae McDermott
- **Activity code:** UG3 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $1,264,646
- **Award type:** 1
- **Project period:** 2024-09-17 → 2025-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10885321

## Citation

> US National Institutes of Health, RePORTER application 10885321, IMProving mobility After revasCularizaTion in Peripheral Artery Disease: the IMPACT PAD Trial (1UG3HL169565-01A1). Retrieved via AI Analytics 2026-05-28 from https://api.ai-analytics.org/grant/nih/10885321. Licensed CC0.

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