Feasibility of Blood Flow Restriction Resistance Exercise for Patients with Intermittent Claudication

Abstract

Intermittent Claudication (IC) is a common and debilitating symptom of peripheral arterial disease (PAD) resulting in significant reduction in exercise performance and quality of life. Supervised exercise programmes are part of first-line treatment for IC proving highly effective for improving exercise performance and alleviating symptoms. Despite this, supervised exercise programmes have poor adherence in part to patients’ inability to tolerate IC related pain during walking exercise highlighting the need for alternative exercise modes. Blood flow restriction resistance exercise (BFR-RE) is a technique that facilitates local muscle hypoxia during resistance exercise to induce hypertrophy, strength, and muscular endurance. BFR-RE presents an exciting alternative modality to improve exercise performance in IC patients though requires research on safety, feasibility, and efficacy. This research explored the acute perceptual, affective, and physiological responses to resistance exercises performed at low-load with BFR (LL-BFR), low-load (LL) and moderate-load (ML) in healthy young and older adults; examined the inter-day reliability of a physical function test battery in IC patients sought to determine suitability of the test battery and smallest worthwhile change for each measure; and conducted a randomised controlled trial to evaluate the safety, feasibility, and efficacy of an 8-week LL-BFR resistance exercise programme in IC patients. No adverse events were recorded during this body of work that was attributed to the protocols or procedures administered. LL-BFR was shown to be more demanding than LL and ML predominately through increased pain (p ≤ 0.024, d = 0.8 – 1.4). However, this did not lead to decrements in affective response and fatigue post exercise. Excellent reliability (≥ 0.92 ICC) of the physical function test battery was observed in IC patients and the minimum likely change (76% chance) was calculated for each measure. The feasibility trial observed high adherence (LL-BFR = 78.3%, LL = 83.8%) and completion rates (LL-BFR = 93%, LL = 87%). Significant clinical improvement (>35 m) in the six-minute walk test (6MWT) was achieved in 86% of patients in LL-BFR but only 46% of patients in LL. Additionally, time to claudication pain during 6MWT was likely increased (44.7 s [20.8, 68.6]) for LL-BFR and likely unchanged (4.4 s [-32.4, 23.6]) for LL. This thesis supports BFR-RE as a safe, feasible and potentially effective exercise mode for IC patients.