The goal of this clinical trial is to assess the feasibility of undertaking a randomized controlled trial assessing the impact of a personalised, intense cardiac rehabilitation programme involving high intensity interval exercise (HIIT) and dietary advice (termed MICROFIT) on symptom burden in patients with microvascular coronary dysfunction.
The main questions it aims to answer are:
1. Feasibility of undertaking randomised controlled trial of MICROFIT in patients with coronary microvascular dysfunction (recruitment rates, retention and adherence, acceptability of MICROFIT and participants' and practitioners' experiences of trial participation) 2. Preliminary data on the effect that MICROFIT has on angina symptoms in patients with microvascular coronary dysfunction, as measured by Seattle Angina Questionnaire 3. Preliminary data on the fidelity and clinical efficacy of MICROFIT
Participants will be randomized to either MICROFIT + Usual Care, or Usual Care group.
Participants in both arms of the trial will:
* Undergo a series of investigations, including cardiopulmonary exercise test (CPET), dual xray absorptiometry (DEXA), echocardiogram, cardiac MRI scan, blood tests, at the start of the trial and again after 6 months * Measure their living activity by using an activity tracker (GeneActiv) as well as a photographic diet diary for a week at the start of the trial and again after 6 months * Complete a series of questionnaires to assess angina symptom burden, mental health and quality of life, at the start of the trial and again after 6 months.
Participants in the intervention arm of the study will:
1. Undergo MICROFIT intervention. MICROFIT includes a combination of exercise and diet management sessions over 24 weeks. It involves:
* 1:1 high-intensity interval training ('HIIT') sessions with a personal trainer and guidance on exercise sessions to be performed at home * 1:1 sessions with a dietician to support them with improvements in diet. 2. Visit clinic on two additional occassions during the trial to discuss their progress with a cardiologist 3. Undergo an interview at the end of the study to discuss their experiences of participation in the study 4. Receive a debrief on their investigation results and progress made at the end of their study
Participants in the Usual Care arm of the study will:
1. Receive standard Usual Care advice regarding lifestyle changes and targeted medical therapy offered to patients with coronary microvascular dysfunction. 2. Receive a debrief on their investigation results and progress made at the end of their study 3. Undergo a 'taster' session with the personal trainer to discover what the intervention involves.
Age ≥18
Angina or angina equivalent symptoms
Unobstructed coronary arteries at the time of coronary angiogram. This will be defined as plaque causing <40% epicardial vessel stenosis or 40-90% with a fractional flow reserve (FFR) ≥0.8
Evidence of microvascular dysfunction on ICA (CFR <2.5 and/or AchFR <1.5)
New York Heart Association class III/IV heart failure
Severe left ventricular impairment (ejection fraction≤35%)
Severe heart valve disease
Significant cardiomyopathy (as assessed by a cardiologist)
Parallel
MICROFIT - personalised high intensity interval training exercise rehabilitation and dietary advice
Other interventionMICROFIT is a 24-week long personalized one-on-one exercise and dietary education intervention, along with home exercise guided by personal trainers. Exercise intervention includes High Intensity Interval Training (HIIT) and dietary advice focuses on incorporation of a Mediterranean-type diet. Phase 1 - Induction (8 weeks) Exercise: Twice-weekly 1-hour personal trainer (PT) supervised exercise sessions. 45 minute homework exercise session once a week. Diet: 1-hour educational session with a dietician, followed by two 30-minute follow up sessions. Phase 2 - Consolidation (10 weeks) Exercise: Once weekly 1 hour PT sessions, two 45 minute homework sessions once a week. Diet: 30-minute sessions every 5 weeks. Phase 3 - Maintenance (6 weeks) Exercise: Supervised 1 hour PT sessions once every 3 weeks, 45-minute homework sessions three times a week. Diet: one final 30 minute session after week 3.
Establish recruitment rate
A key feasibility outcome for a potential future randomised controlled trial will be to establish recruitment rates: defined as the proportion of eligible patients who accept the invitation to participate in the study.
Establish retention rate
A key feasibility outcome for a potential future randomised controlled trial will be to examine retention: defined as the proportion of recruited participants who complete the study.
Establish adherence
A key feasibility outcome for a potential future randomised controlled trial will be to examine adherence: defined as, for participants in the intervention arm, the proportion of offered sessions completed.
Assess acceptability of the intervention
A key feasibility outcome for a potential future randomised controlled trial will be to examine the acceptability of the intervention (MICROFIT) to participants and clinicians. This will be assessed qualitatively by an end of study interview.
Change in anginal symptom burden
Data on anginal symptom burden as measured by the 7-item Seattle Angina Questionnaire (SAQ-7) \[0-100, 0=worst health, 100=full health\] will be collected to guide power calculations for large scale RCT in the future, where it would be the primary outcome.
Change in myocardial perfusion with quantitative stress MRI
An assessment of change in myocardial perfusion reserve \[ratio of myocardial blood flow at hyperaemia/myocardial blood flow at rest\] utilising quantitative stress perfusion cardiac MRI.
Change in myocardial oxygenation
Qualitative and quantitative assessment of change in myocardial oxygenation utilising Oxygenation-Sensitive Cardiac MRI
Change in cardiorespiratory fitness
Serial cardiopulmonary exercise tests will provide a measurement of maximum rate of oxygen consumption attainable during physical exertion (VO2 peak), reported in mL/kg/min.
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Royal United Hospitals Bath NHS Foundation Trust
Lead sponsor
National Institute for Health Research, United Kingdom
Collaborator
