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Background Coronary microvascular dysfunction (CMD), a common endotype of angina with non-obstructed coronary arteries (ANOCA), is linked to poor cardiovascular outcomes, 1 and can significantly impact quality of life, mental health, and functional capacity.2 CMD management strategies focus on symptom control with antianginal therapies, with limited effect and prognostic benefit. While lifestyle changes and risk factor modification are advocated by international guidelines, evidence supporting cardiac rehabilitation for CMD is sparse.3 It is proposed that MICROFIT – a personalised lifestyle intervention programme (figure 1), utilising high intensity interval training and dietary counselling, underpinned by behavioural change techniques, can improve symptoms of angina in patients with CMD.Aim To examine the feasibility of undertaking a multicentre randomised controlled trial (RCT) of the MICROFIT programme versus usual care in patients with CMD and explore its effects on symptoms of angina.Methods MICROFIT (Microvascular Coronary Rehabilitation For Improving Treatment) ( NCT06681896) is a multicentre feasibility RCT comparing the MICROFIT programme to usual care in patients with angina and CMD without obstructive coronary artery disease. Forty participants (aged >18) will be recruited from two centres and randomised 1:1 to each arm of the trial. The primary outcome is feasibility, measured by recruitment and retention, and adherence to the intervention. Participants’ and practitioners’ experience of the programme will be explored qualitatively. The secondary outcome is change in angina symptoms, to inform the design and power calculations for a future RCT. Other exploratory outcomes include changes to functional capacity (VO2 peak), cardiovascular MRI-derived markers of myocardial perfusion and coronary vascular function, and biomarkers of metabolic syndrome. A sub-study will explore experiences of the ANOCA diagnostic pathway from patient and healthcare professionals’ perspective.Abstract P01 Figure 1MICROFIT programme structureConclusion MICROFIT will contribute to the evidence base for efficacy of comprehensive lifestyle intervention programmes in management of CMD, with potential multifactorial benefit to patients.References Gdowski MA, Murthy VL, Doering M, Monroy-Gonzalez AG, Slart R, Brown DL. Association of isolated coronary microvascular dysfunction with mortality and major adverse cardiac events: a systematic review and meta-analysis of aggregate data. J Am Heart Assoc. 2020 May 5;9(9).Humphreys H, Paddock D, Brown S, Berry C, Cowie A, Dawkes S, et al. Living with myocardial ischaemia and no obstructive coronary arteries: a qualitative study. Open Heart. 2024 Feb 8;11(1):e002569.Oliveira J, Hoole SP, Hartley P, Farquhar M, Deaton C, Forsyth F, et al. Exercise-based cardiac rehabilitation effects on severity of angina, HRQoL and exercise capacity in patients with microvascular angina: systematic review and meta-analysis. European Journal of Cardiovascular Nursing 2024 Jul 17;23(Supplement_1).