Optimization of Diet Before Surgery (OptiSurg)

Optimization of Diet Before Surgery (OptiSurg): Effects of Time Restricted Feeding (TRF) Before Vascular Surgery - An Open-label Randomized Controlled Trial of TRF vs Regular Dietary Advices

The overarching goal of this project is to assess whether a controlled short-term Time restricted feeding (TRF) intervention leads to metabolic benefits, improves recovery after vascular surgery and that TRF is safe. Participants suffering from intermittent claudication (Fontaine stage II peripheral artery disease, PAD) will be randomly assigned to a 2-week TRF or active control dietary advices before open surgical revascularization. Prior to the surgery, the investigators will assess the eating patterns of participants with an innovative smartphone application ('app') which is less intrusive and more reliable than food diaries/questionnaires to assess eating behavior and patterns. In the second part of the study, the investigators will investigate whether a short term TRF intervention improves surgical recovery, in the short-term (1 month, primary endpoint) and long-term (optional, up to 1 year), as part of the routine clinical follow-up. This proposal builds on established expertise in the biology of dietary intervention, surgery, and study of eating patterns in human.

Inclusion Criteria:

• Age ≥ 18 years
• Fontaine stage II peripheral artery disease planned for open femoral endarterectomy
• Body mass index ≥ 20 kg/m2
• Smartphone compatible with the app (iOS or Android systems)
• Hypertensive (or on 1 or more blood pressure lowering medication)
• Hypercholesterolemia (or on 1 or more lipid lowering medication)

Exclusion Criteria:

• Diabetes on insulin therapy or sulfonylureas
• Fontaine stage III and IV peripheral artery disease
• Prior revascularization on the index leg within 14 days of the qualifying revascularization.
• Major surgery in the past 3 months
• Myocardial infarction or revascularization (PTA, stent, CABG) in the past 3 months
• Major illness / fever over the previous month, active cancer
• On a diet / weight management or prior bariatric surgery
• Major mental illness, unable to give consent, inability to follow study procedures (language barrier, dementia)
• Current shift work or travel abroad planned in the next month
• Major sleep disorder
• Enrolled in another interventional clinical trial
• Ongoing pregnancy