Optimization of Diet Before Surgery (OptiSurg)

Study Overview
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Brief Summary
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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.

Official Title
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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

Conditions
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Surgery, Time Restricted Feeding

Intervention / Treatment
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* Behavioral: Time restricted feeding
* Behavioral: Standard dietary advices


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Standard dietary advices<br> | Behavioral: Standard dietary advices<br>* Participants will be given standard dietary advices, as recommended by the international nutrition guidelines, and thus are not different from common clinical practice.<br>|
| Experimental: Time restricted feeding<br> | Behavioral: Time restricted feeding<br>* Participants will be advised to eat only during a selected window of 8 hours, and no later than 4pm, with no advice on nutrition quality, quantity or caloric intake. The intervention will include no medication, no medical device, and will last for 2 weeks prior to surgery.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of participants with: Death, Myocardial infarction, Stroke, Surgical re-intervention. | Safety of TRF before vascular surgery | 1 month | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Length of Stay [days] |  | 1 month | 
| Change in systolic and diastolic blood pressure [mmHg] |  | 1 month | 
| Change in ankle and toe brachial index [0.2-1.4] | Improvement in limb perfusion measured as an increase in the reported index | 1 month | 
| Change in weight [gram] |  | 1 month | 
| Change in BMI [kg/m^2] |  | 1 month | 
| Change in total cholesterol levels [mg/dl] |  | 1 month | 
| Change in LDL cholesterol levels [mg/dl] |  | 1 month | 
| Change in HDL cholesterol levels [mg/dl] |  | 1 month | 
| Change in triglyceride levels [mg/dl] |  | 1 month | 
| Change in glycemia [mmol/L] |  | 1 month | 
| Change in insulin levels [pmol/L] |  | 1 month | 
| Change in HbA1c levels [%] |  | 1 month | 
| Adherence to TRF intervention | Adherence will be determined using the smartphone app, by the number of days in which a participant will be adherent to logging and all caloric food items were contained within a 15-min buffer on each side of the selected eating window. | 1 month | 
| Time from randomization to the first occurrence of any of the following major thrombotic vascular events: MI (Myocardial infarction), ischemic stroke, CV (Cardiovascular) death, ALI (Acute limb ischemia), and major amputation or death (any cause). |  | 1 year |