Patients undergoing vascular surgery suffer some of the highest complications rates. Surprisingly, there is no accepted medical therapy to reduce these complications. Time restricted eating (TRE) is a nutritional approach that emphasizes energy intake limited to certain windows of time within the 24-hour cycle, without restriction on energy intake or macronutrients. In healthy young adults, TRE improves cardio-metabolic fitness, but it has not been tested in patients undergoing surgery and suffering from cardiovascular disease. We investigated the feasibility of a pre-operative 2-week, early 8- hour TRE in patient undergoing vascular surgery.

OptiSurg was a randomized, open-label non inferiority clinical trial (ClinicalTrials.gov NCT04627688) in patients with BMI ≥ 20 kg/m2 and Fontaine stage II peripheral artery disease undergoing elective femoral endarterectomy. Patients were randomized with a 1:1 ratio to either diet nutritional counselling (standard of care, ctrl) or a physician selected 8-hour TRE window (from 8am to 4pm) for 2 weeks prior to surgery. Postoperatively, all patients returned to a ctrl diet. The primary composite endpoint was death, myocardial infarction, stroke, and surgical re-intervention at 1-month post-operatively. Key secondary end points were the duration of eating, sleep, blood glucose, body weight, lipidi profile, anckle brachial index (ABI) and quality of life at 1, 3, 6 and 12 months post-operatively.

A total of 12 participants underwent randomization (Ctrl n=6, TRE =6). All patients completed the study: 8 men and 4 women, age 75, 41–87 (median, min-max) years. Adherence to TRE was 86%. The TRE and Ctrl groups reduced their median daily eating window during the 2 weeks dietary intervention from 9.75 (IQR 8.38-10.00) to 6.88 (IQR 4.88-7.38) hours/day and 10.40 (IQR 8.69-11.70) to 8.75 (6.25-11.30) hours/day, respectively. Death, myocardial infarction, stroke, or surgical re-intervention in either group. Surgery improved limb perfusion (ABI) in all patients. Importantly, ABI was significantly higher at 1 month (0.73, IQR 0.71- 0.85 vs. 1.03, IQR 0.91-1.11; p=0.035) and at 1 year (0.70, IQR 0.56-0.83 vs. 0.98, IQR 0.92-1.05; p=0.032) in the TRE group.

Our preliminary study demonstrates that a 2-week 8-hour TRE regimen before vascular surgery is feasible, safe and might improves lower limb perfusion (ABI).