Short-Term Pre-Operative Protein Caloric Restriction in Elective Vascular Surgery Patients: A Randomized Clinical Trial

Abstract

(1) Background: Vascular surgery operations are hampered by high failure rates and frequent occurrence of peri-operative cardiovascular complications. In pre-clinical studies, pre-operative restriction of proteins and/or calories (PCR) has been shown to limit ischemia-reperfusion damage, slow intimal hyperplasia, and improve metabolic fitness. However, whether these dietary regimens are feasible and safe in the vascular surgery patient population remains unknown. (2) Methods: We performed a randomized controlled trial in patients scheduled for any elective open vascular procedure. Participants were randomized in a 3:2 ratio to either four days of outpatient pre-operative PCR (30% calorie, 70% protein restriction) or their regular ad-libitum diet. Blood was drawn at baseline, pre-operative, and post-operative day 1 timepoints. A leukocyte subset flow cytometry panel was performed at these timepoints. Subcutaneous/perivascular adipose tissue was sampled and analyzed. Follow-up was one year post-op. (3) Results: 19 patients were enrolled, of whom 11 completed the study. No diet-related reasons for non-completion were reported, and there was no intervention group crossover. The PCR diet induced weight loss and BMI decrease without malnutrition. Insulin sensitivity was improved after four days of PCR (p = 0.05). Between diet groups, there were similar rates of re-intervention, wound infection, and cardiovascular complications. Leukocyte populations were maintained after four days of PCR. (4) Conclusions: Pre-operative PCR is safe and feasible in elective vascular surgery patients.

Temporal Dynamics of the Intestinal Microbiome Following Short-Term Dietary Restriction

“…Therefore, the diet may have a systemic immunomodulatory role despite our findings of a microbial imbalance. Kip et al subsequently tested the liquid diet on eight vascular surgery patients, with 100% compliance [ 19 ]. Pre-operative improvements in insulin sensitivity were noted, with no differences in surgical outcomes compared to the control group.…”

“…The selected diet was a 4-day calorie- and protein-restricted regimen followed by a return to an individual’s typical diet post-intervention. Preliminary findings have demonstrated the safety and feasibility of the diet [ 19 , 20 ]. The study was approved by the Institutional Review Board at the University of Florida.…”

“…Scandishake ® Mix is a weight gain supplement selected for its low protein content. Each serving of Scandishake ® Mix contains 491 Kcal, which is composed of 4% protein, 42% carbohydrates, and 44% fat [ 19 ]. Four shake flavors were available, and water intake was unrestricted.…”

“…To date, preclinical surgical models have shown improved stress response patterns and favorable surgical outcomes [ 14 , 15 , 16 , 17 , 18 ]. Furthermore, several pilot studies have shown feasibility and safety in surgical cohorts [ 19 , 20 , 21 , 22 ].…”

Short-Term Dietary Restriction Potentiates an Anti-Inflammatory Circulating Mucosal-Associated Invariant T-Cell Response

“…Broadly, attenuation of proinflammatory signaling and production of anti-inflammatory chemokines are proposed mechanisms for its benefits [ 1 , 4 , 5 , 6 ]. Multiple, small, randomized controlled trials have demonstrated StDR safety and feasibility, yet mechanistic insights into its modulation of the human immune system remain limited [ 7 , 8 , 9 ]. The gut microbiome influences systemic immunity, and its modification represents an important area for translational therapeutic development [ 10 , 11 , 12 , 13 , 14 , 15 ].…”