Principal Investigator: C. Keith Ozaki, MD
Vascular surgery operations have high failure rates and frequent occurrence of peri-operative cardiovascular complications. Pre-operative dietary restriction is an emerging research field with the potential to address these problems. In pre-clinical studies, pre-operative protein and calorie restriction (PCR) has been shown to limit tissue damage caused by the return of blood flow to tissue, slow abnormal cell accumulation in blood vessels, and improve metabolic fitness. It is still unknown whether these dietary regimens are feasible and safe in the vascular surgery patient populations.
Background: Vascular surgery operations are hampered by high failure rates and frequent occurrence of peri-operative cardiovascular complications. Pre-operative dietary restriction is an emerging research field with the potential to address these problems. 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 populations remains unknown.
Methods: We performed an open label randomized controlled trial in patients scheduled for any open vascular procedure. Participants were randomized in a 3:2 ratio to either four days of outpatient pre-operative protein-calorie restriction (30% calorie, 70% protein restriction) or their regular ad libitum diet. Blood was drawn at baseline, pre-operative, and post-operative day 1 time-points. An extensive leukocyte subset flow cytometry panel was also performed at these time-points. Peri-procedural subcutaneous and perivascular adipose tissue was sampled and analyzed for adipokine, cytokine, hematology, and chemical blood parameters. Patients were followed for at least one year from the date of surgery.
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 (similar pre-albumin levels between time-points). Insulin sensitivity was improved after 4 days of PCR (p=0.05). Mean follow-up was 442 days. Between diet groups, there were similar rates of re-intervention, wound infection, and cardiovascular complications. Leukocyte populations were maintained after four days of PCR.
Conclusions: Four days of pre-operative outpatient PCR appears safe and feasible in patients scheduled for open vascular surgery.
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