Insights From a Short-Term Protein–Calorie Restriction Exploratory Trial in Elective Carotid Endarterectomy Patients

Open vascular surgery interventions are not infrequently hampered by complication rates and durability. Preclinical surgical models show promising beneficial effects in modulating the host response to surgical injury via short-term dietary preconditioning. Here, we explore short-term protein–calorie restriction preconditioning in patients undergoing elective carotid endarterectomy to understand patient participation dynamics and practicalities of robust research approaches around nutritional/surgical interventions.

We designed a pilot prospective, multicenter, randomized controlled study in patients undergoing carotid endarterectomy. After a 3:2 randomization to a 3-day preoperative protein–calorie restriction regimen (30% calorie/70% protein restriction) or ad libitum group, blood, clinical parameters, and stool samples were collected at baseline, pre-op, and post-op days 1 and 30. Subcutaneous and perivascular adipose tissues were harvested periprocedurally. Samples were analyzed for standard chemistries and cell counts, adipokines. Bacterial DNA isolation and 16S rRNA sequencing were performed on stool samples and the relative abundance of bacterial species was measured.

Fifty-one patients were screened, 9 patients consented to the study, 5 were randomized, and 4 completed the trial. The main reason for non-consent was a 3-day in-hospital stay. All 4 participants were randomized to the protein–calorie restriction group, underwent successful endarterectomy, reported no compliance difficulties, nor were there adverse events. Stool analysis trended toward increased abundance of the sulfide-producing bacterial species Bilophila wadsworthia after dietary intervention (P = .08).

Although carotid endarterectomy patients held low enthusiasm for a 3-day preoperative inpatient stay, there were no adverse effects in this small cohort. Multidisciplinary longitudinal research processes were successfully executed throughout the nutritional/surgical intervention. Future translational endeavors into dietary preconditioning of vascular surgery patients should focus on outpatient approaches.