Increased visceral adiposity fails to predict postoperative complications in Roux-en-Y gastric bypass patients

Salvatore Docimo, Joshua S Winder, Brandon S Dudeck, Brandon Labarge, Ann M Rogers. Penn State Hershey Medical Center

INTRODUCTION

Worse surgical outcomes in obese patients may be explained by a systemic pro-inflammatory  response;  adipose tissue  releases  inflammatory mediators, including tumor necrosis factor-α , interleukin-6 , and leptin [3-5]. Quantitative analysis of visceral adiposity using computerized tomographic (CT)-based measurements has been evaluated as an  effective means of assessing obesity in patients [6-7].  Our objective was to introduce a quantitative measure to study the effect of visceral obesity on  post-operative morbidity and mortality  in patients undergoing Roux-en-y gastric bypass (RYGB).

 METHODS

A retrospective review of patients undergoing RYGB from 2006 – 2013 was performed with institutional review board approval.  All patients who underwent CT  of the abdomen  within 30 days postoperatively were included.  Patient demographics, CT  findings, length of stay (LOS) and complications were evaluated. Preoperative body mass index (BMI) was calculated. Radiologic measurements of adiposity were obtained from preoperative CT scans using OsiriX DICOM (2015) viewer software.  Visceral fat areas (VFA) and subcutaneous fat areas (SFA) were measured from a single axial slice at the level of L4-L5 intervertebral space.  The CT attenuation level to delineate the regions of adipose tissue was set using Hounsfield units of -190 to -30 [11].  The VFA and  SFA were then  measured. The VFA to SFA ratio (V/S) was calculated..  The currently defined obesity threshold is V/S ≥ 0.4 [11,12].  Statistical analysis was performed utilizing Chi-square and Student’s T-test evaluations.

 RESULTS:

51 patients were evaluated.  Twenty-six  had a V/S < 0.4 (average V/S ratio 0.27) and 25  had a V/S ratio > 0.4 (average V/S ratio 0.56; p=0.0001). For the V/S < 0.4 group, the average age and BMI were 42.5 years, 42.98 kg/m2, with 5 (19.2%) males, and 21 (80.8%) females. For the V/S > 0.4 group, the average age and BMI were 49.96 years and 44.58 kg/m2, with 11 (44%) males and 14 (56%) females. The difference in age was significant (p=0.0094).  No significant differences in the postoperative complications (p=0328), LOS (p=0.388), or number of surgical interventions (p=0.679) were noted.

 CONCLUSIONS:

Evaluation of  visceral adiposity among bariatric patients undergoing postoperative CT scans failed to demonstrate a statistically significant difference in complication rate, length of stay or rate of surgical intervention. Given the current safety of laparoscopic bariatric surgery, visceral fat alone is an unlikely marker for increased complications in bariatric patients.

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