Abdominal obesity and the metabolic syndrome: a surgeon's perspective

Adipose Tissue Compartments, Inflammation, and Cardiovascular Risk in the Context of Depression

The neurobiological and behavioral underpinnings linking mental disorders, in particular, major depressive disorder (MDD), with cardiovascular disorders are a matter of debate. Recent research focuses on visceral (intra-abdominal and epicardial) adipose tissue and inflammation and their impact on the development of cardiometabolic disorders. Intra-abdominal adipose tissue is defined as an endocrine active fat compartment surrounding inner organs and is associated with type 2 diabetes mellitus, a risk factor for the later development of cardiovascular disorders. Epicardial (pericardial) adipose tissue is a fat compartment surrounding the heart with close proximity to the arteries supporting the heart. Visceral adipose tissue (VAT) is an important source of inflammatory mediators that, in concert with other risk factors, plays a leading role in cardiovascular diseases. In conjunction with the behavioral (physical inactivity, sedentary lifestyle), psychological (adherence problems), and hormonal (dysfunction of the hypothalamus-pituitary-adrenal axis with subsequent hypercortisolism) alterations frequently accompanying MDD, an enhanced risk for cardiovascular disorders results.

Effects of weight loss intervention on body composition and blood pressure among overweight and obese women: findings from the MyBFF@home study

BACKGROUND

Obesity is related to the increased incidence of hypertension and in healthy individuals, blood pressure changes with age and body mass. The aims of this paper were to evaluate the effectiveness of the weight loss intervention on body composition and blood pressure, and to evaluate the relationship between these factors among housewives in the MyBFF@home study.

METHODS

MyBFF@home intervention was a quasi-experimental study which involved 328 overweight and obese housewives aged 18-59 years old (Control group: 159, Intervention group: 169). Data of the control and intervention group (pre and post intervention who completed the body composition and blood pressure measurements were analysed. Body compositions were measured using the Body Impedance Analyser (InBody 720) and blood pressure (Systolic and Diastolic) was taken using the blood pressure monitoring device (Omron HEM 907) at baseline, 6 month and 12 month. Data analyses (Pearson's correlation test and ANOVA) were performed and analysed using SPSS Statistics for Windows, version 22.0.

RESULTS

Visceral fat area, fat mass and body fat percentage, were all significantly decreased in the intervention group compared to the control group after 6 month intervention (p < 0.05). Systolic blood pressure was reduced significantly by - 6.81 mmHg (95% CI: -9.72,-3.90; p < 0.01) in the intervention and by - 7.95 mmHg (95% CI: -11.69,-4.20; p < 0.01) in the control group after 6 month intervention. Diastolic blood pressure was significantly correlated with BMI (r = 0.19), waist circumference (r = 0.23), body fat mass (r = 0.22), body fat percentage (r = 0.18) visceral fat area (r = 0.22) and skeletal muscle mass (r = 0.14) with p < 0.05. At 12-month follow-up, no significant changes of blood pressure were detected in both groups.

CONCLUSION

There were significant changes in the body fat and systolic blood pressure over 6 month among the participants in the intervention group compared to the control group. However, both groups were unable to sustain the positive changes in the body fats during the maintenance phase. There was a relationship between the body composition and blood pressure during the weight loss intervention and weight loss maintenance phase. Participation among obese housewives in a community-based intervention programme led to the improvements in blood pressure and body composition.

Single Center Experience With Robotic Kidney Transplantation for Recipients With BMI of 40 kg/m2 Or Greater: A Comparison With the UNOS Registry

BACKGROUND

Obesity represents a barrier to kidney transplantation, but the increasing prevalence among renal failure patients has forced some centers to carefully consider such candidates. Morbidly obese patients may be at increased risk of delayed graft function, higher postoperative complications, and inferior graft outcomes. Nevertheless, mortality on the waiting list remains significantly higher than after transplant. We have applied minimally invasive surgery to perform kidney transplant in individuals with body mass index (BMI) of 40 kg/m or greater. We compared our results to the national United Network of Organ Sharing database.

METHODS

The United Network of Organ Sharing registry was reviewed for adult living donor kidney transplant recipients with BMI of 40 kg/m or greater performed from September 2009 to December 2014. We compared transplants performed with robotic technique (RKT) versus patients performed with open surgery at all US centers including our own (open kidney transplant). Subgroup analysis in patients with BMI of 45 kg/m or greater was conducted. We compared outcomes including patient and graft survival, renal function, and technical complications.

RESULTS

Robotic kidney transplantation group had a significantly higher mean BMI overall. The 1-year patient and graft survival rates were similar between groups. Renal function was also similar at 6, 12, and 36 months. Thrombosis caused 1.3% of the graft losses in open kidney transplant and 0% in the RKT group. Interestingly, 52.8% of the overall experience in patients with BMI of 45 kg/m or greater was performed with the robotic technique.

CONCLUSIONS

Robotic surgery offers similar patient and graft survivals with comparable renal function to open technique. Robotic kidney transplantation permits transplantation in extreme BMI categories without additional technical complications. Further studies are required to establish the role of RKT for obese candidates but preliminary data are encouraging.

Modified body adiposity index for body fat estimation in severe obesity

BACKGROUND

The body adiposity index (BAI) comprises a simple method for estimating body fat (BF) that needs to be validated in patients with severe obesity. The present study aimed to determine BAI accuracy with respect to the determination BF in patients with severe obesity.

METHODS

A cross-sectional prospective study comparing two methods for BF estimation was conducted in 433 patients with severe obesity between August 2012 to December 2014. BF was estimated by bioelectrical impedance analysis (BIA) with specific equations developed for BF estimation in patients with severe obesity and BAI. The BF estimation in 240 patients with severe obesity (Group 1: G1) was used to evaluate BAI limitations and to develop a specific equation in this population. The new equation proposed was validated in another 158 patients with severe obesity (Group 2: G2).

RESULTS

There was a significant difference between BF determination by BIA and BAI (P = 0.039). The mean (SD) BF in G1 was 52.3% (6.1%) determined by BIA and 51.6% (8.1%) determined by BAI. Sex, waist-hip ratio (WHR) and obesity grade determined significant errors on BF estimation by BAI. A new equation (modified body adiposity index; MBAI) was developed by linear regression to minimise these errors [MBAI% = 23.6 + 0.5 × (BAI); add 2.2 if body mass index ≥ 50 kg m^-2 and 2.4 if WHR ≥ 1.05]. The new equation reduced the difference [1.2% (5.9%), P < 0.001 to 0.4% (4.12%), P = 0.315] and improved the correlation (0.6-0.7) between methods.

CONCLUSIONS

BAI present significant limitations in severe obesity and MBAI was effective for BF estimation in this population.

Paraesophageal Hernia Repair With Partial Longitudinal Gastrectomy in Obese Patients

BACKGROUND AND OBJECTIVES

Treatment of gastroesophageal reflux disease (GERD) with hiatal hernia in obese patients has proven difficult, as studies demonstrate poor symptom control and high failure rates in this patient population. Recent data have shown that incorporating weight loss procedures into the treatment of reflux may improve overall outcomes.

METHODS

We retrospectively reviewed 28 obese and morbidly obese patients who presented from December 2007 through July 2013 with large or recurrent type 3 or 4 paraesophageal hernia. All of the patients underwent combined paraesophageal hernia repair and partial longitudinal gastrectomy. Charts were retrospectively reviewed, and the patients were contacted to determine symptomatic relief.

RESULTS

Mean preoperative body mass index was 38.1 ± 4.9 kg/m(2). Anatomic failure of prior fundoplication occurred in 7 patients (25%). The remaining 21 had primary paraesophageal hernia, 3 of which were type 4. Postoperative complications included pulmonary embolism (n = 1), pulmonary decompensation (n = 2), and wound infection (n = 1). Mean hospital stay was 5 ± 3 days. Upper gastrointestinal esophagogram was performed in 21 patients with no immediate recurrence or staple line dehiscence. Mean excess weight loss was 44 ± 25%. All of the patients surveyed experienced near to total resolution of their preoperative symptoms within the first month. At 1 year, symptom scores decreased significantly. At 27 months, however, there was a mild increase in the scores. Return of severe symptoms occurred in 2 patients, both of whom underwent conversion to gastric bypass.

CONCLUSIONS

Combined laparoscopic paraesophageal hernia repair with longitudinal partial gastrectomy offers a safe, feasible approach to the management of large or recurrent paraesophageal hernia in well-selected obese and morbidly obese patients. Short-term results were promising; however, intermediate results showed increasing rates of reflux symptoms that required medical therapy or conversion to gastric bypass.

A novel technique for the assessment of preoperative cardiovascular risk: reactive hyperemic response to short-term exercise

BACKGROUND

Perioperative vascular function has been widely studied using noninvasive techniques that measure reactive hyperemia as a surrogate marker of vascular function. However, studies are limited to a static setting with patients tested at rest. We hypothesized that exercise would increase reactive hyperemia as measured by digital thermal monitoring (DTM) in association to patients' cardiometabolic risk.

METHODS

Thirty patients (58 ± 9 years) scheduled for noncardiac surgery were studied prospectively. Preoperatively, temperature rebound (TR) following upper arm cuff occlusion was measured before and 10 minutes after exercise. Data are presented as means ± SD. Statistical analysis utilized ANOVA and Fisher's exact test, with P values <0.05 regarded as significant.

RESULTS

Following exercise, TR-derived parameters increased significantly (absolute: 0.53 ± 0.95 versus 0.04 ± 0.42°C, P=0.04, and % change: 1.78 ± 3.29 versus 0.14 ± 1.27 %, P=0.03). All patients with preoperative cardiac risk factors had a change in TR (after/before exercise, ΔTR) with values falling in the lower two tertiles of the study population (ΔTR <1.1%).

CONCLUSION

Exercise increased the reactive hyperemic response to ischemia. This dynamic response was blunted in patients with cardiac risk factors. The usability of this short-term effect for the preoperative assessment of endothelial function warrants further study.

Evaluation of digital thermal monitoring as a tool to assess perioperative vascular reactivity

AIM

The inflammatory response following tissue injury after major surgery is known to affect endothelial function and vascular reactivity. In this study we evaluated the utility of bedside Digital Thermal Monitoring (DTM) as a surrogate for evaluating vascular function in the postoperative period.

METHODS

Ischemia-induced reactive hyperemia variables were measured in sixty patients scheduled for major thoracic surgery using DTM (VENDYS 5000BC; Endothelix, Inc., Houston, TX, USA) at baseline and at 24, 48, 72 hours, and day 5 postoperatively. Furthermore, baseline DTM variables (TR, aTR and AUCTR) and postoperative kinetics of these variables were compared among patients with and without preoperative chemo-radiation and cardiovascular risk factors.

RESULTS

There were no significant differences in the DTM parameters measured at baseline and on each of the studied postoperative days. Compared to the baseline, the lowest measures of all variables were observed 24 hrs postoperatively and the highest measures of all variables were observed at 72 hrs. Patients with abdominal obesity and smoking had lower DTM values than the rest of the study group.

CONCLUSIONS

In our study, DTM as measured by the VENDYS 5000BC DTM system (Endothelix, Inc.) did not reveal significant changes in ischemia-induced reactive hyperemia (vascular reactivity) between the baseline and after surgery in the postoperative period. Patients with certain cardiovascular risk factors (abdominal obesity, smoking) had a significant lower DTM signal. Whether this novel non-invasive technique is able to serve as a perioperative diagnostic tool for patients in a clinical setting warrants further study.

Preoperative microvascular dysfunction: a prospective, observational study expanding risk assessment strategies in major thoracic surgery

BACKGROUND

Brachial artery reactivity testing (BART)--a surrogate test of microvascular function--predicts cardiac risk in the nonsurgical population and associates it with adverse outcome after vascular surgery. This pilot study investigated BART-derived variables, including flow-mediated dilation (FMD), in preoperative risk stratification for major thoracic surgery.

METHODS

After institutional review board approval, BART was performed in 63 patients before major thoracic surgery. Ultrasonography recorded two-dimensional images and Doppler flow signals of the brachial artery preoperatively at baseline and after induced reactive hyperemia. Variables derived using BART were correlated with preoperative risk factors, established risk scores, and postoperative complications.

RESULTS

The median preoperative FMD value in patients without postoperative complications was 11.5%. This value was used to delineate all patients into two groups: low (FMD < 11.5%) and high (FMD ≥ 11.5%) FMD cohorts. Patients in the low FMD group experienced more postoperative complications: 54% versus 30% had one or more adverse postoperative event, and 11% versus 0% had three or more adverse postoperative events (p < 0.001), respectively. The low FMD group required longer intensive care unit (3.9 ± 2.0 days versus 0.9 ± 0.3 days; p = 0.015) and hospital (14.0 ± 3.3 days versus 6.8 ± 0.6 days; p = 0.007) stays. This cutoff point for FMD accurately predicted 71% of the patients with adverse postoperative events, achieving 71.4% (95% confidence interval, 54.7 to 88.2) sensitivity and 48.6% (95% confidence interval, 32.0 to 65.1) specificity.

CONCLUSIONS

Using BART, preoperative microvascular dysfunction can be identified in patients at increased risk for postoperative complications. These data suggest that larger observational studies and studies exploring preoperative optimization strategies aimed at improving microvascular function are warranted.

The clinical importance of visceral adiposity: a critical review of methods for visceral adipose tissue analysis

As a result of the rising epidemic of obesity, understanding body fat distribution and its clinical implications is critical to timely treatment. Visceral adipose tissue is a hormonally active component of total body fat, which possesses unique biochemical characteristics that influence several normal and pathological processes in the human body. Abnormally high deposition of visceral adipose tissue is known as visceral obesity. This body composition phenotype is associated with medical disorders such as metabolic syndrome, cardiovascular disease and several malignancies including prostate, breast and colorectal cancers. Quantitative assessment of visceral obesity is important for evaluating the potential risk of development of these pathologies, as well as providing an accurate prognosis. This review aims to compare different methods of measuring visceral adiposity with emphasis on their advantages and drawbacks in clinical practice.

Body composition (sarcopenia) in obese patients: implications for care in the intensive care unit

The study of body composition is a rapidly evolving science. In today's environment, there is a great deal of interest in assessing body composition, especially in the obese subject, as a guide to clinical and nutrition interventions. There are some strikingly different compartments of body composition between the obese and the lean patient. We do have the ability to measure body composition accurately, although these techniques can be labor intensive and expensive. The recognition of patients with sarcopenic obesity has identified a potential high-risk patient population. These body composition abnormalities may have even greater importance in the intensive care patient.

Differences in AMPK expression between subcutaneous and visceral adipose tissue in morbid obesity

Adenine monophosphate (AMP) activated protein kinase (AMPK) is an important regulator of obesity. The objective of the present work was to study and compare AMPK protein expression in visceral vs. subcutaneous adipose tissue of morbid obese subjects and to correlate it with adipose tissue characteristics. We selected a total population of 17 extreme obese (BMI>or=40 kg/m2) aged 42.8+/-10.2 years were included in this study. We measured anthropometric and body composition parameters. Adiponectin expression by qRT-PCR, isoproterenol-stimulated lipolytic rates, and AMPK alpha subunits expression by Western blot in adipose tissue explants were determined. Finally plasma concentrations of glucose, triacylglycerols, total cholesterol, HDL-c, LDL-c and insulin were also measured. Our results showed that AMPK alpha expression was higher in subcutaneous than in visceral tissue. A positive correlation between AMPK expression and adiponectin expression in human subcutaneous adipose tissue was observed. Furthermore, a positive correlation between AMPK expression and isoproterenol evoked upregulation of lipolysis rate was also observed. In conclusion, AMPK alpha expression differed according to adipose tissue location. The positive correlation between subcutaneous adipose tissue AMPK and adiponectin or the evoked lipolysis rate could indicate a protective role of AMPK in this tissue, counteracting insulin resistance in morbid obese patients.

Visceral adiposity is not associated with inflammatory markers in trauma patients

BACKGROUND

Excess visceral adiposity induces chronic subclinical inflammation resulting in the metabolic syndrome. Whether excess visceral adiposity impacts posttraumatic inflammatory profiles more is unknown. We hypothesized that obese patients (body mass index >30 kg/m) with higher visceral to subcutaneous adipose tissue distribution would have increased inflammatory outcomes.

METHODS

A secondary analysis of a prospective cohort of adult trauma patients requiring >48 hours of intensive care unit care over a 55-month period was analyzed. Body fat distribution was determined by radiologist review of computed tomography scans at L1. Concentric freeform regions were defined manually, and area was calculated. Visceral adiposity was defined as subcutaneous fat area: visceral area >1.35 (the median), whereas subcutaneous adiposity was defined as a ratio <1.35. Primary outcomes were proinflammatory biomarkers known to be associated with chronic visceral obesity (white blood cell count, interleukin 1, 2, 4, 6, 8, 10, and tumor necrosis factor alpha). Secondary outcomes were all-cause in-hospital mortality, adult respiratory distress syndrome, and nosocomial infections.

RESULTS

Two hundred eighty-one (19%) obese patients with available computed tomography scans from 1,510 trauma patients were included. Visceral adiposity included 140 patients, subcutaneous adiposity included 141 patients. The two groups were similar in regards to age, Trauma Injury Severity Score, and Acute Physiology and Chronic Health Evaluation II score. There was no difference (p > 0.05) in proinflammatory biomarkers. Patients with visceral adiposity had similar clinical outcomes including mortality (p = 0.56), adult respiratory distress syndrome (p = 0.69), and infection (0.43).

CONCLUSIONS

Visceral body fat distribution in obese patients is not associated with increased inflammatory profiles or clinical outcomes after trauma. The impact of injury severity on acute inflammation likely overwhelms the metabolic disturbances and subclinical inflammation associated with visceral obesity in the chronic setting.