Plasma Cholecystokinin Levels after Vertical Banded Gastroplasty: Effects of an Acidified Meal

Background: Although cholecystokinin (CCK) is involved in the short-term regulation of satiety, it has not been investigated in obese patients subjected to bariatric restrictive operations. Methods: 8 morbidly obese patients (BMI 49.1 ± 6.9), 7F and 1M, were investigated before and after vertical banded gastroplasty (VBG). 6 healthy lean volunteers served as the control group. CCK was determined (RIA) after an overnight fast and after the administration of an acidified (pH 3) liquid meal. Blood samples were taken 45 min before the meal, 5 min after it and then every 30 min for 3 hours. Results: There were no differences between groups in basal CCK levels. However, the peak of CCK after the meal was significantly higher (P <0.01) in obese patients after VBG (24.9 ± 18 pmol/l) than before VBG (9.8 ± 6.7 pmol/l) and when compared with the control group (8.0 ± 6.3 pmol/l).The time needed to reach the peak was longer in healthy volunteers (105 ± 24.9 min) than in obese patients before VBG (45 ± 40 min) and after VBG (7.5± 12 min) (P<0.01). Conclusions: VBG increases the peak of CCK secretion and shortens the time to reach it. These changes could contribute to the satiety effects of gastric restrictive operations.     

Impact of Vertical Banded Gastroplasty on Respiratory Insufficiency of Severe Obesity

Background: Respiratory insufficiency associated with morbid obesity can include sleep apnea syndrome (SAS), obesity hypoventilation syndrome (OHS), or a combination of both. The aim of our study was to determine the safety and effectiveness of vertical banded gastroplasty (VBG) in the treatment of severely obese patients with respiratory insufficiency. Methods: From 1983 to 1994, 35 patients (25 males, ten females) who met the criteria for either SAS and OHS (19 patients) or SAS alone (16 patients) underwent VBG. Results: Six patients (17%) died of subsequent pulmonary-cardiac disease despite significant weight loss. Need for nasal continuous positive airway pressure (CPAP) decreased after VBG from 68% of patients preoperatively to 22% postoperatively. Of the ten patients with sleep studies, the apnea/hyponea index decreased from 45 ± 11 events per h preoperatively to 12 ± 6 events per h postoperatively, while per cent ideal body weight (%IBW) also decreased (pre-VBG: 268 ± 12, post-VBG: 204 ± 12). Of the seven patients with arterial blood gases, PaCO₂ decreased from 55 ± 4 torr preoperatively to 41 ± 3 torr postoperatively, and PaO₂ increased from 50 ± 4 torr preoperatively to 73 ± 6 torr postoperatively, while %IBW decreased (pre-VBG: 263 ± 16, post-VBG: 193 ± 14). Conclusion: Respiratory insufficiency is a life-threatening complication of morbid obesity. In morbidly obese patients with respiratory insufficiency, VBG offers improvement in both SAS and OHS. Respiratory insufficiency due to obesity should be considered a strong indication for VBG.     

Plasma Leptin Levels after Vertical Banded Gastroplasty for Morbid Obesity: Effects of an Acidified Meal

Background: Leptin is considered one of the anorectic messengers to the central nervous system in lean subjects. Although it is secreted by the gastric mucosa, there are contradictory evidences of its involvement in mediating the acute satiety effect of the meal in obese patients. The effects of restrictive operations on meal-stimulated leptin secretion are unknown. Methods: The effects of a standard acidified (pH 3) meal on leptin release were investigated in obese patients, before and after vertical banded gastroplasty (VBG). 8 morbidly obese patients (BMI 49.1±6.5) had serum leptin determination after an overnight fast. Samples were taken basally and every 30 minutes after the meal for 3 hours. The test was repeated after 20% BMI reduction. 5 lean volunteers (BMI 22.5±1.7) served as the control group. Results: In obese patients, basal serum leptin fell from 62±20.4 to 23.8±15.7 ng/ml after the operation (P <0.01) but still with significant differences vs the control group (5.6±3 ng/ml). The meal was associated with a significant decrease of serum leptin (ANOVA test, P <0.01), and significant differences between obese patients after surgery and lean subjects were found. Conclusion: Serum leptin was reduced by the meal in obese patients and VBG did not attain satiety through serum leptin changes.     

Different Effects of Vertical Banded Gastroplasty and Roux-en-Y Gastric Bypass on Meal Inhibition of Ghrelin Secretion in Morbidly Obese Patients

A decrease in ghrelin plasma levels in morbidly obese patients subjected to bariatric surgery has been considered to help increase body weight loss. Contradictory results have been described after Roux-en-Y gastric bypass (RYGBP), and no study to date has compared RYGBP and vertical banded gastroplasty (VBG), the two main operations performed in the United States. We investigated the effects of RYGBP (10 patients) and VBG (12 patients) on basal and postmeal ghrelin plasma levels in 22 morbidly obese patients (20 F and 2 M), mean age 42.1 ± 3.7 years, mean weight 115 ± 3.9 kg, mean body mass index (BMI) 43.5 ± 1.7. Before surgery and after a 20% reduction in BMI, ghrelin concentrations (pg/mL; radioimmunoassay [RIA], DRG Diagnostics, Germany) were measured in all patients 45 min before and for 3 h after a standard liquid meal (Osmolite RTH solution, 500 mL, 504 kcal). The results were expressed as mean ± SD. Differences between times and groups were evaluated by Student's t-test and one-way analysis of variance (ANOVA). We found that basal ghrelin plasma levels were reduced after RYGBP (to 73.1 ± 6 pg/mL, p <. 05) but increased after VBG (to 172 ± 26 pg/mL, p <. 0009). After a standard liquid meal, ghrelin plasma levels decreased significantly over 1 h in VBG patients, whereas they remained unchanged in RYGBP patients. Since these results were obtained under the same metabolic and anthropometric conditions, we conclude that RYGBP acts through permanent inhibition of ghrelin secretion, whereas VBG merely restores the mechanisms of ghrelin regulation by nutrients.     

A Preliminary Study of the Optimal Anesthesia Positioning for the Morbidly Obese Patient

Background: Hypoxemia during the induction of general anesthesia for the morbidly obese patient is a major concern of anesthesiologists. The etiology of this pathophysiological problem is multifactorial, and patient positioning may be a contributing factor. The present study was designed to identify optimal patient positioning for the induction of general anesthesia that minimizes the risk of hypoxemia in these patients. Methods: 26 morbidly obese patients (body mass index - BMI 56±3) were randomly assigned to one of three positions for induction of anesthesia: 1) 30° Reverse Trendelenburg; 2) Supine-Horizontal; 3) 30° Back Up Fowler. Mask ventilation, full neuromuscular paralysis and direct laryngoscopy were performed. Any airway difficulties were noted. After endotracheal tube placement, subjects were ventilated for 5 minutes with 1% isoflurane in a mixture of 50% oxygen / 50% air and then disconnected from the ventilation circuit.The time required for capillary oxygen saturation (SaO₂), as measured by pulse oximeter, to decline from 100% to 92% was noted and identified as the safe apnea period (SAP). Ventilation was then immediately re-established.The lowest SaO₂ after resuming ventilation and the time from that nadir to an SaO₂ of 97% were also recorded. Results: BMI and hip-waist ratios of patients in groups 1, 2 and 3 did not significantly differ. There were no differences in airway difficulties between the different groups. The SAP in groups 1, 2 and 3 was 178±55, 123±24 and 153±63 seconds, respectively. The SaO₂ of patients in the reverse Trendelenburg position dropped the least and took the shortest time to recover to 97%. Conclusions: In morbidly obese patients, the 30° Reverse Trendelenburg position provided the longest SAP when compared to the 30° Back Up Fowler and Horizontal-Supine positions. Since on induction of general anesthesia morbidly obese patients may be difficult to mask ventilate and/or intubate, this extra time may preclude adverse sequelae resulting from hypoxemia. Therefore, Reverse Trendelenburg is recommended as the optimal position for induction.     

Low-Back Pain in Morbidly Obese Patients and the Effect of Weight Loss Following Surgery

Background: Although low-back pain (LBP) is a common health problem and a source of significant discomfort, disability and work absences, its incidence, severity and outcome have not been extensively investigated in morbidly obese patients undergoing bariatric surgery. Methods: 50 morbidly obese candidates for vertical banded gastroplasty (VBG) were asked to fill in a questionnaire, to assess the incidence and severity of any existing LBP symptoms. 50 non-obese patients, admitted to our surgical unit for management of several benign conditions, were also asked to fill in the same questionnaire and served as controls. 24 months after VBG, the morbidly obese patients were again evaluated for their LBP symptoms. Results: LBP was identified in 29 morbidly obese patients (58%) preoperatively and in only 12 (24%) of the lean controls (P<0.01). 2 years after VBG, with a significant excess weight loss (P<0.0001), only 10 patients continued to have LBP but less frequently and requiring reduced doses of medications compared with the preoperative condition. In the remaining 19 patients with preoperative positive LBP history, the postoperative weight loss was associated with complete resolution of the symptoms. Conclusion: The frequency of LBP is significantly higher in morbidly obese patients than in lean subjects. Surgical weight reduction results in significant improvement and even disappearance of this obesity co-morbidity.     

Impact of Overweight and Pneumoperitoneum on Hemodynamics and Oxygenation during Prolonged Laparoscopic Surgery

Background Anesthesia adversely affects respiratory function and hemodynamics in obese patients. Although many studies have been performed in morbidly obese patients, data are limited concerning overweight patients [BMI 25–29.9 kg m⁻²]. The aim of this study was to evaluate the effects of prolonged pneumoperitoneum in Trendelenburg position on hemodynamics and gas exchange in normal and overweight patients. Methods We studied 15 overweight and 15 non-obese [BMI 18.5–24.9 kg m⁻²] patients who underwent totally endoscopic robot-assisted radical prostatectomy under general anesthesia with an inspired oxygen fraction of 0.5. A standardized anesthetic regimen was used, and patients were examined at standard times: after induction of anesthesia and Trendelenburg posture, every 30 minutes after establishing pneumoperitoneum, and after the release of the pneumoperitoneum with the patient still in Trendelenburg position. Results After induction of anesthesia and Trendelenburg positioning arterial oxygen pressure [P_aO₂] and alveolar-arterial difference in oxygen tension [A_aDO₂] differed significantly between both groups with lower P_aO₂ [235 ± 27 versus 164 ± 51 mmHg] and higher A_aDO₂ [149 ± 48 versus 76 ± 28 mmHg] values in overweight patients. During pneumoperitoneum, P_aO₂ transient increased above baseline values in overweight patients, whereas A_aDO₂ decreased. Hemodynamic parameters [HR, MAP, and CVP] did not differ significantly between groups. Conclusions Arterial oxygenation and A_aDO₂ are significantly impaired in overweight patients under general anesthesia in Trendelenburg posture. In overweight patients pneumoperitoneum transient reduced the impairment of arterial oxygenation and lead to a decrease in A_aDO₂. Hemodynamic parameters were not affected by body weight.     

Intra-abdominal Pressure in the Morbidly Obese

Background: Recent data suggests that increased intra-abdominal pressure (IAP) is one factor associated with the morbidity of morbidly obese patients, who have a BMI >35 kg/m². IAP has been proposed to be an abdominal compartment syndrome (ACS). This study investigated the characteristics of IAP in morbidly obese patients. Methods: 45 morbidly obese patients (mean BMI 55±2 kg/m²) had IAP measured using urinary bladder pressure. Results: The mean IAP for the morbidly obese group was 12±0.8 cmH₂O, increased when compared to controls (IAP=0±2 cmH₂O). The IAP correlated to the sagittal abdominal diameter, an index of the degree of central obesity (r=+0.83, P<0.02); however, it did not correlate to basal insulin, body weight, or BMI. The end-expiratory IAP did not change when measured after the laparotomy incision was made, but IAP measured in the last 15 patients increased during the first 2 postoperative days. The IAP for patients with pressure-related morbidity (gastroesophageal reflux disease, hernia, stress incontinence, diabetes, hypertension, and venous insufficiency) was 12±1 cmH₂O, while those without these morbidities had an IAP of 9±0.8 cmH₂O. Conclusion: We conclude that IAP is increased in morbid obesity. This increased IAP is a function of central obesity and is associated with increased morbidity. The degree of IAP elevation correlates with increased co-morbidities. We also conclude that elevation in IAP in morbid obesity is not a true ACS but represents a direct mass effect of the visceral obesity.     

Subcutaneous perfusion before and during surgery in obese and nonobese patients

Hypoxia at the surgical site impairs wound healing and oxidative killing of microbes. Surgical site infections are more common in obese patients. We hypothesized that subcutaneous oxygen tension (P_sqO₂) would decrease substantially in both obese and non‐obese patients following induction of anesthesia and after surgical incision. We performed a prospective observational study that enrolled obese and non‐obese surgical patients and measured serial P_sqO₂ before and during surgery. Seven morbidly obese and seven non‐obese patients were enrolled. At baseline breathing room air, P_sqO₂ values were not significantly different (p = 0.66) between obese (6.8 kPa) and non‐obese (6.5 kPa) patients. The targeted arterial oxygen tension (40 kPa) was successfully achieved in both groups with an expected significant increase in P_sqO₂ (obese 16.1 kPa and non‐obese 13.4 kPa; p = 0.001). After induction of anesthesia and endotracheal intubation, P_sqO₂ did not change significantly in either cohort in comparison to levels right before induction (obese 15.5, non‐obese 13.5 kPa; p = 0.95), but decreased significantly during surgery (obese 10.1, non‐obese 9.3 kPa; p = 0.01). In both morbidly obese and non‐obese patients, P_sqO₂ does not decrease appreciably following induction of anesthesia, but decreases markedly (～33%) after commencement of surgery. Given the theoretical risks associated with low P_sqO₂, future research should investigate how P_sqO₂ can be maintained after surgical incision.     

An Adjustable Vertical Banded Gastroplasty does not Eliminate the Risk of Staple-line Disruption

Background: The two main reasons for reoperation after vertical banded gastroplasty (VBG) in the treatment of obesity are staple-line disruption and stomal stenosis. Patients: Seven morbidly obese patients of mean (±SEM) body mass index (BMI) 43.7 ± 1.9 kg/m² treated with an adjustable vertical banded gastroplasty (AVBG). Results: No complications of the band system were reported. Weight-loss [BMI at 2 years follow-up 33.9 ± 6.9 kg/m² (n = 5)] was equivalent to that seen after VBG with a fixed band. Two of the patients developed staple-line disruption at 18 and 24 months after surgery. Conclusion: AVBG allows adjustment of the stoma, but staple-line disruption was common in this small series. It is possible that an excessive filling of the band in order to achieve excess weight loss results in a high pressure in the upper pouch which increases the risk of staple-line disruption.     

Effect of Surgical Weight Loss on Free Radical and Antioxidant Balance: a Preliminary Report

Background:This study observes the effect of surgical weight loss on free radical and antioxidant vitamin balance. Patients and Methods: 22 consecutive morbidly obese patients undergoing vertical banded gastroplasty (VBG) were chosen for the study. Postoperative studies were done at 12 and 24 weeks. Plasma antioxidant and vitamin determinations were performed by HPLC method. Results: Subjects lost a significant amount of weight (P<0.01). Compared to preoperative measurements, postoperative measurements of plasma betacarotene were not statististically different both at 12 and 24 weeks (13.86±1.26 μg/dl, 12.35±1.2, P=0.44; 14.33±2.03, P=0.77; preoperatively, 12 and 24 weeks respectively). Alpha-tocopherol increased slightly at the 12th week; the difference was not significant (8.50±0.77; 9.56±0.82, P=0.37; preoperatively and 12th week respectively). The levels of alpha-tocopherol rose at 24th week significantly (10.89±0.55, P=0.028). The indicator of lipid peroxidation (malondialdehyde) decreased with weight loss (1.505±0.11 μmol/L preoperatively; 0.75±0.062 at 12th week, P=0.01; 0.712±0.05 at 24th week, P<0.01). Conclusion: Our data show that free radical generation falls markedly in association with weight loss after VBG. Surgical weight loss leads to significant decrease in oxidant production and also leads to increase in some antioxidant vitamins. The demon stration of decreased free radical generation and correction of balance between free radicals and antioxidant vitamins has important implications for oxidative mechanisms underlying obesity-associated disorders.     

Boussignac CPAP in the Postoperative Period in Morbidly Obese Patients

Background In the postoperative period hypoventilation and hypoxia with hypercarbia may occur in morbidly obese patients due to the residual influence of general anesthesia drugs, postoperative atelectasis and postoperative pain. Non-Invasive Ventilation (NIV) is a method of improvement of respiratory efficiency in patients not requiring mechanical ventilation. The aim of the study was to compare NIV (Boussignac) CPAP and traditional oxygen delivery via nasal catheter in the postoperative acute care unit (PACU) in morbidly obese patients after open Roux-en-Y gastric bypass (RYGBP). Methods 19 morbidly obese patients scheduled for elective open RYGBP, were randomly divided into 2 groups: CPAP (10 patients) or control (nasal catheter – 9 patients). Patients consisted of: 8 male and 11 female, mean weight 127.76 ± 18.5 kg, height 173.41 ± 9.41 cm, BMI 42.43 ± 3.3 kg/m2, age 35.84 ± 9.05 years. In the PACU, capillary blood gas measurements were taken at 3 Time Points: T1 – 30 min, T2 – 4 hours and T3 – 8 hours after admission. Sample T0 was taken before surgery. For management of postoperative pain, patients received morphine 2 mg/h intravenously and tramadol 100 mg. Results Mean blood gas measurements of all postoperative time points were: pO₂ 81.0 ± 16.0 (range 78.1–85.7) mmHg vs 65.9 ± 4.9 (range 63.8–68.1) mmHg (P < 0.05); pCO₂ 40.6 ± 2.4 (range 39.4–41.8) mmHg vs 41.5 ± 4.0 (range 39.6–43.4) mmHg (P > 0.05), in the CPAP and control groups respectively. In every case, pulse-oxymetry oxygenation was >94%. Conclusion Boussignac CPAP improved blood oxygenation compared to passive oxygenation with a nasal catheter but had no influence on CO₂ elimination in non-CO₂ retaining morbidly obese patients.     

Gastric Emptying of Solids and Semi-solids in Morbidly Obese and Non-obese Subjects: An Assessment Using the <Superscript>13</Superscript>C-Octanoic Acid and <Superscript>13</Superscript>C-Acetic Acid Breath Tests

Background It has been suggested that obesity is associated with an altered rate of gastric emptying. The objective of the present study was to determine whether the rates of solid and semi-solid gastric emptying differ between morbidly obese patients and lean subjects. Methods The Gastric-emptying time (GET) of solid and semi-solid meals were compared between lean healthy subjects and morbidly obese patients enrolled in two previously published studies. GET of solid and semi-solid meals was measured using the ¹³C-octanoic acid breath test and ¹³C-acetic acid breath test, respectively, in 24 lean and 14 morbidly obese individuals of both sexes. Student t-test was used to compare the mean data between the lean and morbidly obese groups. The influence of sex, gender, BMI and morbid obesity on the GET of solid meals was verified by linear regression analysis. Results Mean t(1/2) values of solid GET (± standard deviation) were 203.6 ±  76.0 min and 143.5 ± 19.1 min for lean and obese subjects, respectively (P = 0.0010). Mean t(lag) values of solid GET were 127.3 ± 42.7 min and 98.4 ± 13.0 min for lean and obese subjects, respectively (P = 0.0044). No significant difference in semi-solid GET was observed between the lean and morbidly obese groups. Conclusion The present study demonstrated a significantly enhanced gastric emptying of the solid meal test in morbidly obese patients when compared to lean subjects. This finding is compatible with the hypothesis that rapid gastric emptying in morbidly obese subjects increases caloric intake due to a more rapid loss of satiety.     

A Prospective Comparison of Vertical Banded Gastroplasty and Roux-en-Y Gastric Bypass in a Non-Superobese Population

Background: In the non-superobese population, consensus is currently unavailable in bariatric surgery. We report the results of a prospective comparison of vertical banded gastroplasty (VBG) and Roux-en-Y gastric bypass (RYGBP) in a non-superobese population. Methods: From 1994 to 2000, 179 patients with clinically severe obesity underwent various surgical procedures in our department. During this time a prospective study was undertaken in order to compare VBG with RYGBP in morbidly obese patients with a BMI <50 kg/m². Based on specific criteria including eating behavior, 68 patients were selected to undergo RYGBP and 35 VBG. All patients have undergone complete follow-up evaluation at 1, 3, 6, and 12 months postoperatively and every year thereafter. Results: All patients have now completed their 5th postoperative year. Mean follow-up period to date is 96.5±12.2 months for VBG and 67.6±11.3 months for RYGBP. 3 patients (8.6%) in the VBG group and 9 patients (13.2%) in the RYGBP group are lost to follow-up. Mean excess weight loss (EWL) was always better in the RYGBP group (P=0.0013). The percentage of failure, defined as EWL <25%, was not significantly different between the two procedures. No statistically significant differences were observed between the 2 groups in the total number of non-metabolic complications, and the only statistically significant difference observed in metabolic complications was vitamin B₁₂ deficiency after RYGBP. Frequency of vomiting was significantly less and quality of eating significantly better in RYGBP than in VBG patients. Conclusion: This prospective long-term study, with nearly complete follow-up, suggests that in the non-superobese population, preoperative eating habits may play a role in choosing the most appropriate bariatric operation for each patient. Although RYGBP is associated with better mean weight loss outcomes, the percentage of patients who achieved and maintained ≥50% EWL after VBG in this pre-selected patient population was not significantly different. Each type of operation has advantages and disadvantages, and, if properly chosen, a purely restrictive procedure can be successful for some patients. Therefore, it can be said that the decision regarding which bariatric procedure to perform in non-superobese patients must be based on in-depth preoperative evaluation as well as the patients' own preferences and outcome expectations.     

Results of Bariatric Surgery for Morbid Obesity in Patients Older than 50 Years

Background: Surgery is increasingly used for weight loss in morbidly obese patients. The authors evaluated the safety and efficacy of bariatric surgery in patients older than 50 years. Methods: Prospective data on 62 consecutive patients (Male = 13, Female = 49) undergoing bariatric procedures between 1985-1994 were reviewed. Mean followup was 30 ± 2 months (3-48 months). All data are mean ± sem. Results: Age was 57 ± 1 year (range 50-71 years). Patients had a mean preoperative weight of 125 ± 4 kg (275 ± 9 lb) and 119 ± 6% excess body weight. A total of 68 procedures were performed: vertical banded gastroplasty (VBG = 23), Roux-en-Y gastric bypass (RYGB = 43), and biliopancreatic diversion (BPD = 2). Six patients were converted to RYGB (5) and BPD (1) after failed VBG. Hospital mortality was nil. Complications were wound infection (5), pulmonary (4), gastric leak (2), abscess (1) and others (4). Mean weight loss at 3 years was 55 ± 7 and 33 ± 6% of percent excess body weight for RYGB and VBG, respectively. Postoperative use of medications for arthritis, diabetes mellitus and asthma was reduced by 23%, 62% and 100%, respectively. Satisfaction with the outcome of treatment and weight loss was reported by 81% of patients. Six patients that were converted from jejunoileal bypass (metabolic complications) to VBG gained weight. Conclusions: Bariatric surgery is safe and well tolerated in morbidly obese patients older than 50 years. Weight loss parallels that of younger populations and is greater in patients treated with RYGB in this subgroup. Age should not be a contraindication to bariatric surgery provided the patient has obesity-related medical morbidity. Control of obesity-related co-morbid conditions is improved by weight loss.     

Bariatric Surgery Cannot Prevent Tryptophan Depletion Due to Chronic Immune Activation in Morbidly Obese Patients

Background: Increased activity of the immuno-modulatory enzyme indoleamine-2,3-dioxygenase (IDO) during immune activation, results in tryptophan depletion. Tryptophan metabolic changes reduce serotonin production and cause mood disturbances, depression, and impaired satiety, ultimately leading to increased food intake and obesity. Bariatric surgery significantly diminishes immune mediators by substantial weight reduction. We examined IDO-mediated tryptophan-catabolism in morbidly obese patients compared to lean individuals. Methods: Serum concentrations of kynurenine and tryptophan, calculated kynurenine to tryptophan ratios (kyn trp-1) as an indirect estimate of IDO activity, and neopterin levels reflecting IFN-γ mediated immune activation, were assessed before and after bariatric surgery. The study population included 22 morbidly obese individuals and 20 normal-weight volunteers. Results: Median weight loss after 24.4±5.1 months was 40.6 kg resulting in a reduction of BMI from 44.1 kg/m² to 29.9 kg/m² (P<0.001). Preoperative kyn trp-1 in morbidly obese patients was significantly increased compared to the control group (41.6±20.1 mmol/mol vs 26.5±5.1 mmol/mol; P<0.001). Postoperative weight reduction did not lead to normalization of kyn trp-1 (37.9±14.0 mmol/mol). As a consequence, tryptophan levels were significantly lower in morbidly obese patients (pre-: 51.5±9.2 μmol L⁻¹ and postoperatively: 46.9±7.6 μmol L⁻¹) when compared with those of normal-weight controls (64.8±9.5 μmol L⁻¹; P<0.001). In addition, neopterin levels were elevated in the study population pre- and postoperatively compared to normal-weight volunteers (both P<0.001). Conclusions: Tryptophan depletion in morbidly obese patients is due to chronic immune activation and persists in spite of significant weight reduction following bariatric surgery. This might thereby be responsible for diminished serotonin functions, leading to unchanged satiety dysregulation and a reward-deficiency-syndrome.     

Improvement of Vertical Banded Gastroplasty by Strict Dietary Management

Background: Vertical banded gastroplasty (VBG) has been found to reduce BMI significantly during the first postoperative year. However, the same trend in weight loss has not been established thereafter.The purpose of this study was to evaluate the effects of our dietary program on morbidly obese patients treated with VBG. Methods: A prospective evaluation of 40 obese patients (25 female, 15 male) undergoing VBG over a 3-year period was undertaken. Results: The age range was 24-57 (median 38) years, mean weight 133±2 SD kg, and mean BMI 45±6.4 SD kg/m2. After VBG, a special follow-up program was applied to patients. All patients (100%) were available for follow-up. Operative mortality was zero. 4 patients developed an early postoperative complication, and 1 patient was re-operated because of staple-line disruption 8 months after VBG. BMI decreased to 34±3.2 after 12 months, 27±1.3 after 24 months, and 28±1.4 after 36 months. All patients showed weight loss after VBG, and the weight loss continued with the strict follow-up program during a 3-year period, except in 1 patient who regained the weight lost despite an intact staple-line and stoma. Conclusion: Our policy for patients after VBG appears to be effective.     

Impact of Surgically-Induced Weight Loss on Respiratory Function: A Prospective Analysis

Background: Morbid obesity (MO) causes several degrees of respiratory impairment that may resolve after weight reduction. The aims of the present study were to investigate the frequency of respiratory impairment in a selected cohort of morbidly obese patients with BMI 40-50 kg/m² with no respiratory symptoms and to evaluate the impact of surgically-induced weight loss on respiratory function. Methods: Prospective analysis of respiratory impairment was conducted before surgery and 1 year after surgery in a cohort of patients with MO who underwent vertical banded gastroplasty (VBG). 30 consecutive patients with MO who underwent VBG (14 open and 16 laparoscopic) in a 1-year period were studied. Respiratory function tests, arterial blood gases and hemoglobin were obtained in all patients before and 1 year after VBG. Results: Results were analyzed using the Wilcoxon signed-rank test and Spearman for variables without normal distribution. Mean age was 35±8 years; there were 3 males and 27 females. BMI was 44±4 kg/m² before surgery and 32±4 kg/m² at 1-year follow-up. By respiratory function tests, the diagnosis of obstructive disease was made before surgery in 4 patients and a restrictive disorder was identified in 4 additional patients. Evidence of pulmonary disease was absent in all patients 1 year after surgery. Forced vital capacity, inspiratory and expiratory forces, tidal volume, SaO₂, and PaCO₂ significantly improved after weight reduction. Conclusion: Surgically-induced weight loss significantly improves pulmonary function.     

Left ventricular function and cardiopulmonary performance following surgical treatment of morbid obesity

Background: It is well established that morbid obesity affects the respiratory system and the diastolic function of the heart. During exercise, cardiopulmonary reserve is exhausted because of augmented requirements, leading to a significant intolerance. A study was undertaken to investigate the influence of body weight loss on the characteristics of the left ventricle (LV) and on exercise capacity in obese patients before and 6 months following vertical banded gastroplasty (VBG). Methods: 16 morbidly obese individuals (BMI >40 kg/m²) scheduled for VBG were studied. A symptomlimited cardiopulmonary exercise test and a complete transthoracic echocardiogram were performed 1 day before operation and 6 months postoperatively (after the patients achieved a body weight loss of ≥ 20% of their pre-operative values). Results: Exercise duration increased significantly 6 months following surgery.The mean O₂ consumption at peak exercise (peak VO₂) and at the anaerobic threshold (VO_2AT) was significantly higher after weight loss. 6 months after VBG the LV thickness decreased significantly. Regarding the diastolic indices, isovolumic relaxation time (IVRT) and early/late (E/A) velocity ratio, there was a significant improvement after weight loss. Simple linear regression analysis revealed that peak VO₂ and VO_2AT were significantly correlated with IVRT and E/A velocity ratio. Conclusions: Weight loss after VBG improves the cardiac diastolic function and this is associated with an improvement in cardiopulmonary exercise performance. Left ventricular filling variables could be considered among the most important determinants of exercise intolerance in obese individuals.     

Altered Olfactory Acuity in the Morbidly Obese

Background: Obese individuals have been reported to have a heightened desire for and ability to identify sweets when compared with leaner persons. Smell, like taste, may also be altered in obese persons compared with leaner subjects. This study was designed to determine if the sense of smell is different between morbidly obese and moderately obese individuals. Methods: 101 adult volunteers undergoing preoperative evaluation completed the 12-item Cross-Cultural Smell Identification Test (CC-SIT) before surgical intervention. Age, BMI, and smoking history were also obtained. Results: 101 subjects completed the preoperative CC-SIT (87 female, 14 male). Mean age of the subjects was 40 ± 12 years. Mean BMI was 42.5 ± 12.5 kg/m². 46 subjects (46%) had a BMI >45. 21 were smokers (21%). 9 subjects (9%), all female non-smokers, had a CC-SIT score representing olfactory dysfunction. Subjects with BMI >45 were more likely to have olfactory dysfunction than subjects with BMI <45 (16% vs 4%, P <0.05). Conclusion: Morbidly obese individuals are more likely than moderately obese individuals to demonstrate CC-SIT scores consistent with olfactory dysfunction. The reason for this is unclear but is probably related to metabolic changes occurring in morbidly obese individuals.