Comparative effectiveness of unfractionated and low-molecular-weight heparin for prevention of venous thromboembolism following bariatric surgery.

OBJECTIVE: To evaluate the effectiveness and safety of 3 predominant venous thromboembolism (VTE) prophylaxis strategies among patients undergoing bariatric surgery. DESIGN: Cohort study. SETTING: The Michigan Bariatric Surgery Collaborative, a statewide clinical registry and quality improvement program. PATIENTS: Twenty-four thousand seven hundred seventy-seven patients undergoing bariatric surgery between 2007 and 2012. INTERVENTIONS: Unfractionated heparin preoperatively and postoperatively (UF/UF), UF heparin preoperatively and low-molecular-weight heparin postoperatively (UF/LMW), and LMW heparin preoperatively and postoperatively (LMW/LMW). MAIN OUTCOME MEASURES: Rates of VTE, hemorrhage, and serious hemorrhage (requiring >4 U of blood products or reoperation) occurring within 30 days of surgery. RESULTS: Overall, adjusted rates of VTE were significantly lower for the LMW/LMW (0.25%; P < .001) and UF/LMW (0.29%; P = .03) treatment groups compared with the UF/UF group (0.68%). While UF/LMW (0.22%; P = .006) and LMW/LMW (0.21%; P < .001) were similarly effective in patients at low risk of VTE (predicted risk <1%), LMW/LMW (1.46%; P = .10) seemed more effective than UF/LMW (2.36%; P = .90) for high-risk (predicted risk ≥1%) patients. There were no significant differences in rates of hemorrhage or serious hemorrhage among the treatment strategies. CONCLUSION: Low-molecular-weight heparin is more effective than UF heparin for the prevention of postoperative VTE among patients undergoing bariatric surgery and does not increase rates of bleeding.

Vitamin a deficiency after gastric bypass surgery: an underreported postoperative complication.

Introduction. Few data are available on vitamin A deficiency in the gastric bypass population. Methods. We performed a retrospective chart review of gastric bypass patients (n = 69, 74% female). The relationship between serum vitamin A concentration and markers of protein metabolism at 6-weeks and 1-year post-operative were assessed. Results. The average weight loss at 6-weeks and 1-year following surgery was 20.1 ± 9.1 kg and 44.1 ± 17.1 kg, respectively. At 6 weeks and 1 year after surgery, 35% and 18% of patients were vitamin A deficient, (<325 mcg/L). Similarly, 34% and 19% had low pre-albumin levels (<18 mg/dL), at these time intervals. Vitamin A directly correlated with pre-albumin levels at 6 weeks (r = 0.67, P < 0.001) and 1-year (r = 0.67, P < 0.0001). There was no correlation between the roux limb length measurement and pre-albumin or vitamin A serum concentrations at these post-operative follow-ups. Vitamin A levels and markers of liver function testing were also unrelated. Conclusion. Vitamin A deficiency is common after bariatric surgery and is associated with a low serum concentration of pre-albumin. This fat-soluble vitamin should be measured in patients who have undergone gastric bypass surgery and deficiency should be suspected in those with evidence of protein-calorie malnutrition.

Differential loss of fat and lean mass in the morbidly obese after bariatric surgery.

BACKGROUND: Bariatric surgery has become a common treatment for morbid obesity. The relative changes in body tissue that comprise the substantial weight loss over time are not completely understood. METHODS: We evaluated the differential rates of fat and lean tissue losses in morbidly obese patients who underwent Roux-en-Y gastric bypass surgery. Body composition was assessed using whole-body dual energy X-ray absorptiometry (DXA) performed at two timepoints in the postoperative period. Patients were stratified by the tertile of rapidity of weight loss expressed as percent reduction in body mass index per month. RESULTS: Thirty two patients (25 women, 7 men) with a mean age of 46.7 +/- 10.4 years and an average initial body weight of 141.4 +/- 29.4 kg experienced a 52.3 +/- 16.6 kg (36.5 +/- 5.5%) weight loss over 13.9 +/- 6.0 months. The incremental rates of lean body mass loss by tertiles were 0.3 +/- 0.6, 0.5 +/- 0.2, and 1.0 +/- 0.8 kg/month (P = 0.02), whereas the rates of fat loss were 1.2 +/- 0.9, 1.8 +/- 0.4, and 2.9 +/- 1.0 kg/month (P = 0.0001). The ratios for lean to fat loss among the respective tertiles were 1:4.0, 1:3.6, and 1:3.0. The correlation between rates of lean and fat mass loss was r = 0.37 (P = 0.04). Only three of the 32 patients (9.4%) patients maintained or gained lean mass following Roux-en-Y gastric bypass surgery. CONCLUSIONS: After bariatric surgery, those patients losing weight at the greatest rate appear to have accelerated losses of both lean and fat mass. Few patients maintain lean body mass after bariatric surgery, despite self-reported participation in conventional exercise programs. These data suggest the need for more aggressive interventions to preserve lean body mass during the weight loss phase after Roux-en-Y gastric bypass surgery.

Behavioral predictors of weight regain after bariatric surgery.

BACKGROUND: After bariatric surgery, a lifelong threat of weight regain remains. Behavior influences are believed to play a modulating role in this problem. Accordingly, we sought to identify these predictors in patients with extreme obesity after Roux-en-Y gastric bypass (RYGB). METHODS: In a large tertiary hospital with an established bariatric program, including a multidisciplinary outpatient center specializing in bariatric medicine, with two bariatric surgeons, we mailed a survey to 1,117 patients after RYGB. Of these, 203 (24.8%) were completed, returned, and suitable for analysis. Respondents were excluded if they were less than 1 year after RYGB. Baseline demographic history, preoperative Beck Depression Inventory (BDI), and Brief Symptom Inventory-18 scores were abstracted from the subjects' medical records; pre- and postoperative well-being scores were compared. RESULTS: Of the study population, mean age was 50.6 +/- 9.8 years, 147 (85%) were female, and 42 (18%) were male. Preoperative weight was 134.1 +/- 23.6 kg (295 +/- 52 lb) and 170.0 +/- 29.1 kg (374.0 +/- 64.0 lb) for females and males, respectively, p < 0.0001. The mean follow-up after bariatric surgery was 28.1 +/- 18.9 months. Overall, the mean pre- versus postoperative well-being scores improved from 3.7 to 4.2, on a five-point Likert scale, p = 0.001. A total of 160 of the 203 respondents (79%) reported some weight regain from the nadir. Of those who reported weight regain, 30 (15%) experienced significant regain defined as an increase of > or =15% from the nadir. Independent predictors of significant weight regain were increased food urges (odds ratios (OR) = 5.10, 95% CI 1.83-14.29, p = 0.002), severely decreased postoperative well-being (OR = 21.5, 95% CI 2.50-183.10, p < 0.0001), and concerns over alcohol or drug use (OR = 12.74, 95% CI 1.73-93.80, p = 0.01). Higher BDI scores were associated with lesser risk of significant weight regain (OR = 0.94 for each unit increase, 95% CI 0.91- 0.98, p = 0.001). Subjects who engaged in self-monitoring were less likely to regain any weight following bariatric surgery (OR = 0.54, 95% CI 0.30-0.98, p = 0.01). Although the frequency of postoperative follow-up visits was inversely related to weight regain, this variable was not statistically significant in the multivariate model. CONCLUSIONS: Predictors of significant postoperative weight regain after bariatric surgery include indicators of baseline increased food urges, decreased well-being, and concerns over addictive behaviors. Postoperative self-monitoring behaviors are strongly associated with freedom from regain. These data suggest that weight regain can be anticipated, in part, during the preoperative evaluation and potentially reduced with self-monitoring strategies after RYGB.

Relation between degree of weight loss after bariatric surgery and reduction in albuminuria and C-reactive protein.

BACKGROUND: Bariatric surgery achieves long-term weight loss in obese adults with amelioration of diabetes and hypertension. Improvement in albuminuria and high-sensitivity C-reactive protein (hs-CRP) has also been reported. We investigated, at a weight control center in a community hospital setting, the relation between degree of surgical weight loss and reduction in the cardiovascular risk markers, albuminuria and hs-CRP. METHODS: We performed a retrospective study of 62 obese adults who had undergone Roux-en-Y gastric bypass surgery and had a median follow-up of 15 months. RESULTS: The baseline (preoperative) mean age was 46 years, 82% were women, 26 had a blood pressure of > or =140/90 mm Hg, and 25 had type 2 diabetes. During follow-up (postoperative), a decrease occurred in the body mass index (mean +/- standard deviation 49.2 +/- 8.7 kg/m(2) to 34.1 +/- 8.1 kg/m(2); P <.0001), excess body weight (mean +/- SD 76.1 +/- 23.6 kg to 34.9 +/- 21.7 kg; P <.0001), hemoglobin A1c (mean +/- SD 6.5% +/- 1.3% to 5.6% +/- 0.8%; P <.0001), systolic blood pressure (mean +/- SD 133.7 +/- 14.3 mm Hg to 112.9 +/- 14.6 mm Hg; P < .0001), urine albumin creatinine ratio (from a median of 8.0 mg/g [interquartile range 5.0-29.3] to a median of 6.0 mg/g [interquartile range 3.3-11.5]; P <.0001), and hs-CRP (mean +/- SD 11.2 +/- 9.8 mg/L to 4.7 +/- 5.9 mg/L; P <.0001). The study sample was divided into tertiles of the percentage of excess body weight loss; the mean percentage of excess body weight loss was -37.1% +/- 5.5% in the first tertile, -54.3% +/- 6.8% in the second tertile, and -75.8% +/- 10.9% in the third tertile. The median percentage of change in albuminuria was greatest (median -52.8%, interquartile range -79.1% to -17.5%) in the third tertile, intermediate (median -45.5%, interquartile range -72.4% to 0%) in the second tertile, and lowest (-42.6%, interquartile range -80.5% to 16.7%) in the first tertile (P = .953). The mean percentage of change in hs-CRP was greatest (-72.4% +/- 30.4%) in the third tertile, intermediate (-55.4% +/- 31.9%) in the second tertile, and lowest (-44.8% +/- 30.6%) in the first tertile (P = .037). CONCLUSION: The results of our study have shown that obese adults experience a reduction in albuminuria and hs-CRP after bariatric surgery, with a greater reduction in hs-CRP observed with more surgical weight loss.

Endoscopic management of early upper gastrointestinal hemorrhage following laparoscopic Roux-en-Y gastric bypass.

BACKGROUND AND AIMS: Upper gastrointestinal hemorrhage (UGIH) is an infrequent complication (1-3.8%) following laparoscopic Roux-en-Y gastric bypass (LRYGB). The safety and efficacy of endoscopic management of immediate postoperative bleeding is unknown. We sought to determine how frequently UGIH complicates LRYGB and whether endoscopic management is successful in controlling hemorrhage. METHODS: Retrospective chart review of all patients who developed UGIH following LRYGB from November 2001 to July 2005 at a large suburban teaching hospital. RESULTS: Of 933 patients who underwent LRYGB, 30 (3.2%) developed postoperative UGIH. An endoscopic esophagogastroduodenoscopy (EGD) was performed in 27/30 patients (90%). All were found to have bleeding emanating from the gastrojejunostomy (GJ) staple line. Endoscopic intervention was performed in 24/30 (80%) with epinephrine injection and heater probe cautery being used most commonly. Endoscopic therapy was ultimately successful in controlling all hemorrhage, with 5 patients (17%) requiring a second EGD for rebleeding. No patient required surgery to control hemorrhage. One patient aspirated during the endoscopic procedure with subsequent anoxic encephalopathy and died 5 days postoperatively. Twenty-one patients (70%) developed UGIH in the intraoperative or immediate postoperative period (<4 h postoperative). The mean length of stay was significantly longer in these patients (2.84 vs 4.1, P= 0.001). CONCLUSIONS: (a) UGIH complicates LRYGB in a small but significant number of patients. (b) Bleeding usually occurs at the GJ site. (c) EGD is safe and effective in controlling hemorrhage with standard endoscopic techniques. (d) UGIH occurs most commonly in the immediate postoperative period and may be best managed in the operating room with the patient intubated to prevent aspiration.

Reduction in predicted coronary heart disease risk after substantial weight reduction after bariatric surgery.

In recent years, bariatric surgery has become an increasingly used therapeutic option for morbid obesity. The effect of weight loss after bariatric surgery on the predicted risk of coronary heart disease (CHD) has not previously been studied. We evaluated baseline (preoperative) and follow-up (postoperative) body mass index, CHD risk factors, and Framingham risk scores (FRSs) for 109 consecutive patients with morbid obesity who lost weight after laparoscopic Roux-en-Y gastric bypass surgery. Charts were abstracted using a case-report form by a reviewer blinded to the FRS results. The study included 82 women (75%) and 27 men (25%) (mean age 46 +/- 10 years). Mean body mass index values at baseline and follow-up were 49 +/- 8 and 36 +/- 8 kg/m(2), respectively (p <0.0001). During an average follow-up of 17 months, diabetes, hypertension, and dyslipidemia resolved or improved after weight loss. Thus, the risks of CHD as predicted by FRS decreased by 39% in men and 25% in women. The predicted 10-year CHD risks at baseline and follow-up were 6 +/- 5% and 4 +/- 3%, respectively (p < or =0.0001). For those without CHD, men compared favorably with the age-matched general population, with a final 10-year risk of 5 +/- 4% versus an expected risk of 11 +/- 6% (p <0.0001). Likewise, women achieved a level below the age-adjusted expected 10-year risk of the general population, with a final risk of 3 +/- 3% versus 6 +/- 4% (p <0.0001). In conclusion, weight loss results in a significant decrease in FRS 10-year predicted CHD risk. Bariatric surgery decreases CHD risk to rates lower than the age- and gender-adjusted estimates for the general population. These data suggest substantial and sustained weight loss after bariatric surgery may be a powerful intervention to decrease future rates of myocardial infarction and death in the morbidly obese.

Caloric expenditure in the morbidly obese using dual energy X-ray absorptiometry.

Total caloric expenditure is the sum of resting energy expenditure (REE) and caloric expenditure during physical activity. In this study, we examined total caloric expenditure in 25 morbidly obese patients (body mass index>or=35 kg/m(2)) using dual energy X-ray absorptiometry (DXA) scanning and cardiorespiratory exercise testing. Our results show average REE for all individuals was 2027+/-276 kcal/d and mean net caloric expenditure during 30 min of exercise was 115+/-16 kcals. Assuming the mean of all input values, a strict 1500 kcal/d diet combined with 150 min per wk of structured physical activity, the projected weight change was -7% (8.8+/-6.2 kg) for 6 mo. We conclude that morbidly obese individuals should be able to achieve only a modest weight loss by following minimal national guidelines. These data suggest that more aggressive energy expenditure and caloric restriction targets for long periods of time are needed to result in significant weight loss in this population.

Cardiorespiratory fitness and short-term complications after bariatric surgery.

BACKGROUND: Morbid obesity is associated with reduced functional capacity, multiple comorbidities, and higher overall mortality. The relationship between complications after bariatric surgery and preoperative cardiorespiratory fitness has not been previously studied. METHODS: We evaluated cardiorespiratory fitness in 109 patients with morbid obesity prior to laparoscopic Roux-en-Y gastric bypass surgery. Charts were abstracted using a case report form by reviewers blinded to the cardiorespiratory evaluation results. RESULTS: The mean age (+/- SD) was 46.0 +/- 10.4 years, and 82 patients (75.2%) were female. The mean body mass index (BMI) was 48.7 +/- 7.2 (range, 36.0 to 90.0 kg/m(2)). The composite complication rate, defined as death, unstable angina, myocardial infarction, venous thromboembolism, renal failure, or stroke, occurred in 6 of 37 patients (16.6%) and 2 of 72 patients (2.8%) with peak oxygen consumption (Vo(2)) levels < 15.8 mL/kg/min or > 15.8 mL/kg/min (lowest tertile), respectively (p = 0.02). Hospital lengths of stay and 30-day readmission rates were highest in the lowest tertile of peak Vo(2) (p = 0.005). There were no complications in those with BMI < 45 kg/m(2) or peak Vo(2) > or= 15.8 mL/kg/min. Multivariate analysis adjusting for age and gender found peak Vo(2) was a significant predictor of complications: odds ratio, 1.61 (per unit decrease); 95% confidence interval, 1.19 to 2.18 (p = 0.002). CONCLUSIONS: Reduced cardiorespiratory fitness levels were associated with increased, short-term complications after bariatric surgery. Cardiorespiratory fitness should be optimized prior to bariatric surgery to potentially reduce postoperative complications.