Anemia after bariatric surgery: more than just iron deficiency.

Bariatric surgery for morbid obesity is rapidly gaining popularity. Restrictive and/or malabsorptive surgical interventions result in dramatic weight loss with significantly decreased obesity-related morbidity and mortality. Anemia, which may affect as many as two-thirds of these patients, is of concern and generally thought to be caused by iron deficiency. Although iron deficiency in this population may be frequent given pouch hypoacidity, defunctionalized small bowel, and red meat intolerance, it may not account for all anemias seen. First, there is increasing evidence that obesity creates a state of chronic inflammation. Both iron deficiency anemia and anemia of chronic inflammation present with low serum iron levels. Most studies reporting anemia after bariatric surgery lack serum ferritin determinations so that the relative contribution of inflammation to anemia cannot be assessed. Second, a significant number of anemias after bariatric surgery remain unexplained and may be attributable to less frequently seen micronutrient deficiencies such as copper, fatsoluble vitamins A and E, or an imbalance in zinc intake. Third, although deficiencies of folate and vitamin B(12) are infrequent, study observation periods may be too short to detect anemia attributable to vitamin B(12) deficiency because vitamin B(12) storage depletion takes many years. This review is intended to increase awareness of the mechanisms of anemia above and beyond iron deficiency in the bariatric patient and provide healthcare providers with tools for a more thoughtful approach to anemia in this patient population.

Maladaptive eating patterns after weight-loss surgery.

Weight-loss surgery has been shown to contribute to the improved health and well-being of the clinically severe obese, and for many has been seen as their "last resort." Although the majority of patients who choose this option as a means to achieve a healthier weight are successful, for some patients it is not beneficial. Bariatric surgery is not a panacea, and its immediate and long-term success depends on the patient's ability to incorporate lifestyle and behavioral changes. Patients who are not successful in achieving and maintaining their anticipated weight loss struggle to comply with diet, exercise, and vitamin regimens. Not only do these patients exhibit diminished weight loss, they have put themselves at risk for vitamin and mineral deficiencies and protein malnutrition. Their problematic response to weight-loss surgery may or may not be due to a worsening of presurgical depression, binge eating, emotion-triggered eating, body image, or eating behaviors associated with specific situations such as social events. This paper describes clinical responses we have observed in our bariatric practice. Several case studies are presented to highlight problems we have encountered when following bariatric surgery patients in the early postoperative period, as well as in a long-term setting. Recommendations are made for screening and follow-up of at-risk patients.

Twenty-five years of advances in vascular access: bridging research to clinical practice.

Vascular access has become a key component for a multitude of IV therapies, including parenteral nutrition. Access of the central venous system has been long recognized for its associated complications of infection, thrombosis, and occlusion. Over the past 25 years, clinical practice based on research and innovation has attempted to decrease complication rates and therefore improve the safety of vascular access. This article highlights the research and its influence on catheter care procedures, technology, and education that has led to advances in vascular access. An improved understanding of the pathophysiology associated with catheter-related complications and an ongoing evaluation of new treatment modalities has provided clinicians today with new options for improved patient care and the ability to preserve vascular access options for patients.

Perioperative antibiotic prophylaxis in the gastric bypass patient: do we achieve therapeutic levels?

BACKGROUND: Perioperative surgical antibiotic prophylaxis requires that therapeutically effective drug concentrations be present in the tissues. METHODS: Patients undergoing Roux-en-Y gastric bypass for morbid obesity were given 2 g cefazolin preoperatively, followed by a second dose at 3 hours. Thirty-eight patients were each assigned to 1 of 3 body mass index (BMI) groups: (A) BMI=40-49 (N = 17); (B) BMI=50-59 (N=11); (C) BMI > or= 60 (N=10). Multiple timed serum (baseline; incision, 15, 30, 60 minutes; prior to second prophylactic dose; and closure) and tissue (skin, subcutaneous fat, and omentum) specimens were collected and cefazolin concentration analyzed by microbiological assay. RESULTS: No significant difference was observed in intraoperative fluid replacement or blood loss among BMI groups. Serum antimicrobial concentrations exceeded resistance breakpoint (32 microg/mL) in 73%, 68%, and 52% of BMI groups A, B, and C, respectively. No significant difference in cefazolin concentration was observed in mean incisional skin and closure tissue specimens in groups A, B, and C. A significant decrease in cefazolin concentration was noted in closure adipose (p=.04), initial (p=.03) and closure omentum (p=.05) tissues in groups B and C compared with A. Over 90% of serum samples exhibited therapeutic concentrations covering 53.8% of gram-positive and 78.6% of gram-negative surgical pathogens. However, therapeutic tissue levels were achieved in only 48.1%, 28.6%, and 10.2% of groups A, B, and C, respectively. CONCLUSIONS: Pharmacokinetic analysis suggests that present dosing strategies may fail to provide adequate perioperative prophylaxis in gastric bypass patients.

Anemia after bariatric surgery cannot be explained by iron deficiency alone: results of a large cohort study.

BACKGROUND: We sought to identify the frequency and mechanisms of anemia after bariatric surgery in a bariatric surgery program at the Medical College of Wisconsin, (Milwaukee, WI). Anemia after bariatric surgery has often been attributed to iron deficiency, although an inflammatory component might be present, making the anemia after surgery mechanistically complex. METHODS: The body mass index and hemoglobin (Hb), vitamin B(12), folate, iron, and ferritin levels were extracted from the records of 1125 patients for ≤4 years after Roux-en-Y gastric bypass. Anemia was defined using the World Health Organization criteria. RESULTS: The mean body mass index, Hb, and ferritin decreased after surgery. The body mass index decreased from 50.1 kg/m(2) (95% confidence interval [CI] 49.6-50.6) at baseline to 33.0 kg/m(2) (95% CI 32.3-33.6) at 12 months and remained unchanged thereafter. The Hb level decreased from 13.4 g/dL (95% CI 13.3-13.5) to 12.8 (95% CI 12.6-13.1) and ferritin from 87.5 ng/mL (95% CI 75.2-99.7) to 55.4 (95% CI 42.9-68.0) at 24-48 months, and serum iron increased from 68.4 µg/dL (95% CI 66.8-70.0) to 82.8 (95% CI 76.4-88.7); all P values were <.01. Anemia was present in 12% (95% CI 10-14%) of patients at baseline and had increased to 23% (95% CI 16-30%) at 24-48 months. The changes in ferritin, Hb, and the percentage of patients with anemia were most pronounced in premenopausal women. Vitamin B(12) and folate levels were unaffected. CONCLUSION: The baseline incidence of anemia was greater than expected and increased significantly after surgery. The percentage of those with anemia and low ferritin was most significant in premenopausal women; however, the overall iron bioavailability improved significantly with pronounced weight loss, suggesting a reduction in inflammation. These findings indicate that anemia after bariatric surgery cannot be explained on the basis of iron availability and suggest that other mechanisms, currently undefined, contribute to the development of anemia in these patients.

Hepatic gene networks in morbidly obese patients with nonalcoholic fatty liver disease.

BACKGROUND: Genetic factors alter the risk for nonalcoholic fatty liver disease (NAFLD). We sought to identify NAFLD-associated genes and elucidate gene networks and pathways involved in the pathogenesis of NAFLD. METHODS: Quantitative global hepatic gene expression analysis was performed on 53 morbidly obese Caucasian subjects undergoing bariatric surgery (27 with NAFLD and 26 controls). After standardization of data, gene expression profiles were compared between patients with NAFLD and controls. The set of genes that significantly correlated with NAFLD was further analyzed by hierarchical clustering and ingenuity pathways analyses. RESULTS: There were 25,643 quantitative transcripts, of which 108 were significantly associated with NAFLD (p < 0.001). Canonical pathway analysis in the NAFLD-associated gene clusters showed that the hepatic fibrosis signaling was the most significant pathway in the up-regulated NAFLD gene cluster containing three (COL1A1, IL10, IGFBP3) significantly altered genes, whereas the endoplasmic reticulum stress and protein ubiquitination pathways were the most significant pathways in the down-regulated NAFLD gene cluster, with the first pathway containing one (HSPA5) and the second containing two (HSPA5, USP25) significantly altered genes. The four primary gene networks associated with NAFLD were involved in cell death, immunological disease, cellular movement, and lipid metabolism with several significantly altered "hub" genes in these networks. CONCLUSIONS: This study reveals the canonical pathways and gene networks associated with NAFLD in morbidly obese Caucasians. The application of gene network analysis highlights the transcriptional relationships among NAFLD-associated genes and allows identification of hub genes that may represent high-priority candidates for NAFLD.

Surgical treatment for obesity: ensuring success.

In the United States, obesity has reached epidemic proportions. Serious medical complications, impaired quality of life, and premature mortality are all associated with obesity. Medical conditions such as type 2 diabetes mellitus, hypertension, hyperlipidemia, or sleep apnea can improve or be cured with weight loss. Medical treatment programs focused on diet, behavior modification, and/or pharmacologic intervention have met with limited long-term success. Although surgical treatments for obesity have become popular in recent years, they should only be used as a last resort for weight loss. Not all patients can be considered appropriate candidates for surgery; therefore, guidelines based on criteria from the National Institutes of Health should be used preoperatively to help identify suitable persons. Most individuals who opt for weight-loss surgery have usually struggled for many years with losing weight and keeping it off, but surgery alone will not ensure successful weight loss. Patient education is imperative for long-term success. Moreover, any such educational regimen should include information on diet, vitamin and mineral supplementation, and lifestyle changes, as well as expected weight-loss results and improvements in comorbid conditions. Patients must be willing to commit to a long-term follow-up program intended to promote successful weight loss and weight maintenance and to prevent metabolic and nutritional complications.