Amir Mehran

University of California, Los Angeles, Los Angeles, CA, United States

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Publications (36)92.5 Total impact

  • The American surgeon 02/2013; 79(2):61-2. · 0.92 Impact Factor
  • The American surgeon 05/2012; 78(5):613-4. · 0.92 Impact Factor
  • The American surgeon 05/2012; 78(5):E278-9. · 0.92 Impact Factor
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    ABSTRACT: Obesity affects 32% of adults in the USA. Surgery generates substantial weight loss, but 20-30% fails to achieve successful weight loss. Our objective was to identify preoperative psychosocial factors associated with weight loss following bariatric surgery. We performed a literature search of PubMed® and the Cochrane Database of Reviews of Effectiveness between 1988 and April 2010. Articles were screened for bariatric surgery and weight loss if they included a preoperative predictor of weight loss: body mass index (BMI), preoperative weight loss, eating disorders, or psychiatric disorder/substance abuse. One thousand seven titles were reviewed, 534 articles screened, and 115 included in the review. Factors that may be positively associated with weight loss after surgery include mandatory preoperative weight loss (7 of 14 studies with positive association). Factors that may be negatively associated with weight loss include preoperative BMI (37 out of 62 studies with negative association), super-obesity (24 out of 33 studies), and personality disorders (7 out of 14 studies). Meta-analysis revealed a decrease of 10.1% excess weight loss (EWL) for super-obese patients (95% confidence interval (CI) [3.7-16.5%]), though there was significant heterogeneity in the meta-analysis, and an increase of 5.9% EWL for patients with binge eating at 12 months after surgery (95% CI [1.9-9.8%]). Further studies are necessary to investigate whether preoperative factors can predict a clinically meaningful difference in weight loss after bariatric surgery. The identification of predictive factors may improve patient selection and help develop interventions targeting specific needs of patients.
    Obesity Surgery 08/2011; 22(1):70-89. · 3.10 Impact Factor
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    ABSTRACT: Background Patients undergoing gastric bypass lose substantial weight, but 20% regain weight starting at 2 years after surgery. Our objective was to identify behavioral predictors of weight regain after laparoscopic Roux-en-Y gastric bypass (LRYGB). Methods We retrospectively surveyed 197 patients for factors predictive of weight regain (≥15% from lowest weight to weight at survey completion). Consecutive patients who had bariatric surgery from 1/2003 through 12/2008 were identified from an existing database. Response rate was 76%, with 150 patients completing the survey. Results Follow-up after LRYGB was 45.0 ± 12.7 months, 22% of patients had weight regain. After controlling for age, gender, and follow-up time, factors associated with weight regain included low physical activity (odds ratio (OR) 6.92, P = 0.010), low self-esteem (OR 6.86, P = 0.008), and Eating Inventory Disinhibition (OR 1.30, P = 0.029). Conclusions Physical activity, self-esteem, and maladaptive eating may be associated with weight regain after LRYGB. These factors should be addressed in prospective studies of weight loss following bariatric surgery, as they may identify patients at risk for weight regain who may benefit from tailored interventions.
    Obesity Research & Clinical Practice 01/2011; 5(3). · 0.51 Impact Factor
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    ABSTRACT: Patients undergoing bariatric surgery lose substantial weight (> or = 50% excess weight loss [EWL]), but an estimated 20 per cent fail to achieve this goal. Our objective was to identify behavioral predictors of weight loss after laparoscopic Roux-en-Y gastric bypass. We retrospectively surveyed 148 patients using validated instruments for factors predictive of weight loss. Success was defined as > or =50 per cent EWL and failure as <50 per cent EWL. Mean follow-up after laparoscopic Roux-en-Y gastric bypass was 40.1 +/- 15.3 months, with 52.7 per cent of patients achieving successful weight loss. After controlling for age, gender, and preoperative body mass index, predictors of successful weight loss included surgeon follow-up (odds ratio [OR] 8.2, P < 0.01), attendance of postoperative support groups (OR 3.7, P = 0.02), physical activity (OR 3.5, P < 0.01), single or divorced marital status (OR 3.2, P = 0.03), self-esteem (OR 0.3, P = 0.02), and binge eating (OR 0.9, P < 0.01). These factors should be addressed in prospective studies of weight loss after bariatric surgery, as they may identify patients at risk for weight loss failure who may benefit from early tailored interventions.
    The American surgeon 10/2010; 76(10):1139-42. · 0.92 Impact Factor
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    ABSTRACT: The contribution of physical activity on the degree of weight loss following bariatric surgery is unclear. To determine impact of exercise on postoperative weight loss. Medline search (1988-2009) was completed using MeSH terms including bariatric procedures and a spectrum of patient factors with potential relationship to weight loss outcomes. Of the 934 screened articles, 14 reported on exercise and weight loss outcomes. The most commonly used instruments to measure activity level were the Baecke Physical Activity Questionnaire, the International Physical Activity Questionnaire, and a variety of self-made questionnaires. The definition of an active patient varied but generally required a minimum of 30 min of exercise at least 3 days per week. Thirteen articles reported on exercise and degree of postoperative weight loss (n = 4,108 patients). Eleven articles found a positive association of exercise on postoperative weight loss, and two did not. Meta-analysis of three studies revealed a significant increase in 1-year postoperative weight loss (mean difference = 4.2% total body mass index (BMI) loss, 95% confidence interval (CI; 0.26-8.11)) for patients who exercise postoperatively. Exercise following bariatric surgery appears to be associated with a greater weight loss of over 4% of BMI. While a causal relationship cannot be established with observational data, this finding supports the continued efforts to encourage and support patients' involvement in post-surgery exercise. Further research is necessary to determine the recommended activity guidelines for this patient population.
    Obesity Surgery 02/2010; 20(5):657-65. · 3.10 Impact Factor
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    ABSTRACT: Social support may be associated with increased weight loss after bariatric surgery. The objective of this article is to determine impact of post-operative support groups and other forms of social support on weight loss after bariatric surgery. MEDLINE search (1988-2009) was completed using MeSH terms including bariatric procedures and a spectrum of patient factors with potential relationship to weight loss outcomes. Of the 934 screened studies, 10 reported on social support and weight loss outcomes. Five studies reported on support groups and five studies reported on other forms of social support (such as perceived family support or number of confidants) and degree of post-operative weight loss (total n = 735 patients). All studies found a positive association between post-operative support groups and weight loss. One study found a positive association between marital status (being single) and weight loss, while three studies found a non-significant positive trend and one study was inconclusive. Support group attendance after bariatric surgery is associated with greater post-operative weight loss. Further research is necessary to determine the impact of other forms of social support. These factors should be addressed in prospective studies of weight loss following bariatric surgery, as they may represent ways to improve post-operative outcomes.
    Obesity Reviews 02/2010; 12(2):142-8. · 6.87 Impact Factor
  • Surgery for Obesity and Related Diseases 01/2010; 6(5):557-8. · 4.12 Impact Factor
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    Amir Mehran
    Obesity Surgery 10/2009; · 3.10 Impact Factor
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    ABSTRACT: Laparoscopic sleeve gastrectomy (LSG) as a single-stage restrictive bariatric procedure is becoming increasingly popular, especially in patients who are high risk and/or superobese. Between November 21, 2006, and September 30, 2008, 42 patients underwent LSG at our institution. Average age was 47 +/- 11 years, average body mass index was 54 +/- 10 kg/m2, and 62 per cent were female. Preoperative indications for LSG included contraindication to laparoscopic Roux-en-Y gastric bypass (n = 11), severe coronary artery disease and/or congestive heart failure (n = 3), significant liver disease (n = 3), and patient preference (n = 4). Intraoperative indications for LSG included a foreshortened mesentery with inability to create a gastrojejunostomy (n = 13), extensive adhesions (n = 5), and intraoperative findings concerning for cirrhosis (n = 3). Twelve complications occurred in six patients: laparoscopic to open conversion (n = 1), reoperation (n = 3), nosocomial pneumonia (n = 1), wound infection (n = 1), bleeding (n = 1), pulmonary embolus (n = 1), readmission (n = 3), and superior splenic pole infarction. There was one death resulting from pulmonary embolism that occurred 2 weeks postoperatively. Preliminary excess body weight loss at 3, 6, 9, and 12 months was 29, 32 t, 38, and 30 per cent, respectively, and many patients had improvement or resolution of obesity-related comorbidities. Early review of our experience demonstrates that LSG may be an effective single-stage bariatric procedure. Additional follow up will be necessary to better define its long-term safety and efficacy.
    The American surgeon 10/2009; 75(10):945-9. · 0.92 Impact Factor
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    ABSTRACT: Preoperative weight loss before bariatric surgery has been proposed as a predictive factor for improved patient compliance and the degree of excess weight loss achieved after surgery. In the present study, we sought to determine the effect of preoperative weight loss on postoperative outcomes. A search of MEDLINE was completed to identify the patient factors associated with weight loss after bariatric surgery. Of the 909 screened reports, 15 had reported on preoperative weight loss and the degree of postoperative weight loss achieved. A meta-analysis was performed that compared the postoperative weight loss and perioperative outcomes in patients who had lost weight preoperatively compared to those who had not. Of the 15 articles (n = 3404 patients) identified, 5 found a positive effect of preoperative weight loss on postoperative weight loss, 2 found a positive short-term effect that was not sustained long term, 5 did not find an effect difference, and 1 found a negative effect. A meta-analysis revealed a significant increase in the 1-year postoperative weight loss (mean difference of 5% EWL, 95% confidence interval 2.68-7.32) for patients who had lost weight preoperatively. A meta-analysis of other outcomes revealed a decreased operative time for patients who had lost weight preoperatively (mean difference 23.3 minutes, 95% confidence interval 13.8-32.8). Preoperative weight loss before bariatric surgery appears to be associated with greater weight loss postoperatively and might help to identify patients who would have better compliance after surgery.
    Surgery for Obesity and Related Diseases 09/2009; 5(6):713-21. · 4.12 Impact Factor
  • Surgery for Obesity and Related Diseases 04/2009; 5(5):626-9. · 4.12 Impact Factor
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    Amir Mehran
    Obesity Surgery 01/2009; · 3.10 Impact Factor
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    ABSTRACT: To review our experience with early jejunojejunostomy obstruction (JJO) at a large academic teaching hospital and provide a management algorithm. Early JJO is a known and often overlooked complication of laparoscopic Roux-en-Y gastric bypass. From 2003 to 2007, 1097 patients underwent laparoscopic Roux-en-Y gastric bypass at our institution. Data, including patient demographics, co-morbidities, intraoperative data, peri- and postoperative complications, and outcomes, were prospectively recorded and retrospectively reviewed. Early post-laparoscopic Roux-en-Y gastric bypass JJO occurred in 13 patients (1.2%). The average time to presentation was 15 days (range 5-27). Patients presented with a combination of nausea, vomiting, and abdominal pain; all underwent computed tomography to confirm the diagnosis. The causes of JJO included dietary noncompliance (46%), anastomotic edema (23%), narrowing of the jejunojejunostomy at surgery (23%), and luminal clot (8%). Management was determined using our proposed treatment algorithm. Three patients (23%) required operative intervention, with the remainder successfully treated conservatively. From our experience, we propose a treatment algorithm for standardized management of early JJO, reserving reoperation for those who are acutely ill on presentation or those in whom conservative management fails. A review of our series using this algorithm has suggested that most patients can be successfully treated nonoperatively; however, bariatric surgeons must maintain a low threshold for surgical re-intervention in cases in which rapid recovery is not seen.
    Surgery for Obesity and Related Diseases 12/2008; 5(2):203-7. · 4.12 Impact Factor
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    ABSTRACT: Succinylcholine is a paralytic agent regularly utilized in anesthesia. There are numerous adverse effects of succinylcholine ranging from mild to fatal; one such effect is succinylcholine myalgia. We report the case of a 34-year-old woman who received succinylcholine while undergoing laparoscopic Roux-en-Y gastric bypass and later developed succinylcholine myalgia leading to a prolonged hospital stay and subsequent pneumonia. In the presence of suitable alternative paralytic agents, succinylcholine should be avoided in patients undergoing bariatric surgery. The use of a designated anesthesia team familiar with bariatric operations can help maximize peri-operative management and minimize complications.
    Obesity Surgery 11/2008; 19(4):534-6. · 3.10 Impact Factor
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    ABSTRACT: Bariatric surgery is an effective and durable treatment for morbid obesity in properly selected patients. Surgical outcomes and patient management methods should routinely be reviewed to improve patient care and maintain long-term effectiveness of the bariatric operation. Over a 5-year period, 1096 laparoscopic Roux-en-Y gastric bypass operations were performed at our institution. A comprehensive prospective database was maintained, which included data for comorbidities, operative techniques, perioperative management, complications, and follow up. Many practice patterns such as the omission of routine preoperative sleep apnea testing and biliary ultrasounds remained constant and were validated by the outcomes measured. Several changes, however, were implemented based on outcomes analyses, including antecolic placement of the roux limb, a pars flaccida approach to the creation of the gastric pouch, longer alimentary limbs in superobese patients, and a selective approach to postoperative upper gastrointestinal imaging. Postoperative weight regain and inability to maintain long-term follow up in a significant per cent of patients were two identified and ongoing problems. Maintenance of a bariatric patient database is essential with its routine review resulting in changes to practice patterns and operative techniques. An effective method for long-term patient follow up remains elusive and may contribute to postoperative weight regain in some patients.
    The American surgeon 11/2008; 74(10):962-6. · 0.92 Impact Factor
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    ABSTRACT: Many institutions routinely perform upper gastroesophageal imaging (UGI) studies on their laparoscopic Roux-en-Y gastric bypass (LRYGB) patients after surgery. We had routinely studied our patients with UGI on postoperative day 1 to rule out an anastomotic leak or obstruction, until recently when we abandoned this practice. As previously reported, we found that routine UGI did not contribute significantly to patient care. The purpose of this study was to determine whether patient outcomes were affected by this change in protocol. From March 2004 to September 2005, 508 LRYGB cases were performed at our institution. Linear cutting staplers were used to create both the gastrojejunostomy and the jejunojejunostomy. In each case, the Roux limb was brought up in an antecolic, antegastric configuration. Before changing our protocol, 194 LRYGB cases were performed, and each patient underwent a routine UGI study (group 1). After abandoning this practice, 314 LRYGB cases were performed (group 2), and an UGI study was obtained only if clinical indicators (e.g., tachypnea, tachycardia, nausea, vomiting, low urine output, and/or abdominal pain) were present. The patient demographics, including gender, age, body mass index, length of hospital stay, and complications were recorded in our bariatric database and reviewed retrospectively. A postoperative UGI study was obtained in 204 patients--in 194 patients routinely (group 1) and in 10 patients because of clinical indications (group 2). No obstructions or leaks were found in any of these 204 patients. In group 2, 304 patients were discharged without an UGI series and did well without any leak or obstruction, except for 1 patient who returned 3 months postoperatively with a stricture at his jejunojejunostomy. No statistically significant differences were found between the 2 groups. The results of our study have shown that routine UGI studies after LRYGB do not contribute significantly to postoperative patient care at our institution. We now perform them selectively according to clinical indications, without this change adversely affecting our clinical outcomes.
    Surgery for Obesity and Related Diseases 01/2008; 4(2):122-5. · 4.12 Impact Factor
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    ABSTRACT: Obstructive sleep apnea (OSA) is prevalent in the morbidly obese population. The need for routine preoperative testing for OSA has been debated in bariatric surgery publications. Most investigators have advocated the use of continuous positive airway pressure (CPAP) or bi-level positive airway pressure (BiPAP) in the postoperative setting; however, others have reported pouch perforations or other gastrointestinal complications as a result of their use. From a review of our experience, we present an algorithm for the safe postoperative treatment of patients with OSA without the use of CPAP or BiPAP. From January 2003 to December 2007, 1095 laparoscopic Roux-en-Y gastric bypasses were performed at our institution. Preoperative testing for OSA was not routinely performed. A prospective database was maintained. The data included patient demographics, co-morbidities (including OSA and CPAP/BiPAP use), perioperative events, complications, and follow-up information. Patients with known OSA were not given CPAP/BiPAP after surgery. They were observed in a monitored setting during their inpatient stay, ensuring continuous oxygen saturation of >92%. All patients used patient-controlled analgesia, were trained in the use of incentive spirometry, and ambulated within a few hours of surgery. The outcomes were compared between the OSA patients using preoperative CPAP/BiPAP versus those with OSA without preoperative CPAP/BiPAP versus patients with no history of OSA. A total of 811 patients were included in the study group with no known history of OSA. Of the 284 patients with a confirmed diagnosis of OSA, 144 were CPAP/BiPAP dependent. Statistically significant differences were present in age distribution and gender, with men having greater CPAP/BiPAP dependency. No significant differences were found in body mass index, length of stay, pulmonary complications, or deaths. One pulmonary complication occurred in the OSA, CPAP/BiPAP-dependent group, three in the OSA, non-CPAP group, and six in the no-known OSA group. No anastomotic leaks or deaths occurred in the series. Postoperative CPAP/BiPAP can be safely omitted in laparoscopic Roux-en-Y gastric bypass patients with known OSA, provided they are observed in a monitored setting and their pulmonary status is optimized by aggressive incentive spirometry and early ambulation.
    Surgery for Obesity and Related Diseases 01/2008; 4(4):512-4. · 4.12 Impact Factor
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    ABSTRACT: Gastric erosion is a well-known complication of laparoscopic adjustable gastric band (LAGB) placement for morbid obesity. We describe a novel approach for the removal of an eroded band through a laparoscopic gastrotomy with subsequent intraluminal division and removal of the band. A 67-year-old woman with a body mass index of 35.5 kg/m2 was seen 1 year after LAGB placement performed outside the United States. She had developed dysphagia and regurgitation of undigested food a few months after the procedure. The LAGB had been adjusted twice by her primary surgeons and was completely deflated once her symptoms began. The patient failed to improve and was subsequently referred to our institution where an upper endoscopy revealed intragastric band erosion. The patient was taken to the operating room for LAGB removal; however, standard laparoscopic and endoscopic attempts at band retrieval were unsuccessful. We then attempted a novel laparoscopic technique. An anterior gastrotomy was created, distal to the area of erosion, to facilitate easy intraluminal band division and removal. The gastrotomy was repaired, and a leak test was performed. A postoperative Gastrografin upper gastrointestinal series showed no extravasation. The patient began a diet, was discharged, and was seen in follow-up with complete resolution of her symptoms. The results of this case have shown that laparoscopic transgastric removal of an eroded gastric band is safe and feasible when standard endoscopic and laparoscopic techniques fail.
    Surgery for Obesity and Related Diseases 01/2008; 4(2):194-7. · 4.12 Impact Factor

Publication Stats

382 Citations
92.50 Total Impact Points

Institutions

  • 2004–2013
    • University of California, Los Angeles
      • Department of Surgery
      Los Angeles, CA, United States
    • Bariatric Institute of Greater Chicago
      Hinsdale, Illinois, United States
  • 2005–2008
    • Harbor-UCLA Medical Center
      Torrance, California, United States
  • 2006
    • Children's Hospital Los Angeles
      Los Angeles, California, United States