Ahmed R Ahmed

Imperial College Healthcare NHS Trust, Londinium, England, United Kingdom

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Publications (36)166.55 Total impact

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    Obesity Surgery 08/2015; DOI:10.1007/s11695-015-1840-2 · 3.74 Impact Factor
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    ABSTRACT: Background Many studies quantitatively analyzing scientific papers have appeared in the last 2 years. Citation analysis is a commonly used bibliometric method. In spite of some limitations, it remains a good measure of the impact an article has on a specific field, specialty, or a journal. The aim of this study was to analyze the qualities and characteristics of the 100 most cited articles in the field of bariatric surgery. Methods The Thomson Reuters Web of Knowledge was used to list all bariatric surgery-related articles (BSRA) published from 1945 to 2014. The top 100 most cited BSRA in 354 surgical and high impact general journals were selected for further analysis. Results Most of the articles were published in the 2000s (60 %). The top 100 most cited were published in 17 of the 354 journals. Leading countries were USA followed by Canada and Australia. Most of the articles published (76 %) were clinical experience articles. The most common level of evidence was IV (42 %). Conclusions Many of the milestone papers in bariatric surgery have been included in this bibliometric study. A huge increase in research activity during the last decade is clearly visible in the field. It is apparent that the number of citations of an article is not related to its level of evidence; a fact that is increasingly being emphasized in surgical research
    Obesity Surgery 02/2015; 25(5):900-9. DOI:10.1007/s11695-014-1542-1 · 3.74 Impact Factor
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    ABSTRACT: The objective of the present study was to evaluate the cost-utility of bariatric surgery in a lifetime horizon from a Swedish health care payer perspective. A decision analytic model using the Markov process was developed covering cardiovascular diseases, type 2 diabetes, and surgical complications. Clinical effectiveness and safety were based on the literature and data from the Scandinavian Obesity Surgery Registry. Gastric bypass, sleeve gastrectomy, and gastric banding were included in the analysis. Cost data were obtained from Swedish sources. Bariatric surgery was cost saving in comparison with conservative management. It also led to a substantial reduction in lifetime risk of events: from a 16 % reduction in the risk of transient ischaemic attacks to a 62 % reduction in the incidence of type 2 diabetes. Over a lifetime, surgery led to savings of 8408 and generated an additional 0.8 years of life and 4.1 quality-adjusted life years (QALYs) per patient, which translates into gains of 32,390 quality-adjusted person-years and savings of 66 million for the cohort, operated in 2012. Analysis of the consequences of a 3-year delay in surgery provision showed that the overall lifetime cost of treatment may be increased in patients with diabetes or a body mass index >40 kg/m(2). Delays in surgery may also lead to a loss of clinical benefits: up to 0.6 life years and 1.2 QALYs per patient over a lifetime. Bariatric surgery, over a lifetime horizon, may lead to significant cost savings to health care systems in addition to the known clinical benefits.
    Obesity Surgery 02/2015; 25(7). DOI:10.1007/s11695-014-1567-5 · 3.74 Impact Factor
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    ABSTRACT: The use of inferior vena cava (IVC) filters for prevention of venous thromboembolism (VTE) in bariatric surgery is a contentious issue. We aim to review the evidence for the use of IVC filters in bariatric surgical patients, describe trends in practice, and discuss challenges in developing evidence-based guidelines. The incidence of VTE in modern bariatric procedures with traditional methods of thromboprophylaxis, such as sequential calf compression devices and perioperative low molecular weight heparin, is approximately 2%. A systematic review of the literature was conducted according to PRISMA guidelines. We searched Medline up until July 2013 with the terms "bariatric filter" and "gastric bypass filter." Two investigators independently screened search results according to an agreed list of eligibility criteria. Eighteen studies were included. There were no randomized controlled trials. Data from controlled cohort studies suggest that those who undergo IVC filter insertion preoperatively may be at higher risk of developing deep vein thrombosis (DVT) and pulmonary embolism (PE). A small cohort of patients with multiple risk factors for VTE benefitted from reduced PE-related mortality after preoperative IVC filter insertion. Data from 12 case series reporting VTE outcomes from a total of 497 patients who underwent preoperative IVC filter insertion demonstrated DVT rates of 0% to 20.8% and PE rates ranging from 0% to 6.4%. Published data reporting the safety and efficacy of IVC filter use in bariatric surgical patients is highly heterogeneous. There is no evidence to suggest that the potential benefits of IVC filters outweigh the significant risks of therapy.
    Annals of Surgery 01/2015; 261(1):35-45. DOI:10.1097/SLA.0000000000000621 · 8.33 Impact Factor
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    ABSTRACT: Purpose The objective of this study was to evaluate the current utilization, the level of endorsement by professional societies, and health technology assessment bodies, as well as the reimbursement levels for bariatric surgery in European countries. Materials and Methods We performed an analysis of the indications for bariatric surgery based on national clinical and commissioning guidelines, current utilization of surgery, characteristics of patients who underwent surgery, and reimbursement tariffs in Belgium, Denmark, England, France, Germany, Italy, and Sweden. Data were obtained from national patient registries, administrative databases, and published literature for the year 2012. Results Despite clear consensus outlined in clinical guidelines, significant differences were found in the eligibility criteria for surgery. Patients with no significant comorbidities were deemed eligible if they had a body mass index (BMI) of 40 or 50 kg/m2 in Denmark. Irrespective of the country, patients with comorbidities were eligible if they had a BMI of 35 kg/m2. The highest utilization of bariatric surgery (number of surgeries per 1 M population) was observed in Belgium (928), Sweden (761), and France (571) while Italy (128), England (117), and Germany (72) had the lowest utilization. There was a strong negative correlation between utilization and average BMI level of the patient population (r = −.909, p = 0.005). The annual per capita spending on surgery differed significantly between countries, ranging from €0.54 in Germany to €4.33 in Belgium. Conclusions There are significant variations in the clinical indications, utilization, and funding of bariatric surgery in European countries.
    Obesity Surgery 12/2014; DOI:10.1007/s11695-014-1537-y · 3.74 Impact Factor
  • Ahmed r Ahmed · Suhaib S Ahmad · Sami Ahmad
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    ABSTRACT: Introduction:Many studies quantitatively analyzing the academic literature have appeared in the last two years. These bibliometric studies provide the "bestsellers" for the reader. Citation analysis is a commonly used bibliometric method. In spite of the limitations, it remains a good way for measuring the impact an article has on a specific field, specialty or a journal. Objectives: Our aim of this study was to allocate citation classics and analyze the characteristics of scholarly work in the field of bariatric surgery. Methods: The Thomson Reuters Web of Knowledge was used to list all Bariatric Surgery Related Articles (BSRA) published from 1945-2013. The top 100 most cited BSRA in 354 surgical and general journals were selected for further analysis. Results: Most of the articles were published in the 2000`s ranging from 1963-2009. The top 100 most cited were published in 18 of the 354 journals. Leading countries were USA followed by Canada and Australia. Most of the articles published (77%) were clinical experience articles. The most common level of evidence was IV (42%). Conclusions: Most of the discoveries and milestones in Bariatric surgery research have been included in our bibliometric study. This could provide a source of great reference and value for young investigators and clinicians. Not surprisingly, newer papers, so called 'rising stars', have not made it into the list. It is also apparent that the number of citations of an article is not related to the level of evidence, this can be supported by the fact that many Level IV articles have made it into the list.
    IFSO; 08/2014
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    ABSTRACT: There is paucity of data on Enhanced Recovery After Bariatric Surgery (ERABS) protocols. This feasibility study reports outcomes of this protocol utilized within a tertiary-referral bariatric centre. Data on consecutive primary procedures (laparoscopic gastric bypasses, sleeve gastrectomies and gastric bands) performed over 9 months within an ERABS protocol were prospectively recorded. Interventions utilized included shortened preoperative fasts, intra-operative humidification, early mobilization and feeding, avoidance of fluid overload, incentive spirometry, use of prokinetics and laxatives. Data collected included demographics, co-morbidities, morbidity, mortality, length of stay (LOS) and re-admissions. A total of 226 procedures (age [mean ± SD], 45 ± 11 years, median [interquartile range] BMI 44.9 [41.0-49.0] kg/m(2)) were undertaken: 150 (66 %) bypasses, 47 (21 %) sleeves and 29 (13 %) bands. Hypertension, diabetes mellitus, sleep apnea and limited mobility were present in 40 %, 34 %, 24 % and 9 % of patients, respectively. No anastomotic or staple line leaks/bleeds were encountered. Ten (4.4 %) patients developed postoperative morbidity (mainly respiratory complications). One death occurred from massive pulmonary embolus in a high-risk patient (despite insertion of preoperative-IVC filter). Respective mean ± SD LOS for bypasses, sleeves and bands were 1.88 ± 1.12, 2.30 ± 1.69 and 0.69 ± 0.81 days. Successful discharge on the first postoperative day was achieved in 37 % and 28 % of bypasses and sleeves, respectively. Day-case gastric bands were performed in 48 %. Thirty-day hospital re-admission occurred in six (2.7 %) patients. Applying an ERABS protocol was feasible, safe, associated with low morbidity, acceptable LOS and low 30-day re-admission rates. The presence of multiple medical co-morbidities should not preclude use of an ERABS protocol within bariatric patients.
    Obesity Surgery 12/2013; 24(5). DOI:10.1007/s11695-013-1151-4 · 3.74 Impact Factor
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    ABSTRACT: Obesity is the new epidemic and is associated with an increased risk of diastolic and systolic heart failure. Effective treatment options with drastic results such as bariatric surgery have raised interest in the possible reversal of some of the cardiovascular sequelae. Many studies have assessed individually the effect of weight loss on specific echocardiographic indices, mostly employing nonhomogeneous groups. The purpose of this narrative review is to summarise the effect of bariatric surgery on echocardiographic indices of biventricular function and to help in the understanding of the expected echocardiographic changes in bariatric patients after weight-loss surgery.
    European Journal of Clinical Investigation 11/2013; 43(11):1224-1230. DOI:10.1111/eci.12162 · 2.83 Impact Factor
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    ABSTRACT: Roux-en-Y gastric bypass (RYGB) has greater efficacy for weight loss in obese patients than gastric banding (BAND) surgery. We hypothesise that this may result from different effects on food hedonics via physiological changes secondary to distinct gut anatomy manipulations. We used functional MRI, eating behaviour and hormonal phenotyping to compare body mass index (BMI)-matched unoperated controls and patients after RYGB and BAND surgery for obesity. Obese patients after RYGB had lower brain-hedonic responses to food than patients after BAND surgery. RYGB patients had lower activation than BAND patients in brain reward systems, particularly to high-calorie foods, including the orbitofrontal cortex, amygdala, caudate nucleus, nucleus accumbens and hippocampus. This was associated with lower palatability and appeal of high-calorie foods and healthier eating behaviour, including less fat intake, in RYGB compared with BAND patients and/or BMI-matched unoperated controls. These differences were not explicable by differences in hunger or psychological traits between the surgical groups, but anorexigenic plasma gut hormones (GLP-1 and PYY), plasma bile acids and symptoms of dumping syndrome were increased in RYGB patients. The identification of these differences in food hedonic responses as a result of altered gut anatomy/physiology provides a novel explanation for the more favourable long-term weight loss seen after RYGB than after BAND surgery, highlighting the importance of the gut-brain axis in the control of reward-based eating behaviour.
    Gut 08/2013; 63(6). DOI:10.1136/gutjnl-2013-305008 · 13.32 Impact Factor
  • 17th World Congress of International Federation for the Surgery of; 09/2012
  • 17th World Congress of International Federation for the Surgery of; 09/2012
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    ABSTRACT: Objective. To compare multimedia and standard consent, in respect to patient comprehension, anxiety, and satisfaction, for various surgical/interventional procedures. Data sources. Electronic searches of PubMed, MEDLINE, Ovid, Embase, and Google Scholar were performed. Relevant articles were assessed by 2 independent reviewers. Study selection. Comparative (randomized and nonrandomized control trials) studies of multimedia and standard consent for a variety of surgical/interventional procedures were included. Studies had to report on at least one of the outcome measures. Data extraction. Studies were reviewed by 2 independent investigators. The first investigator extracted all relevant data, and consensus of each extraction was performed by a second investigator to verify the data. Conclusion. Overall, this review suggests that the use of multimedia as an adjunct to conventional consent appears to improve patient comprehension. Multimedia leads to high patient satisfaction in terms of feasibility, ease of use, and availability of information. There is no conclusive evidence demonstrating a significant reduction in preoperative anxiety.
    Surgical Innovation 05/2012; 20(1). DOI:10.1177/1553350612446352 · 1.34 Impact Factor
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    ABSTRACT: The reported remission of type 2 diabetes in patients undergoing Roux-en-Y gastric bypass has brought the role of the gut in glucose metabolism into focus. Our objective was to explore the differential effects on glucose homeostasis after oral versus gastrostomy glucose loading in patients with Roux-en-Y gastric bypass at an academic health science center. A comparative controlled investigation of oral versus gastrostomy glucose loading in 5 patients who had previously undergone gastric bypass and had a gastrostomy tube placed in the gastric remnant for feeding. A standard glucose load was administered either orally (day 1) or by the gastrostomy tube (day 2). The plasma levels of glucose, insulin, glucagon-like peptide 1 and peptide YY were measured before and after glucose loading. Exclusion of the proximal small bowel from glucose passage induced greater plasma insulin, glucagon-like peptide 1, and peptide YY responses compared with glucose loading by way of the gastrostomy tube (P <.05). Exclusion of glucose passage through the proximal small bowel results in enhanced insulin and gut hormone responses in patients after gastric bypass. The gut plays a central role in glucose metabolism and represents a target for future antidiabetes therapies.
    Surgery for Obesity and Related Diseases 03/2012; 8(4):371-4. DOI:10.1016/j.soard.2012.01.021 · 4.94 Impact Factor
  • Susannah M Wyles · Sherif Hakky · Ahmed R Ahmed
    Surgery for Obesity and Related Diseases 07/2011; 7(4):543-5. DOI:10.1016/j.soard.2011.05.002 · 4.94 Impact Factor
  • Andrew Currie · Andrew Chetwood · Ahmed R Ahmed
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    ABSTRACT: Obesity causes a significant healthcare burden and has been shown to be an important risk factor in the development of cardiovascular disease, type 2 diabetes, and increasingly chronic kidney disease. Bariatric surgery is the most effective treatment for obesity and has been shown to drastically improve both blood pressure and diabetic control. However, the interaction of bariatric surgery and renal function is less clear. This review focuses on the effect of bariatric surgery on renal function both in the acute situation, with respect to acute kidney injury, and also on changes in renal function parameters post-bariatric surgery weight loss. The interaction of obesity, bariatric surgery, and nephrolithiasis as a precipitant of acute kidney injury will also be considered. The role of bariatric surgery in pre- and post-renal transplant recipients is discussed as well as possible mechanisms underlying the improvement in renal function.
    Obesity Surgery 02/2011; 21(4):528-39. DOI:10.1007/s11695-011-0356-7 · 3.74 Impact Factor
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    ABSTRACT: Internal hernia (IH) and Roux limb compression (RC) are recognized complications after retrocolic laparoscopic Roux-en-Y gastric bypass for obesity. The aim of the present study was to systematically identify the surgical technical errors leading to these complications. An observational clinical human reliability assessment approach was used to analyze the operating videos of 3 groups: an IH group (n = 12), a Roux compression group (n = 13), and a control group (no complications, n = 21). Two investigators, unaware of the outcomes, reviewed all videos, using special rating software. All errors were categorized using the external error mode system and further described if a direct consequential error (e.g., bleeding) was found. An analysis of data showed that, on average, more errors occurred in the complication groups than in the control group (IH 5.85, Roux compression 3.54, control .90, P < .001). The strongest differences were found for missing intermesenteric stitches on both sides of the Roux limb. Logistic regression analysis showed that a missed stitch between the mesentery of the Roux limb and the transverse mesocolon was an independent predictor for IH (B = 1.727, P = .025). No technical or consequential errors could be identified as responsible for RC. The observational clinical human reliability analysis is a useful method to identify operative failure. For retrocolic, retrogastric laparoscopic Roux-en-Y gastric bypass, a systematic approach for the closure of the transverse mesenteric window might prevent IH complications.
    Surgery for Obesity and Related Diseases 01/2011; 8(2):158-63. DOI:10.1016/j.soard.2010.12.009 · 4.94 Impact Factor
  • Gastroenterology 01/2011; 140(5). DOI:10.1016/S0016-5085(11)62559-6 · 13.93 Impact Factor
  • Susannah M Wyles · Sherif Hakky · Ahmed R Ahmed
    Surgery for Obesity and Related Diseases 11/2010; 6(6):718-20. DOI:10.1016/j.soard.2010.06.003 · 4.94 Impact Factor
  • Susannah Wyles · Sherif Hakky · Ahmed R. Ahmed
    15th World Congress of International Federation for the Surgery of; 08/2010
  • Susannah Wyles · Sherif Hakky · Ahmed R. Ahmed
    15th World Congress of International Federation for the Surgery of; 08/2010

Publication Stats

271 Citations
166.55 Total Impact Points

Institutions

  • 2010–2015
    • Imperial College Healthcare NHS Trust
      Londinium, England, United Kingdom
  • 2009–2015
    • Imperial College London
      • Section of Investigative Medicine
      Londinium, England, United Kingdom
  • 2007–2009
    • University Center Rochester
      Rochester, Minnesota, United States
  • 2006–2008
    • University of Rochester
      • Department of Surgery
      Rochester, New York, United States
  • 2006–2007
    • Highland Hospital
      Oakland, California, United States