T. Karl Byrne

Validation of the obesity surgery mortality risk score in a multicenter study proves it stratifies mortality risk in patients undergoing gastric bypass for morbid obesity.

Background:A scoring system for clinical assessment of mortality risk has been previously proposed for bariatric surgery (Demaria EJ, Portenier D, Wolfe L, Surg Obes Relat Dis. 2007;3:34–40.). The Obesity Surgery Mortality Risk Score (OS-MRS) was developed from a single institution experience of 2075 patients. The current study provides multicenter validation of the value of the OS-MRS. The OS-MRS assigns 1 point to each of 5 preoperative variables, including body mass index ≥50 kg/m2, male gender, hypertension, known risk factors for pulmonary embolism (previous thromboembolism, preoperative vena cava filter, hypoventilation, pulmonary hypertension), and age ≥45 years. Patients with total score of 0 to 1 are classified as ‘A’ (lowest) risk group, score 2 to 3 as ‘B’ (intermediate) risk group, and score 4 to 5 as ‘C’ (high) risk group. Methods:Prospectively-collected data from 4431 consecutive patients undergoing a primary gastric bypass at 4 bariatric programs recruited to validate the proposed system were analyzed to assess OS-MRS as a means of stratifying surgical mortality risk. Results:There were 33 total deaths for an overall mortality for the validation cohort of 0.7% consistent with published standards. Mortality for 2164 class A patients was 0.2%, for 2142 class B patients was 1.1%, and for 125 class C patients was 2.4%. Mortality was significantly different between each of the class A, B, and C groupings (P < 0.05, &khgr;2). Mortality was 5-fold greater in the class B group than in class A. Only 6 patients with all 5 risk factors were identified. Class C patients (n = 125, 3% of total cohort) were characterized by a 12-fold greater mortality than the lowest risk group (A) and a disproportionate 9% of all mortalities. Conclusion:The OS-MRS was found to stratify mortality risk in 4431 patients from 4 validation centers that were nonparticipants in the original defining cohort study. The score represents the first validated scoring system for risk stratification in bariatric surgery and is anticipated to aid informed consent discussions, guide surgical decision-making, and allow standardization of outcome comparisons between treatment centers.

Magnetic resonance imaging differentiates between necrotizing and non-necrotizing fasciitis of the lower extremity.

BACKGROUND Distinction between uncomplicated infective fasciitis and early necrotizing fasciitis can be extremely difficult without operation, yet the management and prognosis of both conditions depend greatly on early recognition and assessment of the extent of involvement. STUDY DESIGN This was a prospective review of the utility of magnetic resonance imaging (MRI) in nine patients with suspected infective or necrotizing fasciitis treated at an academic medical center or a Veterans Administration hospital. RESULTS Magnetic resonance imaging documented fascial inflammation, characterized by low intensity on T1-weighted images and high intensity on T2-weighted images, in all nine patients. Absence of gadolinium contrast enhancement on T1-weighted images reliably detected fascial necrosis in all six patients who required operative debridement. Magnetic resonance imaging was extremely useful in defining the extent of fasciitis and was more accurate in predicting necrosis or pyomyositis than was myoglobinuria or elevation of serum creatine kinase or lactate dehydrogenase. Operation was avoided in two patients without evidence of necrosis on MRI. One patient without evidence of necrosis, explored because of contradictory clinical findings, was confirmed at operation to have cellulitis without necrosis. CONCLUSIONS Magnetic resonance imaging with gadolinium contrast accurately determines the presence of necrosis and the need for operation in patients with fasciitis of the lower extremity. Preoperative determination of the extent of involvement facilitates operative planning.

Predictors of Endoscopic Findings After Roux-en-Y Gastric Bypass

OBJECTIVES:To evaluate predictors of endoscopic findings in symptomatic patients after Roux-en-Y gastric bypass (RYGBP) for obesity.METHODS:A retrospective chart review of 1,001 RYGBP procedures was performed. Two hundred twenty-six (23%) patients were identified as having endoscopy to evaluate upper gastrointestinal symptoms following surgery. Polychotomous logistic regression analysis was used to assess predictors of normal endoscopy, marginal ulcers, stomal stenosis, and staple-line dehiscence.RESULTS:The most common endoscopic findings were 99 (44%) normal postsurgical anatomy, 81 (36%) marginal ulcer, 29 (13%) stomal stenosis, and 8 (4%) staple-line dehiscence. Factors that significantly increase the risk of marginal ulcers following surgery include smoking (AOR = 30.6, 95% CI 6.4–146) and NSAID use (AOR = 11.5, 95% CI 4.8–28). PPI therapy following surgery was protective against marginal ulcers (AOR = 0.33, 95% CI 0.11–0.97). Median time for diagnosis of marginal ulcers following surgery was 2 months, and 77 of 81 (95%) presented within 12 months.CONCLUSIONS:Following RYGBP surgery for obesity, smoking and NSAID use significantly increase the risk of marginal ulceration, and PPI therapy is protective. Because a significant majority of marginal ulcers present within 12 months of surgery, it may be reasonable to consider prophylactic PPI therapy during this time period, especially for high risk patients.

Postoperative left prefrontal repetitive transcranial magnetic stimulation reduces patient-controlled analgesia use.

Background:Several recent studies suggest that repetitive transcranial magnetic stimulation can temporarily reduce pain perception in neuropathic pain patients and in healthy adults using laboratory pain models. No studies have investigated the effects of prefrontal cortex stimulation using transcranial magnetic stimulation on postoperative pain. Methods:Twenty gastric bypass surgery patients were randomly assigned to receive 20 min of either active or sham left prefrontal repetitive transcranial magnetic stimulation immediately after surgery. Patient-controlled analgesia pump use was tracked, and patients also rated pain and mood twice per day using visual analog scales. Results:Groups were similar at baseline in terms of body mass index, age, mood ratings, pain ratings, surgery duration, time under anesthesia, and surgical anesthesia methods. Significant effects were observed for surgery type (open vs. laparoscopic) and condition (active vs. sham transcranial magnetic stimulation) on the cumulative amount of patient-delivered morphine during the 44 h after surgery. Active prefrontal repetitive transcranial magnetic stimulation was associated with a 40% reduction in total morphine use compared with sham during the 44 h after surgery. The effect seemed to be most prominent during the first 24 h after cortical stimulation delivery. No effects were observed for repetitive transcranial magnetic stimulation on mood ratings. Conclusions:A single session of postoperative prefrontal repetitive transcranial magnetic stimulation was associated with a reduction in patient-controlled analgesia pump use in gastric bypass surgery patients. This is important because the risks associated with postoperative morphine use are high, especially among obese patients who frequently have obstructive sleep apnea, right ventricular dysfunction, and pulmonary hypertension. These preliminary findings suggest a potential new noninvasive method for managing postoperative morphine use.

A pilot study evaluating the efficacy of a fully acetylated poly-N-acetyl glucosamine membrane formulation as a topical hemostatic agent ☆ ☆☆

BACKGROUND Topical hemostatic agents are frequently needed for control of intraoperative bleeding. Currently available topical products each have potential drawbacks, making a more effective topical hemostatic agent desirable. This study was performed to evaluate the effectiveness of a particular formulation of a newly available polysaccharide polymer, poly-N-acetyl glucosamine (p-GlcNAc), as a topical hemostatic agent for use in the operating room. Swine splenic incision and splenic capsular stripping hemorrhage models were initially used, with a subsequent pilot human study then performed. METHODS For the swine splenic incision model, anesthetized immature female Yorkshire white swine had a 3 x 8 mm incision created on the spleen. One of 3 agents (p-GlcNAc membrane, oxidized cellulose, or absorbable collagen) was sequentially applied to individual wounds and digitally compressed for 20 seconds. The wound was observed without pressure for 2 minutes. Up to 8 wounds per animal were created in 7 animals. For the swine splenic capsular stripping model a 2 x 2 cm area of capsular stripping on the surface of the spleen to a depth of 3 mm was created. Either p-GlcNAc membrane or oxidized cellulose was applied and digitally compressed for 60 seconds, followed by observation without pressure for 2 minutes. Six wounds per animal were created in 2 animals. If bleeding persisted in either model, a new cycle of compression was applied. These steps were repeated until hemostasis was achieved. No change in hemodynamics or coagulation factors was observed in either model. Subsequently, 10 consecutive patients undergoing elective small-bowel surgery were enrolled on pilot study. A 5 x 3 x 3 mm cruciate incision was created midway between the mesenteric and antimesenteric borders of the small bowel. Either p-GlcNAc membrane formulation or oxidized cellulose was applied (the sequence alternated per patient) with a 400-mg weight used for even, direct pressure. A second cruciate incision was then created on the contralateral side of the bowel to evaluate the second material. The number of applications required for hemostasis was assessed. Hemodynamics, small-bowel pathologic condition, and hematologic parameters were evaluated. RESULTS The p-GlcNAc membrane required fewer cycles of compression in the swine splenic incision model to achieve hemostasis than either absorbable collagen or oxidized cellulose (1.25 vs 2.58 and 3.41, respectively; P < .01) and caused more effective immediate cessation of bleeding (79% for p-GlcNAc vs 17% for both absorbable collagen and oxidized cellulose). With the more traumatic splenic capsular stripping model, p-GlcNAc required fewer cycles of compression to achieve hemostasis than oxidized cellulose (average, 2.5 versus 6.8 respectively; P < .01) and was able to achieve hemostasis with greater efficacy (50%) in 2 applications than did oxidized cellulose (0%; P < .01). When used in the human pilot study, p-GlcNAc membranes required fewer cycles of compression than oxidized cellulose (2.5 vs 5.4, respectively; P < .002), was able to stop bleeding with greater efficacy in 1 cycle of compression (50% vs 0%, respectively; P < .01), and ultimately accomplished hemostasis in 80% of the cases as opposed to 20%. CONCLUSIONS On the basis of its greater hemostatic efficacy as compared with collagen or oxidized cellulose-based products, p-GlcNAc holds promise as an effective topical hemostatic agent and deserves further evaluation.

Placement of Inferior Vena Cava Filters in Bariatric Surgical Patients – Possible Indications and Technical Considerations

Background: Surgical treatment of the morbidly obese has assumed an increasingly important role in both the academic and community setting, while postoperative pulmonary embolism remains a devastating complication. Since the overall incidence remains low, the role for vena cava filter placement in this group is not yet well defined. In addition, the technical challenges and techniques for insertion have not been well-described. We present our experience with filter placment among patients with gastric bypass and the evolution of technique to facilitate safe placement in this group. Methods: From 1995 to August 2003, 586 patients underwent gastric bypass for morbid obesity. Review of registries and records from this period was accomplished to identify patients at MUSC who underwent both the gastric bypass and placement of an inferior vena cava filter. 12 patients were identified by this method. Results: Technical challenges with venous access and imaging are described. 6 patients were identified as potential high risk for thromboembolic complications and had a filter placed preoperatively with a mean postoperative stay of 5.3 days. The 6 patients who required filter placement in the postoperative period as part of the management of postoperative complications had a mean hospital stay of 24.5 days. There were no long-term complications associated with filter placement at a mean follow-up interval of 19 months. Conclusion: Inferior vena cava filter placement is not only feasible and safe for the morbidly obese individual undergoing gastric bypass, but should be strongly considered for patients with risk factors for thromboembolic complications or who experience postoperative complications requiring ICU stay or prolonged immobility.

Executive control circuitry differentiates degree of success in weight loss following gastric‐bypass surgery

While overall success rates of bariatric surgery are high, approximately 20% of patients either regain or never lose the expected amount of weight. The purpose of this study was to determine whether, after gastric‐bypass surgery, the degree of weight loss can be differentiated based on the neural response to food cues.

Preoperative hemoglobin A1c and postoperative glucose control in outcomes after gastric bypass for obesity

BACKGROUND Hemoglobin A1c (HbA1c) is a reliable marker for long-term glycemic control in obese diabetic patients. Roux-en-Y gastric bypass improves HbA1c levels over time. However, it is not clear whether the preoperative HbA1c level is a predictor of the outcome in these patients. Our objectives were to understand the predictive capacity of the preoperative HbA1c level in gastric bypass patients at a single university-based Bariatric Center of Excellence. METHODS We performed a retrospective review of 468 charts from 2006 to 2009 of patients who had undergone Roux-en-Y gastric bypass. Using their preoperative HbA1c status, the patients were categorized and the postoperative outcomes compared. RESULTS Of the 468 patients reviewed, 310 (66.2%) had a HbA1c of <6.5% (group 1), 92 (19.4%) had a HbA1c of 6.5-7.9% (group 2), and 66 (14.1%) had a HbA1c level of >8.0% (group 3). No difference was found among the 3 groups in baseline body mass index, race, procedure type, length of stay, hospital cost, and smoking status. Groups 2 and 3 were associated with older age, male gender, and higher baseline creatinine. Groups 2 and 3 also had a proportionally greater inpatient postoperative blood glucose level. An elevated postoperative glucose level was independently associated with wound infection (P = .008) and acute renal failure (P = .04). Also, group 3 experienced worse outcomes, including less weight loss at 18 months and fewer diabetic remissions. Over time, however, the vast majority in all groups achieved excellent chronic glycemic control, with HbA1c <6.5% after Roux-en-Y gastric bypass. CONCLUSION Poor preoperative glycemic control is associated with worse glucose level control postoperatively, fewer diabetic remissions, and less weight loss. An elevated mean postoperative glucose level is independently associated with increased morbidity.

Gastrointestinal bleeding after gastric bypass surgery: nuisance or catastrophe?

BACKGROUND Bleeding in the early postoperative period after gastric bypass surgery is a rare complication reported in 1-4% of cases. In most cases, the bleeding will be self-limited, resolving after discontinuation of anticoagulation for deep venous thrombosis prophylaxis. Occasionally, however, bleeding can be problematic, resulting in significant postoperative morbidity or even mortality. The purpose of the present study was to review cases of early postoperative gastrointestinal bleeding after gastric bypass to identify possible risk factors and examine outcomes. METHODS A prospective weight loss surgery patient database was reviewed to examine the cases occurring from January 2005 to July 2008. Patients with early postoperative bleeding were identified. The demographics and co-morbidities were compared between those with and without postoperative bleeding. The outcomes of interest included the transfusion requirement, postoperative morbidity, need for reoperation, length of hospital stay, intensive care unit admission, and 30-day mortality. RESULTS A total of 776 patients had undergone gastric bypass during the study period. Of these, 26 (3.3%) were identified with early postoperative bleeding. No significant differences were found in the demographics between the patients with early postoperative bleed and those without. Of the patients with early postoperative bleeding, the most common presenting sign or symptom was tachycardia (46%) followed by melena (32%) and hematemesis (18%). The transfusion requirement range was 0-11 U (average 3.2 U/patient). Of the 26 patients, 4 (15%) required intensive care unit admission and 8 (31%) required reoperation. Four gastrointestinal leaks, one stomal ulceration, and one gastrogastric fistula were identified in the early postoperative bleeding group. One patient (3.8%) in the early postoperative bleeding group died. Compared with nonbleeding patients, those with early postoperative bleeding had a significantly longer hospital stay (4.8 versus 3, P <.0001) and greater mortality rate (7.1% versus .9%, P <.01). CONCLUSION Postoperative bleeding is a significant complication after gastric bypass surgery. Although in many cases, the bleeding will be self-limited, it can result in additional notable complications. In the present study, postoperative bleeding contributed to significantly longer hospital stays and resulted in 1 death. A patient with bleeding after gastric bypass should raise due concern, with attention to the potential attendant complications.

Emotional eating, marital status and history of physical abuse predict 2-year weight loss in weight loss surgery patients.

BACKGROUND Weight loss surgery (WLS) is an effective weight loss treatment for individuals with severe obesity. Psychosocial factors can affect short-term WLS outcomes. This study sought to identify psychosocial predictors of medium-term outcomes. METHODS In this prospective study, 250 consecutive WLS candidates were evaluated between January 1, 2010 and December 31, 2010. Each completed baseline medical, surgical, and psychological evaluations as part of standard of care. Two hundred and four patients had surgery (81.6%). Successful surgical outcome was defined as ≥50% excess weight loss two years post-surgery. RESULTS Comparison of study sample (n=80) and those lost to follow-up (n=124) revealed negligible differences across baseline characteristics. At follow-up, 60% (n=48) of the sample was classified as a success with an average of 72.58% (std dev=13.01%) excess weight lost. The remaining 40% (n=32) was classified as a failure with an average of 33.98% (std dev=13.19%) excess weight lost. Logistic regression revealed that pre-surgical marital status, emotional eating, and history of physical abuse were independently associated with outcome variables, p<0.05. CONCLUSIONS Being married, perhaps as a proxy for social support, is associated with 6.9 times increased odds of medium-term WLS success and emotionally driven disordered eating patterns are associated with 7.4 times increased odds of medium-term WLS success. A history of physical abuse is associated with an 84% decreased odds of successful medium-term outcomes. Further research that studies both the quality and impact of spousal support on weight loss as well as longer-term effects of emotional eating on outcomes is needed. Addressing longer-standing consequence of abuse may improve WLS outcomes.