A multidisciplinary approach to bariatric surgery

Sobering predictions have been included in recent publications analyzing contemporary and historical trends in the worldwide prevalence of obesity. Manpreet S. Mundi, M.D., of the Division of Endocrinology, Diabetes, Metabolism & Nutrition at Mayo Clinic in Rochester, Minn., says: "Currently, the overall prevalence of obesity, defined as a body mass index (BMI) ≥ 30 kg/m2, in the U.S. is 33 percent. It is expected to rise to approximately 50 percent over the next 20 years.

"What is particularly concerning for the U.S. health care industry is that individuals with a BMI ≥ 40 kg/m2 (Class III obesity) are the most rapidly growing subset in the obese population. In fact, we have recently seen a 50 percent increase in individuals with a BMI > 40 kg/m2 and a 75 percent increase in the prevalence of individuals with a BMI > 50 kg/m2."

Dr. Mundi continues: "The devastating impact of obesity's rising prevalence is imminent, in terms of both our citizenry's health and the financial well-being of our health care industry. Major studies performed over the past few decades have found a clear correlation between obesity and the development of chronic metabolic conditions, such as type 2 diabetes mellitus, hypertension and hyperlipidemia.

"We are also obtaining data regarding structural changes to the heart itself. Novel imaging techniques, such as cardiac magnetic resonance imaging, have demonstrated a direct correlation between left ventricular (LV) mass and BMI and fat mass. A recent study revealed that the LV mass doubles at a BMI of 50 kg/m2 compared with a BMI of 20 kg/m2.

"Other studies have also shown associations between obesity and dementia (including Alzheimer's disease), obstructive sleep apnea, osteoarthritis and overall mortality rate. In fact, we may be seeing the first generation of individuals with a lower life expectancy than their parents."

Maria L. Collazo-Clavell, M.D., of the Division of Endocrinology, Diabetes, Metabolism & Nutrition at Mayo Clinic in Rochester, notes: "Despite aggressive research efforts, a novel weight management drug without notable adverse effects is not on the horizon. On the contrary, recent data have forced the Food and Drug Administration to remove from the market many long-standing weight management agents, such as sibutramine, because of their adverse-effect profile.

"Bariatric surgery continues to be the most effective means of long-term weight management in persons with medically complicated obesity, producing a resolution or improvement in many debilitating and life-threatening medical problems, as well as substantially improving quality of life. Not surprisingly, the number of bariatric procedures performed yearly has dramatically increased over the past decade. As of 2011, approximately 225,000 bariatric operations are performed annually in the United States, a nearly 500 percent increase since 2000."

Several operative procedures, including gastric banding (lap band), sleeve gastrectomy, Roux-en-Y gastric bypass and duodenal switch (also referred to as biliopancreatic diversion with duodenal switch), are offered at Mayo Clinic. The Roux-en-Y gastric bypass is the most common (approximately 74 percent of all cases).

Dr. Mundi explains: "Given its lackluster long-term performance, the laparoscopic gastric band procedure has been performed with decreased frequency at Mayo Clinic. A different type of restrictive procedure, the sleeve gastrectomy, has taken its place. This operation continues its historical role as the first part of the duodenal switch; however, in recent years, it has emerged as a stand-alone procedure.

"Sleeve gastrectomy has become the procedure of choice for the management of medically complicated obesity in patients with liver disease. In conjunction with our liver transplant service, we are studying the clinical outcomes of sleeve gastrectomies performed at various stages of liver failure. Long-term outcome data for the sleeve gastrectomy are lacking. Yet, early results show considerable promise in terms of weight loss and improvement or remission of weight-related comorbidities."

Paul A. Lorentz, R.N., of the Division of Endocrinology, Diabetes, Metabolism & Nutrition at Mayo Clinic in Rochester, comments: "Despite the overwhelming benefits to our patients, bariatric surgery is not without complications. As such, pre-surgical patient selection and post-surgical follow-up are critically important.

"To provide optimum patient care, we have implemented an integrated, multidisciplinary approach to each patient seeking bariatric surgery. On referral, the patient begins a journey toward surgery by meeting with an endocrinologist specializing in nutrition, a psychologist specializing in behavior modification and a registered dietitian. A patient-specific, comprehensive medical weight management plan, centered on cognitive behavioral therapy, is then developed. When our behavior modification program is successfully completed, which on average takes three months, the patient is scheduled to meet with a surgeon to discuss which surgery may be best for him or her."

Mr. Lorentz explains further: "Our multidisciplinary approach continues after surgery, with shared medical appointments that occur several times in the year following surgery and annually thereafter. This small group-based model allows for peer support among patients, while controlling health care costs and limiting educational redundancy.

"Patients continue to be engaged as they incorporate lifestyle changes, with the hope of achieving greater and sustained weight loss. This practice model has been well accepted by our patients, as evidenced by a substantial decrease in missed appointments. Patients also report a preference for this model when compared with the conventional (one-on-one) model of care."

Dr. Mundi concludes: "Despite these successes, continued efforts and research are needed to combat the obesity epidemic. An area of active investigation is the unfortunate phenomenon of weight regain after bariatric surgery. We aim to identify the factors contributing to weight regain and the potential interventions to prevent and manage it.

"In conjunction with several collaborators, we are offering multifaceted programs, which include various components of nutritional, behavioral and medical therapies. In addition, we are exploring novel surgical treatment methods, including endoscopic procedures, that target weight maintenance after surgery."