On the Air with…Nicola Scopinaro, MD

| April 26, 2007

Interviewed by Kelvin Higa, MD, FACS

The US experience with the jejunoileal (J-I) bypass was bittersweet. It was an effective weight loss and metabolic instrument, but the side effects, complications, and nutritional consequences gave us a healthy respect for malabsorption. I was recently invited to the Società Italiana di Chirurgia dell’Obesità in Florence, Italy, celebrating the 30th anniversary of the biliopancreatic diversion (BPD). As I am intrigued by the European interest in the gastric bypass and possess great admiration for Professor Scopinaro, I accepted the great honor of interviewing him on this subject. The following represents an annotated conversation that actually began over six years ago between Dr. Scopinaro and myself, and serves as a reflection for those of us in the field of bariatric surgery today who enjoy delving into the history and ideology behind some of its biggest developments. -Kelvin Higa, MD, FACS

Dr. Higa: Professor Scopinaro, of all the modern bariatric procedures today, the BPD has been studied the longest and has the best record in alleviating the comorbid conditions commonly associated with the “metabolic syndrome.” Why do you think this operation has not gained the worldwide popularity and acceptance that the gastric bypass or adjustable gastric band has?

Professor Scopinaro: Generally, especially in the US, there has been a fear of malabsorptive procedures after the experience of the J-I bypass. This is understandable. Even the NIH consensus panel of 1991 only recognized restrictive, or what were thought of as restrictive, procedures—the vertical banded gastroplasty (VBG) and the gastric bypass (GBP). Unfortunately, many insurance companies followed these recommendations and many patients simply did not have the opportunity to choose another option. In other countries, poverty and inadequate access to protein may make the BPD a poor choice in favor of GBP. Overall, I think there is still a great deal of misunderstanding of the principles of the BPD and the regulation and control of the inevitable side effects imposed by the operation.

Dr. Higa: Basically what you are saying is that there is a great deal of ignorance regarding the nutritional aspects concerning the BPD?

Professor Scopinaro: That is correct. When I designed the BPD, it was only after several years of research and animal experiments. Then, in human trials, we modified and refined the technique to optimize long-term weight management and protein metabolism. We now have 30-year experience, and I still find that there is a lot of misunderstanding and myth regarding the BPD.

Dr. Higa: One of the myths concerns the gastric resection. Originally, I suspect the antrectomy was done for prevention of marginal ulceration–H2 blockers were not available at that time, but you describe a “post-cibal” effect of the gastrectomy.

Professor Scopinaro: The post-cibal effect only lasts for a few months; then most BPD patients will consume more volume than prior to surgery. We also experimented with smaller gastric volumes and found that it was necessary to allow for adequate protein intake or run the risk of protein malnutrition.

Dr. Higa: The design of the BPD is to limit overall energy absorption, which you calculate to be about 1250Kcal/day. But you have also found that after BPD, the resting energy expenditure is also higher. This is contrary to what we know of metabolism–individuals who lose weight also lose a great deal of muscle mass; therefore, I would expect basal metabolic rate (BMR) to decrease. How do you explain this?

Professor Scopinaro: Once again, you have to realize the body composition changes after a BPD. Certainly, there is a great deal less adipose tissue as well as muscle mass, but there is greater energy expenditure due to visceral sources. The resting energy expenditure for visceral is about 360Kcal/kg/day as opposed to fat— 5Kcal/kg/day and muscle— 18Kcal/kg/day. So the BPD works by two mechanisms: Limiting total energy absorption independent of food intake and increasing energy expenditure via the visceral compartment.

Dr. Higa: What about protein malabsorption? It seems that many series describe a certain percentage of patients requiring elongation of the alimentary channel for PCM. How do you manage these patients? Professor Scopinaro: The way in which the BPD is constructed limits the absorption of fat to the common channel, but starch and protein are absorbed throughout the alimentary limb. In fact a significant amount of protein is absorbed in the colon. Unlike starch and fat, protein absorption is dependent on oral intake. Therefore, patients can obtain adequate protein absorption depending on their intake. However, also depending on their fat and starch intake, dietary induced diarrhea can exacerbate problems with protein absorption. Most of the time, patients can be counseled as to their diet, increasing their protein intake at the expense of fat and starch, and protein-calorie malnutrition (PCM) is not a problem. Protein absorption occurs at about 70-percent efficiency after BPD and there is a higher fecal loss; therefore, patients must be able to consume at least 90gm protein per day. However, a few patients will require elongation of the alimentary channel at the expense of the biliopancreatic channel with the risk of some weight recidivism. Currently we have only a one-percent late revision rate.

Dr. Higa: When we see PCM after BPD, the first thing we do is blame the procedure, but patient compliance is also an important factor. You have stated that BPD patients are low maintenance: You can operate and then forget about them. Could you help me with this concept? Professor Scopinaro: Once again, you are misquoting me. BPD patients require periodic measurements of micro and macro nutrient levels, but this can be done by their primary physicians, not necessarily their surgeon. As opposed to restrictive operations that require a great deal of program support, BPD patients can achieve excellent weight loss by virtue of limitations in energy absorption rather than energy acquisition. In an experiment, we purposely overfed a group of BPD patients and none of them gained a single kilogram. Once the threshold of absorption is met, all energy intake is wasted. BPD is not just a “tool;” it is an operation that cannot be defeated by excessive calorie intake, as is the case with every restrictive procedure and the GBP. Dr. Higa: A major problem with the BPD has to do with social norms. BPD patients typically have extremely foul flatulence and diarrhea, correct?

Professor Scopinaro: BPD patients typically have one to four soft stools per day and only 1 out of 5 patients feel that the odor is a problem. Most of the time these side effects can be eliminated by dietary changes or by taking oral antibiotics or pancreatic enzymes. Eating without consequence is a myth for both the BPD and GBP.

Dr. Higa: When you first designed the BPD, not much was known about incretins and the role of gut hormones. Has the discovery of these proteins altered your theories about the mechanism of action of the BPD? Professor Scopinaro: Absolutely not. In fact, I think they can explain many of our observations. The BPD has the most powerful effect of any operation, including the GBP on type 2 diabetes mellitus and hyperlipidemia syndromes. The improvements in type 2 diabetes mellitus are independent of the weight loss. This is probably due to the bypass of the proximal foregut as theorized by Francisco Rubino. There is a secondary effect—that of intramyocellular fat depletion associated with reversal of insulin resistance. Both mechanisms help to explain our clinical observations. Dr. Higa: Why do you think the GBP has become so popular, especially in the western cultures? Now there appears to be more interest in the GBP in Europe and South America as well.

Professor Scopinaro: The GBP is a good operation and achieves good short-term weight loss and moderate long-term weight maintenance. It does well with the American diet and with low socioeconomic status. As the American diet becomes more pervasive in other countries, it makes sense that this operation has application as well. In fact, the GBP mechanism of action is similar to the BPD, except in terms of limited fat and starch absorption—its effect on type II diabetes, for example. However, in terms of weight loss, the GBP is totally dependent on calorie intake/acquisition.

Dr. Higa: The duodenal switch is an operation often thought analogous to the BPD; in fact, it is often referred to as “DS-BPD.” However, different surgeons advocate varying limb lengths, and the size of the gastric reservoir does not appear to be consistent. Is the DS an evolutionary operation?

Professor Scopinaro: It is clear that there is no standard to the DS, and this adds to the confusion to which you allude. Even with the BPD, it is very important to measure the intestinal limbs under tension, and this is not the case with the DS; some authors do this, and others do not, especially with respect to laparoscopy. Also, some authors, like Doug Hess, vary the limbs according to a formula based on the overall intestinal length. Likewise, the gastric remnant can be made to be highly restrictive or not at all. So the DS performed by Gary Antoine is more dependent on restriction of the gastric reservoir rather than exploiting the effects of the intestinal bypass. This is probably true of most DS procedures performed today: Patients do not have malabsorption as evidenced by their lack of symptoms and corresponding weight gain depending on calorie intake. Dr. Higa: What you are saying is that the DS today is primarily a restrictive operation and that the intestinal bypass is not being exploited as such? But isn’t this what you have been warning us about all along—combining malabsorption and restriction will result in the mechanism of one with the complications of both?

Professor Scopinaro: Yes, you are finally listening to me. But this does not mean that the DS is a bad operation. I just don’t think we understand it as well as we should. It is not a BPD.

Dr. Higa: Ironically, the sleeve gastrectomy may prove you right if it provides the same weight management as the DS. But there still is a bypass of the proximal intestine, so the effect of the DS would be similar to the GBP and BPD for diabetes, would it not? Also, I do not understand why there is no dumping syndrome after DS. Marceau has shown that gastric emptying is more rapid after the DS as opposed to the “preservation of the pylorus” theory pervasive in today’s literature.

Professor Scopinaro: The presentation of ingested food to the distal small intestine is similar to the BPD, so the avoidance of dumping syndrome must be similar in mechanism. Dr. Higa: One last question, Professor Scopinaro. If you were morbidly obese, which operation would you have performed on yourself? The AGB, BPD, GBP, or DS?

Professor Scopinaro: I would have the GBP.

Dr. Higa: Would you give up smoking?

Professor Scopinaro: No comment!

Dr. Higa is Assistant Clinical Professor in Surgery, UCSFFRESNO, Director, Bariatric and Minimally Invasive Surgery, Fresno Heart and Surgical Hospital, Fresno, California.

Dr. Scopinaro is Professor of Surgery, University of Genoa Medical School, Genoa, Italy, President of the Italian Society of Obesity Surgery, First President and Honorary President of International Federation For The Surgery of Obesity (IFSO). He is also the 2006 ASBS Foundation Outstanding Achievement Award recipient.

Category: Interviews

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