Hospital Practice

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Ileal Bypass for Obesity: Postoperative Perspective William W. Faloon To cite this article: William W. Faloon (1977) Ileal Bypass for Obesity: Postoperative Perspective, Hospital Practice, 12:1, 73-82, DOI: 10.1080/21548331.1977.11707062 To link to this article: https://doi.org/10.1080/21548331.1977.11707062

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Ileal Bypass for Obesity: Postoperative Perspective WILL 1 A M

w.

FA LooN

University of Rochester

Initially, diarrhea is almost universal but becomes self-limited unless the patient persists in overeating. Weight loss averages 75 to 100 lb the first year, with a stable level generally achieved after 18 months. Among the serious potential complications are enteritis, kidney stones, gallstones, and hepatopathology. Some can be anticipated and kept at bay by prophylactic measures like high-protein intake.

l'en years ago, ileal bypass surgery for massive and intractable obesity was considered an experimental and even questionable procedure; today, it is rapidly moving out of that category. Replies to a recent survey by Iber and Cooper reported that no fewer than 4, 500 such operations were Performed during the past 15 years, and it is likely that the actual number approximates double that figure. Thus this can no longer be considered a rare or even uncommon Procedure; moreoever, experience has demonstrated that With an experienced surgical-medical team both mortality and morbidity can be held within acceptable limits. My ~Urpose here is to summarize our own experience with tleal bypass, especially its expectable postoperative comPlications and their treatment; I shall also say something about the physiologic changes, benign or otherwise, induced by the operation. As an earlier article in this journal has emphasized, ileal bYPass should be undertaken only as a "last resort" treatment for obesity (see T.S. Danowski, "The Management of Obesity," HP, April 1976). While mortality in connection with the operation is (or should be) very low, the possibility still exists, and should rule out surgical intervention except where 1) the obesity is massive and 2) all other illethods of reducing it have failed. Massive obesity is considered to exist where the patient is at least 100% over the "ideal" body weight, or at least 100 pounds overweight. In addition, the patient should have a history of being unable to lose weight by diet and/or drugs, or of being able to do so Only temporarily. Other considerations swaying the balance toward surgery would be inability to hold a job or attend to household duties, orthopedic difficulties such as arthritis, and diabetes mellitus, hypertension, and major Problems with leg veins. On the other hand, several factors would weigh against surgery (apart from the age and cardiovascular considera-

tions important in any potential surgical patient). These include a history of inflammatory bowel disease, liver disease, or renal disease. Other, less concrete considerations involve the patient's psychologic state. For some people, obesity appears to be an escape from certain kinds of social responsibility - as it were, a way of hiding from the world beneath a blanket of fat. When the fat is removed, they are unable to cope with the new expectations produced in the people around them. While this problem seems to be a real one, psychiatrists have been unable to agree on which psychologic symptoms can effectively predict the patient's future inability to cope. Some clinicians would exclude anyone under continuing psychiatric care, but this can be ambiguous, since the psychotherapy may well have been undertaken in an effort to deal with the obesity. I would in any case exclude individuals who have undergone frank psychiatric breakdown or have been hospitalized for major (schizophrenic or manicdepressive) psychoses, since extensive experience indicates that postoperative stresses and changes in life-style may induce a recurrence or exacerbation of the psychiatric condition. Our own procedure is to hospitalize patients for 10 days to two weeks for a complete preoperative workup. While not intended for the purpose, this is a way of further screening out poor-risk patients, though most of these have been turned away at an earlier stage. The more important aim is to attempt to anticipate postoperative prob-

Dr. Faloon is Professor of Medicine, University of Rochester School of Medicine and Dentistry, and Chief of Medicine, Highland Hospital, Rochester, N. Y. Acknowledgment is made to Dr. Charles Shennan and Mrs. Susan Flood for their assistance in the studies described. Hospital Practice January 1977

73

lems as well as to establish baselines for evaluating precisely what physiologic changes follow the operation. In addition to the ordinary ECG, chest x-ray, and various chemical tests, we do a gallbladder series, an IV pyelogram (to determine whether kidney stones are present), and a liver biopsy. We also do a number of absorption tests - B12 , 0-xylose, and glucose tolerance, both oral and IV, and have recently added assays of plasma amino acids. As regards the operation itself, there is little to say. Currently, two somewhat different procedures are widely used: an end-to-side anastomosis, with the bypassed intestine remaining attached to the remainder, and an endto-end anastomosis, with the bypassed intestine anastomosed to and draining into the colon (see Danowski reference). At present, in my opinion, there are not enough data to allow any conclusion as to whether one ap-

proach is superior to the other. However, there are a number of minor technical points that are perhaps worth mention. For one thing, we no longer perform a panniculectomy to remove subcutaneous fat at the site of the incision. This was originally done partly for cosmetic reasons and partly to facilitate access. However, we have found that the result is often an unsightly scar, which frequently becomes infected, so that instead we now go in above the panniculus. We have also ceased in most instances to combine the bypass with a cholecystectomy. Many bypass patients have gallstones at the time of operation, but we now generally find it preferable to reserve surgical treatment of this condition to a later time - assuming that symptoms continue. The main reason is difficulty of access: the bypass incision is generally too low to permit the surgeon to reach the gallbladder easi-

Ileal bypass can be formed by two different surgical procedures; neither has as yet demonstrated any clear superiority. With endto-end anastomosis (left), bypassed segment is detached and 74

Hospital Practice January 1977

ly. In addition, the operation is invari· ably a long one: the surgeon must go through three to six inches of tissue merely to reach the peritoneum. Un· less the gallbladder is unusually ac· cessible we prefer to avoid increased time on the table and manipulation of tissue. As a final technical point, we have found that infection can be mini· mized by preparing the patient with neomycin and erythromycin. Operative and postoperative mor· tality averages in the neighborhood of 2% at larger institutions, i.e., where a sizable number of bypass procedures have been and continue to be done. In hospitals that do not have continuing experience with the procedure, the re· suits are poor, ranging up to 1 % in some series. It is also my impression that institutions with excessive mortal· ity tend to treat bypass as entirely or largely a surgical problem, instead of instituting the collaborative medical·

then anastomosed to colon, draining into it just above sigmoid With end-to-side anastomosis (right), bypassed segment of intes tine remains attached to cecum and drains into it.

surgical approach that we have found essential if complications are to be dealt with successfully. We had three deaths among our first 2 5 patients and none among the next 5o. Only one of the three was an operative death; it occurred in a patient Undergoing a "re-bypass" operation. Another was a sudden death, having no apparent connection with the surgery, while the third was almost equivalent to suicide: a patient with postbypass disease of the liver who began drinking. Some degree of postoperative morbidity or protracted discomfort can be expected in all patients, but in about three fourths it is minor, easily controlled, and ultimately self-limited. Dia~rhea is well-nigh universal, begin~•ng almost immediately after the pahent begins to take food orally. Liquid ?ourishment is begun when peristalsis IS restored after operation, and after three days solid foods are introduced. A number of restrictions apply; for example, milk is to be avoided, since it acts as a cathartic early in the postoperative course, as do citrus fruits, especially orange juice. Taking in a ~arge volume of food at any one feedIng also exacerbates diarrhea. The basic problem seems to be mechanical. Since the effective length of the small bowel has been reduced to about two feet beyond the duodenum, even before a meal is finished some food will have reached the colon, Where it serves as an irritant and often produces a bowel movement. In any case, severe diarrhea (up to a dozen bowel movements a day) can be exPected for a period of three to six months, after which it falls off as intestinal absorption improves and the colon becomes more tolerant of irritation. Meanwhile, it can be controlled fairly effectively with paregoric or Lornotil. We ourselves have begun to use calcium carbonate, which Danish hospitals have shown to be a way of controlling diarrhea that is both effective and cheap; in addition, it may induce other desirable effects that I shall discuss later. By about six months, the diarrhea Will have decreased substantially, though it will recur if the patient overeats. Some interesting conclusions in this context have emerged from stud-

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Obese patient, seen in before and after photographs taken a year apart, showed fairly typical pattern of postoperative weight loss. During first two months, she lost some 15 lb/mo, but this slowed to around 10 lb!mo for seven months. Nine months after operation, her weight stabilized at about 58% of the original figure. Hospital Practice January 1977

75

Oxalate kidney stones are not uncommon in postbypass patients, a tendency explained by the fact that the excess fats in the gut combine with calcium ion, which would otherwise bind most dietary oxalate for elimination in the feces. As a result, the free oxalate is reabsorbed into the circulation and eventually reaches the kidney, promoting stone formation (A). The problem can be dealt with in several ways (B): by limiting intake of fats and oxalate-rich foods, by supplementing dietary calcium, or by giving cholestyramine, which somehow limits the free oxalate effect.

ies that ~e have been doing between six and 12 months postoperatively, in an effort to define precisely what changes the operation has produced. The patients are again hospitalized and put on the same low-calorie diet as during the preoperative workup. Unanimously, they tell us that they 76

Hospital Practice January 1971

have less diarrhea than they did at home - a clear indication that they were eating much more than they had been instructed to. Of course some of this is expectable: if the patient .had been able to follow dietary instructions in the past, he might never have needed the operation.

However, these restudies have also demonstrated, by history and actual measurement, that the patients are eating less - up to 3,000 calories fewer per day. They report that they find themselves satisfied with a plate of spaghetti rather than a heaping platter, a bowl of chili rather than a vat, and so on. These reports have been confirmed by some British studies em· ploying bomb calorimetry of patients' stools. Given the reduced intestinal absorption following bypass, one would expect the caloric content of the stools to rise, and so it does, but not enough to account for the weight loss. The only conclusion seems to be that patients are eating less, and that in fact this is a major reason why the operation works. One may well wonder how individuals with a history of being unable to control their food intake for 20 to 40 years can - rather suddenly - begin doing so. There seem to be several reasons. One is the diarrhea itself, the fact that overeating produces an almost instantaneous response in the bowel. Patients who are going to drive even as little as 6o miles, for example, find that they must either skip break· fast or stop along the way two or three times. If they are going out for a social evening, they will for similar reasons eat a very small supper or none at all. This penalty for overeating amounts to what practitioners of behavior mod· ification call "immediate negative reinforcement." There is a less immediate but no less powerful positive reinforcement in that these people are losing substantial amounts of weight, perhaps for the first time in their lives. The rate varies from five to 10 pounds a month, with the average 75 to 100 pounds during the first year; thereafter, the rate drops and by 18 months the weight has generally stabilized. As a result, a woman patient will tell you that she has dropped from a size 50 to size 20 and can buy her clothes in a store instead of having to have them specially made. With such results from having dropped to perhaps 18o pounds, she has a further incentive to get down to 150 pounds. Male patients - though a minority in our series and others - find compa· rabic incentives. One of them, for ex·

?111ple, was a bartender whose duties Included throwing out obstreperous customers. After losing 150 pounds, he was unable to throw them out quite as impressively as he once did - but ~ound that people were asking him, Whatever happened to that big fat guy who used to work here?'' Patients frequently tell us that their friends fail to recognize them; in some cases, the nonrecognition included individuals to whom the patient owed money- an u.nexpected but perhaps beneficial Side effect! A similar "side effect" is seen in a number of women who, having lost weight, become independent of their husbands to the point of di~orcing them and sometimes remarryIng. (Here, perhaps, evaluation of the benefits might vary considerably, depending on whether the patient or her ex-husband was doing the evaluating.) More seriously, it is gratifying to find that patients engage in all sorts of activities that were previously difficult or impossible. Many who lost jobs get new ones, while among the housewives who were never employed, perhaps one in 10 now finds a job. In any case, the housewives can now care for their families better and get out and around. Their self-respect goes up. To return to the postoperative follow-up studies, one finding is that

most patients cmnplain at times of coldness and weakness. They say they need to wear a sweater most of the time or to close the windows when other people are comfortable with them open. This pattern is observed when the patient has lost perhaps 50 pounds and is probably due to reduction of the body's fatty insulation. The weakness probably relates to the reduction of energy stores- notably, the diminution of glycogen stores in the liver. Less common is an anorectic phase in which the patient may dislike the sight or smell of certain foods. This is cause for concern, because it usually turns out that the disliked foods are meats, raising the possibility of serious protein deficiency and liver damage, a point to which I will return later. Other not unusual sequelae are magnesium and potassium and even vitamin deficiencies, though we routinely prescribe multivitamin supplements. Among the more serious potential complications, perhaps the most common is a syndrome now called "bypass enteritis." It is characterized by bloating and distention, producing severe discomfort and often painful cramps; frequent diarrhea, usually of the watery, small-bowel type; and sometimes fever. As described by George Bray of

Skin rash is an occasional and minor sequela of ileal bypass. 1'he lesions resemble those of chickenpox and may be produced

Harbor General Hospital, near Los Angeles, and Ernst Drenick of the Los Angeles VA Hospital, the syndrome appears to result from bacterial overgrowth, either in the bypassed bowel or in the colon itself. In the former case, presumably the irritation and distention following bypass are predisposing factors. When the colon is involved, x-rays show it as enormously distended and apparently obstructed (Bray calls this "pseudo-obstruction"), but if one operates one finds only severe distention. Sometimes the condition known as pneumocystoides intestinales is found, in which gas produces blister-like bubbles within the mucosa. The syndrome is reversible with clindamycin, tetracycline, and possibly penicillin. Most successful is metronidazole, a specific against anaerobes. From this and other evidence, it appears that the principal culprits are anaerobic organisms, which release toxins into the gut. The syndrome occurs in some w% to 15% of patients. Another complication is kidney stone formation, which can be expected in from 5% to 30% of patients. The higher incidence applies in the South (as is true of kidney stones generally). The vast majority are oxalate stones, deriving ultimately from oxalate in the

by precipitation of cryoglobullns in the skin. In any event, they disappear spontaneously in two to three weeks. Hospital Practice January 19n

77

Fatty liver, common in obese individuals, is reduced after bypass operation. Micrographs show liver tissue before operation (top) and 21 months after operation (bottom).

diet that is absorbed in the colon as sodium oxalate, passed into the urine, and precipitated in the kidney as calcium oxalate. The pathology here is complex and quite interesting. Some experiments in San Francisco by Dr. David Earnest have shown that a high-oxalate diet is probably a necessary but not a sufficient condition for formation of these 78

Hospital Practice January 1977

stones in bypass patients. He and his associates found that a diet high in oxalate - spinach is a good source - did not, as had been expected, produce a rise in urinary oxalate. The reason was that the spinach passed through too quickly for the oxalate to be absorbed; when sodium oxalate was given by mouth, it appeared in the urine in large quantities.

This finding is consistent with clini· cal experience, which indicates that kidney stone formation is rare in the immediate postoperative period (i.e., when absorption is at a minimum), but becomes more common around six months, when absorption has im· proved. One might then ask why these patients for the most part did not de· velop kidney stones before operatiou, i.e., when their absorption was at a maximum. The explanation involves an interaction of oxalate, calcium, and fat. Oxalate in the colon is bound by calcium (if the latter is present) as insoluble calcium oxalate, in which form it is excreted in the feces. In oth· er words, it does not get to the kid· neys. If there is fat in the colon, as of course there is after bypass, it com· bincs with calcium to form calcium soaps. This leaves the oxalate free to pass into the bloodstream and thence to the kidney. From this analysis, a rational course of treatment is clear. The most obvi· ous step is to reduce dietary oxalate, which, in addition to spinach, is abundant in rhubarb and in chocolate and cola drinks. (The high consumption of the latter in the South may help ac· count for the high incidence of stones among patients there.) Additionally, dietary fat can be reduced. Finally, ex· tra calcium can be given to compen· sate for that bound by fats (another rc.ason for preferring calcium carbonate as an antidiarrheal agent). Urolo· gists may find this approach incred· ible, since recurrent kidney stones arc normally treated by lowering calcium intake, but experience has shown that in this particular context the calcium does the job. Yet another attack on the problem employs cholcstyramine. In bypass patients, cholestyramine helps prevent kidney stones either by its usual action of binding bile acids, which arc probably important in the absorption of oxalate in the colon, or by binding the oxalate itself. A much rarer complication is liver failure, which occurs in only 1% to :z% of well-managed patients. It manifests itself by the usual signs of anorexia and jaundice and can be confirmed by liver function tests and liver biopsy. The latter reveals marked fatty infiltra· tion, inflammation, and sometimes scarring in the organ. The basic cause

seems to be protein deficiency. Many, Perhaps most, obese individuals consume a diet high in carbohydrates and low in protein, and the problem is aggravated postoperatively by the fact that even such protein as is consumed ~ay be poorly absorbed. Significantly, ~Ver damage is most common in pahents who have lost in excess of 10 Pounds a month during the first six lllonths, implying that either their food intake or their absorption (or both) is below average. The reduced protein intake, however caused, is reflected in a fall in serum amino acids relative to the preoperative baseline. If severe or prolonged, this can lead to a "kwashiorkor syndrome" not unlike the proteindeficiency disease often seen among Undernourished populations in the Underdeveloped countries. As in most other types of liver damage the progression is from fatty liver (not uncommon in obese individuals even before bypass) to frank hepatitis and scarring. Obviously the best way to deal with this problem is to prevent it. In our preoperative discussions with bypass candidates, we emphasize the importance of eating meat every day. We point out that postoperatively the minImum daily protein requirement will be about double the normal minimum (in excess of 6o gm), and we also strongly advise patients that they should abstain from alcohol. If distaste for meat develops postoperatively, patients can ordinarily obtain protein from chicken, fish, eggs, or cheese. While we have not yet quantitated the effect of this prophylactic apProach, it is our clear impression that the incidence of liver disease has been going down. Caught in time, frank hepatopathology is reversible; treatment with amino acids given intravenously is emPhasized. A high-protein diet is naturally desirable, but since its intake may ~e limited by anorexia and absorption IS poor, the intravenous route is used immediately. In addition, we give parenteral multiple vitamins, calcium and magnesium supplements, and an ~ntibiotic, such as neomycin. The last IS intended to reduce ammonia formation in the intestine, thus reducing the

After bypass surgery contrast medium (barium swallow) is seen entering ileum from jejunum just proximal to cecum; some material has refiuxed into the bypassed ileum.

total ammonia load, since intravenous amino acids may increase ammonia formation. In patients with liver damage, hepatic coma may be induced by ammonia overload. It is perhaps worth noting that in cases of "bypass enteritis" actual protein loss occurs through the bowel, in the form of shed cells and/or transuded plasma proteins. This of course is

an added drain on protein and amino acid stores. Assuming that appropriate therapeutic measures have been taken and that the patient maintains an adequate diet, a repeat biopsy four to 12 months later, after the weight has stabilized, will generally indicate that the liver has returned to normal. The achievement of weight stabilization -which is Hospital Practice January 1977

79

a sign that intestinal absorption has increased or that caloric absorption has met caloric expenditure - almost invariably eliminates the possibility of liver disease. A still more rare complication is the appearance of swollen, hot, and inflamed joints occurring at any time after operation, a form of arthritis only recently linked to the bypass operation. A proposed etiology is that the bacterial overgrowth described earlier leads to bacteremia, the formation of cryoglobulins and antibodies to certain intestinal bacteria (which have actually been observed by a group at Massachusetts General Hospital), and the precipitation of antigen-antibody complexes in the joints. Whether or not this is in fact the mechanism, antibiotics appear to produce a dramatic subsidence of symptoms in most patients. Possibly related to postbypass arthritis is a peculiar skin rash that occasion-

tetany. Once the problem is recog· nized, however, it can be easily and quickly corrected. A frequent observation in post· bypass patients - which may or maY not be an actual sequela - is gall· stones. The relationship of the stones to the operation is difficult to interpret because gallstones are of course com· man among obese individuals, espe· Electrolyte depletion - specifical- cially women. Thus in one group of 44 ly of potassium and magnesium - is patients examined preoperatively, sometimes a problem but seems to be some 15% had a history of cholecys· less common than some clinicians had tectomy to remove stones, while ill feared. So long as the patient main- another 25%, either stones could be tains an adequate diet, the kidneys will seen on the x-ray or the gallbladder almost certainly conserve potassium failed to visualize - for a total of 40% adequately. Occasionally, however, with actual or suspected stones. Whell either because of inadequate intake or we restudied, six to 12 months postopabnormally severe malabsorption, eratively, 25 patients whose gallbiad· large quantities of potassium and mag- ders had been normal, we found that nesium will reach the colon and will four had developed stones while pass out in a watery diarrhea; in a few another five patients had developed cases, the hypokalemia and hypomag- non visualization. nesemia progress to the point of actual The high preoperative incidence of stones was not surprising, especiallY since it represented the cumulative effects of many years. But the postop-: erative incidence in originally normal individuals - which works out to 36% over only a year or less - seems un· naturally, suspiciously high. We have tried to check on this by testing the bile for lithogenicity during the regu· Jar six -to-12 -month checkup. One would expect an increase in lithogeni· city.: with chole~terol mobilized frorll fat deposits as weight is lost, the bile would become supersaturated and the cholesterol would precipitate to forrll stones (as in any other group of pa· tients, few of the stones are the bilepigment type). Or so we hypothesized. In fact, we found no consistent rise ill the bile ratio of cholesterol to bile acids at six to 12 months. However, a later study has pinpointed a period three to six weeks after operation ill which cholesterol rises sharply, and it may be that it is in this period that stones are formed that we only observe months later. A final postbypass complication is, to my knowledge, still only a possibil· ity. Many clinicians have feared that steatorrhea could lead to deficiency ifl the fat-soluble vitamins A and D, and thus to some form of rickets, or os· Reoperatior1 (done in a smallnumberof cases either to reverse the bypass because of recalcitrant symptoms or to induce further weight loss) reveals marked hypertrophy of teomalacia. However, though thiS complication has been widely an· bowel, held by surgeon, compared with bypassed segment of ileum below it. 8o

Hospital Practice January 1977

ally develops. The lesions resemble those of chickenpox: punctate, blisterlike spots that are usually most numerc ous on the arms and legs. We believe they may be produced by precipitation of cryoglobulins in the skin. In any event, the rash seems to induce only temporary discomfort and disappears over a period of a week or two.

rcipated, it has not occurred so far as I now. Should it do so, it could be easily corrected by giving the vitamins int~amuscularly, or even by increasing VItamin intake per os. Very occasionally (in perhaps 1% of cases) complications are so severe and so recalcitrant to treatment that they 0 U~eigh any benefits deriving from ~e•ght loss. It is therefore worth notIng that in these rare cases the bypass ~an be reversed, with the intestine beIng. reconnected in its original configurahon. Given the small number of such cases, figures on mortality or lnorbidity are not yet significant. Such reoperation is not without hazard, however, since such patients are virtual~y by definition quite sick to begin ~•th, otherwise the "reversal" operahon would not be considered. We have aim performed nine reoperations to further shorten the bowel. l'hese were for patients who over the first 12 to 18 months had lost 50 to 6o Pounds but wanted to lose more or ~ho, for example, had lost 100 pounds ut had gained back part of it from overeating. The sequelae of these operations differed little if at all from those of the initial operations, though the effects on weight were naturally les~ dramatic. Perhaps the most interestmg finding was that in these individuals the intestine that was functioning had lengthened over the inter~ening period from approximately 18 •~ches of jejunum and ileum combmed to as much as 30 inches. It also appeared that the villi had become n1ore numerous, and it may be that the intestine had become chemically more efficient in absorbing food. l'hese processes - which can be presumed to occur in all patients, though Perhaps to a lesser degree - evidently explain why weight loss ceases by about 18 months postoperation. They are also yet another example of the body's remarkable capacity to compensate for a surgical insult - though •n this case a well-intentioned one. An important phase of our followUp studies involved attempts to define some of the physiologic parameters altered by the bypass operation and their relationship to other variables such as weight loss or the formation of gallstones. For example, we measured fecal fat in 36 follow-up patients and

Photomicrographs of tissue samples taken during bypass procedure (top) show relatively few folds in intestinal mucosae (left) and slender, straight villi (right). Sample from another patient 18 months after bypass (bottom) shows, typically, more and larger mucosal folds and more convoluted villi, both making for more efficient absorption.

found, as expected, that it had increased - usually markedly - in nearly all the group (there were two exceptions). What rather surprised us, however, was that there seemed little relationship between the amount of fecal fat (which presumably reflected the degree of malabsorption at this time) and the amount of weight lost in the first six months after jejunoileostomy.

Fecal fat excretion ranged from 4·9 to so. 7 gm/day, out of a total intake of 65 gm/day, but the individuals at the two extremes of the range had lost almost identical amounts of weight (71 and 73 pounds respectively). And while the patient with the lowest weight loss (23 pounds) excreted distinctly belowaverage amounts of fee a! fat ( 15.8 gm/ day), the one with the highest weight Hospital Practice January 1977

81

loss (114 pounds) had fat excretion only a few grams above average (26.8 gm/day). These findings are consistent with other studies showing no clear relationship between weight loss and calories lost in the stool, whether in the form of fat, carbohydrate, or protein. Obviously there were a number of possible variables at work here, not all of which could be controlled: the rate at which the shortened intestine increased its absorptive capacity (which can be assumed to vary from one individual to another), caloric loss through physical exercise, and, above all, the amount of food taken between the initial discharge from hospital and readmittance for checkup. We were no more successful in tracing a relationship between two other parameters - serum cholesterol and fecal bile acids. Nearly all the patients showed a drop in serum cholesterol, with some 75% showing a significant fall (30 mg/wo ml or more), and half achieving levels below 150 mg!wo ml. Obviously this is fine from the standpoint of preventing heart attacks, but, in theory, one would expect the fall in cholesterol to bear some relationship to the amount of bile acids excreted. No such relationship emerged. We did, however, uncover several apparent relationships between and among fat and bile acids, though their significance is still somewhat ambiguous. For example, we found that patients with high fat excretion (more than 24 gm/day on a 65 gm fat intake)

tended to produce a high proportion of the "primary" bile acids, cholic and chenodeoxycholic acids, while those with moderate fat excretion (under 24 gm/day) produced more of the "secondary" bile acids, deoxycholic and lithocholic acids. This interested us, since lithocholic acid is a known hepatotoxic agent, and liver disease, as noted, is one of the problems encountered postoperatively. However, in high-fat-excretion patients there was no excess of lithocholic acid in the bile, and in the stool, lithocholic acid decreased or disappeared. The probable reason here is that lithocholic acid is normally formed from chenodeoxycholic acid by the action of bacteria in the gut, and in these individuals the intestinal contents may pass through too rapidly for extensive conversion to occur. No relationship between lithocholic acid and liver injury in jejunoileostomy patients has yet been observed. An additional explanation for the low lithocholic acid levels may be a decreased formation of chenodeoxycholic acid. In normal individuals, the pattern of bile acids is about 40% each of cholic and chenodeoxycholic, 20% deoxycholic, and a trace of lithocholic. The postbypass patients, however, averaged about 6o% of cholic to only 20% of chenodeoxycholic acid, apparently because the former is more readily synthesized under conditions of physiologic stress. Perhaps the most significant aspect of the bile acid changes was their possible relationship to gallstones. Chenodeoxycholic acid is nonlithogenic

Selected Reading Proceedings of the Conference of 1ejunoileostomy for Obesity. The Kroc Foundation and National Institute of Arthritis, Metabolic and Digestive Diseases (to be published in the Am·1 Cl in Nutr) Drenick E1 et a!: Bypass enteropathy: intestinal and systemic manifestations following small bowel bypass. 1AMA 236:269, 1976 Dickstein SS, Frame B: Urinary tract calculi after intestinal shunt operations for the treatment of obesity. Surg Gynecol Obstet 136:257, 1973 Wands 1R, LaMont 1T, Mann E, Isselbacher K1: Arthritis associated with intestinal bypass procedure for morbid obesity. N Engl 1Med 294:121, 1976 Solow C, Silverfarb PM, Swift K: Psycho-social effects of intestinal bypass surgery for severe obesity. N Engl 1Med 290:300, 1974 White JJ, Moxley RT, Posefsky T, Lockwood DH: Transient kwashiorkor: a cause of fatty liver following small bowel bypass. Surgery 75: 829, 1974

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Hospital Practice January 1977

and indeed antilithogenic, apparently because it tends to shut off cholesterol synthesis and secretion into the bile; as several articles in this journal have discussed, "cheno" is under trial as a pharmacologic method of dissolving existing stones. Thus a postoperative increase in the ratio of cholic to chenodeoxycholic acid would presumably make individuals more likely to forrn stones, which is consistent with our clinical findings. Both the ambiguities and the apparently significant aspects of these physiologic findings emphasize the importance of long-term studies to determine the impact of bypass on the body. One very interesting study of this sort, which began in 1974, is cur· rently under way in Copenhagen, in· volving all the hospitals there. (So far as bypass surgery is concerned, these are essentially all the hospitals in Den· mark.) Treatment of patients is ran· domized, with two thirds being given bypass surgery and the other third re· ceiving psychotherapy, counseling, appetite-depressant drugs, and de· tailed dietary instructions, everything the doctors can think of to help reduce weight except surgery. Not surprisingly, the average weight loss is much greater in the surgical group, though it is of interest that at least one patient in the nonsurgical group did lose as much weight as the be~t in the op~:;.rated series. Only one death ha!< occurred among the approx· imately 150 patients of both groups, the result of a pulmonary embolus in one of the nonsurgical patients. The series has already proved quite conclusively that in the "hard-core" obese patient, bypass surgery almost invariably produces greater weight loss than purely medical treatment. As the study continues, it should produce valuable data on whether the operated group also shows a reduced incidence of conditions that are often associated with massive obesity, such as hyper· tension, coronary disease, and stroke. If there are benign consequences of the bypass operation in addition to the weight loss itself, we ought to knoW about them. And if it should turn out that there are negative long-tenn consequences, it is even more neces· sary that they be identified and under· stood. cJ

Ileal bypass for obesity: postoperative perspective.

Hospital Practice ISSN: 2154-8331 (Print) 2377-1003 (Online) Journal homepage: http://www.tandfonline.com/loi/ihop20 Ileal Bypass for Obesity: Posto...
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