Gastrointestinal Complications of Vascular Surgery

Symposium on New Methods of Treatment of Gastrointestinal Disease

Gastrointestinal Complications of Vascular Surgery

R. H. Hayward, M.B., Ch.B., T. R. Calhoun, M.D., and F. L. Korompai, M.D.

Gastrointestinal complications related to vascular surgery may occur intraoperatively and postoperatively, are often serious, and sometimes produce a diagnostic or management dilemma. The conditions may be classified as follows: Intestinal obstruction Mechanical Paralytic Superior mesenteric artery Occlusion - Aortoiliac steal syndrome? Intestinal Spasm ~ necrosis Inferior mesenteric artery Occlusion by ligation . . Obstruction ~ Colon necrosis or late stenosis Peptic ulcer Gastric ~ Hemorrhage, perforation Duodenal ------Fistulas Aortoenteric Paraprosthetic-enteric Coexisting lesions Cholelithiasis Small bowel lesion Colon lesion

From the Division of Thoracic and Cardiovascular Surgery, Scott and White Clinic, Temple, Texas

Surgical Clinics of North America - Vol. 59, No.5, October 1979

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GASTROINTESTINAL COMPLICATIONS RELATED TO SUPERIOR MESENTERIC ARTERIAL DISEASE Acute intestinal ischemia resulting from occlusion or stenosis of the superior mesenteric artery may not only severely tax the diagnostic acumen of the surgeon, but also represents a rare but lethal complication for the patient. The symptoms of chronic mesenteric vascular insufficiency are well known, but unfortunately, when acute occlusion occurs, timely diagnosis is rare. While embolic obstruction may produce a sudden onset of pain followed by a bowel movement and then a quiescent period, thrombotic occlusion is rather insidious and tends to mimic other causes of bowel obstruction followed by peritonitis. Histologic changes begin in the wall of the bowel within one hour following vascular obstruction and, with necrosis, blood and massive plasma loss into the intestinal lumen may occur. While initially an abdominal roentgenogram reveals only the signs of intestinal obstruction, subsequently air may be seen in the wall of the bowel confirming death of this organ. Leukocytosis greater than 15,000 cells per cubic millimeter usually occurs, there is hemoconcentration, and liberation of 5-hydroxytryptamine, catecholamines, histamine, and vasoactive polypeptides. 5-Hydroxytryptamine acts like adenosine diphosphate (ADP) in producing platelet aggregation.t" As opposed to embolic obstruction of the more distal portion of the superior mesenteric artery, thrombosis or occlusion of the main trunk leads to ischemia of the entire intestine including the first portion of the duodenum. Diagnosis of intestinal infarction is particularly difficult and although assay of certain enzymes in the blood has been tried, the majority of these tests are inconclusive. Recently, the LimuIus test for endotoxemia has been found to be useful in determining death of the intestine or even severe ischemia with increased permeability." The detection of intestinal infarction is difficult enough when it occurs acutely in the previously well patient, but following abdominal aortic surgery diagnosis is often quite delayed because the surgeon confuses the symptoms with nonspecific postoperative intestinal ileus. The following two case histories illustrate in the first instance the type of postoperative disaster that sometimes befalls the patient, and in the second, how planned surgery can avoid such a calamity.

Case 1 A 52 year old white woman was first examined on November 27, 1973 for symptoms suggesting amaurosis fugax in the right eye and transient ischemic attacks with involvement of the left arm and foot. Evaluation of the vascular system revealed bruits at the carotid bifurcations, bilateral reduction of femoral pulses, an epigastric bruit, and blood pressure in the right arm of 238/100 mm Hg. Angiography revealed 50 per cent stenosis at the origin of the left internal and external carotid arteries and 90 per cent stenosis of the origin of the right internal carotid artery. There were severe atheromatous changes of the abdominal aorta with significant stenosis at the origin of the left renal artery and iliac stenosis on each side (Fig. 1A). On December 3, 1973, a successful right internal carotid endarterectomy was carried out. On January 3, 1974, a similar procedure was performed on the

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Figure 1. A, Abdominal aortogram shows aortoiliac occlusive disease and stenosis of the left renal artery. The film suggests stenosis of the celiac axis artery. B, Collateral filling of the superior mesenteric artery branches (upper arrow) and inferior mesenteric artery (lower arrow) suggesting occlusion of the superior mesenteric artery. C, Lateral abdominal aortogram confirms the presence of severe stenosis of the celiac axis artery and occlusion of the superior mesenteric artery and its branches.

left side. On February 19, 1974, aorto-left common femoral and right external iliac artery bypass grafts with an end-to-end aortic anastomosis and a saphenous vein end-to-end graft to the left renal artery were performed. The inferior mesenteric artery was ligated and a palpable but reduced pulse was noted in the superior mesenteric artery. On the morning following surgery her blood pressure had declined to 150/75 mm Hg and remained within this range throughout the hospital course. On the third postoperative day the patient became confused and left hemiplegia then developed suggesting a right cerebral infarct. By the fifth day, however, she was much improved, mentally clearer, and her bowel sounds were audible, but

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there was still an excessive amount of nasogastric tube drainage. In the next few days, the left hemiplegia essentially resolved, but it proved to be impossible to discontinue nasogastric suction without distention occurring. The possibility of intestinal necrosis was considered, in view of the fact that the white blood count had increased to 30,500 cells/em". The previous angiogram was reviewed and it was noted that there appeared to be stenosis of the celiac axis and occlusion of the superior mesenteric artery, although a lateral view of these vessels had not been obtained (Fig. 1B). A repeat transbrachial aortogram was performed on March 1, 1974 and suggested an increase in celiac axis stenosis with total occlusion of the superior mesenteric artery and no evidence of opacification of the mesenteric tributaries (Fig. Ie). At laparotomy on March 1, 1974, the small bowel, stomach, gallbladder, and liver all appeared to be necrotic. The patient finally died on March 17, 1974.

Case 2 A 61 year old white male presented on February 19, 1967 with a history of hypertension, bilateral leg claudication, and impotence. He had also noted vague abdominal discomfort for a few minutes after eating, these symptoms being more severe following a large meal. He had been troubled with gas and increasing anorexia. He had noted some occasional blurring of vision. On examination, there was a bruit over the right carotid bulb and the only pulse palpable in the lower extremities was a very weak right femoral pulse. Blood pressure was 180/90 mm Hg in the right arm. On February 23, 1967 a transbrachial aortic arch study and an abdominal aortogram were obtained revealing complete occlusion of the left internal carotid artery, high grade stenosis of the right internal carotid, and complete occlusion of the abdominal aorta below the renal arteries. There was apparent occlusion of both the celiac axis and superior mesenteric arteries (Fig. 2). On March 1, 1967 a right internal carotid endarterectomy was performed. On March 30, 1967 exploration of the abdomen revealed that the abdominal aorta below the renal arteries was represented by a small fibrous cord suggesting a congenital coarctation anomaly. Because of this finding, the aortic graft was attached end-to-side to the lower thoracic aorta and then tunneled through the abdomen to the common femoral arteries where bilateral anastomoses were carried out. The blood pressure had remained stable throughout the operative procedure, but on opening the aortic bypass graft, the small bowel immediately turned gray suggesting that it had been acutely deprived of blood. An 8 mm Dacron bypass from the aortic graft to the superior mesenteric artery was constructed. On opening this graft, normal color was restored to the intestine. The patient had an uneventful convalescence following surgery.

These case reports lead to the next question: Why should intestinal ischemia develop following abdominal aortic surgery in patients in whom the intestinal circulation apparently remains undisturbed? Although spasm of the mesenteric circulation has been known to lead to intestinal necrosis, there seem to be other reasons for the occasional appearance of this syndrome in the postoperative patient. 54. 55 Attention was directed to this by Kountz et ale when they described a case of intestinal ischemia following aorto-iliac bypass graft and lumbar sympathectomy.:" An aortogram in their patient revealed blockage of the celiac axis and superior mesenteric arteries, and the patient died following resection of the damaged intestine. The condition of the above vessels prior to the described surgery was not clearly identified by the authors. They described the condition as one of "aorto-iliac steal" and performed some experiments with animals to confirm their view. They felt that re-establishment of circulation to the lower extremities led to a "steal" of blood from the field of distribution of the superior mesen-

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Figure 2. A, Aortogram shows total occlusion of the abdominal aorta at the level of the renal arteries. B, Collateral flow shows some filling of the superior mesenteric circulation (upper arrow) and a meandering artery supplying the left leg (lower arrow). Occlusion of the celiac axis and superior mesenteric artery is suggested by these films.

teric artery. Several similar reports have appeared in the literature since that time, but the descriptions are so infrequent that it is impossible to determine any common precipitating factor with certain ty . 10. 33. 50. 56 Often the preoperative aortogram will demonstrate the so-called meandering mesenteric artery arising from the inferior mesenteric circulation to communicate with and supply the branches of a blocked superior mesenteric artery." This vessel, however, will probably not be seen if there is aortic obstructive disease between the origins of the superior and inferior mesenteric arteries." It is impossible to tell from the few available reports whether the majority of patients had total occlusion of the superior mesenteric and celiac axis arteries prior to the aortic surgery or just severe stenosis. Both instances are described and the possibility of postoperative thrombosis exists. In spite of the interesting hypothesis presented by Kountz, it remains to be proved whether a "steal" can actually occur anywhere in

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the body, but there is little question that arterial stenosis can lead to underperfusion of a given organ. DeBakey described the "borrowinglending" hemodynamic phenomenon (hemometakinesia) and showed that volume flow can vary in different regions of the body according to demand and circumstances.!" It is not unlikely then that the sudden creation of a high flow status to the lower extremities following aortic surgery might at least temporarily lead to a redistribution of blood from the intestine to the periphery as might occur normally with strenuous physical activity. While this physiologic phenomenon might be innocuous in the patient with a normal superior mesenteric artery, it could (perhaps) be disastrous if this artery were occluded or severely stenotic. In Case 1 of this presentation, the presence of celiac axis and superior mesenteric artery disease was not appreciated on the anteroposterior aortogram. The postoperative study revealed that stenosis of the celiac axis had become more severe and confirmed occlusion of the superior mesenteric artery. One could argue that loss of some lumbar collateral vessels contributed to intestinal ischemia, but had the roentgenographic features been noted prior to the initial surgery, it is quite probable that repair of the superior mesenteric artery would have prevented the complication of intestinal infarction. This case illustrates the need for biplane abdominal aortography in all patients with aortic occlusive disease, and we have proceeded accordingly since this unfortunate event. The patient described in case history 2 presented with a history of chronic mesenteric vascular insufficiency, and aortography revealed occlusion of the superior mesenteric and celiac axis arteries. The fact that the intestine turned completely gray following opening of the bypass graft was a most interesting and memorable spectacle. Aortogram revealed a "meandering mesenteric-like artery," but flow in this vessel was caudad to feed the legs. It should be noted that none of the branches of the abdominal aorta was disturbed, as an end-to-side bypass graft was performed from the descending aorta which theoretically might have improved intestinal blood flow by retrograde filling of the inferior collaterals. One can only postulate that a "steal" or redistribution of blood (hemometakinesia) occurred acutely in this patient and there is little doubt that had a superior mesenteric graft not been performed, as had been planned preoperatively, this patient would have suffered intestinal infarction. 3

Summary Acute necrosis of the intestine following aortic graft surgery is difficult to diagnose and is almost invariably fatal in the presence of occlusion or stenosis of the celiac and superior mesenteric artery. The etiology is not always clear in the absence of acute thrombosis, but a "steal" or at least a temporary redistribution of blood to the legs following revascularization may playa role. Prevention is better than treatment; therefore, it is recommended that routine biplane abdominal aortography be obtained in cases of aortic occlusive disease; the

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finding of a meandering mesenteric artery should indicate the need for repair of the superior mesenteric artery, although this finding is not always present; and prophylactic repair of a stenotic or occluded superior mesenteric artery should prevent this calamity.

INFERIOR MESENTERIC ARTERY: CONSIDERATIONS IN ISCHEMIA OF THE COLON The mortality for elective abdominal aneurysmectomy and aortoiliac (or aortofemoral) reconstruction presently is about 4 per cent." The reported incidence of postoperative colonic ischemia is 1 to 2 per cent with mortality ranging from 40 to 65 per cent.": 37 Thus, ischemia of the colon may account for one-fourth of the mortality, and prevention of this complication should contribute significantly to the reduction of operative mortality. The spectrum of colonic ischemia varies from transient diarrhea secondary to mucosal injury to transmural infarction with shock, perforation, and death. An intermediate condition consisting of persistent colitis and late stricture may also occur. One prospective study showed a 6 per cent incidence of colonic ischemia," whereas Smith and Szilagyi reported a 10 per cent incidence." The importance of adequate collateral circulation to the left colon has long been recognized, and the one common denominator of the reported cases of colonic ischemia is ligation of a patent inferior mesenteric artery. At one time emphasis was placed on preservation of one or both internal iliac arteries to maintain collateral flow ;" however, subsequent studies have shown that internal iliac artery preservation alone will not always prevent ischemia." Recently several innovative techniques to predict intestinal viability have been described. They consist of measurement of inferior mesenteric artery stump pressure, use of intravascular fluorescein, measurement of the mesentericantimesenteric temperature gradient, Doppler flow detection in the mesentery and serosa, scanning following injection of ggm technetium labelled microspheres, and use of routine preoperative aortograms." 6. 10.22. 53 Intraoperative flow measurements with an electromagnetic flowmeter might also be useful. Certainly each method has value and may be a better predictor of colon viability than previously used intraoperative standards such as subjective observation of inferior mesenteric artery backflow, the presence of peristalsis in the colon, palpation of mesenteric pulsations, and observation of the color of the colon. However, many of the above methods are not practical. Use of the Doppler has shown promise in at least one series as being the least cumbersome and time-consuming." The most useful information can be gained from a preoperative abdominal aortogram with anteroposterior, lateral, and runoff films.": 6 Such a study gives specific information concerning patency of the celiac, superior mesenteric, inferior mesenteric, and internal iliac arteries. The presence of a large "meandering" mesenteric artery or a congenital anomaly (such as absent middle colic artery or incomplete

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marginal artery of Drummond) is also revealed. Such information allows the surgeon to anticipate the need for reimplantation of the inferior mesenteric artery (or revascularization of the superior mesenteric or celiac arteries). Other important information, such as the extent of an aneurysm, renal artery stenosis, accessory renal arteries, unsuspected aneurysms, and peripheral occlusive disease, may also be obtained. For these reasons we tend to utilize aortography in the preoperative evaluation of patients with abdominal aortic aneurysm as well as in cases of occlusive disease. Some surgeons routinely reimplant a patent inferior mesenteric artery with a button of aortic wall, and present techniques and sutures make such a maneuver simple and expedient; however, in most cases reimplantation is unnecessary, and aortography should make selective use of this technique possible. Boley's work showed contributing factors in intestinal ischemia emphasizing the need to avoid hypotension, low cardiac output, hypovolemia, colonic distention, and use of vasopressors both intraoperatively and postoperatively." All these factors contribute to reactive vasospasm which may result in damaging ischemic effects that may persist after re-establishment of blood flow to the bowel. The mesenteric vasoconstrictive effects of digitalis must also be remembered. Use of rigorous mechanical and antibiotic bowel preparations may be helpful prophylaxis as suggested by animal studies but no prospective data for humans exist. Ligation of the inferior mesenteric artery at its origin not sacrificing any branches is important, and trauma to the left colon must be avoided. Signs and symptoms of colonic ischemia include lower abdominal pain (frequently crampy), direct and rebound tenderness in the left lower quadrant, fever, leukocytosis, tenesmus, and bloody diarrhea. Once perforation occurs, septic shock and death may rapidly ensue. Early diagnosis is important, and routine sigmoidoscopy or colonoscopy should be considered in high risk patients, such as those with a ruptured aneurysm, low cardiac output state, previously patent inferior mesenteric artery, known stenosis or occlusion of the celiac axis and superior mesenteric artery, or documented preoperative or intraoperative hypotension. Any patient suspected of the diagnosis should have sigmoidoscopy (or colonoscopy) and a barium enema. Sigmoidoscopy may reveal submucosal hemorrhage, granular and friable mucosa, or ulceration. Barium enema may show thumbprinting, spasm, ulceration, or perforation acutely, or stricture in the late postoperative period. Early operation with resection of the ischemic colon and colostomy are mandatory in patients with transmural ischemia. The group with mucosal ischemia may be managed conservatively with bowel rest, parenteral fluids (or hyperalimentation), and antibiotics until symptoms subside. Serial endoscopies and barium enemas will help to determine whether the patient requires an operation.

Cases 3 and 4 At Scott and White Memorial Hospital during the past five years, 307 operations on the aorta involved ligation of the inferior mesenteric artery. Two in-

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stances of colonic ischemia were recognized. One was recognized during operation because of duskiness of the sigmoid colon and the inferior mesenteric artery was reimplanted. In spite of that maneuver the colon became necrotic. The patient underwent colectomy and subsequently died of septic complications. In the other case a 77 year old man was admitted with an expanding abdominal aortic aneurysm and intermittent claudication. After resection of the aneurysm an aorto-bilateral femoral graft was placed. He had an apparently uneventful postoperative course and was discharged on the tenth postoperative day. For one month postoperatively he experienced rectal pain and "hemorrhoids" accompanied by frequent bowel movements without blood. Rectal examination revealed a small prolapsed thrombosed hemorrhoid of no apparent significance but proctoscopy showed a stricture at 10 em. Because of obstruction a colostomy was done and he subsequently underwent colon resection for ischemic stricture of the sigmoid colon (Fig. 3).

Ischemia of the left colon is an important contributor to operative mortality and morbidity in aortic surgery. Prevention must be the goal. Preoperative arteriography is the most important means of anticipating this potential disaster. Once transmural necrosis occurs, early colon resection and colostomy offer the only hope for survival.

Figure 3.

Barium enema shows the ischemic stricture of the sigmoid colon.

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AORTOENTERIC FISTULAS Brook was the first to report a postoperative aortointestinal fistula in 1953, only one year after the introduction of aortic replacement with the homograft." The incidence has been as high as 5 per cent;" Two features of the early surgical technique that predisposed to formation of fistulas included the use of silk sutures that lost strength, resulting in a false aneurysm, and the failure to interpose tissue between the suture line and the duodenum, resulting in proximity of the bowel to the prosthetic material that allowed pressure necrosis and ulceration of the bowel. The development of either low grade or virulent infection was also a significant cause of aorto-enteric fistulas. The site of the fistula formation is almost always the proximal aortic suture line though other sites have been occasionally described. 11, 36, 43, 52 The current incidence is reported to be 0.4 per cent." At the Scott and White Memorial Hospital one has occurred in 508 aortic operations in the past five years (see Case 5). The introduction of synthetic suture materials and the recognition for the need to interpose viable tissue between the prosthesis and the duodenum have resulted in a significant decline in the incidence of aortoenteric fistulas." Tissue interposition is accomplished by suturing the left-sided posterior peritoneum to pericaval tissue (Fig. 4A), and tacking the peritoneal remnant along the ascending portion of the duodenum to this interposed layer of posterior peritoneum (Fig. 5). This maneuver effectively eliminates the aortoenteric fistula. During the repair of an abdominal aortic aneurysm, separation of the graft from the duodenum can be achieved by wrapping the remnant of the aneurysm wall around the prosthesis, taking care to overlap the proximal suture line. When an end-to-end aortic anastomosis is constructed in aortoiliac occlusive disease, coverage of the graft and the suture line is no problem. Difficulty may be encountered in finding adequate coverage when an end-to-side technique is

Figure 4. A, The overlapping closure with the posterior peritoneum is interposed between the aortic graft and the ascending portion of the duodenum. B, Omentum is used for separation of the graft from the duodenum. (a) Descending portion of duodenum. (b) Ascending portion of duodenum. (c) Inferior vena cava. (d) Aortic graft. (e) Posterior peritoneumsite of incision.

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Figure 5. The overlapping posterior peritoneal closure is seen from front. (a) Ascending portion of duodenum. (b) Descending portion of duodenum.

used at the level of the infrarenal aorta. The additional anteroposterior dimension may create tension and fragmentation of the posterior peritoneum as it is stretched over the added bulk and other soft tissue coverage becomes mandatory. The most readily available structure is the greater omentum (see Fig. 5B). The technique of omental interposition can also be used when repeat aortic operation becomes necessary, as the majority of fistulas in the era of modern vascular surgery are caused by reoperations with the attendant extra dissection and lack of adequate posterior peritoneum." The same need for tissue coverage applies to any part of the graft and also the distal suture line if they are in close proximity to hollow viscera. Even though the vast majority of fistulas occur between the duodenum and the proximal aortic suture line (Fig. 6) there are reports of fistulization into small bowel, colon,

Figure 6. The "usual" aortoduodenal fistula.

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and appendix. II, 36. 52 Two cases of fistula between a descending thoracic aortic graft and the esophagus have been reported.:'?: 43 Postoperative vascularenteric fistulas can be classified into two types. The first is a suture line to bowel fistula (aortoenteric fistula) in which the bacterial contamination is confined to the area of contact between the ulcerated bowel and prosthesis, and the usual cause is failure of the suture line and formation of a false aneurysm. The second is initiated by infection around the prosthesis with erosion of the abscess into the bowel (paraprosthetic-enteric fistula). The identification of the type of fistula dictates the technical maneuvers for repair. In the first instance conservative measures have been reported to be successful, such as excision of that portion of the graft involved and replacement with a new graft and meticulous isolation of the bowel from the prosthesis." Appropriate antibiotics in high doses should also be administered for 10 days to four weeks. For the second condition treatment must be radical requiring removal of the entire prosthesis and, if the circulation is compromised, an extra-anatomical bypass must be constructed. 14. 46 There have been six cases of prosthetic-enteric fistula reported in cases of aortorenal bypass." 41 The feature common to all of these is the use of a synthetic graft to the right renal artery. The following case report brings the total to seven and demonstrates some of the features enumerated above.

Case 5 A 52 year old white female was seen at Scott and White Clinic for evaluation of postprandial abdominal pain and hypertension in 1967. No bowel lesion was found but angiography revealed severe stenosis of the celiac and complete occlusion of the superior mesenteric artery with most of the bowel circulation coming by way of a "meandering artery" from the inferior mesenteric circulation. The patient also had a severe stenotic lesion of the right renal artery with lateralizing Hippuran renogram. She underwent patch angioplasty of the celiac axis, reimplantation of the superior mesenteric artery, and a saphenous vein graft to the right renal artery on September 12, 1967. The patient continued to have intermittent minor gastrointestinal complaints, primarily diarrhea. Her postoperative renogram showed good function bilaterally. By 1975 the hypertension recurred and an intravenous pyelogram showed no function of the left kidney. An aortogram showed severe left renal artery stenosis with renal atrophy. The right renal artery bypass was occluded proximally. On September 8, 1975 a left nephrectomy and a right renal artery bypass were performed using a Dacron graft. On November 4, 1977 she was readmitted with a history of painless hematemesis followed by bloody stools. Fiberoptic esophagoduodenoscopy revealed bleeding from the duodenum but because of clots and brisk bleeding, the bleeding site could not be identified. She underwent laparotomy expeditiously, and exploration of the antrum and the first portion of the duodenum was carried out because presence of a postbulbar ulcer was suspected. Only after this maneuver was attention directed to the area of adhesion between the fourth portion of the duodenum and the renal graft where a fistula was found between the duodenum and the aortic suture line of the renal artery graft. The graft was excised and the duodenum closed. Because of occlusion of the native right renal artery and the absent left kidney, it was deemed mandatory to maintain the right renal bypass. A new Dacron graft was placed and attached to the aorta well below the previous site. The previous aortic site of anastomosis was oversewn and reinforced with Dacron pledgets. The patient did well postoperatively and was discharged in good condition; however, one month after dis-

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charge exsanguination occurred suddenly. Autopsy revealed recurrence of the fistula between the aortic closure site and the duodenum.

Although this case is unusual in the sense that the fistula occurred between the aortorenal graft and the duodenum, the remaining features are precisely in line with the reported problems of diagnosis and management. Review of the progress notes and the operative note reflects that the presence of the fistula was not suspected preoperatively. The patient was seen by a gastroenterologist and a general surgeon and an ulcer was thought to be the source of bleeding. There was an interval of two years between insertion of the graft and removal of the fistula. The mean time between insertion of a graft and manifestation of the fistula is reported to be two years;" but it has occurred as late as 12 years;" The bleeding may be intermittent, protracted, or massive. The duodenum is involved in formation of the fistulas in 70 to 80 per cent of the cases and the majority of the bleeding is initially per rectum, though hematemesis is present in one third of the cases. In one series abdominal pain was reported to be present in half of the patients." Commonly there is prodromal bleeding with complete cessation of the bleeding prior to the exsanguinating hemorrhage. During this interval, upper gastrointestinal studies are usually nonrevealing. Angiography is similarly often nondlagnostic," though when it does show the presence of even the smallest false aneurysm, expeditious operation is indicated. Jackson et al. reported the diagnostic effectiveness of both upper gastrointestinal and angiographic studies to be about 5 per cent.>' The presence of a soft tissue abscess, septic arthritis, or osteomyelitis distal to the graft should raise great suspicion of an aortoenteric fistula. 14. 19 Timely diagnosis depends on a high index of suspicion provided by the medical history. Hemorrhage of the gastrointestinal tract in a patient with an aortic graft means an aortoenteric fistula until proved otherwise, and suspicion should be greater if there is a history of reoperation." Esophagogastroscopy': 42 and aortography are useful to rule out other causes of hemorrhage and to show the presence of a false aneurysm or irregularity of the suture line. Most often urgency or the above mentioned reasons preclude a preoperative diagnosis. In these instances, exploration of the suture line by mobilization of any adherent loop of bowel is mandatory, thus confirming or ruling out the diagnosis of aortoenteric fistula. The operative mortality is in the range of 60 per cent," and Szilagyi reported an immediate mortality of 53 per cent." An additional late mortality of 21 per cent also occurred from bleeding as a result of recurrence of the fistula.' In summary, aortoenteric fistulas are better prevented than treated. The key to prevention is adequate separation of the suture line and the entire prosthesis from the hollow viscera, especially the third and fourth portions of the duodenum, as shown in the illustrations. When such soft tissue is unavailable or inadequate, then omentum may be used for this purpose. Every effort must be made to avoid juxtaposition of the bowel wall, the prosthesis, and the suture line.

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MANAGEMENT OF DUODENAL ULCER COMPLICATING CARDIOVASCULAR OPERATIVE TREATMENT The presence of duodenal ulcer disease poses a threat of complication following cardiovascular operations. Four years ago, during an eight month period, 104 consecutive cardiac and abdominal aortic procedures were performed at Scott and White Memorial Hospital. Bleeding or perforation of duodenal ulcer requiring another operation complicated the postoperative course of three patients. It therefore appeared desirable to treat patients with coexisting duodenal ulcer disease with a definitive ulcer operation at the time of the vascular procedure if it could be done without risk of contamination resulting from entering the gastrointestinal tract. Parietal cell vagotomy without pyloroplasty meets this criterion. The morbidity of parietal cell vagotomy is low": 27, 28 and the recurrence rate after five years is 6 per cent.:" For these reasons this operation appeared to be an ideal procedure to perform in conjunction with vascular operations. . During the next 18 months, while 309 patients had cardiovascular operations at Scott and White Memorial Hospital, parietal cell vagotomy was performed concomitantly in 10 patients who had duodenal ulcer. The presence of the ulcer was confirmed radiographically or endoscopically in each patient. Table 1 lists the cardiovascular procedures that the parietal cell vagotomy accompanied. The technique used has been described previously;" The vagotomy is performed after reversal of heparinization following the abdominal aortic or cardiac procedure. In the latter case, the sternotomy greatly facilitates exposure, and, since there is no entry into the gastrointestinal tract, separation of the operative sites is not necessary. None of the patients experienced significant gastrointestinal symptoms or operative complications referrable to the gastric procedure. Postoperative studies in nine patients showed resolution of the ulcer. In a 79 year old man, after healing of his duodenal ulcer, a perforated bleeding gastric ulcer developed 13 months following the vagotomy and the patient died of complications. This complication may be considered to be the result of the vagotomy even though he had been asymptomatic for 13 months while taking indomethacin regularly for arthralgia.

Table 1. List of Cardiovascular Operations and Those Accompanied by Parietal Cell Vagotomy (PcV) in 18 Months PROCEDURE

TOTAL DONE

PCV

Coronary artery bypass Aortofemoral grafts Abdominal aortic aneurysm

158 83

5 2

68

3 10

TOTAL

309

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Proximal selective or parietal cell vagotomy is eminently suited as a companion to cardiovascular procedures because the gastrointestinal tract is not entered, avoiding the risk of contamination. It provides good treatment of duodenal ulcer and protection from the complications of this disease, although the ultimate recurrence rate is expected to be greater than that after vagotomy and hemigastrectomy. Should ulcer disease persist or recur, the parietal cell vagotomy does not preclude subsequent resectional therapy. It is our opinion that when cardiovascular disease needs early surgical correction in the presence of active duodenal ulcer disease, the latter can be controlled successfully by concomitant parietal cell vagotomy. Those patients with a history of duodenal ulcer complications who, though presently asymptomatic, may reactivate under the stress of cardiovascular surgery and should also be considered to be candidates for this operation.

CONCOMITANT CARDIOVASCULAR AND GASTROINTESTINAL OPERATIONS When surgically correctable gastrointestinal lesions coexist with cardiovascular conditions that require operative treatment, the issue of priorities arises. The traditional approach is staging of the operations according to recognized or imagined priorities. The dilemma becomes particularly burning when both the cardiovascular and the gastrointestinallesion constitute an immediate threat to the patient's life and both require urgent action. On the cardiovascular side these conditions would be unstable angina, symptomatic or large (greater than 6 em) abdominal aortic aneurysm, or impending loss of tissue in a lower extremity caused by vascular occlusion above the femoral level. On the gastrointestinal side one might be faced with perforation, bleeding, or obstruction. The greatest threat to cardiovascular operations is posed by the possible necessity to operate on an unprepared colon. Every effort must be made to avoid this combination but our experience indicates that unprepared resection of the colon can be done if meticulous surgical technique is followed. The aortic operation should be done first and careful closure of the posterior peritoneum must be accomplished. The colon lesion is then mobilized and the appropriate resection of the mesocolon is done prior to transection of the unprepared bowel. Primary anastomosis must not be performed. An end colostomy with a mucous fistula or a Hartmann type of closure of the distal stump, depending on the anatomical situation, is performed. In the latter instance, the stapling device can be used to good advantage and the cautery is used to transect the bowel between the stapling device and a very closely applied clamp on the specimen side. An additional row of inverting sutures of No. 5-0 Prolene is added in this instance. An intestinal clamp is applied through the abdominal wall opening prepared for the colostomy onto the intact bowel where it is to be transected. Again, the

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adjacent clamp is applied very closely and electrocautery is used for transection of the bowel. The specimen is removed and the proximal end of the colon is pulled through the abdominal wall and held there by the intestinal clamp. The clamp and the end of the colon are covered with antibiotic-soaked pads and left undisturbed throughout the rest of the procedure. Appropriate tacking sutures are applied to the mesocolon and the colostomy on the peritoneal side to avoid internal herniation and retraction of the bowel. A mucous fistula can be formed by the same technique. The operative site is copiously irrigated with antibiotic solution. Our preference is kanamycin or neomycin and Bacitracin. After wound closure maturation of the colostomy can be done immediately or any time in the immediate postoperative period. The preceding technique has been used in two instances in our institution. In one instance a symptomatic abdominal aortic aneurysm was being operated on when an annular lesion of the sigmoid colon was discovered. The patient had significant chronic obstructive pulmonary disease and avoidance of two independent major operations seemed desirable. He recovered from the combined operation without difficulty and had to look forward to only a relatively minor procedure of colostomy closure. In the other instance, the surgery was done for impending loss of the lower extremity caused by thrombosis of an iliac artery aneurysm. A well localized 5 em mass was found in the lower sigmoid colon and was handled in similar fashion to the previous case, with an end colostomy and a Hartmann closure of the rectosigmoid. He also had an uneventful recovery, and closure of the colostomy was done two months later. The presence of a perforated viscus rules out concomitant intraabdominal vascular reconstruction with synthetic graft material. If the circulatory status demands revascularization, the extra-anatomical bypasses such as axillofemoral or femorofemoral need to be used. In the theoretical instance of coexisting perforated viscus and leaking abdominal aortic aneurysm, the latter would have to be excluded from the circulation with vascular staples above and below and a temporary axillobilateral femoral bypass constructed. Ultimately orthotopic re-

Table 2.

Cholecystectomy Parietal cell vagotomy Gastric resection Colon resection Small bowel resection Esophagectomy TOTAL

Cardiovascular Surgery Accompanied by Gastrointestinal Procedures AAA

A-(I)-F

CAB

TOTAL

16

4 2

1 1 1 0

1 1 0 0

3 5 0 0 0 1

23

3

22

8

9

39

AAA = abdominal aortic aneurysm; A-(I)-F coronary artery bypass.

=

10 2 2

1 1

aorto-(iliac)-femoral graft; and CAB

=

GASTROINTESTINAL COMPLICATIONS OF VASCULAR SURGERY

901

construction may be feasible and even necessary as the patency of the axillofemoral graft is limited. Lesions of the small bowel or stomach can usually be handled without serious contamination and readily lend themselves to correction simultaneously with the vascular procedure. It is important to do the vascular procedure first and complete the retroperitoneal closure prior to embarking on the gastrointestinal portion of the operation. Preoperative or intraoperative and postoperative antibiotic coverage is essential. There is a well recognized coincidence between abdominal aortic aneurysm and cholelithiasis which is also borne out by our experience (see Table 2). There seems to be a general agreement that cholecystectomy may be combined with other vascular procedures in the abdomen without a great deal of worry about contamination, as the sites of the two operative procedures lend themselves to easy isolation. We have not used drainage of the gallbladder bed in our combined procedures. There is the impression from private communications." inference from discussion of a paper presented," and a published report" that following abdominal operations an aneurysm present may become more prone to rupture in the immediate postoperative period.

Case 6 A 71 year old man was admitted to a local hospital with abdominal pain, nausea, and vomiting. A roentgenogram showed distended small bowel loops and a large abdominal aortic aneurysm. A barium enema suggested an obstructing transverse colon lesion and the patient was explored. An 8 em intact abdominal aortic aneurysm was confirmed but only sigmoid diverticulitis, nonobstructing, was found, causing a considerable dilemma which was resolved by closure of the abdomen without resectional therapy. The patient recovered and was discharged in good condition and was referred for elective resection of the aneurysm. Before his appointment, three weeks following his laparotomy, he was hospitalized with back and left groin pain and immediate operation confirmed a leaking abdominal aortic aneurysm. His subsequent course was uncomplicated.

The issue of coincidental malignancy and abdominal aortic aneurysm is analyzed by Szilagyi et al.:" Though Szilagyi personally does not believe that there is evidence to suggest that abdominal aortic aneurysm is prone to rupture following an unrelated operation;" review of his data would lend some support to this supposition. He reported on 11 patients in whom the diagnosis of malignant disease and abdominal aortic aneurysm was made preoperatively. In two instances the aneurysm was resected either before or after surgery for the associated disease, and three patients died of malignant or other unrelated disease. Five, however, died of ruptured aneurysms three to 24 months following operation. Another underwent emergency resection of the aneurysm four weeks postoperatively and survived, to die later of metastasis. Based on this type of data and our favorable experience in combined operations we feel that concomitant abdominal aortic aneurysm resection with other urgent intra-abdominal procedures is possible and desirable. Table 1 shows our experience in the past :five years with combined operations. Only one patient died in this group, an 83 year old man

902

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H. HAYWARD ET AL.

who underwent abdominal aortic aneurysm resection and cholecystectomy and succumbed 12 days postoperatively from myocardial infarction. Review of the records failed to disclose any complication that could be attributed to the combination of the procedures. No hard and fast rules dictate the indications for combined procedures." Each operation has to be planned according to the existing conditions and the individual needs of the patient. In addition to the obvious advantage of total correction;" operations may sometimes be combined for the convenience of the patient, allowing him to recuperate from more than one operation simultaneously. The result is a reduction in recovery time, discomfort, time away from work, and expense.

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