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Venous Shunts in Portal Hypertension
VENOUS SHUNTS IN PORTAL HYPERTENSION LEO
V. MULLIGAN, M.D.*
SOME understanding of the disturbed vascular dynamics is necessary for the proper evaluation ·of the therapeutic measures proposed to relieve portal hypertension. It is surprising that, with so much interest having been devoted to this problem, our knowledge in most respects remains very meager, contradictory and theoretical. The basis for portal hypertension in most patients is intrahepatic. It is not difficult to perceive the increased pressure resulting in thrombosis of the hepatic veins (Chiari's syndrome), or in Schistosoma infestation. However, the exact pathogenesis of the increased portal tension in most patients is obscure. In cirrhosis, there is no correlation between the amount of the periportal fibrous tissue and the increase in pressure. The highest pressures have been associated usually with the early cirrhosis. It is probable that the pressure from regenerating liver tissue following necrosis, regardless of the cause, is the basis for the obstruction to portal flow. The development of portal hypertension in some patients, notably those without demonstrable pathological anatomy, may represent a disturbance in an intrahepatic valvular mechanism such as described by Knisely, Bloch and Warner." This would be compatible with the perfusion experiments reported by Herrick" and subsequently confirmed by Dock. Hj- 16 Thomas and Essex" have reported a sphincteric mechanism in the hepatic veins. Maybe this is involved in the development of portal hypertension in some patients without demonstrable pathological anatomy. It is conceivable that an abnormal vascular physiology precedes and in some unknown manner contributes to the anatomical changes noted in certain liver diseases. The pathogenesis of portal hypertension in extrahepatic obstruction of the portal system is usually obvious. The lesion may be congenital or acquired. The thromboses that follow trauma or inflammatory reactions in the vicinity of the portal circulation, e.g., pancreatitis, need no elaboration. Thrombosis of the portal system may occur in adult life without demonstrable cause. Whether the congenital obstructions result, as suggested by Warthin," from a continuation of the obliterative process in
* Assistant Professor of Clinical Surgery, St. Louis University School of Medicine; Associate Surgeon, University Hospitals, St. John's Hospital, DePaul Hospital; Chairman, Unit II, St. Louis City Hospital; Attending Surgeon, Veterans Administration Hospital, Jefferson Barracks, Missouri, and St. Louis County Hospital, Clayton, Missouri. 1465
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the umbilical vein and ductus venosus, or whether it represents an angioma, or intravascular clotting associated with incompletely understood blood groupings or other unknown or unrecognized causes, is interesting speculation but not fundamental to this paper. Whipple'" has described an extrahepatic portal block termed "cavernous transformation" of the portal vein in which the picture is suggestive of a recanalized thrombosis with well developed collaterals surrounding the vein. Blakemore? has encountered extrahepatic obstruction in sixteen of sixty patients with portal hypertension. Linton'" has found the obstruction outside of the liver in fourteen of thirty-four patients treated. Pattison'" described a "thrombotic obliteration" of the portal vein in two of fourteen patients operated upon for hypertension, and in neither was a shunt accomplished. I have encountered it once in seventeen patients with portal hypertension. SYMPTOMS OF PORTAL HYPERTENSION
Regardless of the pathological process involved or its location, the symptoms which usually bring one afflicted with portal hypertension to the surgeon are either hemorrhage from esophageal varices or unrelenting ascites. In 385 patients with cirrhosis of the liver, Ratnoff and Patek'" listed rupture of esophageal varices in the cause of death in 26 per cent. In that series of "untreated" patients, hematemesis occurred in 27 per cent of patients with cirrhosis of the liver. Blakemore" quoted Patek as stating that hematemesis occurred in 33 per cent of 124 cirrhotic patients receiving medical therapy. The inference is that the occurrence of massive hematemesis from esophageal varices presents a serious problem in spite of what is generally considered adequate medical therapy. Blakemore? further quotes Patek as stating that 50 per cent of patients with cirrhosis are dead within one year of the onset of hematemesis. With increasing knowledge of dietary requirements, the role of lipotropic substances in liver physiology, vitamins and so forth, the medical management of various forms of liver disease has improved. Perhaps no symptom reflects the results of this increased knowledge more than the control of ascites and even this response is usually only temporary. There are those patients in whom the filtration pressure is so great, because of the factor of increased portal pressure, that the production of serum proteins cannot overcome the loss in ascitic fluid. These patients experience complete relief from their ascites if the portal pressure can be reduced to a more nearly normal level. As these patients are usually more aware of their symptomatic improvement than those with esophageal varices, they are often the most grateful patients. Naturally, this does not include that group of cirrhotic patients so near liver failure that they no longer are able to 'produce adequate amounts of serum proteins.
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Although hematemesis and ascites are the predominating symptoms that bring the patient to the surgeon, occasionally pain in the left upper quadrant of the abdomen resulting from splenomegaly and perisplenitis may be the presenting symptom. Similarly, the presence of portal hypertension may be manifested initially by melena, menorrhagia, metrorrhagia, by the presence of hemorrhoids.ior by anemia from chronic blood loss. It is becoming increasingly obvious that the complete abdominal exploration in search of the etiology of unexplained bleeding into the gastrointestinal tract must include a determination of the portal pressure. SURGICAL APPROACH TO SYMPTOMS OF PORTAL HYPERTENSION
Historical Aspect. Following the successful performance of a side-toside anastomosis of the portal vein to the inferior vena cava in dogs by the Russian physiologist, Von Eck, in 1877, numerous attempts at clinical application of this principle were made, chiefly in continental Europe. The results were so discouraging that other approaches to the problem were made, such as the indirect anastomosis provided by the omentopexy as suggested by Talma" and by Morison" and others, and also by visceropexy. Although the results were considered encouraging, critical analyses": 19,31 have shown otherwise. Others interested in the problem of control of hemorrhage from esophageal varices have approached the problem by injecting sclerosing solutions into the varices through the esophagoscope; by ligation of veins about the cardia of the stomach; by the ligation of the splenic artery; or by ligation of the superior mesenteric, inferior mesenteric or the coronary veins; by mediastinotomy with packing about the esophagus to establish an inflammatory reaction that would promote thrombosis; esophagogastric resection; gastrectomy and splenectomy. The control of ascites has been attempted by creating a tract leading to the subcutaneous tissues by inserting a spool-like glass or plastic apparatus"; or by the anastomosis of ureter;" kidney pelvis or the saphenous vein to the peritoneal cavity. With the exception of splenectomy in patients with obstruction in the splenic vein to the left of the entrance of the coronary vein, none of the above procedures aim to relieve the hypertension which contributes to the hematemesis and ascites. The lack of success with the above procedures is certainly attested by the enthusiasm rendered the work of Blakemore and Lord 8 in the use of the nonsuture technic in vascular surgery and the initial reports by Whipple" and Blakemore and Lord 9 on the treatment of portal hypertension by venous shunts. Although the nonsuture method of anastomosis has been discarded in the surgery of portal hypertension, it did furnish the impetus for working out the details necessary to the present success in the suture method.
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Confusion has resulted from the application of the term "portacaval" both to the shunting of blood from the portal system to the general venous system, and as used in this paper referring specifically to the shunting of blood through the portal vein into the inferior vena cava. Preoperative Evaluation of the Patient. The examination and preparation of the patient is a very important item, not only from the standpoint of the usual precautions in all major operative procedures but with special reference to the diagnostic aids that may be of help in the localization of the lesion responsible for the hypertension. These patients may present splenomegaly with hypersplenism manifested by a decrease in one or more of the formed blood elements. The degree of depression of these elements fluctuates and is not helpful in locating the obstruction. The history, physical findings and laboratory results compatible with liver impairment are more helpful when positive. Minimal liver impairment as gauged by the "liver profile" may be found in one with severe portal hypertension associated with cirrhosis of the liver, as exemplified by the following: B. V., a 22 year old white man, without overseas service, was admitted to the Veterans Administration Hospital, Jefferson Barracks, Missouri, with hematemesis of one day's duration. ,The past history was not revelant except for extreme dietary deficiencies. The family history revealed that a sister, aged 16" died one year previously of "hemorrhage from Banti's disease," despite treatment with 48 units of blood. Examination revealed the presence of melena. The .spleen was palpable below the level of the umbilicus. The red blood cell count was 2,830,000 with 9 gm. of hemoglobin. There were 4,000 leukocytes per cubic millimeter of blood and the platelet count varied from 40,000 to 60,000. Prothrombin time was 100 percent of normal; cephalin-cholesterol flocculation was 2 plus in forty-eight hours; thymol turbidity was 3.8; serum albumin was 4.5 gm. and serum globulin was 2.3 gm. per 100 cc.; and bromsulfalein retention was 8 per cent. Esophageal varices were demonstrable radiographically. The portal pressure was 500 mm. of saline. A liver biopsy taken at the time of operation revealed an early Laennec's cirrhosis. The splenomegaly and esophageal varices have completely disappeared following a portacaval anastomosis.
Not only are the physical and laboratory findings, when positive, of importance in the localization of the pathology, but, when repeated, give an indication of the efficacy of the rest, high protein diet, lipotropic substances, vitamins, transfusions and serum albumin used in the preparation of the patient. The ability of the liver to produce serum proteins, particularly albumin, seems to be a most important criteria of adequate liver function. Although Blakemore earlier stated that he believed brom-
l
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sulfalein retention greater than 45 per cent was virtually a contraindication, he" subsequently reported successful procedures in patients with 60 to 70 per cent retention. The return of the prothrombin time to a more nearly normal figure following the administration of vitamin K is an encouraging sign but levels of 40 per cent of normal or below are compatible with a successful anastomosis. It is quite probable that with much more prolonged preoperative preparation with massive doses of vitamin K, this value could be brought more nearly to normal but the fear of intercurrent hemorrhage usually discourages unnecessary procrastination. Everyone with considerable experience in managing massive hematemesis from esophageal varices has seen many patients who have continued to bleed over a prolonged period during which they may have received as much as 50 or more units of blood, only to die eventually of uncontrolled hemorrhage. Costello," in reviewing 300 consecutive cases of massive hematemesis, found ruptured espohageal varices as the cause in 8 per cent. The mortality rate in this group was 71 per cent. In view of the very high mortality rate in these patients in spite of all measuresto control the hemorrhage, there will probably soon be justification for considering these patients as surgical emergencies with treatment directed at relieving the portal hypertension. Operating Room. Considerable emphasis has been placed on the physical requirements for successful vascular surgery, such as ultra-violet lights, etc., and the necessity of unusual precautions for sterility. Seventeen patients have been operated in four different teaching hospitals, none of which make any special arrangements for vascular surgery. The results have not indicated that the facilities are inadequate. Anesthesia and Intravenous Fluids. Gas anesthesia is administered through an endotracheal catheter by a competent physician anesthetist. Various anesthetic agents have been employed usually in a "balanced anesthesia" maintaining the maximum oxygen saturation. These have been supplemented, where indicated, by intravenous procaine and curare. The potentialities of the anesthetist deserve more consideration than the nature of the agents employed. In those patients in which the preoperative examination suggests considerable impairment of liver function, barbiturates and opium derivatives are used sparingly. Realizing the possibility of a sudden need for large amounts of blood, two infusions are started with 16 gauge needles and blood is given as indicated. This requirement will vary considerably, but with increased proficiency in technic, usually 3 to 5 units of blood will suffice. Incision. Satinsky'" and Heaney and Humphreys" have very adequately described the positioning of the patient and the incision for a right thoracoabdominal approach, which makes the structures readily accessible for a portacaval shunt. The procedure is technically easier
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with the patient in a true lateral position but most anesthetists find it easier to maintain a maximum degree of oxygenation with the patient more nearly at a 45 degree angle with the table, and then rotating the table when desired. If any doubt exists preoperatively regarding the site of the obstruction, the abdominal portion of the incision is made first and the pathologic condition investigated, and the pressures determined in a branch of the superior mesenteric and coronary veins. In interpreting the findings one must be aware of the variation in the anatomy of the portal system, the most common of which are the emptying of the coronary vein into the splenic vein rather than the portal vein, and the emptying of the inferior mesenteric vein into the superior mesenteric rather than the splenic. If these examinations reveal the obstruction to be intrahepatic, the thoracic portion of the incision is completed, the diaphragm split and the liver rotated into the right side of the thorax. A plexus of veins is frequently encountered about the portal vein and one must be prepared to separate these meticulously. The intercostal approach may be employed instead of resecting a portion of a rib but closure is usually more difficult. Anastomosis. The clamp pictured in Figures 424 and 425 has not been described previously but has proved very successful in the performance of venous anastomoses both experimentally and in patients with portal hypertension. It is designed so that only the anterior and medial portion of the inferior vena cava need be mobilized, thus avoiding the small tributaries which enter posteriorly and are very easily torn. The pressure on the vein is controlled from a single point and thus evenly distributed. The clamp does not produce a "scissors" effect when applied to the vein. It may be employed to constrict a portion of one vein in an end-to-side anastomosis or parts of two veins in a side-to-side shunt. The entire length of the portal vein is mobilized so that ligatures may be applied about the branches of the vein. It is then sectioned through the widened portion of the fork, giving a greater circumference for the anastomosis. Bleeding from the portal vein is controlled by the clamp pictured in Figure 425, B. An elliptical segment measuring approximately 1 by 2 cm. is excised from the vena cava, thus producing more of a stoma than would result from a slit like opening. The anastomosis is completed with an everting, continuous, mattress suture interrupted at four points as described by Blalock.' Frequently some bleeding from the site of the anastomosis follows removal of the clamp but this usually stops spontaneously. If not, additional interrupted sutures may be placed where necessary. Commercially prepared hemostatic agents are not employed in the vicinity of the anastomosis or elsewhere as they tend to invite infection and promote thrombosis. Death occurred on the thirty-first postoperative day in the
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Fig. 424. Photograph of clamp used to occlude a segment of inferior vena cava without complete obstruction of blood flow.
Fig. 425. Diagrammatic representations of the clamps as applied to the inferior vena cava and the portal vein in the end-to-side portacaval anastomosis.
first patient treated. A splenorenal shunt was performed and some commercially prepared hemostatic agent was used to control bleeding in the region of the tail of the pancreas. Postmortem examination revealed a
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small abscess at this site, adjacent to the splenic vein, with thrombosis of the entire portal system. Careful attention to hemostasis by individually controlling each vessel is of paramount importance. The area about the anastomosis is irrigated frequently during the procedure with a saline solution containing 10 mg. of heparin per ounce. Deknatel (5-0) swedged on a small round needle has been found most satisfactory. The recent experimental work of Smith" and of Johnson and Kirby" in which a constriction occurred at the anastomotic site in arterial anastomoses when nonabsorbable sutures were employed but absent when absorbable suture were used, raises the question of the advisability of using absorbable sutures in vascular surgery where growth is a factor to be considered. Only time will tell whether or not these findings are applicable to the venous anastomosis in the surgery of portal hypertension in children. Naturally, the relationships of the veins to be anastomosed must be considered to prevent kinking, twisting and external pressure when the procedure is completed and anatomical relationships restored. The relative merits of end-to-side and side-to-side anastomosis is a matter of controversy. Experimentally, side-to-side anastomoses are more prone to thrombosis unless the vein is ligated distally and then it becomes virtually and end-to-side anastomosis. Probably the obstruction which exists in portal hypertension makes ligature unnecessary. Some clinicians feel that a side-to-side anastomosis should be favored on the basis that it would permit the flow of blood through the liver. It is difficult to believe that much blood will flow through the liver when the pressure is reduced to approximately one-fifth the previous level. At present it is impossible to speculate about the obstruction eventually disappearing as ·so frequently the exact pathogenesis is uncertain. Furthermore, I agree with Blalock' that the side-to-side anastomosis is more difficult to to perform. Certainly this is true if segments of the veins are removed to produce a wider ostium than results merely from slits in the opposing walls of the veins. Other Anastomoses. Exposure of the portal vein may infrequently reveal that it is not suitable for an anastomosis because of atresia, thrombosis or other pathologic condition. The size and accessibility of the superior mesenteric vein makes it a most logical second choice for anastomosis with the inferior vena cava. Normally, it is the next largest vein in the portal system and is usually not involved in the pathological processes that are frequently seen in the splenic vein. Because blood would then be draining from both segments of the superior mesenteric vein, it seems more rational but not necessary to attempt a side-to-side anastomosis at this site despite the increased technical difficulties. The splenorenal anastomosis is probably one of the most frequently
T
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performed at the present time, being preferred by some, such as Linton and his associates." Blakemore":" is of the opinion that splenorenal shunts are less effective in reducing the portal hypertension and are more prone to thrombosis. The only proven or suspected thrombosis in the present group of patients occurred following a splenorenal shunt. Undoubtedly, the fact that fewer vital structures are encountered in this area has prompted some'" to favor this over the portacaval anastomosis. However, the splenic vein is not only smaller in diameter but is frequently so tortuous, sacculated and friable with areas of atrophy and sclerosis that technically it is much more difficult to mobilize and suture. Certainly if it is to be used, the small pancreatic veins should be meticulously isolated and individually ligated rather than employing mass ligatures. Rarely, circumstances may make it mandatory to resort to other parts of the portal system in the treatment of portal hypertension by anastomosis to branches of the inferior vena cava. However, one must be prepared to accept less reduction in the hypertension and a greater tendency to thrombosis at the site of anastomosis in using smaller veins. And likewise, one must be prepared to encounter occasionally a portal system so diffusely pathological that no anastomosis is possible. As a result of the occasional spectacular results in the treatment of socalled Banti's syndrome with splenectomy, one occasionally encounters those who feel "it should be tried" in patients bleeding from esophageal varices. That such is illogical is rapidly becoming accepted and is illustrated by the following case history: E. F., a 25 year old veteran, was admitted to the Veterans Administration Hospital, Jefferson Barracks, Missouri, with a history of hematemesis first appearing approximately four years previously in the Phillipine Islands. A provisional diagnosis of peptic ulcer was made and he was given a bland diet and evacuated to the United States. At a General Hospital the radiographic examination revealed esophageal varices but no evidence-of peptic ulcer. An enlarged spleen was observed and a diagnosis of Banti's syndrome was made. Splenectomy was performed. Hematemesis occurred during the first and third weeks postoperatively and then intermittently with tarry stools until admission to the Veterans Administration Hospital approximately two years later. The red blood cell count was 3,950,000 with a normal platelet and leukocyte count. The cephalin-cholesterol flocculation test was negative and the thymol turbidity was 4.1. The prothrombin time was 75 per cent and the bromsulfalein retention was 2 per cent. The serum albumin was 4.8 and the serum globulin was 2.8 gm. per 100cc. A portacaval anastomosis was performed and the pressure in the portal system fell from 320 to 40 mm. of saline. An intrahepatic obstruction associated with Laennec's cirrhosis was found. There was no bleeding in
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the year following operation and the varices are no longer demonstrable either by esophagoscopy or esophagram.
Fortunately, in this individual, the portal vein was suitable for an anastomosis. However, the occasion could arise where the patient's chance for recovery might be jeopardized by the previous sacrifice of the splenic vein. Splenectomy alone suffices only when the obstruction is in the splenic vein proximal to the entrance of the coronary veins, and surgery should not be attempted unless one is prepared to deal adequately with the situation by splenectomy or venous shunts as indicated by the findings and pressure determinations. Should the preliminary investigation of the abdomen after the abdominal portion of the incision has been made reveal the cause of the portal hypertension to be such that would require a splenectomy or an anastomosis employing the splenic vein, the incision is extended to the left rather than into the right side of the thorax. i
PRESSURE CHANGES IN THE PORTAL SYSTEM
The normal range of pressure in the portal vein is approximately 40 to 100 mm. of saline. The presence of an increase in the general venous pressure must be excluded before assuming that an elevated portal pressure results from an abnormality in the portal system. The highest encountered was previously referred to in this presentation and was 500 mm. of saline. Following the completion of the portacaval anastomosis the portalpressure is lowered, as one would expect with an adequate stoma, to the level of the general venous pressure. The peripheral venous pressure in the veins of the forearm may remain rather constant at normal levels throughout the operative procedure until the clamps are removed after the completion of the anastomosis, and then rise fairly sharply. It has been found to return to normal in about three to twentyfour hours. In only one instance in portacaval anastomosis has the peripheral venous pressure not risen during the operation, and in that patient the portal pressure was 40 mm. of saline at the completion of the anastomosis. As the pressures in the two venous systems are equal on completion of the shunt, it is reasonable to assume that they remain equal following the return of the peripheral venous pressure to normal. The above observations have not been duplicated in the splenorenal shunts. The portal pressure, although lowered, does not return to normal. The peripheral venous pressure has not been elevated at the completion of the shunt in two patients. This is in agreement with the previously expressed belief that splenorenal shunts are less effective in alleviating the portal hypertension. The exact mechanism accounting for the elevation" of the peripheral
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venous pressure following the removal of the clamps may be related to the degree of obstruction of the inferior vena cava and the length of time the clamp remains in place, causing some pooling of blood in thelower portion of the body. Experimental and clinical studies are now being performed in an effort to clarify this point. As yet the indications for subsequent laparotomy have not presented themselves in those patients having equal but elevated peripheral venous and portal pressures following an anastomosis of the portal vein and the vena cava. Such an opportunity would test the assumption previously expressed that probably the portal pressure continues to fall with the peripheral venous pressure until both are within normal range. POSTOPERATIVE MANAGEMENT
The maintenance of the highest possible oxygen content of the blood is considered of prime importance in the postoperative period, especially in patients with intrahepatic obstruction. Sufficient oxygen can usually be .administered to the comfort of the patient with a well regulated oxygen tent or by intranasal catheter. An intercostal catheter is inserted when closing the thoracic wound and connected with a water seal. This is considered important in maintaining complete expansion of the lungs. Whenever indicated, intercostal nerve block is employed to promote deep breathing and the removal of bronchial secretions. Considerable attention has been given in the literature to the control of postoperative distention; however, this has not been a problem in the successful anastomosis. If present, it may indicate some serious complication in the operative area, such as thrombosis. Prostigmine and urecholine may be used if indicated but are rarely necessary. Parenteral administration of fluids can usually be discontinued on the second or third day. Gastric suction was required in one patient following a splenorenal shunt, who died on the thirty-first postoperative day with a thrombosis of the entire portal system. Continuous intravenous heparin had been administered for eight days, maintaining a clotting time of thirty to sixty minutes by the Lee-White method. Although the available information is controversial, one is tempted on the basis of certain reports 33- 34 to employ anticoagulants postoperatively in vascular surgery. This is especially true in venous anastomoses with delayed healing and low pressures. Blakemore" has stated that he likes to institute anticoagulant therapy in patients in whom a reasonably dry operative field can be obtained. However, even with quite exacting care, the control of the coagulation and prothrombin time are most difficult and often very unsatisfactory, even to the point of being dangerous. One of two deaths following a portacaval anastomosis occurred in a 61 year
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old white woman with a well developed Laennec's cirrhosis, on the second postoperative day while receiving continuous intravenous heparin. Postmortem examination revealed hemorrhage into the operative wound, chest and pleural cavities. The anastomosis was patent with no evidence of hemorrhage or thrombosis at this site. Although regular clotting time determinations by the Lee-White method were employed, it is obvious that the control of this patient was inadequate. It is doubtful whether or not heparin has any beneficial effects in properly performed, elective vascular surgery and its use has been discontinued. Blakemore" has frequently referred to avoidance of early ambulation in patients following shunt operations. He has stated that this is based on the feeling that a shift of viscera is apt to cause an angulation at the anastomosis. Three deaths have occurred in sixteen patients following venous anastomoses: one in about forty hours, one on the fourth day and the other on the thirty-first day. These patients had not been ambulated but eleven of the remainder were as soon as the arterial and venous pressures had stabilized, which is usually within sixteen to thirty hours, with no indication that it should not be continued. Theoretically, at least, it is important to maintain the blood pressure and volume at a nearly normal value in the postoperative period as a reduced volume or a sluggish circulation promotes thrombosis. RESULTS
A longer period of observation of a larger number of patients will be necessary for definite conclusions regarding the effect of correcting portal hypertension by the shunting of all or a part of the bloodfrom the portal into the caval system. The effect on the general physiology and especially of hepatic physiology remains in doubt but continuation of this treatment with close clinical observation is justified. Eventually, it may be conclusively demonstrated that there is some temporary or even permament deleterious effect on liver physiology. Nevertheless, on the basis of statistical observations, it would appear that there is an increased life expectancy following a shunt in patients with portal hypertension. Portal hypertension is apparently controlled by an adequate shunt. Hemorrhages from various orifices are controlled and ascites is usually relieved. Esophageal varices have not been demonstrable postoperatively either by esophagoscopy or by radiography. Figure 426 demonstrates well the change noted in the esophagram after the performance of a shunt. Blakemore's experience with venous anastomosis in the treatment of portal ,hypertension surpasses all others. He 7 reported eleven deaths in sixty patients, a mortality of 18 per cent. This includes the results using all types of shunts as well as those in which the nonsuture technic was employed. Both intrahepatic and extrahepatic obstructions are included
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in these figures. Linton" has published a mortality rate of 35 per cent in patients with intrahepatic obstruction with no deaths following an anastomosis for extrahepatic obstruction. He reported a combined mortality rate of 21 per cent in thirty-four patients. Both authors have presented decreasing mortality figures as the number of patients treated has increased. I have found intrahepatic obstruction in sixteen of seventeen patients with portal hypertension. An end-to-side splenorenal shunt was performed in two patients with one death and an end-to-side portacaval anastomosis in fourteen patients with two deaths. Three of these fourteen patients were previously treated by splenectomy. In the single instance
Fig. 426. Esophagrams made before (a) and after (b) a portacaval anastomosis. The irregularities in the barium column attributed to the presence of esophageal varices have completely disappeared.
of extrahepatic obstruction, the portal and superior mesenteric veins were replaced by multiple channels resembling a recanalized thrombus so that an anastomosis was impossible. This is the only instance in which a shunt was attempted unsuccessfully. Although a splenectomy had previously been performed, a second attempt is planned, hoping to find a satisfactory stump of splenic vein or an inferior mesenteric vein that may be employed in a shunt. The combined mortality rate in those patients in whom shunts have been accomplished is 18 per cent. These figures, of course, can be very deceiving and must reflect, in some measure, the willingness to attempt treatment of poor risk patients. With increasing experience in selecting patients, fewer fatalities should result from operating on individuals bordering on "liver failure." The third death in the
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present group is now placed in that category. Likewise, the experiences gained from technical and therapeutic transgressions may be avoided so that it seems probable that eventually a mortality rate well below 10 per cent might be anticipated. In view of subsequent experiences, it seems very probable that two of the three deaths were definitely avoidable. They have led to the discontinuance of the use of commercial hemostatic agents during the operation and of heparin postoperatively.
SUMMARY 1. Brief consideration has been given some of the pathological anatomy and physiology in portal hypertension. 2. The prominent symptomatology in patients with portal hypertension has been reviewed. 3. End-to-side portacaval anastomosis has been presented as the procedure of choice. A technic of anastomosis has been described, including the presentation of a new clamp for occluding a portion of the inferior vena cava. 4. The importance of determining the peripheral venous pressure in. evaluating the portal pressure, both before and after the shunt, has been emphasized. 5. The use of commercially prepared hemostatic agents has been condemned. 6. Postoperative care, including anticoagulant therapy, has been discussed. 7. The results following venous shunts for portal hypertension have been considered in relation to the reduction in portal pressure, the control of symptoms, and mortality rate.
REFERENCES 1. Blalock, Alfred: The Use of Shunt or By-pass Operations in the Treatment of Certain Circulatory Disorders, Including Portal Hypertension and Pulmonic Stenosis. Ann. Surge 125:129-141, 1947. 2. Blalock, A. and Taussig, H. B.: Surgical Treatment of Malformations of Heart in Which There Is Pulmonary Stenosis of Pulmonary Atresia. ~.A.M.A. 128:189-202, 1945. 3. Blakemore, A. H.: Indications ·for Portacaval Anastomosis-Analysis of Cases. Surg., Gynec. & Obst. 84.:645-653, 1947. 4. Blakemore, A. H.: Portacaval Anastomoses-Observations on Technic and Postoperative Care. S. CI.JIN. NORTH AMERICA 28:279-289, 1948. 5. Blakemore, A. H.: Portacaval Anastomosis. Surg., Gynec. & Obst. 87:277279, 1948. 6. Blakemore, A. H.: Portacaval Anastomosis. Surge 24:480-484, 1948. 7. Blakemore, A. H.: Portacaval Anastomosis for Portal Hypertension. Surge 26:99-102, 1949. 8. Blakemore, A. H. and Lord, J. W., Jr.: A Non-suture Method of Blood Vessel Anastomosis. tLA.M.A. 127:685-748, 1945.
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9. Blakemore, A. H. and Lord, J. W., Jr.: The Technic of Using Vitallium Tubes in Establishing Portacaval Shunts in Portal Hypertension. Ann. Surge 122:476-489, 1945. 10. Bradley, S. E., Ingelfinger, F. J., Bradley, G. P. and Curry, J. J.: Estimation of Hepatic Blood Flow in Man. J. Clin. Investigation 24:890-897,1945. 11. Callow, A. D. and Welch, C. S.: Arterial Anastomosis in Experimental Arterial Injury. Surg., Gynec. & Obst. 90:77-85, 1950. 12. Cates, H. B.: Surgical Treatment of Cirrhosis: Prognosis Subsequent to Omentopexy. Arch. Int. Med. 71:183-205, 1943. 13. Costello, Cyril: Massive Hematemesis-Analysis of 300 Consecutive Cases. Ann. Surge 129: 289-298,1949. 14. Crosby, R. C. and Cooney, E. A.: Surgical Treatment of Ascites. New England J. Med. 235: 581-585,1946. 15. Dock, W. Role of Increased Hepatic Arterial Flow in Portal Hypertension of Cirrhosis. Tr. A. Am. Physicians 57:302-306, 1942. 16. Dock, W.: The Clinical Significance of Some Peculiarities of the Circulation in the Kidneys, Liver, Lungs and Heart. New England J. Med. 236:773-782, 1947. 17. Dummond, D. and Morison, R.: Case of Ascites due to Cirrhosis of Liver Cured by Operation. Brit. M. J. 2:728-729, 1896. 18. Ferguson, C.: Ascites, Operation for its Relief: Case Report. J. Urol. 50:164168, 1943. 19. Grinnell, R. S.: Omentopexy in Portal Cirrhosis of Liver with Ascites: Review of Twenty-three Cases. Ann. Surge 101:891-901, 1935. 20. Heaney, John P. and Humphreys, George H., II: The Right Thoraco-abdominal Approach. Ann. Surge 128:948-955, 1948. 21. Herrick, F. A. An Experimental Study Into the Cause of Increased Portal Pressure in Portal Cirrhosis. J. Exper. Med. 9:93-104, 1907. 22. Jameson, E. M. and Savarese, L. A. Familial Portal Cirrhosis in Young Adults. U. S. Nav. M. Bull. 45:270-276, 1945. 23. Johns, T.N.P. A Comparison of Suture and Non-suture Methods for Anas. tomosis of Veins. Surg., Gynec. & Obst. 84:939-942, 1947. 24. Johnson, J. and Kirby, C. K. The Relationship of Suture to the Growth of End-to-end Arterial Anastomoses. Surgery 27:17-25, 1950. 25. Karsner, H. T.: Morphology and Pathogenesis of Hepatic Cirrhosis. Am. J. Clin. Path. 13:569-606, 1943. 26. Kniseley, M. H., Bloch, E. H. and Warner, L.: The Structure and Mechanical Functioning of the Living Live; Lobules of Frogs and Rhesus Monkeys. Proc. Institute of Medicine of Chicago 16:286-289, 1947. 27. Linton, R. R.: Portacaval Shunts in the Treatment of Portal Hypertension with Special Reference to Patients Previously Operated Upon. New England J. Med. 238:723-727, 1948. 28. Linton, R. R. The Surgical Treatment of Bleeding Esophageal Varices by Portal Systemic Venous Shunts with a Report of Thirty-four Cases. Ann. Int. Med. 31:794-804, 1949. 29. Linton, R. R., Jones, E. M. and Volwiler, W.: Portal I-Iypertension-the Treatment by Splenectomy and Splenorenal Anastomosis with Preservation of Kidney. S. CLIN. NORTH AMERICA 27:1162-1170, 1947. 30. Linton, R. R., Hardy, I. B. and Volwiler, W.: Portacaval Shunts in the Treatment of Portal Hypertension. Surg., Gynec. & Obst. 87:129-144,.)948. 31. Mayo, W. J.: Surgical Treatment of Hepatic Cirrhosis. Ann. Surge 80:419-424, 1924.
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32. Morison, R.: A Case of Ascites Due to Liver Cirrhosis Treated by Operation. Ann. Surge 38:361-366, 1903. 33. Murray, Gordon: Heparin in the Surgical Treatment of Blood Vessels. Arch. Surge 40:307-325, 1940. 34. Murray, Gordon: Heparin in Thrombosis and Blood Vessel Surgery. Surg., Gynec. & Obst. 72:340-344, 1941. 35. Pattison, A. C.: Use of Portacaval Anastomosis in Portal Cirrhosis. Tr. VVest. S. A. 56:54-66, 1948. 36. Ratnoff, O. D. and Patek, A. J., Jr.: The Natural History of Laennec's Cirrhosis of the Liver. Medicine 21:207-268, 1942. 37. Ravenna, Paolo: Banti's Syndrome (Fibrocongestive Splenomegaly). Arch. Int. Med.66:879-892, 1940. 38. Satinsky, Victor, P.: Thoraco-abdominal Approach for Portacaval Anastomosis. Ann. Surge 128:938-947, 1948. 39. Schatzki, R.: Roentgen Demonstration of Esophageal Varices-Its Clinical Significance. Arch. Surge 41:1084-1100, 1940. 40. Schumacker, H. B., Jr., Abramson, D. I. and Lampert, H. H.: The Use of Anticoagulants in the Surgery of Aneurysms and Arteriovenous Fistulas, with Particular Reference to Dicoumarol. Surgery 22:910-918, 1947. 41. Smith, Sidney: Unpublished data. . 42. Talma, S.: Chirurgische Offnung Neuer Sietenbahnen fur das Blunt der Vena Porta. Berl. kline VVschr. 35:833-836, 1898. 43. Thomas, VV. D. and Essex, H. E. Observations on the Hepatic Venous Circulation with Special Reference to the Sphincteric Mechanism. Am. J. Physiol. 158:303-310, 1949. 44. VVarthin, A. S.: The Relation of Thrombophlebitis of the Portal and Splenic Veins to Splenic Anemia and Banti's Disease. Internat. Clin, 4:189-226, 1910. 45. VVelch, C. S.: Technic for Portacaval Anastomosis (Eck Fistula). Surg., Gynec. & Obst. 85:492-494, 1947. 46. VVhipple, A. 0.: Problem of Portal Hypertension in Relation to Hepatosplenopathies. Ann. Surge 122:449-475, 1945. 47. VVhipple, G. H.~ Robscheit-Robbins,F. S. and Hawkins, VV. B.: Eck Fistula Liver Subnormal in Producing Hemoglobin and Plasma Proteins on Diets Rich in Liver and Iron. J. Exper. Med. 81:171-191, 1945.
V. MULLIGAN, M.D.*
SOME understanding of the disturbed vascular dynamics is necessary for the proper evaluation ·of the therapeutic measures proposed to relieve portal hypertension. It is surprising that, with so much interest having been devoted to this problem, our knowledge in most respects remains very meager, contradictory and theoretical. The basis for portal hypertension in most patients is intrahepatic. It is not difficult to perceive the increased pressure resulting in thrombosis of the hepatic veins (Chiari's syndrome), or in Schistosoma infestation. However, the exact pathogenesis of the increased portal tension in most patients is obscure. In cirrhosis, there is no correlation between the amount of the periportal fibrous tissue and the increase in pressure. The highest pressures have been associated usually with the early cirrhosis. It is probable that the pressure from regenerating liver tissue following necrosis, regardless of the cause, is the basis for the obstruction to portal flow. The development of portal hypertension in some patients, notably those without demonstrable pathological anatomy, may represent a disturbance in an intrahepatic valvular mechanism such as described by Knisely, Bloch and Warner." This would be compatible with the perfusion experiments reported by Herrick" and subsequently confirmed by Dock. Hj- 16 Thomas and Essex" have reported a sphincteric mechanism in the hepatic veins. Maybe this is involved in the development of portal hypertension in some patients without demonstrable pathological anatomy. It is conceivable that an abnormal vascular physiology precedes and in some unknown manner contributes to the anatomical changes noted in certain liver diseases. The pathogenesis of portal hypertension in extrahepatic obstruction of the portal system is usually obvious. The lesion may be congenital or acquired. The thromboses that follow trauma or inflammatory reactions in the vicinity of the portal circulation, e.g., pancreatitis, need no elaboration. Thrombosis of the portal system may occur in adult life without demonstrable cause. Whether the congenital obstructions result, as suggested by Warthin," from a continuation of the obliterative process in
* Assistant Professor of Clinical Surgery, St. Louis University School of Medicine; Associate Surgeon, University Hospitals, St. John's Hospital, DePaul Hospital; Chairman, Unit II, St. Louis City Hospital; Attending Surgeon, Veterans Administration Hospital, Jefferson Barracks, Missouri, and St. Louis County Hospital, Clayton, Missouri. 1465
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the umbilical vein and ductus venosus, or whether it represents an angioma, or intravascular clotting associated with incompletely understood blood groupings or other unknown or unrecognized causes, is interesting speculation but not fundamental to this paper. Whipple'" has described an extrahepatic portal block termed "cavernous transformation" of the portal vein in which the picture is suggestive of a recanalized thrombosis with well developed collaterals surrounding the vein. Blakemore? has encountered extrahepatic obstruction in sixteen of sixty patients with portal hypertension. Linton'" has found the obstruction outside of the liver in fourteen of thirty-four patients treated. Pattison'" described a "thrombotic obliteration" of the portal vein in two of fourteen patients operated upon for hypertension, and in neither was a shunt accomplished. I have encountered it once in seventeen patients with portal hypertension. SYMPTOMS OF PORTAL HYPERTENSION
Regardless of the pathological process involved or its location, the symptoms which usually bring one afflicted with portal hypertension to the surgeon are either hemorrhage from esophageal varices or unrelenting ascites. In 385 patients with cirrhosis of the liver, Ratnoff and Patek'" listed rupture of esophageal varices in the cause of death in 26 per cent. In that series of "untreated" patients, hematemesis occurred in 27 per cent of patients with cirrhosis of the liver. Blakemore" quoted Patek as stating that hematemesis occurred in 33 per cent of 124 cirrhotic patients receiving medical therapy. The inference is that the occurrence of massive hematemesis from esophageal varices presents a serious problem in spite of what is generally considered adequate medical therapy. Blakemore? further quotes Patek as stating that 50 per cent of patients with cirrhosis are dead within one year of the onset of hematemesis. With increasing knowledge of dietary requirements, the role of lipotropic substances in liver physiology, vitamins and so forth, the medical management of various forms of liver disease has improved. Perhaps no symptom reflects the results of this increased knowledge more than the control of ascites and even this response is usually only temporary. There are those patients in whom the filtration pressure is so great, because of the factor of increased portal pressure, that the production of serum proteins cannot overcome the loss in ascitic fluid. These patients experience complete relief from their ascites if the portal pressure can be reduced to a more nearly normal level. As these patients are usually more aware of their symptomatic improvement than those with esophageal varices, they are often the most grateful patients. Naturally, this does not include that group of cirrhotic patients so near liver failure that they no longer are able to 'produce adequate amounts of serum proteins.
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Although hematemesis and ascites are the predominating symptoms that bring the patient to the surgeon, occasionally pain in the left upper quadrant of the abdomen resulting from splenomegaly and perisplenitis may be the presenting symptom. Similarly, the presence of portal hypertension may be manifested initially by melena, menorrhagia, metrorrhagia, by the presence of hemorrhoids.ior by anemia from chronic blood loss. It is becoming increasingly obvious that the complete abdominal exploration in search of the etiology of unexplained bleeding into the gastrointestinal tract must include a determination of the portal pressure. SURGICAL APPROACH TO SYMPTOMS OF PORTAL HYPERTENSION
Historical Aspect. Following the successful performance of a side-toside anastomosis of the portal vein to the inferior vena cava in dogs by the Russian physiologist, Von Eck, in 1877, numerous attempts at clinical application of this principle were made, chiefly in continental Europe. The results were so discouraging that other approaches to the problem were made, such as the indirect anastomosis provided by the omentopexy as suggested by Talma" and by Morison" and others, and also by visceropexy. Although the results were considered encouraging, critical analyses": 19,31 have shown otherwise. Others interested in the problem of control of hemorrhage from esophageal varices have approached the problem by injecting sclerosing solutions into the varices through the esophagoscope; by ligation of veins about the cardia of the stomach; by the ligation of the splenic artery; or by ligation of the superior mesenteric, inferior mesenteric or the coronary veins; by mediastinotomy with packing about the esophagus to establish an inflammatory reaction that would promote thrombosis; esophagogastric resection; gastrectomy and splenectomy. The control of ascites has been attempted by creating a tract leading to the subcutaneous tissues by inserting a spool-like glass or plastic apparatus"; or by the anastomosis of ureter;" kidney pelvis or the saphenous vein to the peritoneal cavity. With the exception of splenectomy in patients with obstruction in the splenic vein to the left of the entrance of the coronary vein, none of the above procedures aim to relieve the hypertension which contributes to the hematemesis and ascites. The lack of success with the above procedures is certainly attested by the enthusiasm rendered the work of Blakemore and Lord 8 in the use of the nonsuture technic in vascular surgery and the initial reports by Whipple" and Blakemore and Lord 9 on the treatment of portal hypertension by venous shunts. Although the nonsuture method of anastomosis has been discarded in the surgery of portal hypertension, it did furnish the impetus for working out the details necessary to the present success in the suture method.
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Confusion has resulted from the application of the term "portacaval" both to the shunting of blood from the portal system to the general venous system, and as used in this paper referring specifically to the shunting of blood through the portal vein into the inferior vena cava. Preoperative Evaluation of the Patient. The examination and preparation of the patient is a very important item, not only from the standpoint of the usual precautions in all major operative procedures but with special reference to the diagnostic aids that may be of help in the localization of the lesion responsible for the hypertension. These patients may present splenomegaly with hypersplenism manifested by a decrease in one or more of the formed blood elements. The degree of depression of these elements fluctuates and is not helpful in locating the obstruction. The history, physical findings and laboratory results compatible with liver impairment are more helpful when positive. Minimal liver impairment as gauged by the "liver profile" may be found in one with severe portal hypertension associated with cirrhosis of the liver, as exemplified by the following: B. V., a 22 year old white man, without overseas service, was admitted to the Veterans Administration Hospital, Jefferson Barracks, Missouri, with hematemesis of one day's duration. ,The past history was not revelant except for extreme dietary deficiencies. The family history revealed that a sister, aged 16" died one year previously of "hemorrhage from Banti's disease," despite treatment with 48 units of blood. Examination revealed the presence of melena. The .spleen was palpable below the level of the umbilicus. The red blood cell count was 2,830,000 with 9 gm. of hemoglobin. There were 4,000 leukocytes per cubic millimeter of blood and the platelet count varied from 40,000 to 60,000. Prothrombin time was 100 percent of normal; cephalin-cholesterol flocculation was 2 plus in forty-eight hours; thymol turbidity was 3.8; serum albumin was 4.5 gm. and serum globulin was 2.3 gm. per 100 cc.; and bromsulfalein retention was 8 per cent. Esophageal varices were demonstrable radiographically. The portal pressure was 500 mm. of saline. A liver biopsy taken at the time of operation revealed an early Laennec's cirrhosis. The splenomegaly and esophageal varices have completely disappeared following a portacaval anastomosis.
Not only are the physical and laboratory findings, when positive, of importance in the localization of the pathology, but, when repeated, give an indication of the efficacy of the rest, high protein diet, lipotropic substances, vitamins, transfusions and serum albumin used in the preparation of the patient. The ability of the liver to produce serum proteins, particularly albumin, seems to be a most important criteria of adequate liver function. Although Blakemore earlier stated that he believed brom-
l
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sulfalein retention greater than 45 per cent was virtually a contraindication, he" subsequently reported successful procedures in patients with 60 to 70 per cent retention. The return of the prothrombin time to a more nearly normal figure following the administration of vitamin K is an encouraging sign but levels of 40 per cent of normal or below are compatible with a successful anastomosis. It is quite probable that with much more prolonged preoperative preparation with massive doses of vitamin K, this value could be brought more nearly to normal but the fear of intercurrent hemorrhage usually discourages unnecessary procrastination. Everyone with considerable experience in managing massive hematemesis from esophageal varices has seen many patients who have continued to bleed over a prolonged period during which they may have received as much as 50 or more units of blood, only to die eventually of uncontrolled hemorrhage. Costello," in reviewing 300 consecutive cases of massive hematemesis, found ruptured espohageal varices as the cause in 8 per cent. The mortality rate in this group was 71 per cent. In view of the very high mortality rate in these patients in spite of all measuresto control the hemorrhage, there will probably soon be justification for considering these patients as surgical emergencies with treatment directed at relieving the portal hypertension. Operating Room. Considerable emphasis has been placed on the physical requirements for successful vascular surgery, such as ultra-violet lights, etc., and the necessity of unusual precautions for sterility. Seventeen patients have been operated in four different teaching hospitals, none of which make any special arrangements for vascular surgery. The results have not indicated that the facilities are inadequate. Anesthesia and Intravenous Fluids. Gas anesthesia is administered through an endotracheal catheter by a competent physician anesthetist. Various anesthetic agents have been employed usually in a "balanced anesthesia" maintaining the maximum oxygen saturation. These have been supplemented, where indicated, by intravenous procaine and curare. The potentialities of the anesthetist deserve more consideration than the nature of the agents employed. In those patients in which the preoperative examination suggests considerable impairment of liver function, barbiturates and opium derivatives are used sparingly. Realizing the possibility of a sudden need for large amounts of blood, two infusions are started with 16 gauge needles and blood is given as indicated. This requirement will vary considerably, but with increased proficiency in technic, usually 3 to 5 units of blood will suffice. Incision. Satinsky'" and Heaney and Humphreys" have very adequately described the positioning of the patient and the incision for a right thoracoabdominal approach, which makes the structures readily accessible for a portacaval shunt. The procedure is technically easier
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with the patient in a true lateral position but most anesthetists find it easier to maintain a maximum degree of oxygenation with the patient more nearly at a 45 degree angle with the table, and then rotating the table when desired. If any doubt exists preoperatively regarding the site of the obstruction, the abdominal portion of the incision is made first and the pathologic condition investigated, and the pressures determined in a branch of the superior mesenteric and coronary veins. In interpreting the findings one must be aware of the variation in the anatomy of the portal system, the most common of which are the emptying of the coronary vein into the splenic vein rather than the portal vein, and the emptying of the inferior mesenteric vein into the superior mesenteric rather than the splenic. If these examinations reveal the obstruction to be intrahepatic, the thoracic portion of the incision is completed, the diaphragm split and the liver rotated into the right side of the thorax. A plexus of veins is frequently encountered about the portal vein and one must be prepared to separate these meticulously. The intercostal approach may be employed instead of resecting a portion of a rib but closure is usually more difficult. Anastomosis. The clamp pictured in Figures 424 and 425 has not been described previously but has proved very successful in the performance of venous anastomoses both experimentally and in patients with portal hypertension. It is designed so that only the anterior and medial portion of the inferior vena cava need be mobilized, thus avoiding the small tributaries which enter posteriorly and are very easily torn. The pressure on the vein is controlled from a single point and thus evenly distributed. The clamp does not produce a "scissors" effect when applied to the vein. It may be employed to constrict a portion of one vein in an end-to-side anastomosis or parts of two veins in a side-to-side shunt. The entire length of the portal vein is mobilized so that ligatures may be applied about the branches of the vein. It is then sectioned through the widened portion of the fork, giving a greater circumference for the anastomosis. Bleeding from the portal vein is controlled by the clamp pictured in Figure 425, B. An elliptical segment measuring approximately 1 by 2 cm. is excised from the vena cava, thus producing more of a stoma than would result from a slit like opening. The anastomosis is completed with an everting, continuous, mattress suture interrupted at four points as described by Blalock.' Frequently some bleeding from the site of the anastomosis follows removal of the clamp but this usually stops spontaneously. If not, additional interrupted sutures may be placed where necessary. Commercially prepared hemostatic agents are not employed in the vicinity of the anastomosis or elsewhere as they tend to invite infection and promote thrombosis. Death occurred on the thirty-first postoperative day in the
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Fig. 424. Photograph of clamp used to occlude a segment of inferior vena cava without complete obstruction of blood flow.
Fig. 425. Diagrammatic representations of the clamps as applied to the inferior vena cava and the portal vein in the end-to-side portacaval anastomosis.
first patient treated. A splenorenal shunt was performed and some commercially prepared hemostatic agent was used to control bleeding in the region of the tail of the pancreas. Postmortem examination revealed a
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small abscess at this site, adjacent to the splenic vein, with thrombosis of the entire portal system. Careful attention to hemostasis by individually controlling each vessel is of paramount importance. The area about the anastomosis is irrigated frequently during the procedure with a saline solution containing 10 mg. of heparin per ounce. Deknatel (5-0) swedged on a small round needle has been found most satisfactory. The recent experimental work of Smith" and of Johnson and Kirby" in which a constriction occurred at the anastomotic site in arterial anastomoses when nonabsorbable sutures were employed but absent when absorbable suture were used, raises the question of the advisability of using absorbable sutures in vascular surgery where growth is a factor to be considered. Only time will tell whether or not these findings are applicable to the venous anastomosis in the surgery of portal hypertension in children. Naturally, the relationships of the veins to be anastomosed must be considered to prevent kinking, twisting and external pressure when the procedure is completed and anatomical relationships restored. The relative merits of end-to-side and side-to-side anastomosis is a matter of controversy. Experimentally, side-to-side anastomoses are more prone to thrombosis unless the vein is ligated distally and then it becomes virtually and end-to-side anastomosis. Probably the obstruction which exists in portal hypertension makes ligature unnecessary. Some clinicians feel that a side-to-side anastomosis should be favored on the basis that it would permit the flow of blood through the liver. It is difficult to believe that much blood will flow through the liver when the pressure is reduced to approximately one-fifth the previous level. At present it is impossible to speculate about the obstruction eventually disappearing as ·so frequently the exact pathogenesis is uncertain. Furthermore, I agree with Blalock' that the side-to-side anastomosis is more difficult to to perform. Certainly this is true if segments of the veins are removed to produce a wider ostium than results merely from slits in the opposing walls of the veins. Other Anastomoses. Exposure of the portal vein may infrequently reveal that it is not suitable for an anastomosis because of atresia, thrombosis or other pathologic condition. The size and accessibility of the superior mesenteric vein makes it a most logical second choice for anastomosis with the inferior vena cava. Normally, it is the next largest vein in the portal system and is usually not involved in the pathological processes that are frequently seen in the splenic vein. Because blood would then be draining from both segments of the superior mesenteric vein, it seems more rational but not necessary to attempt a side-to-side anastomosis at this site despite the increased technical difficulties. The splenorenal anastomosis is probably one of the most frequently
T
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performed at the present time, being preferred by some, such as Linton and his associates." Blakemore":" is of the opinion that splenorenal shunts are less effective in reducing the portal hypertension and are more prone to thrombosis. The only proven or suspected thrombosis in the present group of patients occurred following a splenorenal shunt. Undoubtedly, the fact that fewer vital structures are encountered in this area has prompted some'" to favor this over the portacaval anastomosis. However, the splenic vein is not only smaller in diameter but is frequently so tortuous, sacculated and friable with areas of atrophy and sclerosis that technically it is much more difficult to mobilize and suture. Certainly if it is to be used, the small pancreatic veins should be meticulously isolated and individually ligated rather than employing mass ligatures. Rarely, circumstances may make it mandatory to resort to other parts of the portal system in the treatment of portal hypertension by anastomosis to branches of the inferior vena cava. However, one must be prepared to accept less reduction in the hypertension and a greater tendency to thrombosis at the site of anastomosis in using smaller veins. And likewise, one must be prepared to encounter occasionally a portal system so diffusely pathological that no anastomosis is possible. As a result of the occasional spectacular results in the treatment of socalled Banti's syndrome with splenectomy, one occasionally encounters those who feel "it should be tried" in patients bleeding from esophageal varices. That such is illogical is rapidly becoming accepted and is illustrated by the following case history: E. F., a 25 year old veteran, was admitted to the Veterans Administration Hospital, Jefferson Barracks, Missouri, with a history of hematemesis first appearing approximately four years previously in the Phillipine Islands. A provisional diagnosis of peptic ulcer was made and he was given a bland diet and evacuated to the United States. At a General Hospital the radiographic examination revealed esophageal varices but no evidence-of peptic ulcer. An enlarged spleen was observed and a diagnosis of Banti's syndrome was made. Splenectomy was performed. Hematemesis occurred during the first and third weeks postoperatively and then intermittently with tarry stools until admission to the Veterans Administration Hospital approximately two years later. The red blood cell count was 3,950,000 with a normal platelet and leukocyte count. The cephalin-cholesterol flocculation test was negative and the thymol turbidity was 4.1. The prothrombin time was 75 per cent and the bromsulfalein retention was 2 per cent. The serum albumin was 4.8 and the serum globulin was 2.8 gm. per 100cc. A portacaval anastomosis was performed and the pressure in the portal system fell from 320 to 40 mm. of saline. An intrahepatic obstruction associated with Laennec's cirrhosis was found. There was no bleeding in
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the year following operation and the varices are no longer demonstrable either by esophagoscopy or esophagram.
Fortunately, in this individual, the portal vein was suitable for an anastomosis. However, the occasion could arise where the patient's chance for recovery might be jeopardized by the previous sacrifice of the splenic vein. Splenectomy alone suffices only when the obstruction is in the splenic vein proximal to the entrance of the coronary veins, and surgery should not be attempted unless one is prepared to deal adequately with the situation by splenectomy or venous shunts as indicated by the findings and pressure determinations. Should the preliminary investigation of the abdomen after the abdominal portion of the incision has been made reveal the cause of the portal hypertension to be such that would require a splenectomy or an anastomosis employing the splenic vein, the incision is extended to the left rather than into the right side of the thorax. i
PRESSURE CHANGES IN THE PORTAL SYSTEM
The normal range of pressure in the portal vein is approximately 40 to 100 mm. of saline. The presence of an increase in the general venous pressure must be excluded before assuming that an elevated portal pressure results from an abnormality in the portal system. The highest encountered was previously referred to in this presentation and was 500 mm. of saline. Following the completion of the portacaval anastomosis the portalpressure is lowered, as one would expect with an adequate stoma, to the level of the general venous pressure. The peripheral venous pressure in the veins of the forearm may remain rather constant at normal levels throughout the operative procedure until the clamps are removed after the completion of the anastomosis, and then rise fairly sharply. It has been found to return to normal in about three to twentyfour hours. In only one instance in portacaval anastomosis has the peripheral venous pressure not risen during the operation, and in that patient the portal pressure was 40 mm. of saline at the completion of the anastomosis. As the pressures in the two venous systems are equal on completion of the shunt, it is reasonable to assume that they remain equal following the return of the peripheral venous pressure to normal. The above observations have not been duplicated in the splenorenal shunts. The portal pressure, although lowered, does not return to normal. The peripheral venous pressure has not been elevated at the completion of the shunt in two patients. This is in agreement with the previously expressed belief that splenorenal shunts are less effective in alleviating the portal hypertension. The exact mechanism accounting for the elevation" of the peripheral
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venous pressure following the removal of the clamps may be related to the degree of obstruction of the inferior vena cava and the length of time the clamp remains in place, causing some pooling of blood in thelower portion of the body. Experimental and clinical studies are now being performed in an effort to clarify this point. As yet the indications for subsequent laparotomy have not presented themselves in those patients having equal but elevated peripheral venous and portal pressures following an anastomosis of the portal vein and the vena cava. Such an opportunity would test the assumption previously expressed that probably the portal pressure continues to fall with the peripheral venous pressure until both are within normal range. POSTOPERATIVE MANAGEMENT
The maintenance of the highest possible oxygen content of the blood is considered of prime importance in the postoperative period, especially in patients with intrahepatic obstruction. Sufficient oxygen can usually be .administered to the comfort of the patient with a well regulated oxygen tent or by intranasal catheter. An intercostal catheter is inserted when closing the thoracic wound and connected with a water seal. This is considered important in maintaining complete expansion of the lungs. Whenever indicated, intercostal nerve block is employed to promote deep breathing and the removal of bronchial secretions. Considerable attention has been given in the literature to the control of postoperative distention; however, this has not been a problem in the successful anastomosis. If present, it may indicate some serious complication in the operative area, such as thrombosis. Prostigmine and urecholine may be used if indicated but are rarely necessary. Parenteral administration of fluids can usually be discontinued on the second or third day. Gastric suction was required in one patient following a splenorenal shunt, who died on the thirty-first postoperative day with a thrombosis of the entire portal system. Continuous intravenous heparin had been administered for eight days, maintaining a clotting time of thirty to sixty minutes by the Lee-White method. Although the available information is controversial, one is tempted on the basis of certain reports 33- 34 to employ anticoagulants postoperatively in vascular surgery. This is especially true in venous anastomoses with delayed healing and low pressures. Blakemore" has stated that he likes to institute anticoagulant therapy in patients in whom a reasonably dry operative field can be obtained. However, even with quite exacting care, the control of the coagulation and prothrombin time are most difficult and often very unsatisfactory, even to the point of being dangerous. One of two deaths following a portacaval anastomosis occurred in a 61 year
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old white woman with a well developed Laennec's cirrhosis, on the second postoperative day while receiving continuous intravenous heparin. Postmortem examination revealed hemorrhage into the operative wound, chest and pleural cavities. The anastomosis was patent with no evidence of hemorrhage or thrombosis at this site. Although regular clotting time determinations by the Lee-White method were employed, it is obvious that the control of this patient was inadequate. It is doubtful whether or not heparin has any beneficial effects in properly performed, elective vascular surgery and its use has been discontinued. Blakemore" has frequently referred to avoidance of early ambulation in patients following shunt operations. He has stated that this is based on the feeling that a shift of viscera is apt to cause an angulation at the anastomosis. Three deaths have occurred in sixteen patients following venous anastomoses: one in about forty hours, one on the fourth day and the other on the thirty-first day. These patients had not been ambulated but eleven of the remainder were as soon as the arterial and venous pressures had stabilized, which is usually within sixteen to thirty hours, with no indication that it should not be continued. Theoretically, at least, it is important to maintain the blood pressure and volume at a nearly normal value in the postoperative period as a reduced volume or a sluggish circulation promotes thrombosis. RESULTS
A longer period of observation of a larger number of patients will be necessary for definite conclusions regarding the effect of correcting portal hypertension by the shunting of all or a part of the bloodfrom the portal into the caval system. The effect on the general physiology and especially of hepatic physiology remains in doubt but continuation of this treatment with close clinical observation is justified. Eventually, it may be conclusively demonstrated that there is some temporary or even permament deleterious effect on liver physiology. Nevertheless, on the basis of statistical observations, it would appear that there is an increased life expectancy following a shunt in patients with portal hypertension. Portal hypertension is apparently controlled by an adequate shunt. Hemorrhages from various orifices are controlled and ascites is usually relieved. Esophageal varices have not been demonstrable postoperatively either by esophagoscopy or by radiography. Figure 426 demonstrates well the change noted in the esophagram after the performance of a shunt. Blakemore's experience with venous anastomosis in the treatment of portal ,hypertension surpasses all others. He 7 reported eleven deaths in sixty patients, a mortality of 18 per cent. This includes the results using all types of shunts as well as those in which the nonsuture technic was employed. Both intrahepatic and extrahepatic obstructions are included
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in these figures. Linton" has published a mortality rate of 35 per cent in patients with intrahepatic obstruction with no deaths following an anastomosis for extrahepatic obstruction. He reported a combined mortality rate of 21 per cent in thirty-four patients. Both authors have presented decreasing mortality figures as the number of patients treated has increased. I have found intrahepatic obstruction in sixteen of seventeen patients with portal hypertension. An end-to-side splenorenal shunt was performed in two patients with one death and an end-to-side portacaval anastomosis in fourteen patients with two deaths. Three of these fourteen patients were previously treated by splenectomy. In the single instance
Fig. 426. Esophagrams made before (a) and after (b) a portacaval anastomosis. The irregularities in the barium column attributed to the presence of esophageal varices have completely disappeared.
of extrahepatic obstruction, the portal and superior mesenteric veins were replaced by multiple channels resembling a recanalized thrombus so that an anastomosis was impossible. This is the only instance in which a shunt was attempted unsuccessfully. Although a splenectomy had previously been performed, a second attempt is planned, hoping to find a satisfactory stump of splenic vein or an inferior mesenteric vein that may be employed in a shunt. The combined mortality rate in those patients in whom shunts have been accomplished is 18 per cent. These figures, of course, can be very deceiving and must reflect, in some measure, the willingness to attempt treatment of poor risk patients. With increasing experience in selecting patients, fewer fatalities should result from operating on individuals bordering on "liver failure." The third death in the
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present group is now placed in that category. Likewise, the experiences gained from technical and therapeutic transgressions may be avoided so that it seems probable that eventually a mortality rate well below 10 per cent might be anticipated. In view of subsequent experiences, it seems very probable that two of the three deaths were definitely avoidable. They have led to the discontinuance of the use of commercial hemostatic agents during the operation and of heparin postoperatively.
SUMMARY 1. Brief consideration has been given some of the pathological anatomy and physiology in portal hypertension. 2. The prominent symptomatology in patients with portal hypertension has been reviewed. 3. End-to-side portacaval anastomosis has been presented as the procedure of choice. A technic of anastomosis has been described, including the presentation of a new clamp for occluding a portion of the inferior vena cava. 4. The importance of determining the peripheral venous pressure in. evaluating the portal pressure, both before and after the shunt, has been emphasized. 5. The use of commercially prepared hemostatic agents has been condemned. 6. Postoperative care, including anticoagulant therapy, has been discussed. 7. The results following venous shunts for portal hypertension have been considered in relation to the reduction in portal pressure, the control of symptoms, and mortality rate.
REFERENCES 1. Blalock, Alfred: The Use of Shunt or By-pass Operations in the Treatment of Certain Circulatory Disorders, Including Portal Hypertension and Pulmonic Stenosis. Ann. Surge 125:129-141, 1947. 2. Blalock, A. and Taussig, H. B.: Surgical Treatment of Malformations of Heart in Which There Is Pulmonary Stenosis of Pulmonary Atresia. ~.A.M.A. 128:189-202, 1945. 3. Blakemore, A. H.: Indications ·for Portacaval Anastomosis-Analysis of Cases. Surg., Gynec. & Obst. 84.:645-653, 1947. 4. Blakemore, A. H.: Portacaval Anastomoses-Observations on Technic and Postoperative Care. S. CI.JIN. NORTH AMERICA 28:279-289, 1948. 5. Blakemore, A. H.: Portacaval Anastomosis. Surg., Gynec. & Obst. 87:277279, 1948. 6. Blakemore, A. H.: Portacaval Anastomosis. Surge 24:480-484, 1948. 7. Blakemore, A. H.: Portacaval Anastomosis for Portal Hypertension. Surge 26:99-102, 1949. 8. Blakemore, A. H. and Lord, J. W., Jr.: A Non-suture Method of Blood Vessel Anastomosis. tLA.M.A. 127:685-748, 1945.
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9. Blakemore, A. H. and Lord, J. W., Jr.: The Technic of Using Vitallium Tubes in Establishing Portacaval Shunts in Portal Hypertension. Ann. Surge 122:476-489, 1945. 10. Bradley, S. E., Ingelfinger, F. J., Bradley, G. P. and Curry, J. J.: Estimation of Hepatic Blood Flow in Man. J. Clin. Investigation 24:890-897,1945. 11. Callow, A. D. and Welch, C. S.: Arterial Anastomosis in Experimental Arterial Injury. Surg., Gynec. & Obst. 90:77-85, 1950. 12. Cates, H. B.: Surgical Treatment of Cirrhosis: Prognosis Subsequent to Omentopexy. Arch. Int. Med. 71:183-205, 1943. 13. Costello, Cyril: Massive Hematemesis-Analysis of 300 Consecutive Cases. Ann. Surge 129: 289-298,1949. 14. Crosby, R. C. and Cooney, E. A.: Surgical Treatment of Ascites. New England J. Med. 235: 581-585,1946. 15. Dock, W. Role of Increased Hepatic Arterial Flow in Portal Hypertension of Cirrhosis. Tr. A. Am. Physicians 57:302-306, 1942. 16. Dock, W.: The Clinical Significance of Some Peculiarities of the Circulation in the Kidneys, Liver, Lungs and Heart. New England J. Med. 236:773-782, 1947. 17. Dummond, D. and Morison, R.: Case of Ascites due to Cirrhosis of Liver Cured by Operation. Brit. M. J. 2:728-729, 1896. 18. Ferguson, C.: Ascites, Operation for its Relief: Case Report. J. Urol. 50:164168, 1943. 19. Grinnell, R. S.: Omentopexy in Portal Cirrhosis of Liver with Ascites: Review of Twenty-three Cases. Ann. Surge 101:891-901, 1935. 20. Heaney, John P. and Humphreys, George H., II: The Right Thoraco-abdominal Approach. Ann. Surge 128:948-955, 1948. 21. Herrick, F. A. An Experimental Study Into the Cause of Increased Portal Pressure in Portal Cirrhosis. J. Exper. Med. 9:93-104, 1907. 22. Jameson, E. M. and Savarese, L. A. Familial Portal Cirrhosis in Young Adults. U. S. Nav. M. Bull. 45:270-276, 1945. 23. Johns, T.N.P. A Comparison of Suture and Non-suture Methods for Anas. tomosis of Veins. Surg., Gynec. & Obst. 84:939-942, 1947. 24. Johnson, J. and Kirby, C. K. The Relationship of Suture to the Growth of End-to-end Arterial Anastomoses. Surgery 27:17-25, 1950. 25. Karsner, H. T.: Morphology and Pathogenesis of Hepatic Cirrhosis. Am. J. Clin. Path. 13:569-606, 1943. 26. Kniseley, M. H., Bloch, E. H. and Warner, L.: The Structure and Mechanical Functioning of the Living Live; Lobules of Frogs and Rhesus Monkeys. Proc. Institute of Medicine of Chicago 16:286-289, 1947. 27. Linton, R. R.: Portacaval Shunts in the Treatment of Portal Hypertension with Special Reference to Patients Previously Operated Upon. New England J. Med. 238:723-727, 1948. 28. Linton, R. R. The Surgical Treatment of Bleeding Esophageal Varices by Portal Systemic Venous Shunts with a Report of Thirty-four Cases. Ann. Int. Med. 31:794-804, 1949. 29. Linton, R. R., Jones, E. M. and Volwiler, W.: Portal I-Iypertension-the Treatment by Splenectomy and Splenorenal Anastomosis with Preservation of Kidney. S. CLIN. NORTH AMERICA 27:1162-1170, 1947. 30. Linton, R. R., Hardy, I. B. and Volwiler, W.: Portacaval Shunts in the Treatment of Portal Hypertension. Surg., Gynec. & Obst. 87:129-144,.)948. 31. Mayo, W. J.: Surgical Treatment of Hepatic Cirrhosis. Ann. Surge 80:419-424, 1924.
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32. Morison, R.: A Case of Ascites Due to Liver Cirrhosis Treated by Operation. Ann. Surge 38:361-366, 1903. 33. Murray, Gordon: Heparin in the Surgical Treatment of Blood Vessels. Arch. Surge 40:307-325, 1940. 34. Murray, Gordon: Heparin in Thrombosis and Blood Vessel Surgery. Surg., Gynec. & Obst. 72:340-344, 1941. 35. Pattison, A. C.: Use of Portacaval Anastomosis in Portal Cirrhosis. Tr. VVest. S. A. 56:54-66, 1948. 36. Ratnoff, O. D. and Patek, A. J., Jr.: The Natural History of Laennec's Cirrhosis of the Liver. Medicine 21:207-268, 1942. 37. Ravenna, Paolo: Banti's Syndrome (Fibrocongestive Splenomegaly). Arch. Int. Med.66:879-892, 1940. 38. Satinsky, Victor, P.: Thoraco-abdominal Approach for Portacaval Anastomosis. Ann. Surge 128:938-947, 1948. 39. Schatzki, R.: Roentgen Demonstration of Esophageal Varices-Its Clinical Significance. Arch. Surge 41:1084-1100, 1940. 40. Schumacker, H. B., Jr., Abramson, D. I. and Lampert, H. H.: The Use of Anticoagulants in the Surgery of Aneurysms and Arteriovenous Fistulas, with Particular Reference to Dicoumarol. Surgery 22:910-918, 1947. 41. Smith, Sidney: Unpublished data. . 42. Talma, S.: Chirurgische Offnung Neuer Sietenbahnen fur das Blunt der Vena Porta. Berl. kline VVschr. 35:833-836, 1898. 43. Thomas, VV. D. and Essex, H. E. Observations on the Hepatic Venous Circulation with Special Reference to the Sphincteric Mechanism. Am. J. Physiol. 158:303-310, 1949. 44. VVarthin, A. S.: The Relation of Thrombophlebitis of the Portal and Splenic Veins to Splenic Anemia and Banti's Disease. Internat. Clin, 4:189-226, 1910. 45. VVelch, C. S.: Technic for Portacaval Anastomosis (Eck Fistula). Surg., Gynec. & Obst. 85:492-494, 1947. 46. VVhipple, A. 0.: Problem of Portal Hypertension in Relation to Hepatosplenopathies. Ann. Surge 122:449-475, 1945. 47. VVhipple, G. H.~ Robscheit-Robbins,F. S. and Hawkins, VV. B.: Eck Fistula Liver Subnormal in Producing Hemoglobin and Plasma Proteins on Diets Rich in Liver and Iron. J. Exper. Med. 81:171-191, 1945.