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Postgrad Med J: first published as 10.1136/pgmj.39.451.299 on 1 May 1963. Downloaded from POSTGRAD. MED. J. (I963), 39, 299

PORTAL AND ITS RADIOLOGICAL INVESTIGATION J. H. MIDDLEMISS, M.D., F.F.R., D.M.R.D. F. G. M. Ross, M.B., B.Ch., B.A.O., F.F.R., D.M.R.D. From the Department of Radiodiagnosis, United Bristol Hospitals

PORTAL hypertension is a condition in which there branch of the portal but may drain into the right is an blood in the branch. abnormally high pressure Small which are present on the serosal surface portal system of veins which eventually leads to of the and in the surrounding peritoneal folds splenomegaly and in chronic cases, to haematem- draining the diaphragm and are known as esis and melaena. accessory portal veins. They may unite with the portal The circulation is in that it vein or enter the liver independently. portal unique The hepatic arises normally from the coeliac exists between two sets of , i.e. the axis but it may arise as a separate trunk from the aorta. capillaries of the spleen, , gall-bladder It runs upwards and to the right and divides into a and most of the gastro-intestinal tract on the left and right branch before entering the liver at the one and the sinusoids of the liver on the porta hepatis. The venous return starts as small thin-walled branches other hand. The liver parallels the lungs in that in the centre of the lobules in the liver. They join inter-

it receives a blood supply from an arterial source, lobular branches which coalesce and finally unite to by copyright. the hepatic artery, and a venous source, the form two or three hepatic veins which enter the inferior vein. vena cava just before it terminates in the right auricle. portal The liver lobules each have a small hepatic vein in the centre and in defined areas round the periphery there The Portal Circulation are portal tracts each of which contains a radicle of the Blood passes from the splanchnic into the portal vein, hepatic artery and a small bile duct. The spleen, pancreas, gall-bladder, stomach and intestines hepatic cells are arranged in sheets which are traversed from branches of the abdominal aorta. From the sinuses by the sinusoids so that one-cell-thick plates of hepatic in the splenic pulp, the blood is collected into several cells are formed. These plates form an irregular sponge tributaries which unite at the hilum of the spleen to form which surrounds spaces or lacunae in which the sinusoids are connective tissue the splenic vein, which runs to the right along the upper suspended by fibrils. Between http://pmj.bmj.com/ posterior aspect of the pancreas to the region of the neck individual hepatic cells are bile canaliculi from which of the pancreas. As it crosses the upper , it bile passes to collecting ductules which run to the portal receives as tributaries the , the left tracts. Here small bile ducts are formed which drain gastro-epiploic, pancreatic, inferior mesenteric and left eventually into the extra-hepatic bile ducts. gastric veins. The superior mesenteric vein is formed in The sinusoids are thus modified capillaries lined with the root of the mesentery from union of the jejunal and endothelial cells on a basement membrane and some of ileal veins, the ileo-colic, right and middle colic and their cells are specially adapted reticulo-endothelial cells inferior pancreatico-duodenal veins. The portal vein known as Kupffer cells. The sinusoids form a honey- usually forms behind the neck of the pancreas, but comb or 'hepatic labyrinth' in the lobules which

through on September 24, 2021 by guest. Protected occasionally in front of the pancreas, by the union of the blood flows from the peripheral portal vein to the central superior mesenteric and splenic veins at the level of the hepatic vein. The hepatic artery divides into fine body of the second lumbar vertebra. The portal vein branches in the portal tracts which form a net- runs upwards and to the right, but occasionally hori- work that drains into the portal vein and peripheral zontally, in the free edge of the lesser omentum, behind sinusoids. Some hepatic artery blood enters the sinusoids the duodenal bulb and common bile duct, to terminate direct and it has been shown histologically that these at the porta hepatis where it divides into two and some- small hepatic contain muscle pads and ring times three branches, which pass into the liver. The muscle in their walls which presumably control the terminations of the left gastric and inferior mesenteric hepatic artery blood flow. The principle of the lobule veins are variable. In two-fifths of persons they enter the as a structural unit involves complete separation of the splenic vein; in a further two-fifths they enter the portal portal and hepatic veins, the terminal branches of which and superior mesenteric veins respectively, and in the interdigitate with lobular parenchyma interposed in all remaining one-fifth the left gastric vein enters the junc- places between them. However, anastomoses betweer tion of the portal and splenic veins and the inferior them have been claimed and are supposed to be open in mesenteric the junction of the superior mesenteric and the absence of digestion. splenic veins. In about 90% of people several veins The liver is surrounded by the hepatic capsule from enter the portal vein including the pyloric vein on the which a connective tissue stroma extends into the portal left side and the cystic and superior pancreatico- tracts and the central canals. Within the lobule, radial duodenal veins on the right side. Para-umbilical veins collagenous fibres connect the central part of the lobule from the falciform ligament usually drain into the left to the periphery and a fine reticulum supports the Postgrad Med J: first published as 10.1136/pgmj.39.451.299 on 1 May 1963. Downloaded from

300 POSTGRADUATE MEDICAL JOURNAL IVfay I963 sinusoids. On the surface of the liver interlobular an incidental post-mortem finding. The hepatic connective tissue unites with the capsule and through veins are occluded at their this connection capsular vessels communicate with the usually partially point portal vein but not the hepatic vein. of union with the inferior vena cava, The total liver blood flow is about 1,500 ml./min. either spreading from the inferior vena cava or in adults, of which about 80% is contributed by the occurring primarily in their ostia; it is most portal vein. The liver blood flow can be measured by the to some other such bromsulphthalein excretion method or by radio-active commonly secondary isotopes. as pressure or invasion by hepatic neoplasms. The portal pressure can be measured at laparotomy by connecting a saline manometer to a cannula inserted Obstruction into an unobstructed vein of the portal system: the (b) Intra-hepatic fact that the abdomen is open probably makes very little The low pressure gradient between the portal difference to the reading. It has been shown, however, and hepatic veins results in easy obstruction that the intrasplenic pressure is a relatively accurate to the blood flow. The obstruction indication of the portal venous pressure, though naturally portal may it is slightly higher than the pressure in the portal vein be temporary or permanent. itself. This is estimated by percutaneous needle punc- Any condition that causes tension in the ture, usually in combination with trans-splenic portal capsule, such as acute hepatitis, will probably venography. Another indirect method is to estimate the obstruct the blood flow wedged hepatic vein pressure by passing a cardiac portal temporarily leading catheter through the right auricle into the inferior to but the pressure returns vena cava and thence into an hepatic vein. The catheter to normal when the lesion resolves. tip is passed out into the liver so that its external A longer-standing portal hypertension arises circumference blocks the internal circumference of an in conditions which result in a fibrous hepatic vein. response Normal portal pressures are: in the liver, and hepatic cirrhosis is considered Intrasplenic .. 3 to 17 mm. Hg to be the main cause of intra-hepatic obstruction. Portal vein .. 7.5 to I6 ,, No matter what the cause of the cirrhosis, the Sinusoidal .. 6 to 8 ultimate histological picture varies little. Portal Temporary occlusion of the portal vein in normal in cirrhosis is obstruc- persons causes the portal venous pressure to rise hypertension produced by by copyright. immediately to 40 to 50 mm. Hg and it remains at this tion of the portal vein branches by fibrosis; by level so long as the obstruction is maintained. pressure by regenerating liver nodules on the small hepatic veins and by presinusoidal anasto- Portal Hypertension moses between the hepatic artery and portal The portal venous pressure may be raised as vein in the fibrous septa of the cirrhotic liver a result of increased inflow through the splanchnic resulting in an increased hepatic artery blood flow. arteries or due to increased resistance to the The aetiological factors which may give rise to outflow from the of veins. Increased intra-hepatic portal obstruction may be listed portal system as follows: inflow is only likely to be significant if the inflow http://pmj.bmj.com/ resistance is diminished, which occurs in cases (i) Virus hepatitis.-Most cases of virus of splenic artery-vein fistulke. Increased resistance hepatitis resolve completely and do not lead to to the outflow of the portal venous blood is portal hypertension. It is not known why a few caused by (a) conditions which raise the hepatic progress to hepatic fibrosis sufficient to lead to the venous pressure (post-or supra-hepatic obstruc- development of portal hypertension. It is thought tion), (b) lesions of the liver itself (intra-hepatic by some workers that some cases of portal hyper- obstruction), and (c) lesions affecting the portal tension with hepatic fibrosis may be due to a and splenic veins (extra-hepatic obstruction). previous unidentified virus hepatitis without on September 24, 2021 by guest. Protected jaundice but this cannot be proved until there is (a) Supra-hepatic Obstruction a serological test for virus hepatitis. This will occur in congestive heart failure and (2) Nutritional Deficiency.-There is experi- constrictive pericarditis. If the portal hyper- mental evidence that a low protein diet, in spite tension is secondary to a generalized rise in of an adequate calorie intake, causes diffuse venous pressure, it will be of no consequence hepatic cell necrosis and post-necrotic scarring. clinically as a collateral circulation will only There is a high incidence of cirrhosis of the liver develop if there is a pressure gradient between and portal hypertension in Africa and the East the portal and systemic veins. In veno-occlusive and poor nutrition has been blamed for this. disease, which occurs in the West Indies and some However, it is possible that the poor nutritional other tropical and sub-tropical countries, the state may merely increase the liability to infection. small hepatic veins are occluded by subendo- (3) Alcoholism.-It is not known whether thelial oedema with subsequent collagenization. alcohol produces the cirrhosis as a direct toxic The Budd-Chiari syndrome is due to thrombosis effect on the liver cells or as a result of the high of the large hepatic veins, and in many cases it is calorie and low protein diet usual in alcoholics. Postgrad Med J: first published as 10.1136/pgmj.39.451.299 on 1 May 1963. Downloaded from

May I963 MIDDLEMISS and ROSS: Portal Hypertension and its Radiological Investigation 301 (4) Heemochromatosis.-Iron accumulates in involved simultaneously or separately. The the liver and leads to fibrosis and portal hyper- obstruction is usually produced by intravascular tension. thrombosis. The possible causes may be listed (5) Hepato-lenticular Degeneration.-In this as follows: condition there is an excess of copper in the liver (i) Cirrhosis of the Liver.-In patients who have with cirrhosis of post-necrotic or portal type. long standing portal obstruction the veins of the (6) Congenital Syphilis.-This very rarely leads portal system may show intimal lesions and there to portal hypertension as a result of a fine peri- is slowing or almost complete stasis of the portal cellular cirrhosis with marked fibrous tissue blood flow. These factors favour intravascular reaction. thrombosis, which may be mural or fill the entire (7) Bilharzia.-The ova of Schistosoma mansoni vein. Recanalization may take place in time and and Schistosoma japonicum obstruct the branches there may be calcification in the mural thrombus. of the portal vein and give rise to periportal Infarction of the small bowel will occur if the fibrosis. thrombus extends to the superior mesenteric vein. (8) Biliary Cirrhosis.-This may occur in a (ii) Portal Phlebitis.-Before the introduction of primary form or be secondary to chronic extra- and antibiotics suppurative phle- hepatic biliary obstruction such as from gall- bitis was almost invariably fatal. Now the infection stones or to the common bile duct, and may be overcome by antibiotic therapy but the infrequently it may lead to portal hypertension. legacy will be . Infection (9) Congenital Fibrosis of the Liver.-This is a anywhere within the drainage area of the portal rare presinusoidal type of obstruction occurring and splenic veins may cause portal phlebitis, in children. The changes do not appear to be the commonest being the appendix and neonatal progressive and the only symptom is hsematemesis. umbilical infection. (Io) Granulomatous Lesions.-Sarcoidosis affects (iii) Tumours.-Primary or secondary tumours the liver and has been followed by portal hyper- may exert pressure on or invade directly the tension. portal or splenic vein and this may be 'followed by copyright. (iI) Thickened Liver Capsule.-Cases of portal by intravascular thrombosis. The commonest hypertension have been encountered associated site is in the porta hepatis. with a very thickened liver capsule which may (iv) Blood Disorders.-Any blood disease which be calcified in places. These cases may result carries an increased risk of intravascular throm- from massive peripheral necrosis of the liver bosis may cause portal vein thrombosis, e.g. parenchyma, and traces of portal tracts may be polycythaemia rubra vera. found in the fibrous tissue of the capsule. (v) Trauma.-Rarely portal vein thrombosis (I2) Hepatic Neoplasm.-Primary hepatic car- or scarring is secondary to injury during opera- cinoma, which sometimes shows calcification, is tions, particulary cholecystectomy. Portal vein http://pmj.bmj.com/ not uncommon in hepatic cirrhosis. Primary thrombosis also is liable to occur after splenectomy hepatic neoplasms may also occur in children. or portocaval anastomosis. However, ligation of Metastatic carcinoma in the liver may also on the portal vein does not always give rise to mani- rare occasions lead to portal hypertension and festations of portal hypertension. External haematemesis. trauma to the upper abdomen may occasionally (13) Unknown Etiology.-In about 50% of the cause portal vein thrombosis but it is almost cases of hepatic cirrhosis with portal hypertension impossible to correlate cause and effect. on September 24, 2021 by guest. Protected no definite aetiology can be found. In many of (vi) Congenital.-It is now recognized that most these cases the pathological condition in the liver cases of extra-hepatic portal obstruction, even in is stationary and the only condition that endangers young persons, are acquired, and congenital the life of the patient is the portal hypertension. lesions, such as persistent foetal valves in the There are other cases in which there is no portal vein producing secondary thrombosis, extra-hepatic obstruction and in which the liver must be very rare. shows only slight histological variation from normal with no increase in fibrous tissue and with Effects of Portal Hypertension portal tracts either normal or showing only a In time, portal hypertension produces ana- little cellular infiltration. It is possible that tomical and functional changes in the splanchnic vascular spasm may play a part in obstructing circulation mainly associated with the development the blood flow through the liver in these cases. of a collateral circulation and congestive spleno- megaly. This occurs where the portal and (c) Extra-hepatic Obstruction systemic circulations join and the portal blood is Obstruction of the portal vein may occur in diverted into systemic channels. It develops any part of its course and the splenic vein may be particularly round the oesophagus and the gastric Postgrad Med J: first published as 10.1136/pgmj.39.451.299 on 1 May 1963. Downloaded from

302 POSTGRADUATE MEDICAL JOURNAL May I963 fundus, retroperitoneally and in the falciform ligament. The spleen is always enlarged in portal hypertension but its size is not proportional to the degree of elevation of the portal pressure. The enlargement is partly due to congestion but long standing congestion causes structural changes which take time to resolve. The splenic enlarge- ment can give rise to the blood changes of hyper- splenism, i.e. anaemia, leucopenia and throm- bocytopenia. Probably as the result of infarcts, vascular adhesions may develop between the spleen and the abdominal wall. It is usually but not always palpable. The only clinical findings due directly to the portal hypertension are associated with the collateral circulation. Patients with intra-hepatic obstruction may also have clinical features of their liver disease which will not be discussed here. If there are extensive varices up the cesophagus the most serious danger is haemorrhage which may be a slow ooze leading to anaemia and melaena or more frequently a severe haematemesis which comes suddenly and without warning. Less than io% of haematemeses in patients in Great Britain are due. to portal hypertension. However, in by copyright. Africa and Central and South America and in children in Great Britain, portal hypertension is the commonest cause. The factor which precipitates the haemorrhage may be peptic ulceration of the varices, trauma from food particles or sudden rise in intra-abdominal or portal pressure. The intervals between hemor- rhages are very variable, ranging from a few days to several years. It is very unusual for a patient http://pmj.bmj.com/ to die from his first haemorrhage but his prognosis is worse than that of the patient bleeding from FIG. xa and Ib.-Supine and erect films showing peptic ulceration. Following haemorrhage the as filling defects in the fundus. patient may pass into the state of liver failure or suffer neuropathic symptoms and even pass Barium Examination.-The demonstration of a into coma from absorption of protein products collateral circulation by barium examination of from digestion of the blood in the gut. the upper alimentary tract must be the next on September 24, 2021 by guest. Protected step. Gastric varices are best outlined by coating The Radiological Investigation of Portal the fundus of the stomach with neat barium Hypertension (the authors prefer Micropaque) by first lying the In cases of sudden hemorrhage clinical distinc- patient supine and then bringing him into the tion of portal hypertension from peptic ulceration erect or prone position so that a double barium/ may be difficult. air contrast of the fundus is produced. So as not Straight X-ray.-In such cases an over- to get too much barium in the stomach it is best to penetrated view of the chest or tomography when start examining the patient by looking for gastric the patient can be moved may be helpful to varices. The varices appear as lobulated or demonstrate the enlarged azygos and hemiazygos rounded filling defects in the fundus and in the veins and a plain film of the abdomen may reveal region of the upper part of the lesser curve. splenic enlargement that cannot be palpated. Sometimes they appear as thickening and tortu- When the patient is fit enough gastric and ceso- osity of the mucosal folds in the fundus. On other phageal varices as well as other possible causes of occasions they are so large that they present as a hamatemesis should be sought by barium examina- large soft tissue filling defect on the medial side tion. which will be apparent against the air in the Postgrad Med J: first published as 10.1136/pgmj.39.451.299 on 1 May 1963. Downloaded from

May 1963 MIDDLEMISS and ROSS: Portal Hypertension and its Radiological Investigation 303 Varices may just involve the lower end of the oesophagus or they may extend right up into the neck. Bubbles of air may simulate varices. They are, however, more translucent than varices, not constant and usually facetted. The accuracy of barium examination in the demonstration of varices is difficult to determine as there is reluc- tance of many surgeons to pass an cesophagoscope on these patients. Barium studies, of course, will only demonstrate submucosal varices and oeso- phagoscopy is the only practical method of inspecting the cesophageal mucosa. The difficulty always is to demonstrate small varices, as large varices are usually obvious. Different workers claim a varying accuracy of demonstration of known cesophageal varices from about 14% to 87%. Selection of cases probably accounts largely for the very differing accuracy figures. There are other difficulties in the detection of varices. It has been established that the dimen- sions of varices vary from time to time with spontaneous fluctuations in portal pressure and with changes in blood volume, such as occur after a hemorrhage. Occasionally large gastric varices are seen radiologically without the presence of FIG. 2.- sophageal varices. oesophageal varices. This may be due to the by copyright. FIG. 2.--. peculiarities of the collateral circulation with drainage of the gastric varices into the retro- gastric fundus or cause a smooth lobulated filling peritoneal veins or in cases of splenic vein throm- defect in the barium-filled fundus in the supine bosis, drainage back from the fundus into a left position. In these cases the mass of varices has gastric vein entering directly into a patent portal to be distinguished from a carcinoma (Fig. I). vein and not into the thrombosed splenic vein. (Esophageal varices will only be demonstrated For practical purposes the demonstration of on good mucosal pattern films of the lower end varices by radiological or methods cesophagoscopy http://pmj.bmj.com/ of the oesophagus. Neat Micropaque is used and can be taken as definite evidence of appreciable if this is unsuccessful, due to non-adhesion of the portal hypertension. There are cases, however, barium, Microtrast is then used. Small varices with large collateral channels in which the portal will only show in the relaxed oesophagus and care pressure is normal or near normal. In these must be taken to see that the radiographs are not cases it is thought that the size of the collateral exposed when a contraction wave is present or channels has lowered the peripheral resistance of when the oesophagus is full of barium, as these the portal circulation sufficiently to lower the features will obliterate varices. The least use- pressure. on September 24, 2021 by guest. Protected ful position is the erect. The best position is the Portal Venography.-The object of portal prone, with the left side raised and after that the venography is to demonstrate the state of the supine position with the right side raised. The splenic and portal veins, the site of an obstruction respiratory phase should be midway between and the presence or absence of thrombi in these inspiration and expiration. The Valsalva and veins so that the optimal surgical approach can Muller manoeuvres are occasionally useful for be planned. The fact that portal hypertension bringing out the varices, but in most cases they is present is determined by the prior measurement are unhelpful. Small varices produce some of the intrasplenic pressure, but the showing thickening of, and small rounded projections on, of a large collateral circulation in cases with near the borders of the mucosal folds at the lower normal pressures indicates appreciable obstruction end of the oesophagus and also filling defects on the in the outflow from the liver. esophageal outline. Large varices produce Trans-splenic Portal Venography.-Provided linear, globular or worm-like filling defects of splenectomy has not previously been performed varying size and are associated with dilatation of this examination is performed first, by percutane- the oesophagus and complete distortion of the mu- ous splenic puncture. This is done under local cosal pattern of the relaxed oesophagus (Fig. 2). anesthetic in adults: a general anesthetic is given Postgrad Med J: first published as 10.1136/pgmj.39.451.299 on 1 May 1963. Downloaded from

304 POSTGRADUATE MEDICAL JOURNAL May i963 to children. Occasionally a general anaesthetic is required with adults, and it is done by this method in the operating theatre when it is desired to go straight on to a shunt operation, particularly in patients who have had a recent severe hmema- temesis. In adults it is very important to explain carefully to the patient every step of the examination so that their full co-operation is secured. Particularly is it explained that once the needle is in position they must breath only very shallowly while the intra-splenic pressure is being measured, and that when they are told to stop breathing at the time ofthe injection and taking of the films, they must hold their breath in whatever phase of respiration they are at that time. Some patients tend to take a huge inspiration before stopping breathing. This phenomenon may ac- count for the occasional cases where varices are FIG. 3.-Normal portal venogram showing splenic vein shown at barium swallow and not demonstrated and portal vein, the latter branching within the by liver. The streaming effect due to non-opaque portal venography. Premedication is by 75 mg. blood from the superior mesenteric vein can be seen. pethidine intramuscularly. A test dose ofthe con- trast medium is given in spite of the known limita- the first film has been taken. The needle is then tions of its efficiency in detecting sensitivity re- withdrawn actions. A control film istaken to check the patient's and the patient allowed to breath again. position and the radiographic factors. Two 17/14 The patient's immediate reactions are a good indication of the success or failure of the examina-by copyright. films are placed transversely in a modified Potter- tion. If they experience a feeling of warmth Bucky tray, the top film being lead backed to across the upper abdomen, the contrast medium protect the lower one from radiation. The films has been successfully injected into the spleen are so positioned that the top of the iliac crest and has crossed the upper abdomen in the veins. just appears on the bottom of the film and If they experience local left-sided pain during the this allows coverage of the lower part of the injection and particularly if it radiates to the tip oesophagus. The X-ray tube column is off- of the left shoulder some of the contrast medium centred from the Bucky tray so that access to the has run left side of the patient is not impeded. This into the peritoneum around the under- method has been found quite adequate for this surface of the diaphragm. This pain is not http://pmj.bmj.com/ examination in the of the present writers, usually severe and it is accentuated by respiration. though in other schools a serial changer is used. If there is no immediate pain but severe local The spleen is punctured either below the costal left-sided pain develops a few minutes later, the margin, if it is large enough, or in the inter- injection has gone under the splenic capsule, and costal space in line with the apex of the spleen if there is pain down the left side of the abdomen if into the pelvis the contrast medium has tracked it is only just palpable, i.e. the 8th or 9th inter- down the left paracolic gutter. Should the space. If the spleen is impalpable it is punctured on September 24, 2021 by guest. Protected over the area of maximum examination be a failure it is never repeated on dullness. The needle the same day. If there are no immediate contrast is a I7 S.W.G. needle and it is inserted through medium the abdominal wall down to the spleen in a reactions the patient is returned to the direction upwards, backwards and medially and ward and kept on a half-hourly pulse chart for the resistance as it enters the spleen can be felt. three hours. Apart from the dangers of injecting It is then advanced a centimetre or so and blood the contrast medium into any patient the particular dripping slowly from it indicates that it is correctly dangers of trans-splenic portal venography are sited. A saline pressure manometer is attached hemorrhage either into the spleen itself or into and the intrasplenic pressure recorded. The the peritoneum from tear of the spleen at the syringe, containing 30 ml. 85% Hypaque warmed puncture site. In most cases intraperitoneal to I20°F, is now connected to the needle and the haemorrhage is minimal and undetectable, but patient is instructed to hold his breath in a mid- occasionally a small quantity of blood may be respiratory phase. The injection is made rapidly found in the peritoneum at laparotomy a few by hand and the first film taken two thirds of the days later. way through the injection and the second about Operative Portal Venography.-This is per- three seconds later. The Bucky is recharged after formed if the patient has had a previous splenec- May I963 MIDDLEMISS and ROSS: Portal Hypertension and its Radiological Investigation 305 Postgrad Med J: first published as 10.1136/pgmj.39.451.299 on 1 May 1963. Downloaded from divides into the left and right branches, occasionally with a middle branch. These branches divide again into smaller branches within the liver usually by simple forking, decreas- ing in size as they pass to the periphery of the liver. The branches of the left lobe can be seen passing to the left below the diaphragm. When the contrast medium the larger branches in the liver it then enters the sinusoids, at which time the liver is seen to be diffusely opaque, i.e. a hepatogram is obtained. This gradually clears. Where the superior mesenteric vein joins the splenic vein a streaming effect is usually produced by the non-opaque blood entering from the superior mesenteric vein, causing a less opaque stream in the centre of the left half of the vein which with FIG. 4.-Portal venogram in intra-hepatic obstruction. portal gradually merges The splenic vein is tortuous and there are collateral the right part of the vein. A similar streaming channels through the left gastric vein and gastric effect is seen in the splenic vein from its branches varices. The portal vein is of normal calibre. in the spleen. (ii) Appearances of Intra-hepatic Obstruction.- The plain film will show splenomegaly which tomy or if for any reason the portal vein has not may assume various shapes. The spleen may dte been demonstrated prior to laparotomy. The oval or elongated or it may be tucked up under anterior end of the right thoraco-abdominal the diaphragm. The stomach gas shadow is incision used for porto-caval anastomosis is displaced to the right and occasionally linear made first and the same vein is used which has calcification may be seen in the portal, splenic by copyright. been cannulated for measuring the portal venous or superior mesenteric veins. On the portal pressure. The anasthetist orders the patient to venogram the splenic and portal veins are patent stop breathing, 20 to 30 ml. 85% Hypaque is and usually wide. The splenic vein exhibits injected, and two 17/14 fast films are taken, the various degrees of tortuosity depending on the first two thirds of the way through the injection amount of shift of the splenic hilum to the right. and the second as soon after the injection as Various collateral pathways will be shown by possible, using a simple cassette tunnel and a retrograde flow of the contrast medium along mobile X-ray unit. them (Fig. 4). Usually the left gastric vein fills and The contraindications to portal venography varices in the region of the upper part of the http://pmj.bmj.com/ are considered to be: lesser curve of the stomach are outlined. These (I) Age: Porto-caval anastomoses are not usually may be small and numerous or few and very performed on patients over the age of large. Varices from the fundus of the stomach 60 years so, in general, advanced age is a may also be filled from the short gastric veins. contraindication. The contrast medium then passes above the (2) Jaundice. diaphragm in front of and on either side of the time less than of normal. thoracic as varices are filled. (3) Aprothrombin 75% spine cesophageal on September 24, 2021 by guest. Protected (4) Inadequate number of blood platelets, Several smaller gastric varices may be filled i.e. less than ioo,ooo/cu.mm. from the upper border of the splenic vein. Occasionally a large para- from the Radiological Findings in Portal Venography left branch of the portal vein may be filled. (i) Normal Appearances.-Normal portal veno- This passes downwards and to the left towards grams are not often obtained (Fig. 3). From the the lower abdomen. Superior and inferior pool of contrast medium in the splenic pulp one or mesenteric veins may also be filled retrogradely more intrasplenic branches of the splenic vein as well as capsular veins round the spleen and may be outlined. These converge on the hilum vessels in the vascular adhesions to the lateral and to form the main splenic vein which forms a posterior abdominal wall. Through these latter slight curve as it passes from left to right hori- channels the inter-costal veins and anastomoses zontally across the upper abdomen. To the right through the lumber and left renal veins may lead to of, or in front of the body of the second lumbar filling of the inferior vena cava. Distortion of the vertebra it joins the portal vein. This vein passes portal radicles within the liver may also be seen. upwards to the right for a short distance and Occasionally a large omental vein is filled, draining 306 POSTGRADUATE MEDICAL JOURNAL May I963Postgrad Med J: first published as 10.1136/pgmj.39.451.299 on 1 May 1963. Downloaded from

i,,akf FIG. 5.-Portal venogram in extra-hepatic obstruction at the entrance of the portal vein into the liver.

FIG. 6.-Portal venogram in extra-hepatic obstruction where the block affects all the portal vein. Multiple collateral channels are shown. 4 by copyright.

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FIG. 7.-Portal venogram in extra-hepatic obstruction in the splenic vein. Large, tortuous, varicosities are shown crossing the abdomen and a connection FIG. 8.-Portal venogram in extra-hepatic obstruction with the inferior vena cava has been established. where the block affects the splenic vein. to some part of the lateral abdominal wall. by other structures, such as choledochal cyst. Thrombi in the portal and splenic veins will (iii) Extra-hepatic The Obstruction. appear- on September 24, 2021 by guest. Protected show either as complete obstruction of the vein, ances will vary with the site of obstruction. diffuse narrowing of the vein or as a localized (a) At the Entrance of the Portal Vein into the marginal filling defect. Ifthe thrombus is marginal Liver.- The splenic and portal veins are patent on the anterior or posterior wall of the vein it but the portal vein is completely obstructed at will show as a central or near-central filling the extreme hepatic end. A mass of small veins defect which may be elongated giving an appear- surround the site of the obstruction and they ance rather like streaming, but it is constant on extend into the liver where the intra-hepatic serial films in comparison with true streaming branches may be poorly filled. This irregular net- which will vary its appearance and be distal to work of para-portal veins of varying size gives an the entrance of a large vein. A number of thrombi appearance like a venous angioma (Fig. 5). This in the portal vein do not show up by portal has led to the supposition that this meshwork of venography, but such thrombi do not preclude veins is a congenital abnormality, the so-called a porto-caval anastomosis being performed as cavernomatous malformation of the portal vein. they can be removed at operation. Extrinsic The extent of its range will depend on the extent pressure on the portal vein may be caused of the original obstruction. The resistance to May I963 MIDDLEMISS and ROSS: Portal Hypertension and its Radiological Investigation 307 Postgrad Med J: first published as 10.1136/pgmj.39.451.299 on 1 May 1963. Downloaded from the flow of the blood through these tortuous of the inferior vena cava or by side-to-side channels must be very great as the portal venbus anastomosis of the portal vein to the inferior pressure is frequently above 30 mm. Hg. Colla- vena cava. These are the only operations which terals over the surface of the liver may be shown reduce the portal . and if the right branch only is obstructed there If there are no suitable veins for anastomosis may be filling of a large para-umbilical vein. gastric or cesophageal transection may be carried (b) All the Portal vein.-In such cases only the out, experienced surgeons now favouring the splenic vein and collateral channels are filled latter, in which, through a left thoracotomy (Fig. 6). The portal vein may be bypassed by incision, the lower end of the oesophagus is para-portal collaterals which may be few and divided longitudinally through the muscle coat fairly large, or a mass of very small veins. The and the mucosa divided and re-sutured, any contrast medium is frequently sidetracked down vessels on the surface of the oesophagus being tied. one or two large collaterals, such as the left gastric The most serious of a porto- vein, inferior mesenteric vein or through the caval anastomosis is portal systemic encephalo- retroperitoneal collaterals to the left pathy, which may even arise in patients who have and into the inferior vena cava (see Fig. 7). not had such an anastomosis performed and who (c) Splenic and Portal Veins.-No contrast have a large portal systemic collateral circulation. medium enters the portal or splenic vein and a It has been shown that some of the neuro- mass of collaterals are shown usually crossing logical symptoms which occur in cases of liver the abdomen towards the porta hepatis (Figs. 7 disease are due to shunting of portal blood directly and 8). These represent . The into the systemic circulation whence it reaches collaterals may extend up and down the left side the brain before it has passed through the liver. of the lumbar spine and in which case they are Porto-caval anastomosis produces such a shunt usually veins of the retroperitoneal tissues in the and cases would be expected to arise after it. lienorenal ligament and . Inter-costal There is no doubt that the condition is due to and diaphragmatic veins may also be filled. some protein breakdown product containing (d) False Extra-hepatic Obstruction.-If the nitrogen entering the systemic circulation. The by copyright. pressure in the portal vein or splenic vein is very encephalopathy manifests itself in a variety of high, presumably due to higher sinusoidal ways but in the same patient each episode tends pressure or large arterio-venous shunts, there may to hold to a constant pattern. The commonest be reversal of blood flow in the portal and splenic symptom is increasing drowsiness passing into veins. In these cases the contrast medium injected coma, but some patients may pass very suddenly into the spleen will not enter the splenic or portal from an apparently normal state to complete veins and will be diverted down large collateral unconsciousness and equally suddenly return to channels. However, if the contrast medium is their earlier condition. injected into a jejunal vein at laparotomy, the In the hands of some surgeons the operative http://pmj.bmj.com/ splenic and portal veins will be demonstrated. It treatment of portal hypertension, either by porto- is for this reason that operative portal venography caval anastomosis or if this is not possible, by is always carried out on patients whose portal aesophageal transection, has been very successful. and splenic veins are not filled on the trans- Recurrent hematemesis after porto-caval ana- splenic route. stomosis is rare, and its incidence after cesophageal transection greatly reduced. Discussion In the initial of investigation possible cases of on September 24, 2021 by guest. Protected The main operations for portal hypertension portal hypertension and in the subsequent have one of the following objects: detailed pre-operative investigation of such cases, (I) To reduce portal-venous pressure to safe radiological procedures have an important and limits by wide venous anastomosis. essential part to play. These procedures carry (2) To cut off the flow of portal blood to no great risk, but if they are to be of value it is bleeding varices. essential that they should be carried out by an (3) Reduction offlow through the liver. experienced team and with very great considera- The only veins of the portal circulation available tion to every detail of the procedures. for anastomosis to veins of the systemic circulation are the portal and splenic veins. Porto-caval Summary anastomosis is performed if the obstruction is in The anatomy of the portal circulation is the liver. Spleno-renal anastomosis can be described and the of portal hyper- performed if the portal vein is occluded. Porto- tension discussed. Radiological procedures for caval anastomosis is performed either by ana- the investigation of such cases are then considered stomosing the end of the portal vein to the side and the appearances described in detail.