Vein Shunt Research Articles

Preparation of Thoracic and Intestinal Lymph Duct Shunts in Calves

The thoracic or intestinal lymph duct was successfully cannulated in 40 Holstein calves. To maintain body fluid balance, thoracic duct lymph was returned directly to the thoracic duct or to the jugular vein. Both shunts remained patent up to 5 weeks, but the thoracic duct-duct shunts required less maintenance than the thoracic duct-jugular vein shunts.Intestinal duct lymph was returned directly to the intestinal duct, to the jugular vein, or to the posterior vena cava. Intestinal duct-duet shunts were not satisfactory because lymph flow was restricted by the poor aspiratory action of the return cannula. It was difficult to maintain the long length of tubing needed to connect the intestinal duct cannula to the jugular vein catheter in the intestinal duct-jugular vein shunts. The most satisfactory route for intestinal lymph return was via the posterior vena cava because a minimum length of tubing was exteriorized, clotting in the venous end of the vena cava catheter was never a serious problem, and there was good aspiratory action in the vena cava catheter. Intestinal duct-vena cava shunts were maintained for up to 5 weeks. Preliminary results with one calf suggest the feasibility of establishing thoracic duct-posterior vana cava shunts.

Use of a jugular vein shunt in the rat bioassay.

Abstract The placement of a "jugular vein shunt" is described for use in the intact rat bioassay preparation. Intravenous injections of test substances are made directly into the bloodstream through the shunt. This eliminates the need for additional administration of fluid which is necessary to flush the test substance when a regular intravenous cannula is used. It also permits the accurate delivery of minute volumes of injectate to the rat.

Nonthrombogenic extracorporeal portosystemic shunt.

In spite of ideal present day management, 25% of patients who bleed from esophageal varices continue to succumb to hemorrhage. Those who fail to respond to conservative measures require surgical intervention. Major surgery on a patient already taxed by exsanguinating hemorrhage and hepatic decompensation is accompanied by a high mortality. White et al,1Piccone and LeVeen,2and Christopherson et al3have recently described the use of an umbilical systemic vein shunt with low operative mortality to control bleeding from esophageal varices. Their reports indicate that flows obtained under existing portosystemic pressure differentials were sufficient to abate exsanguination. Gott et al4have described a non thrombogenic coating technique for surfaces using graphite, heparin sodium, and benzalkonium chloride. Zarins et al5have recently reported their results with splenofemoral or external jugular shunts to relieve portal hypertension in dogs utilizing the Gott graphite-benzalkonium-heparin coating. We6have developed

Encephalopathy after portacaval shunting managed with lactulose

Lactulose, a synthetic ketose consisting of one molecule of fructose and one of galactose chemically united, has been used to treat four patients with hepatic encephalopathy after portasystemic vein shunts. Theoretically the sugar is helpful because it lowers colon pH, which in turn lowers blood ammonium by inhibiting bacterial amino acid deaminases and diminishes ammonium transport from the colon. The sugar is also mildly cathartic. Sorbitol, a relatively inert 6-carbon sugar, also mildly cathartic, was used as a control in a double blind study. Objective criteria used were blood ammonium levels, electroencephalographic tracings, colon pH, and number of hospital admissions required. No evidence of toxicity was noted with either sugar. The underlying liver disease did not appear to be altered. In general, patients were helped by lactulose. Sorbitol was also occasionally helpful, suggesting that the cathartic effect of both sugars was beneficial. Further investigation, particularly a detailed bacteriologic and biochemical study to document the mechanism of action of lactulose and similar sugars in the large intestine, is important because the use of lactulose offers a new approach to the treatment of hepatic encephalopathy.

Experience with the corpus cavernosum-saphenous vein shunt in the treatment of priapism

Es wird über 5 Fälle von Priapismus, bei denen eine Anastomose zwischen der Vena saphena magna und dem Corpus cavernosum penis durchgeführt wurde, berichtet. Da die venose Stase in den Schwellkòrpern des Penis bei längerem Bestehen über eine Trabekelfibrose zur Impotenz führt und bei Fallen, die frühzeitig operiert wurden, die Potenz erhalten blieb, wird vorgeschlagen, bei alien Fallen von Priapismus diese Operation so früh wie móglích durchzuführen.

Thoracic duct-to-pulmonary vein shunt in the treatment of experimental right heart failure.

Elevated venous pressure in right heart failure leads not only to an increase in lymph formation but also to progressive resistance in the neck to the return of lymph to the circulation via the thoracic duct. Sequestration of fluid behind the failing heart tends to protect the circulation but at the same time leads to the clinical manifestations of heart failure. The present study was performed on 40 dogs with combined tricuspid insufficiency and pulmonary stenosis. Thoracic duct lymph flow was greatly increased. Pressure was considerably greater in the systemic veins than in the pulmonary vein beyond the right heart obstruction. Lymph flow was substantially enhanced when the thoracic duct was connected to the lower pressure pulmonary veins. Furthermore, direct anastomosis of the thoracic duct to the pulmonary vein resulted in fall in systemic venous pressure, increase in renal excretion of salt and water, and reduction in ascites. These results indicate that alterations in the flow of thoracic duct lymph have important bearing on the manifestations and treatment of right heart failure.

Dependence of ventricular distensibility on filling of the opposite ventricle.

Dependence of ventricular distensibility on filling of the opposite ventricle.

Pulmonary artery to vein shunts in obstructive pulmonary disease

Forty-six patients with chronic respiratory disease were studied; all but two had obstructive pulmonary disease. In none were intracardiac shunts or pulmonary arteriovenous fistulas detected. In four patients with obstructive pulmonary disease a direct pulmonary artery to vein connection was identified by peripheral pulmonary wedge arteriography. The findings in these four patients (history, physical examination, electrocardiography, chest roentgenography, cardiac catheterization, pulmonary function studies and angiography), compared with those in the remaining patients in whom no shunt was visualized, revealed no discriminating differences. All patients with pulmonary artery to vein connections had moderately severe obstructive pulmonary disease and moderate degrees of pulmonary hypertension. Pulmonary vascular resistance was significantly increased. When measured, the arterial blood pO 2 at the end of a twenty minute period of oxygen breathing was significantly decreased. However, many patients without definitely identifiable shunts showed similar degrees of abnormality. Since many of the latter had arterial blood pO 2 of from 134 to 350 mm. Hg during 100 per cent oxygen breathing, it is likely that arteriovenous shunts were present but not identified by the method of pulmonary arteriography employed.

Diverting adrenal venous effluent through portal circulation in dogs.

IT HAS BEEN shown abundantly that the liver can reduce or alter the biological activity of certain steroid hormones. 1-6 Perfusion studies in vitro have shown that gonadal and adrenal steroid hormones are metabolized by the liver. 5,6 There are many clinical and experimental observations relating the adrenal cortex to hypertension. It has been demonstrated that bilateral adrenalectomy abolishes experimental renal hypertension 7,8 ; adequate replacement therapy with adrenal cortical extract or desoxycorticosterone after adrenalectomy may fully reestablish experimental renal hypertension, 9 hypertensive vascular disease may be produced in rats by the administration of desoxycorticosterone and by the administration of a crude suspension of anterior pituitary gland. 10 Although there have been a few attempts to create adrenal vein-portal vein shunts, 11-13 the technique has not been entirely satisfactory. Complete diversion of the venous effluent of the adrenal is difficult to achieve due to the great number of vascular connections of

EFFECT OF A LIVER BYPASS AND OVERTRANSFUSION ON "TRAPPING" OF RED CELLS.

SummaryIn anesthetized dogs, the measured cell and plasma volumes, protein concentration, venous hematocrit and BVRcells were the same before and after bypassing the liver with a portal vein to femoral vein shunt. An overtransfusion of blood after the bypass produced significant changes in all measured circulatory parameters. At the end of the experiment the volume of trapped cells was 33 % of the cells infused, and the escaped plasma was 93% of the infused. Protein lost represented 78% of the infused. Circulatory and venous hematocrits were the same after the bypass and transfusion, suggesting that under these circumstances cells and plasma were evenly distributed throughout the circulation. Mean arterial pressure was reduced slightly after insertion of the bypass and also after the overtransfusion. Portal venous pressure increased when the liver was bypassed and further increased after the transfusion following the bypass.

Portal decompression procedures in children

Two types of portal venous shunting procedures designed primarily for small children are discussed. The central splenorenal anastomosis would appear to be superior to the conventional splenorenal shunt as judged by the critical factor of freedom from further upper gastrointestinal bleeding. The inferior vena cava to superior mesenteric vein shunt is designed for patients in whom the splenic vein cannot be used. The results with these two types of shunts are sufficiently encouraging so that we prefer to perform shunts in average sized children over four years of age with bleeding varices rather than more complex, direct local procedures designed to obliterate the varices.

Hepatic coma and ammonia metabolism in dogs.

^HEPATIC COMA or encephalopathy may be classified as "spontaneous" with liver failure but little rise in blood ammonia, or "exogenous" with toxic symptoms from very high ammonia levels.¹The latter occurs after portal-systemic vein shunting operations and is generally attributed to the inability of the liver to detoxify ammonia through the normal pathways of the Krebs-Hensleit urea cycle. It is thought that in "spontaneous" hepatic encephalopathy, on the other hand, many enzymatic and metabolic systems simultaneously are adversely affected in the liver leading to coma refractory to treatment. This variety is therefore not characterized by the predominating influence of one biochemical defect. Clinically the gradation is not sharp and many intermediate states are observed. Both types of coma were observed in the laboratory in dogs following portacaval shunt operations in which "Eck's fistulae" were formed. In a previous report it was pointed out that the high blood ammonia

Lowering blood ammonia with protamine.

One of the very puzzling aberrations that occurs in liver disease is the elevation of blood ammonia.¹Though this is not a constant finding it is often seen in patients with liver failure, especially those suffering from cirrhosis who have had portasystemic vein shunt operations.²Here the ammonia level may rise to several times the normal value and is thought to be at least in part responsible for symptoms of hepatic coma. This has been documented both in the laboratory and clinically where tremors, lethargy, staggering gait, coma, and death have been caused by elevating the blood ammonia and where such symptoms may be ameliorated before the terminal stages by lowering it.^1,3 Of the several methods currently used to lower blood ammonia, one of great theoretical interest is the administration of arginine.⁴The amino acid plays an important role in the Krebs-Henseleit cycle in which ammonia

Gasometric studies in carotid-internal jugular anastomosis in the neck; preliminary report on human experiences.

THE USE of cervical carotid artery-internal jugular vein anastomosis as a means of revascularizing the brain has been championed by Beck, McKhann, and Belnap. 1 Experimental work in the rhesus monkey 2 revealed that such an anastomosis does not result in increase in the oxygen content of the superiorsagittal sinus blood; in many of the experiments the oxygen content of the superior sagittal sinus blood is actually lower after the shunt. Angiographic studies in the rhesus monkey after a shunt reveal that blood usually courses up one jugular vein to the lateral sinus and across to the opposite lateral sinus and down the contralateral jugular vein or it courses through the tributaries in the neck to the opposite jugular vein. Tarlov and others 3 found that in carotid artery-internal jugular vein shunts in human beings the postoperative angiographic pattern is essentially the same as the results of the above-described work

Blood flow determinations and cardiodynamic effects of a venous shunt in pulmonary hypertension.

Conclusion1. In acute experiments producing increased pulmonary vascular pressure in dogs, the capacity of a pulmonary vein-azygous vein shunt was found to be up to 8% of the total cardiac output.2. There was no consistent evidence that the presence of the shunt produced or added to the strain on the right ventricle or interfered with the filling pressure of the left ventricle.