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Biomedical subjects

G Kleber

Publications and source records attributed to G Kleber.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Transjugular liver puncture].

The transjugular liver biopsy is a method which allows assessment of hepatic tissue from patients with contraindications against classical percutaneous biopsy. A catheter with a long biopsy needle within is inserted into the jugular vein and then pushed forward through the Vena cava into a hepatic vein in order to carry out the biopsy of the liver. Indications for this examination are biopsies in patients with considerably impaired coagulation or tense ascites. It is possible, if necessary, to measure free and wedged pressure within the liver veins during this examination. On average, in 93% of all examinations enough tissue is yielded to allow for satisfactory judgement of histological changes; the rate of success is little less than that with percutaneous biopsies. However, considering all aspects, this technique gives good results. Lethal complications are rare (0.17%); the total complication rate is about 12%, 0.5-2.7% are severe. Although this method needs more time and technical equipment than percutaneous biopsy, the procedure has to be considered as an important technique for the evaluation of terminal liver disease.

Biopsy, Needle↗
PubMed1992

Hemodynamic effects of calibrated stenosis of the superior mesenteric artery in conscious rats with portal vein stenosis.

Because superior mesenteric arterial blood flow is increased in portal hypertension and plays a role in elevated portal pressure, mechanical reduction of artery diameter should induce decreases in portal pressure and superior mesenteric arterial blood flow. In this study, calibrated superior mesenteric artery stenosis (induced with a 22-gauge needle) was performed in rats simultaneously with portal vein stenosis or 2 wk after creation of portal vein stenosis. Hemodynamic studies were performed 3 wk after induction of portal vein stenosis in conscious, unrestrained rats. At that time, neither weight loss nor digestive tract alterations were observed in rats with arterial stenosis. In neither group of rats with arterial stenosis was portal tributary blood flow significantly different from that of normal rats; nor was it significantly lower than in rats with portal vein stenosis without arterial stenosis. In both groups of rats with arterial stenosis, portal pressure was significantly lower (12.1 +/- 1.6 mm Hg and 12.5 +/- 1.8 mm Hg, respectively) than in rats subjected to portal vein stenosis (15.4 +/- 1.5 mm Hg) but significantly higher than in controls (7.2 +/- 1.0 mm Hg). In rats with arterial stenosis, cardiac index was also significantly lower than that in rats with portal vein stenosis but higher than that in controls. In conclusion, this study shows that both early and late superior mesenteric artery stenosis significantly reduce the degree of portal hypertension and the hyperkinetic state of rats with extrahepatic portal hypertension. Thus we can speculate that superior mesenteric artery stenosis might provide a new therapeutic approach for portal hypertension.

Analysis of Variance↗
PubMed1992

Persistence of a hyperdynamic circulation in cirrhotic rats following removal of the sympathetic nervous system.

The sympathetic nervous system is thought to play a role in the pathogenesis of the hyperdynamic circulation associated with portal hypertension. However, the extent of this role is unknown. After elimination of all neurological control by pithing, systemic and regional hemodynamics were studied in rats with portal hypertension caused by either portal vein stenosis or biliary cirrhosis. In normal rats, pithing induced a two-thirds decrease in mean arterial pressure and cardiac index. Compared with pithed normal rats, pithed portal vein-stenosed rats showed similar values for mean arterial pressure, cardiac index, and portal tributary blood flow. In contrast, pithed cirrhotic rats still showed hyperdynamic circulation with increased cardiac index and portal tributary blood flow. Although pithing dramatically reduced portal pressure in all groups, portal pressure remained significantly higher in portal hypertensive rats than in normal rats. These results indicate that in rats with portal vein stenosis, the sympathetic nervous system plays a major role in hemodynamic alterations, whereas in rats with cirrhosis, nonneurogenic factors participate in the pathogenesis of the hyperdynamic circulation.

Animals↗
PubMed1992

Hemodynamic effects of endotoxin and platelet activating factor in cirrhotic rats.

Acute infections may influence the hemodynamic alterations of liver disease. Therefore, the hemodynamic effects of endotoxin (LPS E. coli 0111:B4) in conscious, normal, and cirrhotic rats were compared. Endotoxin decreased cardiac index in cirrhotic but not in normal rats. Although the effect of endotoxin on portal tributary blood flow was minor in all animals, a reduction in portal pressure was found in cirrhotic rats. Because the most marked hemodynamic effects were observed in cirrhotic rats, the second part of our study investigated whether platelet activating factor played a role in endotoxin-induced hemodynamic alterations in the cirrhotic model. Platelet activating factor reduced cardiac index and kidney blood flow but did not influence portal tributary blood flow. Two antagonists to platelet activating factor reduced the adverse renal blood flow lowering effects of endotoxin in cirrhotic rats. Thus, it is suggested that the hemodynamic changes observed in cirrhosis may be aggravated during acute infections. Under this condition, antagonists to platelet activating factor may be of benefit in the prevention of hemodynamic complications induced by endotoxin.

Animals↗
PubMed1992

Effects of theophylline on hemodynamics and tissue oxygenation in patients with cirrhosis.

Since adenosine may play a role in the hyperdynamic circulation of cirrhosis, we examined the effects of theophylline (an adenosine receptor antagonist) on systemic and splanchnic hemodynamics, tissue oxygenation and sympathoadrenal activity in patients with cirrhosis and liver failure. Theophylline (aminophylline) was administered intravenously for 30 min. Six patients received a dose of 3 mg/kg and eight others a dose of 6 mg/kg. The low dose caused plasma theophylline concentrations of 7.4 +/- 1.8 mg/ml (mean +/- S.E.), and induced a significant increase in heart rate from 84 +/- 5 to 93 +/- 8 beats/min. This dosage did not significantly change other hemodynamic values, oxygen (O2) consumption, or sympathoadrenal activity. The high dose elicited plasma theophylline concentrations of 15.8 +/- 4.0 mg/ml. This dose significantly increased heart rate from 78 +/- 5 to 87 +/- 7 beats/min and significantly decreased right atrial pressure from 2.5 +/- 1.0 to 1.4 +/- 0.8 mmHg, stroke volume from 52 +/- 3 to 47 +/- 5 ml.beat-1.m-2 and systolic arterial pressure from 140 +/- 5 to 129 +/- 6 mmHg. In contrast, O2 consumption, sympathoadrenal activity, and all other hemodynamic values (including azygos blood flow) were not significantly modified. As a result, we conclude that, in patients with cirrhosis, theophylline may cause decreased stroke volume which lowers systolic arterial pressure. In our patients theophylline also had a positive chronotropic effect but no vasoconstrictor effect on systemic and splanchnic circulation. Finally, theophylline did not improve tissue oxygenation in patients with cirrhosis.

Adult↗
PubMed1992

Prophylaxis of first variceal bleeding.

Surgical, endoscopic and pharmacological treatment options are available for prophylaxis of first upper intestinal haemorrhage in cirrhotic patients. Randomized controlled trials have revealed that a prophylactic portocaval shunt operation should not be performed because its beneficial effect on the bleeding rate is outweighed by a slightly increased mortality. Prophylactic portal non-decompressive surgery (mainly gastro-oesophageal vascular disconnection) has been shown to reduce the bleeding rate and mortality in Japanese cirrhotic patients. However, further trials in different populations must confirm this positive effect. beta-blockers have fewer side-effects and are probably more effective for prophylaxis of the first bleed than sclerotherapy, but survival is only marginally influenced. Nadolol is preferable to propranolol. The effect of sclerotherapy is in part related to the technical experience of the physician. Although sclerotherapy has only minor effects on the bleeding rate, it is associated with a trend towards a prolonged survival. This may be caused by non-specific effects. On the basis of the published trials, only preliminary recommendations can be given. Prophylactic treatment may be useful in cirrhotic patients who are at high risk of bleeding. Life quality may be improved with continuous beta-blocker treatment. Some studies suggest that alcoholics with large varices may also profit from regular prophylactic sclerotherapy performed by experienced physicians.

Adrenergic beta-Antagonists↗
PubMed1992

[Hemodynamic effects of the administration of terlipressin alone or combined with nitroglycerin in patients with cirrhosis].

Terlipressin (Glypressin), a synthetic analog of vasopressin, induces arteriolar vasoconstriction which causes both a portal hypotensive effect and certain side-effects on the systemic circulation (elevated arterial pressure and reduced cardiac output). The combination of nitroglycerin with terlipressin might accentuate the portal hypotensive effect and prevent the side-effects on the systemic circulation. The aim of this study was to examine the systemic and splanchnic hemodynamic responses to terlipressin administered alone or combined with nitroglycerin in patients with cirrhosis. Systemic and splanchnic hemodynamics were measured before and 1 h after a bolus of terlipressin (1 to 2 mg IV) given alone (n = 10) or in association with nitroglycerin infusion (25 micrograms/min, n = 9). Terlipressin alone significantly increased the arterial pressure by 21%, systemic vascular resistance by 60%, and significantly decreased cardiac output by 23%. The right atrial and pulmonary pressures significantly increased and the wedged hepatic venous pressure and hepatic venous pressure gradient significantly decreased by 8% and 16%, respectively. The combined therapy decreased the cardiac output by 20%, but did not significantly modify the other systemic and splanchnic hemodynamic values. No significant differences were found between terlipressin and the combined therapy concerning changes in wedged hepatic venous pressure or hepatic venous pressure gradient. We conclude that in patients with cirrhosis, nitroglycerin prevents the deleterious vasoconstrictor and vasopressor effects of terlipressin. However, the combined therapy, as terlipressin alone, decreases the cardiac output.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1991

Variability of hemodynamic values and plasma catecholamine concentrations over a one-hour period in conscious, restrained rats.

Restrained conscious rats have been widely used for physiological and pharmacological hemodynamic studies. In this condition, the variability of the circulation is unclear. Repeated measurements in restrained normal rats showed stable systemic hemodynamics (cardiac output ranging from 130 +/- 14 to 174 +/- 10 mL/min, mean arterial pressure ranging from 109 +/- 9 to 117 +/- 5 mmHg) and splanchnic hemodynamics (splanchnic blood flow ranging from 8.51 +/- 1.89 to 13.01 +/- 1.45 mL min-1 100 g-1 body wt) over a period of 1 hr. Slight but not significant hemodynamic variations, however, occurred in pulmonary blood flow. Similarly, plasma noradrenaline concentrations did not vary over this period (plasma noradrenaline level ranging from 186 +/- 36 to 358 +/- 64 pg/mL). These plasma noradrenaline concentrations were similar to those measured in a group of conscious unrestrained rats 3 hr after recovery from surgery (292 +/- 60 pg/mL). A significant correlation was observed between plasma noradrenaline concentration and heart rate.

Animals↗
PubMed1991

Reduction of transmural oesophageal variceal pressure by metoclopramide.

In nineteen patients with portal hypertension and oesophageal varices, transmural variceal blood pressure was determined endoscopically by direct puncture of the varices before and after intravenous administration of 20 mg metoclopramide or placebo. No change in pressure was observed after placebo (mean difference -1.3 +/- 24.5%, N.S.), however, metoclopramide reduced the pressure by 17.6 +/- 18.6% (p = 0.02). Our results suggest that metoclopramide may be beneficial for the prevention or treatment of variceal haemorrhage.

Aged↗
PubMed1991

Adenosine and hemodynamic alterations in cirrhotic rats.

This study evaluated the hypothesis that adenosine may participate in the hemodynamic alterations observed in conscious unrestrained cirrhotic rats. In sham-operated rats, adenosine (20 micrograms.100 g body wt-1.min-1 iv) induced hyperdynamic circulation and significantly increased portal pressure, mimicking the hemodynamic changes observed in cirrhosis. Although adenosine significantly increased hyperdynamic circulation and portal pressure in cirrhotic rats, these changes were significantly less marked than in sham-operated rats. 8-Phenyltheophylline (20 micrograms.100 g body wt-1.min-1 iv), a specific and potent adenosine antagonist, significantly decreased portal tributary blood flow in sham-operated rats (-18.0 +/- 5.6%) but did not have a significant effect in cirrhotic rats. The limited effect of 8-phenyltheophylline was not due to an insufficient dose, since the dose administered antagonized the hemodynamic effect of exogenous adenosine up to 40 micrograms.100 g body wt-1.min-1. We conclude that in certain circumstances, although adenosine may aggravate the hyperdynamic circulation, in normal conditions, the hemodynamic alterations observed in cirrhotic rats are not mediated by adenosine.

Adenosine↗
PubMed1991

Prediction of variceal hemorrhage in cirrhosis: a prospective follow-up study.

Endoscopic, clinical, and laboratory parameters including presence of varices in the gastric fundus, red color sign, diameter and number of variceal columns, platelet count, and the Child status were assessed in 109 patients with cirrhosis and esophageal varices without previous variceal bleeding. During a mean follow-up period of 21 months, the predictive values of these parameters with regard to first bleeding incidence and mortality rate were studied. The incidence of bleeding was 29%, and the mortality rate 46%. Endoscopic criteria (presence of varices in the gastric fundus, presence of the red color sign, and size of the largest varix) as well as alcoholic etiology of cirrhosis showed a significant positive correlation with the bleeding incidence but not with mortality. Contrary to this, two factors of the Child classification (encephalopathy and ascites) and age positively correlated with mortality but not with the bleeding incidence.

Adult↗
PubMed1991

Plasma catecholamines in patients with presinusoidal portal hypertension: comparison with cirrhotic patients and nonportal hypertensive subjects.

During a hemodynamic study, plasma catecholamine concentrations were measured in the pulmonary artery and in the hepatic vein in 18 presinusoidal portal hypertensive patients. Results were compared with those in 15 nonportal hypertensive subjects and in 24 cirrhotic patients in good condition (grade A, according to Pugh's classification). Plasma norepinephrine concentrations in the pulmonary artery or in the hepatic vein were not significantly different between nonportal hypertensive subjects (mean +/- S.E.M.: 271 +/- 36 and 83 +/- 11 pg/ml, respectively) and presinusoidal portal hypertensive patients (273 +/- 33 and 84 +/- 11 pg/ml, respectively). These concentrations were, however, elevated in cirrhotic patients (408 +/- 47 and 256 +/- 45 pg/ml, p less than 0.05 in comparison with the two other groups). These differences suggest that increased sympathetic nervous activity in cirrhosis is associated with the presence of liver disease or increase in sinusoidal pressure. Differences in plasma epinephrine concentrations were not significant among the three groups of patients. However, the existence of a significant correlation between pulmonary artery plasma epinephrine concentration and cardiac index (r2 = 0.46, p less than 0.01) in patients with presinusoidal portal hypertension suggests that the adrenal medulla could play a role in the pathophysiology of the hyperkinetic syndrome of these patients.

Adult↗
PubMed1989

Pressure of intraoesophageal varices assessed by fine needle puncture: its relation to endoscopic signs and severity of liver disease in patients with cirrhosis.

In 40 patients with cirrhosis and oesophageal varices transmural variceal pressure was assessed endoscopically by fine needle puncture and related to endoscopic signs as well as to the severity of liver disease. Transmural pressure was significantly (p less than 0.01) higher in the presence of a red colour sign (26.7 (7.8) cm H2O) than in its absence (19.1 (6.6) cm H2O). Transmural pressure, however, was not significantly related to diameter or number of varices (diameter greater than 5 mm: 23.7 (8.4), diameter less than or equal to 5 mm: 22.2 (7.9) cm H2O; number greater than 3: 23.2 (8.0), number less than or equal to 3: 22.2 (7.8) cm H2O). The Child status (Child A: 23.9 (8.0), Child B/C: 21.3 (8.1) cm H2O) and individual Child-Pugh parameters including ascites (ascites present: 23.2 (8.3) cm H2O ascites absent: 22.8 (8.1) cm H2O) were not significantly related to transmural variceal pressure. We conclude that the endoscopic visibility of a red colour sign on the varices is associated with a high transmural oesophageal variceal pressure. Our results favour the hypothesis that variceal pressure may be of major importance for the development of the red colour sign.

Ascites↗
PubMed1988

Somatostatin does not reduce oesophageal variceal pressure in liver cirrhotics.

Transmural oesophageal variceal pressure was determined by direct puncture of the varices in 27 patients with liver cirrhosis and oesophageal varices. Variceal pressure was not influenced three to six minutes after somatostatin bolus administration and slightly increased during somatostatin infusion. Thus, potential haemostatic benefits of somatostatin cannot be explained by pressure reductions in the varices.

Blood Pressure↗
PubMed1988

Risk indicators of variceal bleeding.

Variceal bleeding is a catastrophic event in the history of liver cirrhotics. However, in more than half of the patients it never occurs. Thus, measures to prevent bleeding should be undertaken only in patients at the highest risk of bleeding. Risk indicators should help to select those patients. Hemodynamic and endoscopic parameters as well as liver function and coagulation status and the patient's history have been studied in relation to the bleeding incidence. The following parameters are correlated with an increased bleeding risk: The first year after diagnosis of varices, a positive history of variceal bleeding, presence of varices with large diameters, high blood pressures or a red colour sign, concomitant gastric varices or development of a liver cell carcinoma. Other parameters may be of less importance for the occurrence of variceal bleeding.

Endoscopy↗