Effect of volume expansion on systemic hemodynamics and central and arterial blood volume in cirrhosis

Changing trends in transfusion practice in liver transplantation

PURPOSE OF REVIEW

Prevention of excessive blood loss is an important issue in the perioperative management of liver transplantation. This review describes changing trends in blood products use, risk predicting of blood transfusion, variability in use and practices, as well as transfusion safety during liver transplantation.

RECENT FINDINGS

Over the last 20 years, the average use of blood products per case has considerably decreased. There are marked interinstitutional differences in blood use. Differences in patient population characteristics and surgical techniques are a partial explanation, but differences in transfusion practices probably account for a substantial part of the variability. Recent data have sparked off ongoing controversy relating to volume replacement therapy and its impact on blood loss. New studies emphasize the risks associated with transfusion in liver transplantation.

SUMMARY

Recent studies call for continuing every reasonable effort to minimize the use of blood components and can guide us in new approaches to this vital problem.

Haemodynamic effects of plasma-expansion with hyperoncotic albumin in cirrhotic patients with renal failure: a prospective interventional study

Background

Patients with advanced cirrhosis of the liver typically display circulatory disturbance. Haemodynamic management may be critical for avoiding and treating functional renal failure in such patients. This study investigated the effects of plasma expansion with hyperoncotic albumin solution and the role of static haemodynamic parameters in predicting volume responsiveness in patients with advanced cirrhosis.

Methods

Patients with advanced cirrhosis (Child B and C) of the liver receiving albumin substitution because of renal compromise were studied using trans-pulmonary thermodilution. Paired measurements before and after two infusions of 200 ml of 20% albumin per patient were recorded and standard haemodynamic parameters such as central venous pressure (CVP), mean arterial pressure (MAP), systemic vascular resistance index (SVRI), cardiac index (CI) and derived variables were assessed, including global end-diastolic blood volume index (GEDVI), a parameter that reflects central blood volume

Results

100 measurements in 50 patients (33 m/17 w; age 56 years (± 8); Child-Pugh-score 12 (± 2), serum creatinine 256 μmol (± 150) were analyzed. Baseline values suggested decreased central blood volumes GEDVI = 675 ml/m² (± 138) despite CVP within the normal range (11 mmHg (± 5). After infusion, GEDVI, CI and CVP increased (682 ml/m² (± 128) vs. 744 ml/m² (± 171), p < 0.001; 4.3 L/min/m² (± 1.1) vs. 4.7 L/min/m² (± 1.1), p < 0.001; 12 mmHg (± 6) vs. 14 mmHg (± 6), p < 0.001 respectively) and systemic vascular resistance decreased (1760 dyn s/cm⁵/m² (± 1144) vs. 1490 dyn s/cm⁵/m² (± 837); p < 0.001). Changes in GEDVI, but not CVP, correlated with changes in CI (r² = 0.51; p < 0.001). To assess the value of static haemodynamic parameters at baseline in predicting an increase in CI of 10%, receiver-operating-characteristic curves were constructed. The areas under the curve were 0.766 (p < 0.001) for SVRI, 0.723 (p < 0.001) for CI, 0.652 (p = 0.010) for CVP and 0.616 (p = 0.050) for GEDVI.

Conclusion

In a substantial proportion of patients with advanced cirrhosis, plasma expansion results in an increase in central blood volume. GEDVI but not CVP behaves as an indicator of cardiac preload, whereas high baseline SVRI is predictive of fluid responsiveness.

Hemodynamic alterations in liver cirrhosis

In cirrhotic patients, portal hypertension is often associated with a hyperdynamic circulatory syndrome, with high cardiac output and reduced systemic vascular resistance and arterial pressure. The hyperdynamic circulatory syndrome is due to arterial vasodilation that mainly occurs in the splanchnic circulation, while vascular resistance in the other circulatory districts is normal or increased, accordingly with the degree of portal hypertension, liver impairment and activation of the renin-aldosterone and sympathetic nervous system. The mechanism(s) leading to splanchnic vasodilation is unclear. A favored hypothesis translocation of intestinal bacteria and/or some their products, such as endotoxin, into the interstitial space in the splanchnic organs results in the local release of vasodilating factors such as nitric oxide, carbon monoxide and others.

Cirrhotic cardiomyopathy

Decompensated liver cirrhosis is characterized by a peripheral vasodilation with a low-resistance hyperdynamic circulation. The sustained increase of cardiac work load associated with such a condition may result in an inconstant and often subclinical series of heart abnormalities, constituting a new clinical entity known as "cirrhotic cardiomyopathy". Cirrhotic cardiomyopathy is variably associated with baseline increase in cardiac output, defective myocardial contractility and lowered systo-diastolic response to inotropic and chronotropic stimuli, down-regulated beta-adrenergic function, slight histo-morphological changes, and impaired electric "recovery" ability of ventricular myocardium. Cirrhotic cardiomyopathy is usually clinically latent or mild, likely because the peripheral vasodilation significantly reduces the left ventricle after-load, thus actually "auto-treating" the patient and masking any severe manifestation of heart failure. In cirrhotic patients, the presence of cirrhotic cardiomyopathy may become unmasked and clinically evident by certain treatment interventions that increase the effective blood volume and cardiac pre-load, including surgical or transjugular intrahepatic porto-systemic shunts, peritoneo-venous shunts (LeVeen) and orthotopic liver transplantation. Under these circumstances, an often transient overt congestive heart failure may develop, with increased cardiac output as well as right atrial, pulmonary artery and capillary wedge pressures.

Reduced baroreflex sensitivity in alcoholic cirrhosis: relations to hemodynamics and humoral systems

In cirrhosis, arterial vasodilatation leads to central hypovolemia and activation of the sympathetic nervous and renin-angiotensin-aldosterone systems. As the liver disease and circulatory dysfunction may affect baroreflex sensitivity (BRS), we assessed BRS in a large group of patients with cirrhosis and in controls who were all supine and some after 60 degrees passive head-up and 30 degrees head-down tilting in relation to central hemodynamics and activity of the sympathetic nervous and renin-angiotensin-aldosterone systems. One-hundred and five patients (Child classes A/B/C: 21/55/29) and 25 (n=11 + 14) controls underwent a full hemodynamic investigation. BRS was assessed by cross-spectral analysis of variabilities between blood pressure and heart rate time series. The median BRS was significantly lower in the supine cirrhotic patients, 3.7 (range 0.3-30.7) ms/mmHg than in matched controls (n=11): 14.3 (6.1-23.6) ms/mmHg, P<0.001. A stepwise multiple-regression analysis revealed that serum sodium (P=0.044), heart rate (P=0.027), and central circulation time (P=0.034) independently correlated with BRS. Head-down tilting had no effects on BRS, but, after head-up tilting, BRS was similar in the patients (n=23) and controls (n=14). In conclusion, BRS is reduced in cirrhosis in the supine position and relates to various aspects of cardiovascular dysfunction, but no further reduction was observed in parallel with the amelioration of the hyperdynamic circulation after head-up tilting. The results indicate that liver dysfunction and compensatory mechanisms to vasodilatation may be involved in the low BRS, which may contribute to poor cardiovascular adaptation in cirrhosis.

Prognosis in patients with cirrhosis and mild portal hypertension

OBJECTIVE

Sixty to 70% of upper gastrointestinal bleeding episodes in patients with cirrhosis are caused by oesophageal varices. Prophylaxis is indicated in patients with varices and a hepatic venous pressure gradient (HVPG) above 12 mmHg. The study of the natural history of patients with lower HVPG has been sparse. In this study, long-term survival and the risk of complications in mild portal hypertension were analysed.

MATERIAL AND METHODS

Sixty-one patients with cirrhosis and HVPG below 10 mmHg were included in the study. Data were collected from medical files and National Patient Registries. Variceal bleeding, hepatic encephalopathy and death related to cirrhosis were registered. Thirty-nine patients were graded as Child class A, 19 as class B and 3 as class C. Median survival time was 11 years.

RESULTS

Twenty-eight patients (46%) developed one or more complications: variceal bleeding in 10 (16%) and hepatic encephalopathy in 18 patients (30%). Twenty-three patients (38%) died from complications of cirrhosis. Two patients (3%) died from variceal bleeding, another two (3%) from gastrointestinal bleeding of unidentified source. Survival rate was significantly decreased compared with that in the background population.

CONCLUSIONS

The frequency of complications in patients with mild portal hypertension is considerable, and guidelines for follow-up or medical prophylaxis are warranted. The risk of bleeding from oesophageal varices is low and bleeding-related deaths rare.

Pulmonary blood volume and transit time in cirrhosis: relation to lung function

BACKGROUND/AIMS

In cirrhosis a systemic vasodilatation leads to an abnormal distribution of the blood volume with a contracted central blood volume. In addition, the patients have a ventilation/perfusion imbalance with a low diffusing capacity. As the size of the pulmonary blood volume (PBV) has not been determined separately we assessed PBV and pulmonary transit time (PTT) in relation to lung function in patients with cirrhosis and in controls.

METHODS

Pulmonary and cardiac haemodynamics and transit times were determined by radionuclide techniques in 22 patients with alcoholic cirrhosis and in 12 controls. The lung function including diffusing capacity for carbon monoxide (DL, CO) was determined by conventional single breath technique.

RESULTS

In the patients, PTT was shorter, 3.9+/-1.2 vs 5.7+/-1.0 s in the controls, P<0.001, and the PBV was lower, 362+/-151 vs 587+/-263 ml, in the controls, P<0.005. Both PTT and PBV were lowest in patients with advanced disease. DL, CO was reduced in the patients and correlated significantly with PTT (r=0.58, P=0.007) and PBV (r=0.49, P<0.03).

CONCLUSIONS

The results suggest that the reduced PBV contributes to the reduced effective blood volume in cirrhosis. The relation between PBV and PTT and the low diffusing capacity suggests the pulmonary vascular compartment as an important element in the pathophysiology of the lung dysfunction in cirrhosis.

Determinants of the renin-angiotensin-aldosterone system in cirrhosis with special emphasis on the central blood volume

OBJECTIVE

Several studies have shown activation of the renin-angiotensin-aldosterone system (RAAS) in cirrhosis. Although the activated RAAS may have several determinants, the system is often considered a surrogate marker of effective hypovolaemia. In this study we investigated the activity of the RAAS and its potential determinants with special focus on the central and arterial blood volume (CBV).

MATERIAL AND METHODS

Eighty-nine patients (Child class A/B/C: 19/41/29) and 32 controls were included in the study. All were given a haemodynamic examination with measurement of determinants of the RAAS, including the CBV. Circulating plasma renin concentrations were measured using an immunoradiometric assay.

RESULTS

Arterial renin concentrations were significantly higher in the patients than in the controls (p < 0.003). Plasma renin correlated significantly with several indicators of liver dysfunction and splanchnic and systemic haemodynamics (r = - 0.56-0.55), but only weakly with CBV (r = - 0.25, p < 0.02). In a multivariate regression analysis, plasma renin was determined by serum sodium, alkaline phosphatases and systolic blood pressure (p < 0.04 to p < 0.001).

CONCLUSIONS

CBV correlates weakly with circulating renin, and activation of the RAAS can therefore only partly be considered as an indicator of central hypovolaemia. Mechanisms other than central hypovolaemia relating to the liver disease and portal hypertension contribute significantly to the RAAS activation.

Liver cirrhosis and arterial hypertension

Characteristic findings in patients with cirrhosis are vasodilatation with low overall systemic vascular resistance, high arterial compliance, increased cardiac output, secondary activation of counter-regulatory systems (renin-angiotensin-aldosterone system, sympathetic nervous system, release of vasopressin), and resistance to vasopressors. The vasodilatory state is mediated through adrenomedullin, calcitonin gene-related peptide, nitric oxide, and other vasodilators, and is most pronounced in the splanchnic area. This constitutes an effective (although relative) counterbalance to increased arterial blood pressure. This review considers the alterations in systemic hemodynamics in patients with cirrhosis in relation to essential hypertension and arterial hypertension of the renal origin. Subjects with arterial hypertension (essential, secondary) may become normotensive during the development of cirrhosis, and arterial hypertension is rarely manifested in patients with cirrhosis, even in cases with renovascular disease and high circulating renin activity. There is much dispute as to the understanding of homoeostatic regulation in cirrhotic patients with manifest arterial hypertension. This most likely includes the combination of vasodilatation and vasoconstriction in parallel.

Cardiopulmonary complications in chronic liver disease

Patients with cirrhosis and portal hypertension exhibit characteristic cardiovascular and pulmonary hemodynamic changes. A vasodilatatory state and a hyperdynamic circulation affecting the cardiac and pulmonary functions dominate the circulation. The recently defined cirrhotic cardiomyopathy may affect systolic and diastolic functions, and imply electromechanical abnormalities. In addition, the baroreceptor function and regulation of the circulatory homoeostasis is impaired. Pulmonary dysfunction involves diffusing abnormalities with the development of the hepatopulmonary syndrome and portopulmonary hypertension in some patients. Recent research has focused on the assertion that the hemodynamic and neurohumoral dysregulation are of major importance for the development of the cardiovascular and pulmonary complications in cirrhosis. This aspect is important to take into account in the management of these patients.

Management of cirrhotic ascites: physiological basis of diuretic action

Ascites is a significant complication of cirrhosis that occurs in approximately 50% of patients. The mortality rate is high in patients with cirrhosis and ascites. Conventional interventions rest with dietary sodium restriction, diuretic use, large-volume paracentesis, peritoneovenous shunts and transjugular intrahepatic portosystemic shunts. The mainstay of therapy, however, is the judicious use of diuretics. This article reviews the physiological basis of diuretic use in patients with cirrhosis and ascites, as well as recent concepts on the pathogenesis of ascites formation. Through a better understanding of the pathophysiology of ascites formation and the mechanism of action of diuretics, improved extracellular fluid balance can be achieved in these patients.

Detection of early central circulatory transits in patients with cirrhosis by gamma variate fit of indicator dilution profiles

Patients with cirrhosis have hyperdynamic circulation with abnormally distributed blood volume and widespread arteriovenous communications. We aimed to detect possible very early (i.e., before 4 s) and early (i.e., after 4 s) central circulatory transits and their potential influence on determination of central and arterial blood volume (CBV). Thirty-six cirrhotic patients and nineteen controls without liver disease undergoing hemodynamic catheterization were given central bolus injections of albumin with different labels. Exponential and gamma variate fits were applied to the indicator dilution curves, and the relations between flow, circulation times, and volumes were established according to kinetic principles. No significant very early central circulatory transits were identified. In contrast, early (i.e., 4 s to maximal) transits corresponding to a mean of 5.1% (vs. 0.8% in controls; P < 0.005) of cardiac output (equivalent to 0.36 vs. 0.05 l/min; P < 0.01) were found in cirrhotic patients. These early transits averaged 7.7 vs. 12.7 and 17.2 s of ordinary central transits of cirrhotic patients and controls, respectively (P < 0.001). Early transits were directly correlated to the alveolar-arterial oxygen difference in the cirrhotic patients (r = 0.46, P < 0.01) but not in controls (r = 0.04; not significant). There was good agreement between the CBV determined by the conventional indicator dilution method and that determined by separation of early and ordinary transits by the gamma variate fit method (1.51 vs. 1.53 liter; not significant). In conclusion, no very early central circulatory transits were identified in cirrhotic patients. A significant part of the cardiac output undergoes an early transit, probably through pulmonary shunts or areas with low ventilation-perfusion ratios in cirrhotic patients. Composite determination of CBV by the gamma variate fit method is in close agreement with established kinetic methods. The study provides further evidence of abnormal central circulation in cirrhosis.

Hypertension and liver disease

Arterial hypertension is a common disorder with a frequency of 10% to 15% in subjects in the 40- to 60-year age group. Yet most reports find the prevalence of arterial hypertension in patients with chronic liver disease (cirrhosis) much lower. In this review, we consider the alterations in systemic hemodynamics in cirrhosis. The most characteristic findings in cirrhotic patients are vasodilatation with low systemic vascular resistance, increased cardiac output, high arterial compliance, secondary activation of counterregulatory systems (sympathetic nervous system, renin-angiotensin-aldosterone system, neuropituitary release of vasopressin), and resistance to vasopressors. The vasodilatory state is mediated through nitric oxide, calcitonin gene-related peptide, adrenomedullin, and other vasodilators, and is most pronounced in the splanchnic area. This constitutes an effective (although relative) counterbalance to increased arterial blood pressure. Subjects with established arterial hypertension (essential, secondary) may become normotensive during the development of cirrhosis, and arterial hypertension is rarely manifested in patients with cirrhosis, even in cases with renovascular disease and high circulating renin activity. There is much dispute as to the understanding of homeostatic regulation in cirrhotic patients with manifest arterial hypertension. This is a topic for future research.

Effects of tilting on central hemodynamics and homeostatic mechanisms in cirrhosis

Patients with cirrhosis have a hyperdynamic circulation and an abnormal blood volume distribution with central hypovolemia, an activated sympathetic nervous system (SNS) as well as the renin-angiotensin-aldosterone system (RAAS). As the hyperdynamic circulation in cirrhosis may be present only in the supine patient, we studied the humoral and central hemodynamic responses to changes with posture. Twenty-three patients with alcoholic cirrhosis (Child-Turcotte-Pugh classes A/B/C: 2/13/8) and 14 healthy controls were entered. Measurements of central hemodynamics and activation of SNS and RAAS were taken in the supine position, after 30 degrees head-down tilting, and after 60 degrees passive head-up tilting for a maximum of 20 minutes. After the head-up tilting, the central blood volume (CBV) decreased in both groups, but the decrease was significantly smaller in patients than in controls (-19% vs. -36%, P <.01). Central circulation time increased only in the patients (+30% vs. -1%, P <.01). The absolute increases in circulating norepinephrine and renin after head-up tilting were significantly higher in the patients than in the controls (P <.05 and P <.01, respectively). In patients with cirrhosis, changes in SNS and RAAS were related to changes in arterial blood pressure, systemic vascular resistance, heart rate, non-CBV, plasma volume, and arterial compliance. In conclusion, cardiovascular and humoral responses to changes in posture are clearly abnormal in patients with cirrhosis. Head-up tilting decreases the CBV less in patients with cirrhosis, and the results suggest a differential regulation of central hemodynamics in patients with cirrhosis.

Effects of tilting on central hemodynamics and homeostatic mechanisms in cirrhosis

Patients with cirrhosis have a hyperdynamic circulation and an abnormal blood volume distribution with central hypovolemia, an activated sympathetic nervous system (SNS) as well as the renin-angiotensin-aldosterone system (RAAS). As the hyperdynamic circulation in cirrhosis may be present only in the supine patient, we studied the humoral and central hemodynamic responses to changes with posture. Twenty-three patients with alcoholic cirrhosis (Child-Turcotte-Pugh classes A/B/C: 2/13/8) and 14 healthy controls were entered. Measurements of central hemodynamics and activation of SNS and RAAS were taken in the supine position, after 30 degrees head-down tilting, and after 60 degrees passive head-up tilting for a maximum of 20 minutes. After the head-up tilting, the central blood volume (CBV) decreased in both groups, but the decrease was significantly smaller in patients than in controls (-19% vs. -36%, P <.01). Central circulation time increased only in the patients (+30% vs. -1%, P <.01). The absolute increases in circulating norepinephrine and renin after head-up tilting were significantly higher in the patients than in the controls (P <.05 and P <.01, respectively). In patients with cirrhosis, changes in SNS and RAAS were related to changes in arterial blood pressure, systemic vascular resistance, heart rate, non-CBV, plasma volume, and arterial compliance. In conclusion, cardiovascular and humoral responses to changes in posture are clearly abnormal in patients with cirrhosis. Head-up tilting decreases the CBV less in patients with cirrhosis, and the results suggest a differential regulation of central hemodynamics in patients with cirrhosis.

Acute non-selective beta-adrenergic blockade reduces prolonged frequency-adjusted Q-T interval (QTc) in patients with cirrhosis

BACKGROUND/AIMS

Earlier studies have shown a prolonged frequency-adjusted Q-T interval (QTc>0.440 s(1/2)) in a substantial fraction of patients with cirrhosis. The effect of beta-blockade on QTc is unknown, and its determination was the aim of the study.

METHODS

Seventeen patients with cirrhosis received 80 mg propranolol orally during a haemodynamic investigation with measurements at baseline and 90 min after propranolol ingestion.

RESULTS

Beta-blockade reduced cardiac output (-21%, P<0.001), heart rate (-20%, P<0.001), and the hepatic venous pressure gradient (HVPG, -17%, P<0.02). The mean QTc=0.460 s(1/2) was prolonged compared to 0.410 s(1/2) in age-matched controls (P<0.01). Whereas QTc decreased during beta-blockade in the cirrhotic patients (from 0.460 to 0.440 s(1/2), P<0.01), no effect was found in the subgroup with normal QTc (0.429 vs. 0.422 s(1/2), ns), and a reduction was seen in the patients with prolonged QTc (from 0.488 to 0.456 s(1/2), P<0.01). The percentage decrease in QTc was related to the reduction in HVPG (r=0.48, P=0.03) and cardiac output (r=0.56, P=0.02).

CONCLUSIONS

Acute non-selective beta-blockade reduces prolonged QTc towards normal values in patients with cirrhosis. The clinical significance of QTc reduction in arrhythmia is a topic for future research.

Humoral and cardiac effects of TIPS in cirrhotic patients with different "effective" blood volume

The aim of this study was to evaluate the cardiac effects of transjugular intrahepatic portosystemic shunts (TIPS) in cirrhotic patients with different effective blood volume. Two-dimensional echocardiography was performed before and 7 and 28 days after TIPS insertion in 7 cirrhotic patients with PRA <4 ng/mL/h (group A, normal effective blood volume) and 15 with PRA >4 ng/mL/h (group B, reduced effective blood volume). Before TIPS, most cirrhotic patients showed diastolic dysfunction as indicated by reduced early maximal ventricular filling velocity (E)/late filling velocity (A) ratio. Patients of group B differed from patients of group A because of smaller left ventricular volumes and stroke volume, indicating central underfilling. After TIPS insertion, portal decompression was associated with a significant increase of cardiac output (CO) and a decrease of peripheral resistances. The most important changes were recorded in patients of group B, who showed a significant increase of both the end-diastolic left ventricular volumes and the E/A ratio and a significant decrease of PRA. In conclusion, these results show that the hemodynamic effects of TIPS differ according to the pre-TIPS effective blood volume. Furthermore, TIPS improves the diastolic cardiac function of cirrhotic patients with effective hypovolemia. This result is likely due to a TIPS-related improvement of the fullness of central blood volume.

Plasma volume expansion by albumin in cirrhosis. Relation to blood volume distribution, arterial compliance and severity of disease

BACKGROUND/AIMS

The aim of the study was to investigate the effect of a standard albumin load on blood volume distribution, arterial compliance, and the renin-angiotensin-aldosterone system in patients with different degrees of cirrhosis.

METHODS

31 patients with cirrhosis (Child classes A/B/C=8/14/9) received an intravenous infusion of 40 g human serum albumin during a haemodynamic investigation.

RESULTS

Whereas plasma- and blood volume increased by 23 and 15%, respectively (P<0.001), a significant increase in central blood volume was found only in class A patients (+8%, P<0.05), but not in class B or class C patients (+2.7%, not significant (n.s.)). In contrast, arterial compliance only increased significantly in class C patients (+18%, P<0.05), but not in class A or class B patients (+6%, n.s.). Plasma renin activity (PRA) decreased significantly in class C patients (-31%, P<0.05). When all patients were compared, the change in arterial compliance was inversely correlated to the change in PRA (r=-0.50, P<0.01).

CONCLUSIONS

Although infusion of albumin does not expand the central blood volume in patients with advanced cirrhosis, the results indicate a significant improvement in the low effective arterial blood volume of such patients, which may be important in the prevention of circulatory dysfunction.

Central and noncentral blood volumes in cirrhosis: relationship to anthropometrics and gender

The size of the central and arterial blood volume (CBV) is essential in the understanding of fluid retention in cirrhosis. Previously, it has been reported decreased, normal, or increased, but no reports have analyzed CBV with respect to gender and lean body mass. The aim of the present study was by means of an optimized technique to reassess it in a large group of patients with cirrhosis compared with healthy controls and matched controls in relationship to their body dimensions and gender. Eighty-three patients with cirrhosis (male/female, 60:23), 67 patients without liver disease (male/female, 22:45), and 14 young healthy controls (male/female, 6:8) underwent a hemodynamic investigation with determination of cardiac output, central circulation time, and CBV determined according to kinetic principles. Related to gender, CBV was lower in male cirrhotics (1.48 +/- 0.30 liter) than in matched and young controls (1.68 +/- 0.33 and 1.72 +/- 0.33 liter, respectively; P < 0.05-0.01). No significant differences in CBV were seen between female cirrhotics and controls. Absolute and adjusted CBVs were lower in the females than in men with cirrhosis (P < 0.001), and men with cirrhosis had lower absolute and body weight-adjusted CBVs than matched controls (P < 0.01). Normalized values of CBV (%total blood volume) were significantly lower in patients with cirrhosis (25 +/- 4%) than in matched controls (31 +/- 7%) and young controls (28 +/- 4%; P < 0.02). CBV correlated significantly with anthropometrics, including lean body mass (r = 0.68-0.82; P < 0.0001). In conclusion, the CBV of patients with cirrhosis was lower than that of controls when adjusted for body dimensions and gender. There are significant gender differences, and signs of underfilling are more pronounced in male than in female patients. The results emphasize the importance of adjustments of blood volumes for anthropometrics and gender.

Cardiac output determined by echocardiography in patients with cirrhosis: comparison with the indicator dilution technique

BACKGROUND/AIMS

Measurement of cardiac output in hyperkinetic patients with cirrhosis by Doppler echocardiography is increasingly reported, but has not been validated. We have compared simultaneous measurements of cardiac output by Doppler echocardiography (CO(d)) and by the indicator dilution technique (CO(I)).

METHODS

Twelve patients with cirrhosis were studied. CO(d) was measured as the spatial mean velocity of the left ventricular outflow tract, multiplied by the cross-sectional area and the heart rate. CO(I) was determined by the standard indicator dilution technique after injection of 125I albumin and 99mTc albumin into the right atrium and subsequent sampling from the femoral artery.

RESULTS

The mean CO(d) and CO(I) were similar (7.20 vs 7.15 l/min, NS). A highly significant correlation was present between CO(d) and CO(I) (r = 0.86, P < 0.0001; slope 0.91, Y(0) = 0.78 l/min). However, the mean squared difference between CO(d) and CO(I) was 2.3 (l/min)2. A Bland-Altman plot revealed no trend with the level of cardiac output. The standard deviation (0.79 vs 0.30 l/min, P < 0.01) and the coefficient of variation (10.5 vs 4.2%, P < 0.01) of duplicate measurements were significantly higher with the Doppler technique.

CONCLUSION

Doppler measurements of cardiac output in groups of patients with cirrhosis are accurate with respect to the group mean, but marked disagreements of over- and underestimation were seen in individual patients. The reproducibility of the Doppler technique is acceptable, although not as good as that of the indicator dilution technique.

Review article: volume expansion in patients with cirrhosis

Adequate size and distribution of the circulating medium are important for cardiovascular function, tissue oxygenation, and fluid homoeostasis. Patients with cirrhosis have cardiovascular dysfunction with a hyperkinetic systemic circulation, abnormal distribution of the blood volume, vasodilation with low systemic vascular resistance, increased whole-body vascular compliance, and increased arterial compliance. The effectiveness and temporal relations of plasma/blood volume expansion depend highly on the type of load (water, saline, oncotic material, red blood cells). Patients with cirrhosis respond in some aspects differently from healthy subjects, owing to their disturbed circulatory function and neurohormonal activation. Thus the increase in cardiac output and suppression of the renin-angiotensin-aldosterone system and sympathetic nervous system during volume expansion may be somewhat blunted, and in advanced cirrhosis, especially the non-central parts of the circulation, including the splanchnic blood volume, are expanded by a volume load. Infusion of oncotic material (preferably albumin) is important in the prevention of post-paracentesis circulatory dysfunction. In conclusion, volume expansion in advanced cirrhosis is qualitatively and quantitatively different from that of healthy subjects, and in those with early cirrhosis. Timely handling is essential, but difficult as it is a balance between the risks of excess extravascular volume loading and further circulatory dysfunction in these patients with a hyperdynamic, but hyporeactive, circulation.

Review article: albumin for circulatory support in patients with cirrhosis

Renal function abnormalities and ascites in cirrhosis are the final consequence of a circulatory dysfunction characterized by marked splanchnic arterial vasodilation. This causes a reduction in effective arterial blood volume and the homoeostatic activation of vasoconstrictor and sodium-retaining systems. Albumin is very effective in preventing renal failure associated with large-volume paracentesis and spontaneous bacterial peritonitis, conditions that are known to cause an impairment of circulatory function in patients with cirrhosis and ascites. Moreover, albumin administration improves survival in patients with spontaneous bacterial peritonitis. In patients with hepatorenal syndrome the administration of vasoconstrictor drugs in combination with albumin improves circulatory and renal function markedly and survival slightly. By contrast, the administration of albumin without vasoconstrictors has marginal or no effects on renal function in this setting.

Cirrhotic cardiomyopathy: a pathophysiological review of circulatory dysfunction in liver disease

The systemic circulation in patients with cirrhosis is hyperdynamic with an increased cardiac output and heart rate and a reduced systemic vascular resistance as the most pronounced alterations. The concomitant cardiac dysfunction has recently been termed "cirrhotic cardiomyopathy", which is an entity different from that seen in alcoholic heart muscle disease. Clinically, these patients present with sodium fluid retention and strain often unmasks the presence of latent heart failure. No specific treatment can yet be recommended but caution should be used with respect to procedures that may stress the heart such as shunt implantation and liver transplantation.

Blood volume distribution in patients with cirrhosis: aspects of the dual-head gamma-camera technique

BACKGROUND/AIMS

Patients with cirrhosis have increased total blood volume (TBV). The size of the "effective" blood volume has been closely investigated, whereas the distribution of the blood volume outside the thorax has not been examined. The aim was to estimate the blood volume distribution in patients with cirrhosis and portal hypertension, using a dual-head gamma-camera technique (DHGCT) and to validate this technique.

METHODS

Twenty-three patients with cirrhosis, 11 non-cirrhotic control patients, and six healthy controls had their blood volume distribution determined by the DHGCT.

RESULTS

The close relation between the estimated blood volume in the thorax region and the central and arterial blood volume, obtained by the dynamic indicator dilution technique (r=0.87, P<0.001), indicates validity of the DHGCT. Whole-body scintigraphy showed altered blood volume distribution in the cirrhotic patients with increased splanchnic blood volume (SpBV: 25.0 vs. 18.2% of TBV in controls, P<0.001), and all but one patient with hepatic venous pressure gradient above 12 mmHg had SpBV above 20% of TBV, but the blood volumes in the liver region were similar.

CONCLUSIONS

DHGCT is a valid method of estimating the blood volume distribution. Patients with cirrhosis and portal hypertension have grossly increased blood pooling in the splanchnic region, indicating splanchnic congestion.

Management of ascites

The evaluation of ascites includes a directed history, focused physical examination, and diagnostic paracentesis with ascitic fluid analysis. Dietary sodium restriction and oral diuretics are the mainstay of therapy for the majority of patients with cirrhotic ascites. Transjugular intrahepatic portocaval shunt has emerged as the treatment of choice for selected patients with refractory ascites, although serial large-volume paracenteses should be attempted first. Early diagnosis, broad-spectrum antibiotics, and albumin infusion contribute to the successful management of spontaneous bacterial peritonitis (SBP). Referral for liver transplant evaluation should be considered at the first sign of decompensation and should not be delayed until development of ominous clinical features, such as refractory ascites and SBP.

Arterial compliance in patients with cirrhosis: stroke volume-pulse pressure ratio as simplified index

Arterial function may be altered in patients with cirrhosis. We determined compliance of the arterial tree (C(1)) in relation to systemic and splanchnic hemodynamic derangement and clinical variables. C(1) and the stroke volume-pulse pressure index (SV/PP) were significantly higher (+62% and +40%, respectively; P < 0.001) in cirrhotic patients (n = 49) than in control subjects (n = 19), and a close correlation between C(1) and SV/PP was found in both cirrhotic patients (r = 0.86, P < 0.001) and control subjects (r = 0.96, P < 0.001). Univariate analysis showed significant relations between C(1) and SV/PP on one side and age, sex, body weight, portal pressure, systemic hemodynamics, biochemical variables, and severity of disease on the other. In the multiple-regression analysis, sex, age, mean arterial blood pressure, systemic vascular resistance, and biochemical variables were significant independent predictors of SV/PP (P < 0.005-0.00001). In conclusion, arterial compliance is elevated in cirrhosis. A simplified SV/PP index seems to reflect abnormalities in the arterial compliance of these patients.

Hepatorenal failure

Since the description of HRS more than 100 years ago, significant advances have been made in understanding the pathophysiology of HRS and in the management of these patients. There is now a therapeutic armamentarium: medical (ornipressin plus plasma volume expansion), radiographic (TIPS shunt), and surgical (liver transplantation). The diagnosis of HRS is no longer synonymous with a death sentence; instead, it is a therapeutic challenge, and a coordinated approach by intensivists, hepatologists, nephrologists, interventional radiologists, and transplant surgeons is needed to continue to improve the prognosis of cirrhotic patients presenting with HRS. Increased understanding of HRS will allow preventative rather than therapeutic measures to be used. As in all fields of medicine, these advances will come only with innovative clinical investigation.

Early effects of total paracentesis and albumin infusion on muscle sympathetic nerve activity in cirrhotic patients with tense ascites

BACKGROUND/AIMS

Cirrhotic patients with ascites are characterized by a marked activation of the sympathetic and the renin-angiotensin-aldosterone system. Total paracentesis is associated with a short-lived suppression of the renin-angiotensin-aldosterone system. Little information exists as to whether this favourable effect is parallelled by sympathoinhibition.

METHODS

In 16 Child C cirrhotic patients (age: 57.1+/-6.2 years, mean+/-SEM) with tense ascites we assessed the time course of the effects of total paracentesis followed by intravenous albumin (6-8 g/l of ascites) on beat-to-beat mean arterial pressure (Finapres), heart rate, plasma norepinephrine, epinephrine (high performance liquid chromatography) and muscle sympathetic nerve activity (microneurography, peroneal nerve). Measurements were obtained under baseline conditions, during staged removal of ascitic fluid (250 ml/min) and 24 h later. The patient remained supine throughout the study period.

RESULTS

Total paracentesis (10.6+/-1.3 l) induced a decrease in mean arterial pressure (from 95.0+/-2.6 mmHg to 88.2+/-3.2 mmHg, p<0.01), in heart rate (from 82.5+/-3.3 beats/min to 77.1+/-2.8 beats/min, p<0.01) and a reduction in plasma norepinephrine values (from 782+/-133 pg/ml to 624+/-103 pg/ml, p<0.01), which were substantially maintained 24 h later. In eight patients muscle sympathetic nerve activity did not change during paracentesis (from 65+/-7.1 bursts/min to 65+/-7.4 bursts/min, p=NS), but a marked reduction was observed 24 h later (48.4+/-5.6 bursts/min, p<0.01).

CONCLUSIONS

These data provide the first evidence that total paracentesis exerts an acute marked sympathoinhibitory effect. Whether this is a long-lasting phenomenon and to what extent plasma expansion with albumin contributes to this effects need to be further addressed.

Effects of increasing blood hemoglobin levels on systemic hemodynamics of acutely anemic cirrhotic patients

BACKGROUND/AIMS

In experimental portal hypertension, blood hemoglobin levels have been shown to influence the hyperdynamic circulatory state. The aim of this study was to assess the hemodynamic effects of increasing hemoglobin concentration in human portal hypertension.

METHODS

Sixteen cirrhotic patients recovering from a variceal bleeding episode were randomly assigned to receive two units of packed red cells or 500 ml of a protein solution. Systemic and portal hemodynamics, and rheological and hormonal parameters were measured at baseline and after expansion.

RESULTS

Both groups were similar with respect to the degree of liver failure, severity of the bleeding episode, activation of the endogenous vasopressor systems, and hemodynamic parameters. The administration of either erythrocytes or a protein solution prompted a similar increase in total blood volume and suppression of vasopressor systems. Both groups of patients experienced similar increases in wedged hepatic venous pressure. Hepatic venous pressure gradient was not significantly modified but tended to increase in erythrocyte-transfused patients. Cardiopulmonary pressures increased, but this increment was significant in the non-blood-transfused patients only. Cardiac output decreased in erythrocyte-transfused patients, while it increased in the group receiving a protein solution. Red blood cell transfusion resulted in an increase in systemic vascular hindrance (resistance/blood viscosity), whereas the administration of a protein solution prompted a decrease in this parameter, thus reflecting true vasoconstriction and vasodilation, respectively.

CONCLUSIONS

An increase in blood hemoglobin in acutely anemic cirrhotic patients attenuates their hyperdynamic circulation beyond viscosity-dependent changes, an effect which might be counteracted by the effects on portal venous pressure gradient.

Increased expression of endothelin receptors in the vasculature of portal hypertensive rats: role in splanchnic hemodynamics

Portal hypertension (PHT) is characterized by increased portal pressure caused in part by a reduction in mesenteric vascular resistance. The aim of this study was to evaluate the role of endothelin (ET) and specific ET receptors in maintaining the vasculopathy of PHT. PHT was created in Sprague-Dawley rats by a partial portal vein ligation. Control animals were sham-operated. ET receptor expression was determined in the superior mesenteric artery of sham and PHT rats by in situ autoradiography, radioligand binding analysis, and reverse-transcription polymerase chain reactions (RT-PCR). The pressor response to ET-1 was determined in vitro using isolated vascular rings and in vivo by measuring mean arterial pressure, splanchnic blood flow, and portal venous pressure following treatment with ET and selective ET receptor antagonists. The pressor response to ET in vitro was significantly enhanced in PHT concomitant with increased ET-A and ET-B receptor expression. There was a significant increase in the peak pressor response to ET (10 microg/kg intravenously) in portal hypertensive rats without any significant change in plasma ET-1 levels. There was no significant difference in the peak splanchnic blood flow or portal venous pressure response following ET-A receptor blockade with JKC-301 infusion (200 microg/kg intravenously). In contrast, ET-B receptor blockade with IRL-1038 (200 microg/kg intravenously) preferentially decreased splanchnic blood flow and portal venous pressure in portal hypertensive rats. These data suggest that enhanced ET-B receptor expression in portal hypertensive vessels contributes to the maintenance of elevated portal pressure in these animals.

Management of adult patients with ascites caused by cirrhosis

Ascites is the most common of the major complications of cirrhosis. The development of ascites is an important landmark in the natural history of cirrhosis and has been proposed as an indication for liver transplantation. The initial evaluation of a patient with ascites should include a history, physical evaluation, and abdominal paracentesis with ascitic fluid analysis. Treatment should consist of abstinence from alcohol, sodium restricted diet, and diuretics. This regimen is effective in approximately 90% of patients. The treatment options for the diuretic-resistant patients include serial therapeutic paracenteses, liver transplantation, and peritoneovenous shunting.

Effect of octreotide on systemic, central, and splanchnic haemodynamics in cirrhosis

BACKGROUND/AIMS

Cirrhosis with portal hypertension is associated with changes in the splanchnic and systemic haemodynamics, and subsequent complications, such as bleeding from oesophageal varices, have led to the introduction of long-acting somatostatin analogues in the treatment of portal hypertension. However, reports on the splanchnic and systemic effects of octreotide are contradictory and therefore the aim of the present study was to assess the effects of continuous infusion of octreotide on central and systemic haemodynamics, portal pressures, and hepatic blood flow.

METHODS

Thirteen patients with cirrhosis underwent liver vein catheterisation. Portal and arterial blood pressures were determined at baseline and 10, 30, and 50 min after a bolus injection of octreotide 100 micrograms, followed by continuous infusion of octreotide 100 micrograms/ h for 1 h. Hepatic blood flow, cardiac output, central and arterial blood volume, and central circulation time were determined at baseline and 50 min after the start of the octreotide infusion.

RESULTS

The mean arterial blood pressure increased during the first 10 min (p < 0.0005), but returned to baseline after 50 min. The central and arterial blood volume (-16%, p < 0.005) and the central circulation time (-8%, p < 0.05) were significantly decreased after 50 min, whereas the cardiac output did not change significantly. The hepatic venous pressure gradient and the hepatic blood flow did not change significantly at any time after infusion of octreotide.

CONCLUSIONS

Octreotide does not affect the portal pressure or hepatic blood flow, whereas it may further contract the central blood volume and thereby exert a potentially harmful effect on central hypovolaemia in patients with cirrhosis. However, these early effects do not exclude the possibility that administration of longacting somatostatin analogues over a longer period may have a beneficial effect.