Hemodynamic and humoral changes after liver transplantation in patients with cirrhosis

Hepatic blood flow and splanchnic oxygen consumption in patients with liver failure. Effect of high-volume plasmapheresis

Liver failure represents a major therapeutic challenge, and yet basic pathophysiological questions about hepatic perfusion and oxygenation in this condition have been poorly investigated. In this study, hepatic blood flow (HBF) and splanchnic oxygen delivery (DO2, sp) and oxygen consumption (VO2,sp) were assessed in patients with liver failure defined as hepatic encephalopathy grade II or more. Measurements were repeated after high-volume plasmapheresis (HVP) with exchange of 8 to 10 L of plasma. HBF was estimated by use of constant infusion of D-sorbitol and calculated according to Fick's principle from peripheral artery and hepatic vein concentrations. In 14 patients with acute liver failure (ALF), HBF (1.78 +/- 0.78 L/min) and VO2,sp (3.9 +/- 0.9 mmol/min) were higher than in 11 patients without liver disease (1.07 +/- 0.19 L/min, P <.01) and (2.3 +/- 0.7 mmol/min, P <.001). In 9 patients with acute on chronic liver disease (AOCLD), HBF (1.96 +/- 1.19 L/min) and VO2,sp (3.9 +/- 2.3 mmol/min) were higher than in 18 patients with stable cirrhosis (1.00 +/- 0.36 L/min, P <.005; and 2.0 +/- 0.6 mmol/min, P <.005). During HVP, HBF increased from 1.67 +/- 0.72 to 2.07 +/- 1.11 L/min (n=11) in ALF, and from 1.89 +/- 1.32 to 2.34 +/- 1.54 L/min (n=7) in AOCLD, P <.05 in both cases. In patients with ALF, cardiac output (thermodilution) was unchanged (6.7 +/- 2.5 vs. 6.6 +/- 2.2 L/min, NS) during HVP. Blood flow was redirected to the liver as the systemic vascular resistance index increased (1,587 +/- 650 vs. 2, 020 +/- 806 Dyne. s. cm-5. m2, P <.01) whereas splanchnic vascular resistance was unchanged. In AOCLD, neither systemic nor splanchnic vascular resistance was affected by HVP, but as cardiac output increased from 9.1 +/- 2.8 to 10.1 +/- 2.9 L/min (P <.01) more blood was directed to the splanchnic region. In all liver failure patients treated with HVP (n=18), DO2,sp increased by 15% (P <.05) whereas VO2,sp was unchanged. Endothelin-1 (ET-1) and ET-3 were determined before and after HVP. Changes of ET-1 were positively correlated with changes in HBF (P <.005) and VO2,sp (P <.05), indicating a role for ET-1 in splanchnic circulation and oxygenation. ET-3 was negatively correlated with systemic vascular resistance index before HVP (P <.05) but changes during HVP did not correlate. Our data suggest that liver failure is associated with increased HBF and VO2, sp. HVP further increased HBF and DO2,sp but VO2,sp was unchanged, indicating that splanchnic hypoxia was not present.

Exercise and organ transplantation

Life-saving treatment of disease by organ transplantation has become increasingly important. Annually over 35,000 transplantations of vital organs are carried out world-wide and the demand for knowledge regarding exercise in daily life for transplant recipients is growing. The present review describes whole-body and organ reactions to both acute exercise and regular physical training in persons who have undergone heart, lung, liver, kidney, pancreas or bone marrow transplantation. In response to acute exercise, the majority of cardiovascular, hormonal and metabolic changes are maintained after transplantation. However, in heart transplant recipients organ denervation reduces the speed of heart rate increase in response to exercise. Furthermore, lack of sympathetic nerves to transplanted organs impairs the normal insulin and renin responses to exercise in pancreas and kidney transplant recipients, respectively. In contrast, surgical removal of sympathetic liver nerves does not inhibit hepatic glucose production during exercise, and denervation of the lungs does not impair the ability to increase ventilation during physical exertion. Most studies show that physical training results in an improved endurance and strength capacity in almost all groups of transplant recipients, which is of importance for their daily life. With a little precaution, organ transplant recipients can perform exercise and physical training and obtain effects comparable with those achieved in the healthy population of similar age.

Splanchnic hyperemia after liver transplantation in patients with end-stage liver disease

Systemic and splanchnic hemodynamic parameters were evaluated in 12 patients with cirrhosis before and 3 and 6 months after liver transplantation. Results were compared with those obtained in 8 healthy subjects. Three months after liver transplantation recipients had an increase in mean arterial pressure (98 +/- 7 v 78 +/- 9 mmHg; P < .05), an insignificant decrease in cardiac index (3. 4 +/- 0.6 v 4.0 +/- 1.0 L . min-1 . m-2), and a marked increase in peripheral vascular resistance (1,563 +/- 308 v 800 +/- 205 dyne . s . cm-5; P < .05) compared with pretransplantation values. Portal blood flow was also significantly increased (1,494 +/- 200 v 829 +/- 130 mL/min; P < .05). These hemodynamic changes were more pronounced 6 months after transplantation (mean arterial pressure, 100 +/- 8 mmHg; cardiac index, 3.0 +/- 1.0 L . min-1 . m-2; P < .01; peripheral vascular resistance, 1,680 +/- 405 dyne . s . cm-5; portal blood flow, 1,520 +/- 180 mL/min). Systemic hemodynamics 6 months after liver transplantation were similar to those observed in the healthy control group (mean arterial pressure, 95 +/- 6 mmHg; cardiac index, 2.9 +/- 0.9 L . min-1 . m-2; peripheral vascular resistance, 1,480 +/- 380 dyne . s . cm-5). However, portal blood flow was still significantly higher than in healthy controls at 6 months (1,520 +/- 180 v 910 +/- 140 mL/min; P < .05). This study shows that systemic hemodynamics are normalized after liver transplantation. However, an increase in portal blood flow occurs and persists for at least 6 months after liver transplantation. Further studies are needed to clarify the cause of the abnormally high portal flows.

Hepatic plasma flow estimated according to Fick's principle in patients with hepatic encephalopathy: evaluation of indocyanine green and D-sorbitol as test substances

The magnitude of hepatic plasma flow in patients with liver failure and hepatic encephalopathy (HE) is unknown because a reliable flow estimate has not been available. The purpose of this study was to estimate hepatic plasma flow in patients with HE and to evaluate indocyanine green (ICG) and sorbitol as test compounds. Fourteen patients with acute liver failure (ALF) and nine patients with chronic liver failure (CLF), all with HE grade II or more, were studied. After hepatic vein catheterization, hepatic plasma flow was estimated by use of constant infusion, simultaneous arterial and hepatic vein concentration measurements, and calculated according to Fick's principle. The hepatic extraction fraction of D-sorbitol 0.179+/-0.144 (mean+/-SD) was higher than the hepatic extraction fraction of ICG 0.054+/-0.085 (P < .001). The low hepatic extraction fraction of ICG rendered this compound unfit for estimation of hepatic plasma flow in these patients. In contrast, by using D-sorbitol the hepatic plasma flow could be estimated in 21 of 23 patients with a median SD of 8.4% (range, 2.6% to 29%). The D-sorbitol estimated hepatic plasma flow was 1.2+/-0.5 L/min (n = 12) in patients with ALF and 1.4+/-0.9 L/min (n = 9) in patients with CLF. These values are higher than what has been reported in normal subjects and in patients with cirrhosis without HE. An elevated hepatic flow should increase oxygen delivery and may enhance the failing liver's ability to remove substances from the blood. At the same time, hepatic first pass metabolism is reduced. We conclude that an elevated hepatic flow in these patients is of clinical importance.

Splenic impedance indices: a useful method to monitor patients after liver transplantation?

Splenic Doppler impedance indices are influenced, in portal hypertensive patients, by the resistance of the portal system. The aim of the study was to verify the usefulness of these indices in evaluating the presence of a pathological increase in portal resistance in patients with complications after liver transplantation. Splenic impedance indices have been evaluated in 46 patients before orthotopic liver transplantation (OLT), and 2 days, 1, 4, 8, and 12 to 18 months after transplantation. The results showed that spleen size slowly decreased after liver transplantation. From a baseline longitudinal diameter value of 18.0+/-3.6 cm (M+/-SD), the decrease was by 0%+/-3%, 8%+/-8%, 13%+/-9%, 15%+/-11%, and 14%+/-11% at 2 days and 1, 4, 8, and 12 to 18 months after liver transplantation. Splenic impedance indices-resistance index = (peak systolic - end diastolic) / peak systolic velocity; pulsatility index = (peak systolic - end diastolic) / mean velocity-which were increased before liver transplantation, showed a rapid decrease to normal values: resistance index: from 0.62+/-0.08 to 0.55+/-0.08 after 2 days, and to 0.49+/-0.09, 0.51+/-0.10, 0.54+/-0.10, 0.55+/-0.11 after 1, 4, 8, 12-18 months; pulsatility index: from 0.96+/-0.21 to 0.82+/-0.17 after 2 days, and to 0.69+/-0.19,0.72+/-0.21, 0.81+/-0.26, 0.84+/-0.26 after 1, 4, 8, and 12 to 18 months. Patients who had a good outcome, without any major complications, showed a clear and steady decrease in splenic impedance indices. On the contrary, patients who had complications affecting portal resistance (e.g., acute rejection, relapse of chronic hepatitis C virus-related hepatitis or cirrhosis, stenosis of portal anasthomosis, portal thrombosis), showed a lack of decrease, or, after an initial decrease, a subsequent re-increase in splenic impedance indices to pathological values. Splenic impedance indices measured in patients with complications were higher than those of patients without complications (P < .0004). Specificity and sensitivity of splenic impedance indices in the evaluation of the presence of complications increasing portal resistance were good. In conclusion, after OLT, splenic impedance indices could be useful aspecific parameters for identifying patients with complications that are able to affect or increase portal resistance.

Selective impairment of endothelium-mediated vasodilation in liver transplant recipients with cyclosporin A-induced hypertension

Arterial hypertension is commonly observed in orthotopic liver transplantation (OLT) recipients receiving cyclosporin A (CsA), but the precise pathogenetic mechanisms remain partially unknown. The aim of this study was to investigate endothelium-dependent and -independent dilation and adrenergic constriction of resistance vessels of OLT recipients treated with CsA. Vascular reactivity was examined in 22 OLT patients, 10 with and 12 without arterial hypertension, and in 10 control subjects by assessing the forearm blood flow response to the brachial artery infusion of increasing concentrations of methacholine chloride, sodium nitroprusside, and phenylephrine. In 10 OLT patients, the response to methacholine was also examined after acetylsalicylate. The ratio of serum nitrite and nitrate to serum creatinine was lower (P < .05) in OLT patients with hypertension than in nonhypertensive patients and controls. Basal forearm flow was similar in the three groups. Methacholine vasodilation was impaired in the hypertensive patients as shown by a lower maximum forearm vasodilator response and a shift in the dose response curve to methacholine to the right compared with the nonhypertensive OLT patients and the controls. The response to methacholine was not modified after salicylate. Forearm flow response to nitroprusside was similar in the three groups. No differences between the patients and the controls were found in the maximum forearm flow contraction in response to phenylephrine. An impairment in endothelium-dependent vasodilation could mediate arterial hypertension in OLT patients immunosuppressed with CsA.

Perioperative plasma concentrations of endothelin and natriuretic peptides in children undergoing living-related liver transplantation

To investigate the clinical significance of endothelin (ET), natriuretic peptides, and the renin-angiotensin-aldosterone system in pediatric liver transplantation, we measured plasma levels of ET, atrial and brain natriuretic peptides (ANP, BNP), aldosterone, and plasma renin activity in 18 patients (aged 0.5-12 yr; median 1 yr) undergoing living-related liver transplantation due to congenital biliary atresia and severe liver cirrhosis. Before transplantation, the plasma ET level (28.9 +/- 2.5 [mean +/- SEM] pg/mL) was increased compared with that of healthy children (10-18 pg/mL), but decreased during the anhepatic phase (22.5 +/- 1.6 pg/mL). It increased again after reperfusion and remained at high levels in the early postoperative period (postoperative day 3, 27.8 +/- 3.0 pg/mL). Plasma levels of ANP and BNP and aldosterone and plasma renin activity were also high before surgery. Plasma ANP and BNP did not change significantly during surgery. After transplantation, plasma BNP significantly increased, and plasma ANP tended to increase. Plasma aldosterone increased markedly during the anhepatic phase, although plasma renin activity decreased. After transplantation, plasma aldosterone and plasma renin activity both decreased to within normal levels. Mean arterial blood pressure increased gradually after reperfusion and surgery (postoperative day 3, 35.7 +/- 5.2% increase). No substantial differences in these variables occurred between the younger (< or = 1.0 yr, n = 9) and older patients (> 1.0 yr, n = 9). These results suggest that ET production in the cirrhotic liver is augmented and ET, natriuretic peptides, and the renin-angiotensin-aldosterone system all play some role in the circulatory regulation during perioperative periods of pediatric liver transplantation.

Hemodynamics after orthotopic liver transplantation: study of associated factors and long-term effects

Among 68 liver transplant recipients, 190 hemodynamic studies were performed to evaluate the role of sepsis, anemia, acute graft rejection, and persistent portosystemic shunts. The hemodynamic outcome after orthotopic liver transplantation (OLT) in stable patients was also determined. Patients with sepsis showed a significant increase in cardiac index (5.1 +/- 0.9 vs. 3.4 +/- 0.7 L/min m2) and hepatic venous pressure gradient (6.3 +/- 2.9 vs. 3.3 +/- 2.1 mm Hg), compared with patients without sepsis. Cardiac index was higher in patients with, than in patients without, anemia (4.1 +/- 0.6 vs. 3.0 +/- 0.6 L/min m2). The hepatic venous pressure gradient was higher in patients with than in patients without acute graft rejection (5.1 +/- 2.9 vs. 2.6 +/- 1.2 mm Hg). Among patients with acute rejection, the hepatic venous pressure gradient was higher in patients with severe rejection than in those with moderate or mild rejection (7.2 +/- 3.3 vs. 4.6 +/- 2.4 and 2.8 +/- 0.9 mm Hg). In the postoperative period, in patients undergoing transplantation for acute liver failure, the hepatic blood flow was normal and significantly lower than in patients receiving transplant for cirrhosis (1.15 +/- 0.37 vs. 1.96 +/- 0.71 L/min). In patients undergoing transplantation for cirrhosis, cardiac index, azygos, and hepatic blood flows significantly decreased after 1 year compared with the first 6 postoperative months. Multivariate analysis showed that sepsis, anemia, and time after OLT were independent variables influencing cardiac index. Sepsis, time after OLT, and the existence of portosystemic shunts were independent variables influencing hepatic blood flow.(ABSTRACT TRUNCATED AT 250 WORDS)

Systemic arteriovenous malformations: a feature of advanced liver disease

Arterial and arteriovenous abnormalities are reported in association with advanced liver disease, those most commonly recognised are spider naevi, pulmonary arteriovenous shunts, and generalised vasodilatation. The first two cases of peripheral systemic arteriovenous malformations in association with cirrhosis are reported. After liver transplantation in one of these patients the vascular malformation regressed. A review of published works shows that other vascular complications of advanced liver disease such as pulmonary shunts and generalised vasodilation also regress after orthotopic liver transplantation.