Cirrhotic cardiomyopathy: causes and consequences

Dobutamine stress echocardiography for evaluating cirrhotic cardiomyopathy in liver cirrhosis

Background/Aims

The blunted ventricular systolic and diastolic contractile responses to physical and pharmacological stress in cirrhosis are termed cirrhotic cardiomyopathy (CCM). CCM has been known to involve multiple defects in the β-adrenergic signaling pathway. The aim of this study was to determine whether cirrhotic patients have blunted cardiac responses to catecholamine stimulation through dobutamine stress echocardiography (DSE).

Methods

Seventy-one cirrhotic patients with normal left ventricular (LV) chamber size and ejection fraction were enrolled. The LV systolic and diastolic functions were evaluated by two-dimensional and Doppler echocardiography at rest and during peak dobutamine infusion (40 µg/kg/min). An abnormal response was defined as a decrease of less than 10% in LV end-diastolic volume, a decrease of less than 20% in end-systolic volume, and an increase of less than 10% in LV ejection fraction (EF) at peak dobutamine infusion, based on previously used criteria. The early/late diastolic flow (E/A) ratio and diastolic parameters were also measured.

Results

A blunted LV response to dobutamine was observed in 18 of 71 cirrhotic patients (25.4%). The baseline EF was significantly higher in 18 patients with a blunted DSE response than that of those with a normal DSE response (P<0.05). The baseline and peak E/A ratios, which are common diastolic dysfunction markers, were higher in the cirrhosis group than in the control group (P<0.001). No adverse events associated with DSE were observed.

Conclusions

Blunted cardiac responses to dobutamine stimulation, which are implicated in defects in the β-adrenergic signaling pathway, might contribute to the pathogenesis of CCM in patients with cirrhosis.

Hemodynamic alterations in cirrhosis and portal hypertension

Portal hypertension (PHT) is associated with hemodynamic changes in intrahepatic, systemic, and portosystemic collateral circulation. Increased intrahepatic resistance and hyperdynamic circulatory alterations with expansion of collateral circulation play a central role in the pathogenesis of PHT. PHT is also characterized by changes in vascular structure, termed vascular remodeling, which is an adaptive response of the vessel wall that occurs in response to chronic changes in the environment such as shear stress. Angiogenesis, the formation of new blood vessels, also occurs with PHT related in particular to the expansion of portosystemic collateral circulation. The complementary processes of vasoreactivity, vascular remodeling, and angiogenesis represent important targets for the treatment of portal hypertension. Systemic and splanchnic vasodilatation can induce hyperdynamic circulation which is related with multi-organ failure such as hepatorenal syndrome and cirrhotic cadiomyopathy.

N-terminal pro B-type natriuretic peptide and the evaluation of cardiac dysfunction and severity of disease in cirrhotic patients

PURPOSE

Cardiac dysfunction and hyperdynamic systemic circulation may be present in patients with cirrhosis. The purpose of this study was to identify relations between plasma levels of N-terminal-proBNP (NT-proBNP), reflecting early ventricular dysfunction, and the severity of liver disease and cardiac dysfunction in cirrhotic patients.

MATERIALS AND METHODS

Sixty-three cirrhotic patients and 15 controls (group 1) were enrolled in this study. Plasma levels of NT-proBNP were determined in echocardiographically examined patients, which were allocated to 1 of 3 groups according to Child-Pugh classification or into 2 groups, i.e., a compensated group without ascites (group 2) and decompensated group with ascites (group 3).

RESULTS

Plasma NT-proBNP levels were significantly higher in cirrhotic patients (groups 2 and 3) than in age-matched controls (155.9 and 198.3 vs. 40.3 pg/mL, respectively, p < 0.05). NT-proBNP levels were significantly increased in Child class C patients than in classes B and A (250.0 vs. 168.6 and 119.6 pg/mL, respectively, p < 0.05). Left atrial dimension, wall thickness of left ventricle, and EF or E/E' were significantly increased, and EDT was prolonged in cirrhotic patients than in controls. Increased LVMI and decreased E/A ratio were noted in the group of patients with ascites as compared with the other groups.

CONCLUSION

Plasma NT-proBNP levels were high in cirrhotic patients and are likely to be related to the severity of disease. Advanced cirrhosis is associated with advanced cardiac dysfunction, and NT-proBNP levels has predictive value for concomitant cardiac dysfunction and cirrhosis progression.

Cardiac dysfunction in cirrhosis

Cirrhosis is known to be associated with numerous cardiovascular abnormalities. These include increased cardiac output and decreased arterial pressure and total peripheral resistance. Despite this increased baseline cardiac output, patients with cirrhosis show an attenuated systolic and diastolic function in the face of pharmacological, physiological and surgical stresses, as well as cardiac electrical abnormalities such as QT prolongation. These abnormalities have been termed cirrhotic cardiomyopathy. The pathogenic mechanisms that underlie this syndrome include impairment of the beta-adrenergic receptor signalling, cardiomyocyte plasma membrane function, intracellular calcium kinetics, and humoral factors such as endogenous cannabinoids, nitric oxide and carbon monoxide. Cirrhotic cardiomyopathy is believed to contribute to the cardiac dysfunction that can be observed in patients with transjugular intrahepatic portosystemic stent-shunt insertion and liver transplantation. Insufficient cardiac contractile function may also play a role in the pathogenesis of hepatorenal syndrome precipitated by spontaneous bacterial peritonitis. In this review, the clinical features, pathogenic mechanisms, clinical consequences and management options for cirrhotic cardiomyopathy are discussed.

Therapy insight: Cirrhotic cardiomyopathy

Liver cirrhosis is associated with several cardiovascular disturbances. These disturbances include hyperdynamic systemic circulation, manifested by an increased cardiac output and decreased peripheral vascular resistance and arterial pressure. Despite the baseline increase in cardiac output, cardiac function in patients with cirrhosis is abnormal in several respects. Patients show attenuated systolic and diastolic contractile responses to stress stimuli, electrophysiological repolarization changes, including prolonged QT interval, and enlargement or hypertrophy of cardiac chambers. This constellation of cardiac abnormalities is termed cirrhotic cardiomyopathy. It has been suggested that cirrhotic cardiomyopathy has a role in the pathogenesis of cardiac dysfunction and even overt heart failure after transjugular intrahepatic portosystemic shunt placement, major surgery and liver transplantation. Cardiac dysfunction contributes to morbidity and mortality after liver transplantation, even in many patients who have no prior history of cardiac disease. Depressed cardiac contractility contributes to the pathogenesis of hepatorenal syndrome, especially in patients with spontaneous bacterial peritonitis. Pathogenic mechanisms underlying cirrhotic cardiomyopathy include cardiomyocyte-membrane biophysical changes, attenuation of the stimulatory beta-adrenergic system and overactivity of negative inotropic systems mediated via cyclic GMP. The clinical features, general diagnostic criteria, pathogenesis and treatment of cirrhotic cardiomyopathy are discussed in this review.