Most published studies show the right ventricular pressure, pulmonary artery pressure (PAP), and left atrial or pulmonary capillary wedge pressure (PCWP) to be at the upper normal limit but within the normal range during rest (table 1); the severity of the liver disease per se does not seem to affect cardiac pressures.
30–32 However, fluid retention with formation of ascites and haemodynamic disturbances with increased blood volume may result in increased right atrial pressure (RAP),
30 and paracentesis with removal of ascitic fluid has been shown to lower the RAP, PAP, and PCWP.
33 Physical exercise, pharmacological stress, and therapeutic procedures may affect cardiac pressures. Thus, the left ventricular end diastolic pressure increases but the cardiac stroke index and left ventricular ejection fraction fall during exercise, which indicates an abnormal ventricular response to an increase in ventricular filling pressure.
19,31,34 Reduced left ventricular afterload (reduced systemic vascular resistance, low arterial blood pressure, and increased arterial compliance) may mask left ventricular failure.
14,19,35–37 By infusion of angiotensin, Limas
et al38 increased the systemic vascular resistance by 30% and found that the PCWP, which reflects left ventricular end diastolic volume, increased twice with no change in CO. A failure to increase CO despite an increased ventricular filling pressure indicates that normalisation of the afterload impairs cardiac performance and unmasks left ventricular failure.
38 Interestingly, this effect on the PCWP was not improved after addition of digoxin. Similar results, with increases in the RAP, PAP, right ventricular pressure, and PCWP, have been achieved by normalising the arterial blood pressure with infusion of terlipressin and octreotide.
39–41 Infusion of a plasma protein solution increased CO, as well as RAP, PAP, and PCWP, whereas infusion of packed red blood cells did not change these variables.
42 In a recent study by Forrest
et al,
43 oral administration of the adenosine antagonist theophylline significantly decreased PAP and PCWP, thus suggesting that adenosine could be implicated in the cardiovascular dysfunction present in cirrhosis. Surprisingly, lowering the afterload by infusion of the nitric oxide donor L-arginine in cirrhotic patients produced significantly increased RAP, PAP, and PCWP, despite a decreased arterial blood pressure.
44 However, it is possible that this is a direct effect of nitric oxide on myocardial contractility.
Transvenous intrahepatic portosystemic shunt (TIPS) is frequently used in the treatment of bleeding oesophageal varices and refractory ascites.
45 Insertion of a TIPS results in an immediate increase in the ventricular preload because a high splanchnic blood flow is delivered into the systemic circulation. Several studies have noted an aggravation of the hyperdynamic circulation with increased CO, RAP, PAP, and PCWP immediately after TIPS placement.
46–48 However, cardiac pressures and CO tend to become normal two or three months after this therapeutic procedure and some authors report no or only transient changes in cardiac pressures after TIPS insertion.
49,50 In the past, a peritoneovenous shunt for treatment of refractory ascites was frequently implanted. This procedure, which further increased CO, was in a considerable number of patients complicated by the development of pulmonary oedema indicating a latent cardiac inability unmasked by the increased preload.
51 At present, it is not possible to predict which patients will develop cardiac complications such as high output congestive heart failure after implantation of TIPS and peritoneovenous shunts, and the procedures should be considered with caution in patients with limited cardiac reserve.
46,48Most patients with cirrhosis have almost normal cardiac pressures when resting supine. These pressures become abnormally raised by procedures stressing the heart, such as pharmacological vasoconstriction, exercise, and the increased portosystemic shunting resulting from insertion of a TIPS. This should be considered when applying these procedures in patients with limited cardiac reserve, but at present no specific guidelines for the identification of patients at risk can be given.