Assessment of central blood volume in cirrhosis by radionuclide angiography: what does it really mean?

Effects of transjugular intrahepatic portosystemic shunt (TIPS) on blood volume distribution in patients with cirrhosis

BACKGROUND

Cirrhosis is accompanied by portal hypertension with splanchnic and systemic arterial vasodilation, and central hypovolaemia. A transjugular intrahepatic portosystemic shunt (TIPS) alleviates portal hypertension, but also causes major haemodynamic changes.

AIMS

To investigate effects of TIPS on regional blood volume distribution, and systemic haemodynamics.

METHODS

Thirteen cirrhotic patients had their regional blood volume distribution determined with gamma-camera technique before and after TIPS. Additionally, we measured systemic haemodynamics during liver vein and right heart catheterization. Central and arterial blood volume (CBV) and cardiac output (CO) were determined with indicator dilution technique.

RESULTS

After TIPS, the thoracic blood volume increased (+10.4% of total blood volume (TBV), p<0.01), whereas the splanchnic blood volume decreased (-11.9% of TBV, p<0.001). CO increased (+22%, p<0.0001), and systemic vascular resistance decreased (-26%, p<0.001), whereas CBV did not change. Finally, right atrial pressure and mean pulmonary artery pressure increased after TIPS (+50%, p<0.005; +40%, p<0.05, respectively).

CONCLUSIONS

TIPS restores central hypovolaemia by an increase in thoracic blood volume and alleviates splanchnic vascular congestion. In contrast, CBV seems unaltered. The improvement in central hypovolaemia is therefore based on an increase in thoracic blood volume that includes both the central venous and arterial blood volume. This is supported by an increase in preload, combined with a decrease in afterload.

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.