Pulmonary vascular complications of chronic liver disease: Pathophysiology, imaging, and treatment

Abstract

To review the pathogenesis of pulmonary vascular complications of liver disease, we discuss their clinical implications, and therapeutic considerations, with emphasis on potential reversibility of the hepatopulmonary syndrome after liver transplantation. In this review, we also discuss the role of imaging in pulmonary vascular complications associated with liver disease.

Keywords: Hepatopulmonary syndrome; Yttrium-90 microsphere embolization hepatocellular carcinoma; portopulmonary hypertension; pulmonary arteriovenous shunts.

Figure 1

99Technetium macroaggregated albumin perfusion imaging in a patient with HPS shows a right to left shunt. The 99mTc-MMA has entered the systemic circulation and has perfused the kidneys

Figure 2

99Technetium macroaggregated albumin perfusion imaging in a patient with HPS shows a right to left shunt. The 99mTc-MMA has entered the systemic circulation and distributed to systemic organs. Normally, <5% of the isotope can be quantitated over the brain. In HPS, there is >6% uptake in the brain as in this case. (Courtesy Durre-e-Sabih Multan)

Figure 3

In preparation for hepatic radioembolization with Yttrium-90 glass microspheres 99Technetium macroaggregated is given via the hepatic artery and regions of interest are drawn over lungs, liver and background. Less than 5% systemic shunt of 99Technetium macroaggregated is normal. The 5–15% is insignificant and we proceed to Yttrium-90 glass microspheres with a standard 150 Gy dose. With a systemic shunt of 10–25%, the dose of Yttrium-90 glass microspheres is modified to 110-130 Gys. (Courtesy Dr. Ghulam Mustafa Shah, Department of Medical King Abdul Aziz Medical City Riyadh)

Figure 4

In preparation for hepatic radioembolization with Yttrium-90 glass microspheres 99Technetium macroaggregated is given via the hepatic artery and regions of interest are drawn over lungs, liver, and background. With a systemic shunt greater than 25% Yttrium-90 glass microspheres embolization is contraindicated. (Courtesy Dr. Ghulam Mustafa Shah Syed, Head Nuclear Medicine Section, Department of Medical Imaging, King Fahad Hospital, King Abdul Aziz Medical City Riyadh)

Figure 5

A coned view of a CXR of lung basis with HPS shows bibasilar nodular or reticulonodular opacities. These are seen in 5–13.8% of patients with CLD and 46–100% of patients with HPS. These opacities are shown to represent dilated lung vessels on computed tomography as shown

Figure 6

A CXR of lung basis of 47-year-old woman with HPS shows basilar reticulonodular opacities at the left lung base and left mid-zone. These opacities which represent dilated lung vessels are seen on both sides on CT as shown

Figure 7

Axial contrast enhanced CT (right) and a pulmonary angiogram (left) show dilated pulmonary vasculature in a 53-year-old man with CLD associated with HPS

Figure 8

(a) Illustrate the application of hepatic radioembolization with Yttrium-90 glass microspheres 99Technetium following quantitative estimation of a right to left intracardiac shunt by a 99Technetium macroaggregated perfusion lung scan. These series of images (b, c) illustrate the benefit of hepatic radioembolization with Yttrium-90 glass microspheres in a cystic hepatocellular carcinoma. There is an initial necrosis of the tumor followed by almost complete shrinkage. (Courtesy Dr Ghulam Mustafa Shah Syed, Department of Medical Imaging, Abdul Aziz Medical City Riyadh)

Figure 9

It is important that larger right to left shunts through pulmonary arteriovenous malformations are excluded by cross-sectional imaging when testing for HPS and when consideration is being given for hepatic radioembolization with Yttrium-90 glass microspheres. These coronal and sagittal reconstructions of contrast enhanced CT show a large arteriovenous malformation at the left lung base

Figure 10

Axial contrast enhanced images of the liver and lungs on an 82-year-old woman with PPH showing portal vein thrombosis, which is associated with pulmonary embolism supporting the theory that PPH may be secondary to embolic material entering the lungs via the portosystemic venous shunts associated with PoH although no varices are seen in this patient

Figure 11

A CXR of a 41-year-old man with cirrhosis and PPH show enlarged hila and peripheral pruning of the vessels secondary to PH. An axial contrast enhanced CT through the pulmonary arteries of another patient with PPH showing aneurismal dilatation of the main pulmonary artery and the right pulmonary artery with peripheral pruning due to PH

Figure 12

A CXR on a patient with PPH secondary to cirrhosis shows a dilated pulmonary conus and aneurismal dilatation of the right pulmonary artery. The image on the left is coronal reconstruction of contrast enhanced CT on the same patient, which depicts a probable re-canalized thrombus underlying the aneurismal dilatation of the right pulmonary artery

Figure 13

Pulmonary angiography on a patient with PPH showing dilatation of the pulmonary arteries and pruning of the peripheral vessels