Keywords
Embolization for shunt reduction - hereditary hemorrhagic telangiectasia - intrahepatic
shunts - liver vascular malformation
Introduction
Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant disorder seen
approximately in one in 5000–8000 individuals.[1] It presents with vascular malformations (VM) in the nose, skin, liver, gastrointestinal
tract, brain, and lung. Telangiectasia is the VM seen in HHT where there is direct
communication between the arterioles and venules without the intervening capillaries.
This abnormal communication can result in shunts between various vascular beds in
the solid organs and hallow viscera. Definitive clinical diagnosis of HHT can be made
based on the presence of at least three of four Curacao criteria,[2] published in 2000. They are 1. Epistaxis, 2. Cutaneous or mucosal VM, 3. Presence
of visceral telangiectasia, and 4. Positive family history. Liver involvement is seen
in approximately 75% of people with HHT.[2] Although only a small 8%–10% of these patients develops symptomatic liver pathology,
the rest remains asymptomatic.
Case Report
We are presenting a patient who presented with upper gastrointestinal (GI) bleed and
epistaxis with anemia. On further evaluation, she was found to have telangiectasia
in the nose and multiple angioectasias in the stomach and in the duodenum in upper
GI endoscopy. This triad of findings, 1. Spontaneous recurrent epistaxis, 2. Telangiectasia
of nose, and 3. Visceral telangiectasia, fulfill 3 Curacao criteria to qualify for
definitive diagnosis of HHT. Further evaluation with contrast-enhanced computed tomography
(CECT) was done to rule out chronic liver parenchymal disease. The CECT revealed heterogenous
enhancement of the periphery of the liver in the arterial phase [Figure 1A] which becomes homogenous in the venous phase [Figure 1B]. In addition, there was moderately enlarged proper hepatic artery measuring 10 mm
in diameter (normal <7 mm) and abnormally dilated intrahepatic branches of the hepatic
artery and early filling of the portal venous branches [Figures 2A], [B] and [3]. There were abnormal tortuous vascular channels along the ligamentum teres with
early filling of the branches of portal vein [Figures 3] and [4]. There were faintly enhancing tortuous vascular channels along the intrahepatic
branches of the hepatic artery. There was slight reduction in the volume of the left
lobe of liver. The surface of the liver was smooth. All these imaging features were
suggestive of intrahepatic arterio-portal shunts with possible secondary chronic liver
parenchyma disease. She was treated symptomatically with cauterization of the nasal
telangiectasia, nasal packing, and blood transfusion for anemia. Few small telangiectasia
lesions in the stomach showed active bleed during endoscopy and these lesions were
treated with argon plasma coagulation.
Figure 1 (A and B): Contrast-enhanced CT axial section shows heterogenous enhancement of the liver parenchyma
in the arterial phase (A) which becomes homogenous in the venous phase (B)
Figure 2 (A and B): Axial CT image in the arterial phase acquisition (A) and 3D volume rendered image
(B) showing enlarged hepatic artery proper, measuring more than 10 mm. There is enlarged
proper hepatic artery and its branches (long thin arrows in B) and early filling of
the portal venous branch (short thick arrow in B) seen with fuzzy margins
Figure 3 (A and B): Coronal (A) and sagittal (B) maximum intensity projection (MIP) images showing enlarged
hepatic artery branches— long thin arrows (in A and B)—and early filling of the portal
venous branches—short thick arrow (in a and B). The enlarged main hepatic artery is
marked with arrow head in B
Figure 4: Axial CT image showing multiple tortuous early filling portal venous branches along
the ligamentum teres (arrows) seen along with the left hepatic artery branches
Discussion
In HHT, clinical symptoms occur in approximately 8% of the people.[3] There is a distinct female preponderance in symptomatic patients, with majority
of the patients presenting in their fourth decade.[3] Presenting features are secondary to high-output cardiac failure (most common),[3] portal hypertension, GI bleed either from varices due to portal hypertension or
angioectasia of the mucosa of the GI tract, and biliary disease. Other less common
forms of clinical presentation in the liver and GIT are portosystemic encephalopathy
and abdominal angina. The basic pathophysiology in liver involvement is development
of intrahepatic VMs. Liver vascularity is unique by the way of presence of dual arterial
supply and presence of dormant, potential portosystemic shunts, like paraumbilical
vein, which can open up in any form of disturbance in the equilibrium of liver circulation.
The VMs in the liver can lead to three different types of vascular shunts.[3], [4] These are 1. Arterio-venous (AV) shunt (between the hepatic artery and hepatic vein),
2. Arterio-portal (AP) shunt (between the hepatic artery and portal vein), and 3.
Portal venous (PV) shunt (between portal vein and hepatic vein).[1] Shunts are usually extensive. The shunts can be visualized by imaging studies if
they are macroscopic. Frequently they can be microscopic and not seen in imaging.
Each predominant type of shunt gives rise to distinct clinical manifestation.
AV shunt
This is the most common symptomatic VM. It usually affects women. The presenting clinical
feature is related to high-output cardiac failure.[1] AP shunt can also involve liver leading to biliary ischemia and ischemic necrosis
of the bile duct[5] due to steal phenomenon. The loss of integrity of the bile duct due to ischemia
can lead to biliomas and intrahepatic biliary cysts mimicking Caroli’s disease. In
chronic cases, secondary sclerosing cholangitis develops with stricture and abnormal dilatation of intrahepatic bile ducts. Biliary
ischemia-related complications are seen exclusively in women.[3]
AP shunt
This is the second most common shunt after AV shunting. Shunting of blood from the
hepatic artery to the portal vein causes portal hypertension. Secondary to portal hypertension, there can be ascites, varices formation, and GI
bleed. In addition, there can be formation of focal nodular hyperplasia and nodular regenerative hyperplasia in the liver. It equally affects men and women. The diagnosis is made based on hepatic venous
pressure gradient which should be more than or equal to 10 mmHg.
PV shunt
This is the least common type of shunt and usually causes high-output cardiac failure.
Rarely, this can cause focal nodular hyperplasia and nodular regenerative hyperplasia
in the liver which can lead to portal hypertension and cirrhosis.
Diagnosis of HHT is made based on the Curacao criteria.[2] Imaging is indicated to confirm the diagnosis if three of the four clinical criteria
are not met. In addition, imaging has to be done to look for associated complications
like liver cirrhosis. In a known case of HTT, the presence of ascites, GI bleed, and
abdominal pain should raise the suspicion of liver involvement and imaging should
be performed. Doppler study can show abnormal tortuous vessels in the liver. CECT
and MRI can reveal multiple liver VMs. There can be enlarged hepatic artery, normal
≤7 mm,[1] heterogenous enhancement of the liver in the arterial phase of contrast study which
becomes homogenous in the venous phase.
CT is the recommended imaging modality of choice. In CECT, the type of shunt can be determined in two-third of patients.
The majority of patients with liver disease will show AV shunt. Biliary disease is
generally seen in the late phase of the disease. The gold standard to establish the
type of shunt is angiography.[3] Angiography can clearly demonstrate the early, subtle VMs and mesenteric steal syndrome.
However, in the majority of the patients, the diagnosis can be established with less
invasive imaging methods like CECT.
Treatment
No treatment needed in asymptomatic patients with liver involvement. Primarily, the
management is medical with treatment of anemia and correcting coagulation abnormalities.[6] High-output cardiac failure and complications of portal hypertension are treated
in the standard way like treating cardiac failure and portal hypertension due to other
etiologies. It should be noted that trans-jugular intrahepatic porta systemic shunt
(TIPS) creation may not be effective in the treatment of GI bleed secondary to telangiectasia
of the GI tract. Shunt reduction procedures like embolization may be considered in
patients with cardiac failure and mesenteric ischemia.[7] However, these procedures are associated with high morbidity and mortality and have
only transient therapeutic effect. In carefully selected patients, few sessions of
endovascular embolization may be effective in reducing portosystemic shunt and alleviating
mesenteric ischemia. Ultimately patients might require liver transplantation, which
can be curative.
Conclusion
HHT is a rare cause of vascular dysplasia involving many organs and systems. Although
the majority of the patients remain asymptomatic, high index of suspicion should be
kept not to miss liver involvement by the disease. Radiologists should be aware of
the imaging findings and possible treatment options like shunt reduction embolization
offered by us. Life-threatening complications like high-output cardiac failure not
responding to maximum medical therapy and severe biliary ischemia should be recognized
and these patients should be referred for an early liver transplant.
