Keywords CT arterioportography - porto-mesenteric venous disease - variceal bleeding - transjugular
intrahepatic portosystemic shunt - mesenteric venous stent
Introduction
Computed tomography arterioportography (CTAP) has been used to assess the presence,
location, and number of primary and secondary tumors in the liver.[1 ] In this technique, the superior mesenteric or splenic arteries are selectively catheterized.
CT of the liver is performed during the portal venous phase following intra-arterial
injection of contrast material. This was once considered the most sensitive test for
detecting hepatic tumors but is now replaced with contrast-enhanced magnetic resonance
imaging (MRI).[2 ] Recently, the utility of CTAP in assessing the patency of portal and mesenteric
veins, and the physiological effects of portal hypertension, including various portosystemic
collateral pathways, has been reported in pediatric patients.[3 ]
[4 ] In this study, we report the clinical utility of CTAP in assessing the complex portal
and mesenteric venous anatomy before interventional therapy in patients who presented
with an extrahepatic portal or mesenteric venous occlusion and variceal bleeding.
CT Arterioportography: Technique
CT Arterioportography: Technique
A standard protocol was applied for CTAP in all the cases presented in this study.
The superior mesenteric artery was catheterized with a 5F catheter via a right femoral
arterial access in an angiography suite. A digital subtraction angiography (DSA) of
the superior mesenteric artery was performed in an anteroposterior projection, and
the image acquisition was continued to include the venous phase. The time required
to opacify the portal vein from the initial intra-arterial contrast material injection
was calculated. This time was used during CTAP as the time delay from contrast material
injection to image acquisition. The patient was transferred to a dual-energy multi-detector
CT scanner (SOMATOM Force, Siemens, Germany). CT images were acquired during the arterial
phase, portovenous phase, and delayed phase. The arterial and portovenous phases were
obtained in dual-energy mode (0.5mm detector width, rotation time of 0.25sec, 80kVp,
and 140kVp, and table speed of 70 cm/s). The delayed venous phase images were acquired
in single energy mode at 140kVp. Images were reconstructed at 1 mm slice thickness
at 70keV and 50keV. Data were reconstructed in multiplanar reformations and three-dimensional
volume rendering. The arterial catheter was removed, and the arterial access was closed
with a closure device. The intervention was performed a few days later.
Case 1
A 57-year-old man presented with acute upper gastrointestinal bleeding. He was hemodynamically
stable. Prior history was significant for a known superior mesenteric vein thrombosis
10 years prior to presentation, which was managed conservatively with anticoagulation.
An endoscopy at admission showed large submucosal varices with active bleeding in
the third portion of the duodenum. The bleeding varix was treated endoscopically.
A contrast-enhanced CT ([Fig. 1A ]) and a subsequent contrast-enhanced MRI of the abdomen showed large duodenal varices
and focal questionable narrowing of the superior mesenteric vein. The rest of the
portomesenteric and splenic veins were normal. A superior mesenteric angiography ([Fig. 1B, C ]) showed a patent superior mesenteric artery, no arteriovenous malformation, multiple
midline varices, and a patent portal vein but inadequate opacification of the superior
mesenteric vein. CTAP ([Fig. 1D–E ]) demonstrated focal web-like structures within the proximal superior mesenteric
vein and large duodenal varices. The portal vein and the rest of the superior mesenteric
vein were patent.
Fig. 1 (A ) Contrast-enhanced computed tomography (CT) showed extensive paraduodenal varices
arising from the superior mesenteric vein (SMV) (likely due to the history of SMV
thrombosis). The arterial (B ) and venous (C ) phase digital subtraction angiography of superior mesenteric arteriography show
a normal artery and multiple duodenal varices with poor opacification of the portal
and mesenteric veins. (D ) Computed tomography arterioportography (CTAP) shows severe focal stenosis/webs (white
arrowheads) of the proximal SMV at its junction with the portal vein. (E ) Three-dimensional reconstruction from CTAP shows the stenosis and extensive paraduodenal
SMV varices. (F ) Superior mesenteric venography showing focal proximal occlusion secondary to the
web and opacification of duodenal varices. (G ) Late-phase image from superior mesenteric venography shows duodenal varices filling
the main portal vein. (H ) and (I ) SMV balloon angioplasty and stent placement via transhepatic approach and poststent
venogram demonstrating patent flow through the SMV stent and a marked decrease in
the caliber and number of para-duodenal varices.
Under moderate sedation and a transhepatic portal venous approach, the superior mesenteric
venous webs were crossed with a combination of a 5F Kumpe catheter and 0.035” angled
hydrophilic guide wire. A superior mesenteric venography ([Fig. 1F–G ]) showed focal occlusion of the proximal superior mesenteric vein secondary to the
web and subsequent flow of contrast material into the portal vein via the duodenal
varices. The focal occlusions were treated with balloon angioplasty using a 6 × 40mm
high-pressure balloon (Conquest, Boston Scientific, Natick, Massachusetts, United
States) and subsequently by placing a 12mm x 40mm Protégé self-expanding bare metallic
stent (Medtronic, Minneapolis, Minnesota, United States) ([Fig. 1H ]). The stent was dilated to 10 mm with a 10 × 40mm Armada balloon (Abbott, Plymouth,
Minnesota, United States). Postintervention, superior mesenteric venography ([Fig. 1I ]) showed a widely patent portal and mesenteric veins with no opacification of duodenal
varices. The patient was prescribed warfarin for 6 months and aspirin for life. A
1-month follow-up CT and ultrasound at 28 months showed a patent stent with no significant
duodenal varices. Endoscopy at 3 months showed no duodenal varices. Clinically, the
patient reported no recurrent gastrointestinal bleeding.
Case 2
A 34-year-old man with a history of recurrent upper and lower gastrointestinal bleeding
from duodenal and jejunal varices was referred to interventional radiology. He had
multiple episodes of variceal bleeding, which were treated with endoscopic therapies.
His medical history was significant for chronic portal vein thrombosis from infancy,
Factor V Leiden deficiency, prior cardiac surgery for congenital cardiac defects,
splenectomy for portal hypertension, and failed splenorenal and mesocaval surgical
shunts. CT demonstrated an occluded main portal vein but a patent superior mesenteric
vein. A superior mesenteric angiography ([Fig. 2A ]) showed inadequate opacification of the portomesenteric veins due to the blush of
overlying structures and the bowel. CTAP was performed to assess for collaterals,
varices, and anatomy of intrahepatic portal veins.
Fig. 2 (A ) Superior mesenteric artery angiogram with obscuration of portomesenteric veins from
the blush of overlying structures and the bowel. There is faint visualization of the
distal ileocolic vein and intrahepatic portal branches. (B ) Computed tomography arterioportography showed a chronically occluded portal vein
with extensive portosystemic collaterals. Note the large superior mesenteric collateral,
which contributed to gallbladder varices. This vein was used to create the mesocaval
shunt (C ) percutaneous access of the superior mesenteric vein (SMV) collateral (RAO -40/CAUD
-6.6) (D ) and (E ) SMV access via inferior vena cava (IVC) approach after access with a 21-gauge needle
(anteroposterior [AP] projection; arrowhead, solid arrow, and arrow show catheters
in SMV, IVC, and replaced right hepatic artery, respectively). (F ) Post-stent subtraction venogram (AP projection) demonstrated patent blood flow through
the stent with a decrease in the caliber of the collaterals. RAO, Right Anterior Oblique
Projection; CAUD, Caudal Projection.
CTAP showed a chronically occluded portal vein with extensive portosystemic collaterals,
including a large superior mesenteric collateral that contributed to peri-gallbladder
varices, varices around the gastric antrum, gastric fundus, duodenum, lower esophagus,
descending colon, and rectum, and pericapsular varices around the left lobe draining
into the left portal vein and mild nodularity of the anterior liver contour consistent
with cirrhosis ([Fig. 2B ]).
A few weeks later, the patient underwent a successful direct intrahepatic mesocaval
shunt between the inferior vena cava and the large superior mesenteric collateral
that contributed to the gallbladder varices. This was performed via a transjugular
venous approach, aided by a transfemoral venous intravascular ultrasound guidance
and percutaneous access to the collateral from the mid-abdomen ([Fig. 2C–E ]). A constrained Viatorr (Gore, Flagstaff, Arizona, United States) graft was used
for the mesocaval shunt, and the stent was dilated to 10mm. The procedure was complicated
by intraprocedural thrombosis of the stent graft and the superior mesenteric vein,
successfully treated with suction thrombectomy. Post-stent subtraction venogram demonstrated
patent blood flow through the stent with a decrease in the caliber of the collaterals
([Fig. 2F ]). The patient was discharged on Apixaban. The mesocaval shunt remained patent on
ultrasound during the 10-month follow-up with no clinical signs of variceal bleeding.
The patient had one hepatic encephalopathy episode, which was successfully treated
with medical therapy.
Case 3
A 51-year-old woman with a known diagnosis of autoimmune hepatitis and biliary stricture
presented with massive upper gastrointestinal bleeding during endoscopic retrograde
cholangiopancreatography (ERCP). The patient had a prior history of main portal vein
thrombosis and splenic vein thrombosis with peribiliary varices. MRI showed peribiliary
varices ([Fig. 3A ]), but the extent of main portal vein obstruction and intrahepatic portal vein status
was unclear. A superior mesenteric angiography ([Fig. 3B ]) showed inadequate opacification of the portomesenteric veins due to the blush of
overlying structures and the bowel.
Fig. 3 (A ) Magnetic resonance imaging scan showing peribiliary varices. (B ) Superior mesenteric artery angiogram with limited visualization of portomesenteric
veins. (C ) and (D ) Computed tomography arterioportography showed occlusion of the main portal vein
from the splenoportal confluence and up to portal vein bifurcation, occlusion of proximal
right and left portal veins but reconstituted and patent distal left and distal right
portal vein branches. The splenic vein was occluded. There were large peribiliary
varices. The perihepatic collaterals connected the left gastric veins to the left
portal vein. (E ) and (F ) transjugular portosystemic stent shunt (TIPS) placement between the middle hepatic
vein and the left portal vein. (G ) Post-TIPS and variceal embolization, there was good flow from the superior mesenteric
vein to the right atrium.
CTAP ([Fig. 3C, D ]) showed occlusion of the main portal vein from the splenoportal confluence and up
to portal vein bifurcation, occlusion of proximal right and left portal veins but
reconstituted and patent distal left and distal right portal vein branches. The splenic
vein was occluded. There were large peribiliary varices. The perihepatic collaterals
connected the left gastric veins to the left portal vein.
Under general anesthesia and intravascular ultrasound guidance, the left portal vein
was accessed from the middle hepatic vein via a transjugular venous approach using
a Colapinto needle (Ring Set, Cook Medical, Bloomington, Illinois, United States;
[Fig. 3E, F ]). The occluded left and main portal veins were crossed with a 0.018” guide wire
and microcatheter, which were subsequently upsized for a 0.035” wire. The occluded
veins were dilated, and a Viatorr stent graft was placed across the parenchymal tract.
The peribiliary varices were embolized using 33% n -butyl cyanoacrylate. Post-transjugular portosystemic stent shunt (TIPS) and variceal
embolization, there was good flow from the superior mesenteric vein to the right atrium
([Fig. 3G ]). The procedure was subsequently complicated by stent thrombosis 4 weeks later,
which was treated with suction thrombectomy, portal vein angioplasty, and additional
perisplenic and gastric variceal embolization. During a 5-month follow-up, the patient
had no bleeding episodes and had successful ERCP and biliary stent exchanges. CT at
2 months showed patent TIPS and patent portomesenteric veins.
Discussion
Conventional CT and DSA have limitations when imaging the portomesenteric venous system
due to the dilution of iodinated contrast material in the venous system. Mesenteric
venous imaging during DSA is also prone to artifacts from the blush of overlying structures
and the bowel. CTAP is capable of objectively and comprehensively revealing all types
of portomesenteric venous anomalies in a three-dimensional manner. It can provide
excellent opacification and delineation of portomesenteric veins, including occlusion
length, intravascular webs, venous collaterals, and bleeding varices. This ability
of CTAP is extremely valuable in complex cases that require interdisciplinary discussions
involving interventional radiologists, surgeons, and gastroenterologists to determine
the most suitable management approach.
In the case series described above, CTAP helped us identify portosystemic collaterals
that were not visible on CT and DSA and offered alternative access routes for interventional
radiological shunt creation and treatment of varices. It also helped evaluate the
patency and direction of flow in the mesenteric veins and the specific source of the
varices. This allowed complex recanalization and extra-anatomic bypass to treat extrahepatic
portal and mesenteric venous obstruction in the cases we described. There were no
complications related to CTAP.
Therefore, CTAP can be implemented before considering more invasive procedures, as
it provides valuable insights for individualized management. Though a hybrid-CT (angio-CT)
suite streamlines the process of acquiring CTAP images, the technique provides high
value and should be considered even in institutions where a hybrid suite is not available.
