AJR 2000; 175:537-539
© American Roentgen Ray Society
Mechanic and Pharmacologic Treatment of a Saddle Embolus to the Portal Vein After Liver Transplantation and Portacaval Hemitransposition
Susan M. Weeks1,
James R. Alexander1,
Jeet Sandhu1,
Matthew A. Mauro1,2,
Jeffrey H. Fair2 and
Paul F. Jaques1,2
1
Department of Radiology, University of North Carolina at Chapel Hill, CB#7510,
Chapel Hill, NC 27599-7510.
2
Department of Surgery, University of North Carolina at Chapel Hill, CB#7510,
Chapel Hill, NC 27599-7510.
Received October 25, 1999;
accepted after revision January 12, 2000.
Address correspondence to S. M. Weeks.
Introduction
Percutaneous mechanic maceration, suction thrombectomy, and
catheter-directed pharmacologic thrombolytic therapy have been successfully
used for the treatment of massive pulmonary embolus
[1,
2]. We report an unusual case
of embolization in the portal vein of a patient who underwent liver
transplantation requiring ligation of the suprarenal inferior vena cava with
formation of an end-to-end portacaval anastomosis. This embolus, presumed to
have originated from the lower extremity deep venous system, was successfully
treated using the aforementioned techniques.
Subject and Methods
A 21-year-old woman was referred to our transplantation staff for
examination of cirrhosis caused by thrombosis of the portal vein. A
hypercoagulable workup revealed negative findings. A preoperative visceral
angiogram revealed thrombosis of the portal, superior mesenteric, and inferior
mesenteric veins, with visualization of multiple enlarged mesenteric varices.
The patient underwent orthotopic liver transplantation; the portal, superior
mesenteric, and inferior mesenteric veins were chronically thrombosed, and teh
left renal vein was atretic. Subsequently, the suprarenal inferior vena cava
was ligated and an end-to-end portacaval anastomosis was created, using the
inferior vena cava to provide portal inflow. The hepatic arterial and biliary
anastomoses were conventionally performed.
The patient did well postoperatively. However, 3 months after
transplantation, she developed fever and left lower quadrant pain; Doppler
sonography revealed decreased portal vein velocities and nonoccluding thrombus
in the right portal vein. Portal venography was performed through a 5-French
pigtail catheter (Angiodynamics, Queensbury, NY) via a right common femoral
vein approach and revealed a large nonoccluding saddle embolus lodged at the
portal vein bifurcation (Fig.
1A). Duplex imaging of the lower extremities revealed no thrombus
in the venous system; however, it was believed that the most likely source of
the embolus was from the lower extremities because this system provided the
only inflow to the portal vein.
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Fig. 1A. —21-year-old woman who, 3 months earlier, underwent orthotopic liver
transplantation and portacaval hemitransposition. Initial portogram obtained
by right common femoral vein approach shows flow-limiting saddle embolus
(arrows) lodged in main, right, and left portal veins.
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Initial therapy was directed at disrupting the embolus to improve inflow.
This task was mechanically accomplished using a 5-French pigtail catheter that
was lodged in the embolus; the catheter was rotated aggressively, and repeated
venography revealed fragmentation of the thrombus, with multiple small emboli
now lodged in peripheral portal branches
(Fig. 1B). The catheter was
exchanged for an 8-French guiding catheter (Trax; Mallinkrodt Medical, St.
Louis, MO), and aspiration suction thrombectomy was performed
(Fig. 1C). Multiple fragments
of what appeared to be well-organized thrombus were removed. A 20-cm infusion
catheter (Unifuse; Angiodynamics) was placed in the right posterior segmental
portal vein branch in which thrombus burden remained particularly high. An
initial bolus of 250,000 U/hr of urokinase (Abbokinase; Abbott Laboratories,
North Chicago, IL) was administered, followed by a constant infusion of
120,000 U/hr. Repeated venography performed 18 hr later revealed interval
thrombolysis but several persistent defects in multiple peripheral portal vein
branches. Suction thrombectomy was repeated using an 8-French guiding
catheter, and removal of multiple emboli was successful. Urokinase was resumed
at the previous rate. Repeated portography 9 hr later revealed no change
(Fig. 1D). Urokinase was
discontinued and the patient was successfully converted from heparin to
Coumadin (DuPont, Wilmington, DE). The patient remained on Coumadin for 6
months after the intervention. Sonography performed 3 weeks and 10 months
after the intervention revealed normal portal vein velocities and appropriate
hepatopedal flow; the patient has been asymptomatic for 20 months. Portography
performed at 20 months for elevated liver function tests revealed wide patency
of the portal vein, with no thrombus identified in the portal venous
system.
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Fig. 1B. —21-year-old woman who, 3 months earlier, underwent orthotopic liver
transplantation and portacaval hemitransposition. Venogram obtained after
mechanic disruption of embolus with 5-French pigtail catheter (Angiodynamics,
Queensbury, NY) shows diminished thrombus burden centrally, with multiple
peripheral occluding thrombi (arrows) now evident.
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Fig. 1C. —21-year-old woman who, 3 months earlier, underwent orthotopic liver
transplantation and portacaval hemitransposition. Venogram obtained after
suction thrombectomy with 8-French guiding catheter shows improved distal flow
(arrow).
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Fig. 1D. —21-year-old woman who, 3 months earlier, underwent orthotopic liver
transplantation and portacaval hemitransposition. Venogram obtained after
repeated suction thrombectomy and 27 hr of thrombolytic therapy shows
excellent intrahepatic portal venous flow, with very small amount of residual
thrombus identified peripherally. Intervention was terminated.
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Discussion
In the past, thrombosis of the portal venous system was considered an
absolute contraindication to liver transplantation
[3]. However, changes in
surgical and percutaneous interventional techniques have addressed venous
thrombosis, both acute and chronic. In the case of acute portal venous
thrombosis, transhepatic catheter-directed thrombolysis may be performed.
Alternatively, surgical thrombectomy may be performed at the time of
transplantation. Chronic portal venous occlusion can be overcome by using
other visceral veins to provide adequate portal inflow to the transplanted
liver, including the splenomesenteric confluence, splenic vein, and superior
mesenteric vein; this task may require placement of an interposition graft
[4]. When these more
conventional options are not feasible, other inflow vessels may be used,
including enlarged varices such as the left-sided gastric vein
[5], a choledochal vein, or the
right colic vein [6].
In our patient, lack of a suitable native or collateral vein led to
ligation of the suprarenal inferior vena cava with formation of an end-to-end
anastomosis with the donor portal vein, providing excellent portal venous
inflow. This technique, portacaval hemitransposition, is a modification of
total portacaval transposition first proposed in 1953
[7]. Liver transplantation
using portacaval hemitransposition, both before and after thrombosis, has been
associated with complications, including portal venous hypertension, variceal
hemorrhage, and pulmonary embolus
[8].
The treatment used for our patient is similar to recent therapies
recommended for the endovascular treatment of large, flow-occluding emboli in
the pulmonary circulation, including mechanic fragmentation and
catheter-directed thrombolysis
[1]. In these patients, therapy
is directed at increasing the amount of perfused lung by fragmenting large
flow-occluding emboli so that the same volume of clot would obstruct a smaller
volume of tissue. Additionally, fragmentation would increase the overall
thrombus surface area so that thrombolytic therapy might be more successful.
Similar clinical efficacy in the treatment of pulmonary embolus has also been
shown with mechanic clot maceration, suction thrombectomy, and
catheter-directed thrombolysis using a combination of heparin and urokinase
[2].
In our patient, the immediate goal was to fragment the flow-limiting
embolus, similarly increasing the volume of perfused liver while
simultaneously increasing the total exposed thrombus surface area for more
efficient pharmacologic thrombolysis. An 8-French guiding catheter then proved
sufficient to remove multiple fragmented emboli from the peripheral veins
(Fig. 1C). An overnight
infusion of urokinase resulted in thrombolysis, and excellent intrahepatic
portal venous flow was identified at the conclusion of the procedure.
In summary, portacaval hemitransposition is a surgical option available to
patients with diffuse mesenteric venous thrombosis who are awaiting hepatic
transplantation. An unusual complication that can result from this procedure
includes embolization of the portal vein from lower extremity deep venous
thrombosis. Percutaneous mechanic techniques and pharmacologic thrombolytic
therapy previously described for the treatment of massive pulmonary embolus
can be effective in resolving or substantially reducing the portal venous
thrombus burden, thereby maintaining the patency of the portal venous
system.
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Introduction
Subject and Methods
