|
 |
|||||||
Radiology
Membranous
obstruction of intrahepatic inferior vena cava: Curative treatment by insertion
of Wallstent.
A 52-year-old man, a chronic alcoholic, was admitted in September 2001 with progressive fatigue, weight gain and varicosities of the abdominal wall for 10 years. In 1991, the patient had presented for the first time with history of hemetemsis and malena. Physical examination demonstrated mild hepatomegaly but no signs of liver cell failure. Sonography showed the echogenic lesion in the intrahepatic portion of Inferior Vena Cava (IVC) (Fig 1).
IVC gram performed through
the femoral route demonstrated complete conical obstruction of the IVC about
2 cms below the level of the right atrium with 2 cms thrombosis within, and
marked collateralization through the azygous and hemiazygous system (Fig 2
a & b). The left renal vein was dilated and multiple tortuous veins were
seen at the left renal hilum. There was retrograde filling of hepatic veins.
Cavagram performed through the cephalic route showed a blind pouch at base
of right atrium (Fig 2 c).
Correlating sonography and the findings on the IVC gram, a diagnosis of complete membranous obstruction of the hepatic IVC with thrombosis within was established. Subsequently local thrombolysis with infusion of one million units of streptokinase was attempted but there was no change in the status of membrane (Fig 3).
IVC membranotomy followed by percutaneous balloon angioplasty (PTA) was attempted in a subsequent sitting which was successful to some extent with IVC gram showing mild residual stenosis (Fig 4a and 4b)
In June 1993, the patient again presented with abdominal distension. Sonography revealed changes of portal hypertension in the form of ascitis, splenomegaly, dilated hepatic veins, multiple collaterals at the splenic hilum and in retropancreatic region and the reocclusion of hepatic IVC. An IVC gram confirmed the findings of a large segment (2.5 cms) membranous occlusion (Fig 5).
Repeated three attempts of membranotomy were failed during the next 8 years.
During the present admission, physical examination revealed changes of liver cell failure in the form of gynaecomastia and smaller testes. There were prominent anterior abdominal veins. The liver spanned 15 cms, extended 8 cms below the mid right costal margin. Brawny edema and chronic venous stasis changes were seen in both lower limbs. Color Doppler and IVC cineangiogram (taken in anterioposterior and left lateral views) findings were similar as before (Fig 6).
Membranotomy, percutaneous
balloon plasty and stenting: - After determining the exact location and
length of the obstructed segment under multidirectional fluoroscopy via the
right femoral vein, the complete membranous lesion was crossed with a stiff
end of a regular guide wire (0.035 inch diameter) with a multipurpose catheter
for back up, until it reached the right atrium (Fig 7) A small amount of contrast
medium was injected after every small passage to confirm the correct direction
of the wire path until the right atrium was reached. Also, the patient was
regularly asked for any sensation of chest pain as patient feels pain only
if the path of the guide wire/membranotomy needle is not in correct direction.
The floppy tip of the exchange wire was kept in the SVC. Because of the tight
stenosis, an initial dilation with an 8,10 mm balloon catheters was required
to allow subsequent passage of the larger balloon (Medi-tech XXL, Boston scientific
16mm 4 cms)(Fig 8). Following angioplasty, there was residual stenosis (Fig.
9.)
After balloon dilatation, stent delivery was introduced over exchange wire. A 14 × 55-mm Schneider Wall- Stent was deployed after its appropriate placement (fig 10a) Balloon dilatation was performed after stent deployment for the residual stenosis. Post procedure, there was significant improvement following PTA and stenting with disappearance of paravertrebral collaterals (fig 10 b). Post procedure management included intravenous heparin administered for the first 24 hrs followed by oral aspirin till date.
Clinically, the abdominal discomfort and fatigue disappeared within 6 hrs following the procedure. In patient’s own word- "I am feeling much lighter in the abdomen than ever before. The leg edema and varicosities of the abdominal wall also became less. There is no recurrence of hemetemesis.
Follow up sonography revealed widely patent stent and normal flow on color doppler study on 2 and 3 months follow up (Fig.11 a , b respectively) .
Discussion :
The Budd-Chiari syndrome (BCS) is not an uncommon, often fatal illness resulting from hepatic venous outflow obstruction. The obstruction may be due to coarctation or thrombosis of the major hepatic veins (classical BCS) or hepatic/suprahepatic venacava or, as is more common in the orient, membranous obstruction of the IVC. BCS probably represents a spectrum. Clinically, two forms have been identified. The acute syndrome is invariably associated with extensive blockage of the major hepatic veins, sometimes associated with IVC occlusion, resulting in congestive liver cell necrosis. The important etiologic factors are related to hypercoagulabilty of blood. The patients with chronic BCS generally have membranous occlusion of the IVC (MOVC). Three types of this membranous obstruction have been described. In type 1, the IVC is obstructed by a thin membrane at the level of entrance to the right atrium. This membrane may be complete or partial with central hole. In type 2, a segment of the IVC (length varies) is absent. In these cases, the IVC gram shows a characteristic conical narrowing at the level of obstruction. In type 3, there is complete obstruction of the IVC secondary to thrombosis.
The origin and nature of the membranous obstruction of IVC is disputed. Evidence for both congenital and acquired etiologies have been reported including congenital malformations, neonatal obliterative changes, acquired thrombophlebitis and combination of some of the above. The "congenital hypothesis" suggest that embryologic malformation occurs during the stage when the liver and associated vessel systems develop, and either a failure of the hepatic segment of the IVC to join in the right hepatocardiac channel or an extension of the normal obliteration of the ductus venosus into the inferior venacava may then be caused. Protagonists of the "acquired origin" theory have demonstrated transition of IVC thrombosis to complete membranous obstruction and marked stenosis. They have also emphasized the wide variability in the anatomic location of the membrane, its variable thickness and its late presentation as evidence to refute the "congenital anomaly" theory.
Why thrombosis forms in the hepatic portion of the IVC remains unanswered. Kretz suggested that the intima of the IVC is mechanically and microscopically damaged by respiratory movements of the diaphragm and invites thrombosis. Coughing may also be responsible for mechanical damage. An additional mechanism favoring this theory is the eddying blood currents in this portion of the IVC where the flow from the hepatic veins join that of the IVC at a right angle.
Diagnosis of MOVC is usually not difficult. USG and color doppler readily demonstrate IVC obstruction or stenosis, occlusion of large hepatic veins as echogenic material, caudate lobe hypertrophy and other features of portal hypertension. CT may show focal or scattered areas of diminished attenuation with patchy enhancement in the liver. MRI has additional advantages in delineating occluding membrane without the need for contrast material. Cavography will demonstrate the level of obstruction as well as extensive collateral veins that eventually drain into the SVC. To accurately demonstrate the thickness of the obstructing membrane, simultaneous catheterization of the IVC and SVC is required, but may also be delineated in the late phase of inferior cavography when the right atrium is opacified through collaterals.
Several surgical and other interventional techniques have been used to treat BCS. Medical therapy, which consists of managing the ascites, correcting coagulapathy, and improving nutrition, results in limited success because it has no effect on the underlying pathophysiology.
Surgical treatment aims at the relief of portal hypertension and intrahepatic venous congestion. Orthotopic liver transplantation can be curative but morbidity and mortality with these surgical intervention results are high. Other methods of treatment have therefore been sought.
In acute BCS, local thrombolytic therapy followed by stent insertion, if required, may be curative. The introduction of PTA with a balloon catheter offers a new therapeutic option. Eguchi was the first to describe successful balloon membranotomy for obstruction of the IVC. Generally the short term results of PTA are good to excellent, with symptoms alleviated (even disappearing) after treatment as in this patient and most patients return to normal living. However restenosis/obstruction does occur at various intervals after PTA, which necessitates repeat PTA. The various factors responsible for such recurrence include insufficient dilatation, residual pathologic tissue and intimal hyperplasia and elastic recoil. To maintain vascular patency and prevent restenosis following balloon dilatation, expandable vascular endoprosthesis were introduced. The inherent continuous radial expansion pressure of the stenosis keeps the vessel patent for a longer time. Also stents prevent elastic recoil and reduce the resistance to blood flow and thrombosis formation.
Case 11 : contributed
by Ashwin Garg
Other Cases
A 52-year-old man, a chronic alcoholic, was admitted in September 2001 with progressive fatigue, weight gain and varicosities of the abdominal wall for 10 years. In 1991, the patient had presented for the first time with history of hemetemsis and malena. Physical examination demonstrated mild hepatomegaly but no signs of liver cell failure. Sonography showed the echogenic lesion in the intrahepatic portion of Inferior Vena Cava (IVC) (Fig 1).
 |
| Fig 1 |
 |
 |
| Fig. 2a | Fig. 2b |
 |
|
| Fig. 2c | |
Correlating sonography and the findings on the IVC gram, a diagnosis of complete membranous obstruction of the hepatic IVC with thrombosis within was established. Subsequently local thrombolysis with infusion of one million units of streptokinase was attempted but there was no change in the status of membrane (Fig 3).
 |
| Fig 3 |
IVC membranotomy followed by percutaneous balloon angioplasty (PTA) was attempted in a subsequent sitting which was successful to some extent with IVC gram showing mild residual stenosis (Fig 4a and 4b)
 |
 |
| Fig. 4a | Fig. 4b |
In June 1993, the patient again presented with abdominal distension. Sonography revealed changes of portal hypertension in the form of ascitis, splenomegaly, dilated hepatic veins, multiple collaterals at the splenic hilum and in retropancreatic region and the reocclusion of hepatic IVC. An IVC gram confirmed the findings of a large segment (2.5 cms) membranous occlusion (Fig 5).
 |
|
| Fig. 5 |
Repeated three attempts of membranotomy were failed during the next 8 years.
During the present admission, physical examination revealed changes of liver cell failure in the form of gynaecomastia and smaller testes. There were prominent anterior abdominal veins. The liver spanned 15 cms, extended 8 cms below the mid right costal margin. Brawny edema and chronic venous stasis changes were seen in both lower limbs. Color Doppler and IVC cineangiogram (taken in anterioposterior and left lateral views) findings were similar as before (Fig 6).
 |
| Fig. 6 |
 |
| Fig. 7 |
 |
 |
| Fig. 8 | Fig. 9 |
 |
 |
| Fig. 10a | Fig.10b |
After balloon dilatation, stent delivery was introduced over exchange wire. A 14 × 55-mm Schneider Wall- Stent was deployed after its appropriate placement (fig 10a) Balloon dilatation was performed after stent deployment for the residual stenosis. Post procedure, there was significant improvement following PTA and stenting with disappearance of paravertrebral collaterals (fig 10 b). Post procedure management included intravenous heparin administered for the first 24 hrs followed by oral aspirin till date.
Clinically, the abdominal discomfort and fatigue disappeared within 6 hrs following the procedure. In patient’s own word- "I am feeling much lighter in the abdomen than ever before. The leg edema and varicosities of the abdominal wall also became less. There is no recurrence of hemetemesis.
Follow up sonography revealed widely patent stent and normal flow on color doppler study on 2 and 3 months follow up (Fig.11 a , b respectively) .
 |
 |
| Fig. 11a | Fig.11b |
Discussion :
The Budd-Chiari syndrome (BCS) is not an uncommon, often fatal illness resulting from hepatic venous outflow obstruction. The obstruction may be due to coarctation or thrombosis of the major hepatic veins (classical BCS) or hepatic/suprahepatic venacava or, as is more common in the orient, membranous obstruction of the IVC. BCS probably represents a spectrum. Clinically, two forms have been identified. The acute syndrome is invariably associated with extensive blockage of the major hepatic veins, sometimes associated with IVC occlusion, resulting in congestive liver cell necrosis. The important etiologic factors are related to hypercoagulabilty of blood. The patients with chronic BCS generally have membranous occlusion of the IVC (MOVC). Three types of this membranous obstruction have been described. In type 1, the IVC is obstructed by a thin membrane at the level of entrance to the right atrium. This membrane may be complete or partial with central hole. In type 2, a segment of the IVC (length varies) is absent. In these cases, the IVC gram shows a characteristic conical narrowing at the level of obstruction. In type 3, there is complete obstruction of the IVC secondary to thrombosis.
The origin and nature of the membranous obstruction of IVC is disputed. Evidence for both congenital and acquired etiologies have been reported including congenital malformations, neonatal obliterative changes, acquired thrombophlebitis and combination of some of the above. The "congenital hypothesis" suggest that embryologic malformation occurs during the stage when the liver and associated vessel systems develop, and either a failure of the hepatic segment of the IVC to join in the right hepatocardiac channel or an extension of the normal obliteration of the ductus venosus into the inferior venacava may then be caused. Protagonists of the "acquired origin" theory have demonstrated transition of IVC thrombosis to complete membranous obstruction and marked stenosis. They have also emphasized the wide variability in the anatomic location of the membrane, its variable thickness and its late presentation as evidence to refute the "congenital anomaly" theory.
Why thrombosis forms in the hepatic portion of the IVC remains unanswered. Kretz suggested that the intima of the IVC is mechanically and microscopically damaged by respiratory movements of the diaphragm and invites thrombosis. Coughing may also be responsible for mechanical damage. An additional mechanism favoring this theory is the eddying blood currents in this portion of the IVC where the flow from the hepatic veins join that of the IVC at a right angle.
Diagnosis of MOVC is usually not difficult. USG and color doppler readily demonstrate IVC obstruction or stenosis, occlusion of large hepatic veins as echogenic material, caudate lobe hypertrophy and other features of portal hypertension. CT may show focal or scattered areas of diminished attenuation with patchy enhancement in the liver. MRI has additional advantages in delineating occluding membrane without the need for contrast material. Cavography will demonstrate the level of obstruction as well as extensive collateral veins that eventually drain into the SVC. To accurately demonstrate the thickness of the obstructing membrane, simultaneous catheterization of the IVC and SVC is required, but may also be delineated in the late phase of inferior cavography when the right atrium is opacified through collaterals.
Several surgical and other interventional techniques have been used to treat BCS. Medical therapy, which consists of managing the ascites, correcting coagulapathy, and improving nutrition, results in limited success because it has no effect on the underlying pathophysiology.
Surgical treatment aims at the relief of portal hypertension and intrahepatic venous congestion. Orthotopic liver transplantation can be curative but morbidity and mortality with these surgical intervention results are high. Other methods of treatment have therefore been sought.
In acute BCS, local thrombolytic therapy followed by stent insertion, if required, may be curative. The introduction of PTA with a balloon catheter offers a new therapeutic option. Eguchi was the first to describe successful balloon membranotomy for obstruction of the IVC. Generally the short term results of PTA are good to excellent, with symptoms alleviated (even disappearing) after treatment as in this patient and most patients return to normal living. However restenosis/obstruction does occur at various intervals after PTA, which necessitates repeat PTA. The various factors responsible for such recurrence include insufficient dilatation, residual pathologic tissue and intimal hyperplasia and elastic recoil. To maintain vascular patency and prevent restenosis following balloon dilatation, expandable vascular endoprosthesis were introduced. The inherent continuous radial expansion pressure of the stenosis keeps the vessel patent for a longer time. Also stents prevent elastic recoil and reduce the resistance to blood flow and thrombosis formation.
Our patient experienced immediate and short-term clinical improvement following stenting. Patients, in whom satisfactory patency cannot be obtained by PTA, or for those with restenosis/obstruction after PTA, stent placement is emerging as effective option with the anticipation of improved results.