Radiological intervention and the Budd-Chiari syndrome

JF Griffith FRCR(UK)and SPOlliff FRCR(UK) Department of Radiology, Queen Elizabeth Hospital, Birmingham, UK, B152TH myeloproliferative disorder' Inthe East, the dominant site of obstruction is usually the NC and only a minority have an underlying myeloproliferative disorder>" NC obstruction may be a sequel of a congenital venous web anomaly frequently complicated by thrombosis 5-10 It is classified as membranous O_e"cavalweb'), ifit extends over 1-2mm, or segmental ifit extends over a few centimetres. NC obstruction in BCS may also be due to caudate lobe hypertrophy, direct tumour invasion or extrinsic compression by hepatic tumour.


linical presentation
The presenting symptoms depend on the dominant site of obstruction. If this is the hepatic veins, patients usually present acutely with progressive hepatic engorgement, hepatic impairment and portal hypertension cumulating in hepatic encephalopathy. 1.2Conversely;ifthe dominant site of obstruction is the NC, patients present with a chronic history oflower limb swelling dating backmanyyeara'ê Aetiology Aetiology alsovariesaccording to the principal site of obstruction. In the West, most patients with BCS have an obstruction to their hepatic veins (either centrilobular or main). In about one-third, the cause is unknown/ while most of the remain- der have an underlying 13 SA JOURNAL OF RADIOLOGY. May 1996 topage14 Radiological Intervention and the Budd-Chiari Svnclrorrie (e.g.caudate lobe hypertrophy) and features of portal hypertension. The hepatic veins may be engorged, irregular, filled with thrombus or absent. Triphasic flow may be dampened (Figure 1b) or reversed. Collaterals (intrahepatic, subcapsular) with a characteristic curved or "hockey stick" appearance may be visible. The NC may be narrowed, displaced by caudate hypertrophy or contain intraluminal thrombus":" Venography remains the gold standard diagnostic tool (Figures 2a, Sa and 6a,b).
Inferior venography isinitially performed to assess intrinsic NC obstruction or significant extrinsic compression which may be present in sixty fiveper cent. 3 The exact length,location and direction of obstruction can be assessed by simultaneous injections of catheter placed on either side of the obstruction. IS Pressure measurements are obtained from the infrahepatic, intrahepatic and suprahepatic NC as an adjunct to surgical planning.
A transjugular approach allows easiest access to the hepatic veins. The walls of the NC should be gently probed with a suitablyshaped catheter to locate the hepatic venous ostia. Flush inferior vena cavography alone cannot be relied upon to opacify severely stenosed venous ostia. Once cannulated, free and wedged venous measurements are obtained to give an assessment of portal hypertension, the hepatic wedged venous pressure correlating roughly with the degree of portal hypertension.
Hepatic venography allows assessment of venous calibre, stenoses and thrombosis of either the largeor smallveins (the latter evidenced by a "spider's web" appearance which reflects partially recanalised and collaterised third and fourth order venules). A liver biopsy may be taken at the same time. This allows assessment of hepatic fibrosis and differentiates BCS-type changes ("perisinusoidal congestion") from hepatic venocclusive-type change where the terminal hepatic venules are obliterated.

Venographic abnormalities at presentation
In patients with dominant hepatic venous obstruction, the degree oflirnitation of hepatic venous flow at presentation is striking.The most venographic patterns evident at presentation are (i) a"spider's web" appearance alone without obstruction to the main hepatic veins,(ii) complete occlusion of allthree veins or (iii) an occlusion of two out of three veins with a severe stenosis of the remaining vein. A critical level of hepatic vein occlusion must be reached before symptoms develop. This issupported by a prevalence of asymptomatic hepatic venous obstruction present in postmortems of 0.183%.16 Intrahepatic collaterals will usually be established at presentation. Similarly, with dominant lVC obstructions, a short ("membranous") or long segment ("segmental") stenosis/occlusion with established azygos and hemiazygos collaterals is typical, accompanied by varying degrees of obstruction to the main hepatic veins.

op.tiorrs
This may be supportive medical treatment, surgicalor radiological.

Medical management
Medical management involvestreating underlying myeloproliferative disorders, anticoagulationofhypercoagulable patients, control of ascites and lactulose/ dietary restriction to treat hepatic encephalopathy.

Surgical treatment
Surgical management consists of peritoneovenous shunts, dorsocranial liver resection with venous reconstruction, portosysternic shunting, direct venous repair and orthotopic liver transplantation.' Mesocavalshunts (which involve interposition of an autologous or dacron graft between the NC and the superior mesenteric vein) are unsuitable for patients with high caval pressures. Mesoatrial shunts (preferred if the NC pressure is high) involve interposition of a long narrow polyethylene prosthesis between the superior mesenteric vein and the lapsgs 15 Rad iologica I Intervention and the Budd-Chiari Syndrome right atrium over the liver surface. These grafts are prone to occlusion due to low flow states and graft thrombogenicity.' Nevertheless, the 5-year survival for patients undergoing mesocaval or mesoatrial shunts is60-75%.3 Hepatic transplantation isreserved for those patients with advanced hepatic fibrosis.

Radiological intervention
Since percutaneous angioplasty of an

Patient suitability for radiological intervention
We reviewed 47 patients admitted over an eight year period with BeS. 1 Of these 17 (37%) who were suitable for radiological intervention, two had tumour-related Bes and one underwent repeated dilatations of asurgicallyplaced mesocaval shunt. Proper patient selection is important, the decision to proceed with radiological intervention being made following assessment of hepatic biopsy, ultrasound and venography findings.
Patients unsuitable for venoplasty are those with (i) portal vein thrombosis, (ii) established hepatic fibrosis,(iii) a "spider's web" appearance alone on venography without stenoses of the main hepatic veins, and (iv) complete thrombosis of all hepatic veins. Thrombolysis isineffective in the last group asthrombosis typically extends out into the fifth order hepatic vein radicals and these smaller veins are difficult to clear effectively due to hepatofugal venous flow.Therefore, if the main veins are cleared, there is usuallyinsufficient inflow to maintain patency. Patients in groups (iii) and (iv) may be suitable forTIPS.

Standard radiological intervenfional techniques
Patient preparation includes drainage of ascites, correction of clotting factors and omission of anticoagulant therapy (prior to percutaneous transhepatic procedures). Intravenous antibiotics are routinely administered. Procedures are tolerated well using intravenous sedation! analgesia with appropriate monitoring. The standard radiological techniques are hepatic and Ne venoplasty and! or recanalisation usually performed through a jugular and femoral approach respectively (Figures 3a-d). For hepatic vein dilatations, we generally use a 6F right internal jugular sheath, a general purpose angled catheter to cannulate and a standard angioplasty catheter to dilate the vein (to 12 mm) until waisting is abolished. The usual stricture encountered is at the venous ostium, is short, hard to dilate and recoils following deflation of the balloon (Figures2a,b). Nevertheless, although there may not be much visible widening of the stricture following repeated dilatations (Figure 2b), a reduced pressure gradient, increased blood flow and symptomatic improvement does follow. For Ne obstructions, either one large balloon or up to four smaller balloons placed side to side (introduced via the femoral veins) can be used (Figures 3c,d). Thrombus, ifpresent, in either the Ne or the hepatic veins should be cleared by thrombolysis to dilatation to

Recurrence of hepatic stenoses
Restenosis is the rule rather than the exception. 2 !.26Five out of 18 (28%) initial angiographic dilatations in our series failed to provide adequate venous return in the first instance due to a combination of restenosis and thrombosis.' Adopting an aggressive attitude to re-intervention during the early treatment period with re-dilatation, use of thrombolytic agents and stent deployment as necessary improved our initial successrate from 72%t083%.! 16 SA JOURNAL OF RADIOLOGY. May 1996 Regular review is mandatory. HV restenosis occurred in all patients followed up for longer than 10 months although the duration between restenoses may vary. Generally, lVe stenoses recur less frequendythanhepatic veinstenoses. 5,2!. 24 The aim of post -intervention surveillance is to re-intervene before critical stenosis or occlusions recur, particularly as they may pre-date clinical or biochemical deterioration. We adopt a policy of regular clinical and ultrasound assessment (varying from three-monthly, six-monthly and yearly once the patient is stabilised) supplemented by hepatic venography annually (or sooner should clinical, biochemicalor ultrasonic deteriora tion occur). Whilst this policy is uniformly well to page 17 c) A guide wire was passed to the right atrium and snared. tolerated, in occasional circumstances where frequent repeat dilatation is necessary;stent insertion has been undertaken. Radiologicalintervention does not address the underlying pathophysiology of hepatic venous outflow obstruction. Thus the disease can never be deemed cured and continued review is essential.

Stenting
NC stent deployment has been reported more commonly than hepatic veinstenting. We reserve stenting for situations where a) the patient is critically ill and initial dilatations are unsuccessful, b) repeated re-dilatation is required at short intervals on review and c) malignant disease.
Where there is significant lVC narrowing, placement of an intrahepatic stent may reduce caval pressure to allow mesocaval shunting rather than more hazardous mesoatrial shunting. As reduction in liverswellingmay lead to apparent stent movement, we aim to deploy hepatic vein stents with the tip not protruding much beyond the venous ostium. NC stents should not extend into the right atrium or the infrahepatic NC where they will interfere with liver removal (if transplantation is subsequently required).

Safety of radiological intervention
Very few complications following radiological intervention forBCS havebeen reported.
NC stent migration is the only significant complication reported to date." In 49 angiographic dilatations (including 11 recanalisations), we had three serious complications.' In one patient, a small pseudo aneurysm of a right hepatic artery branch presented as haemobilia within days of percutaneous transhepatic intervention. Cephalad migration of two interlaced upper lVC stents into the right atrium by approximately 3 cm occurred in another patient. This cephalad migration may have precipitated an increased frequency of atrial tachyarrythmias. Myocardial puncture (without haemodynarnic compromise) occurred in another patient during recanalisation of an upper NC occlusion.

Effectiveness of radiologi!=al Intervention
Overall,the efficacyof radiologicalintervention compares favourably with surgical shunting.A"markedimprovement" (i.e. with no symptoms related to hepatic venous outflow obstruction) following radiological intervention wasseen in 10ofthe 18 (56%) patients. Some of the patients developed recurrent progressivesymptoms in the weeks priortore-intervention. "Improvement" (Le. continued mild symptoms of hepatic venous outflow obstruction) was seen in 4 out ofl8 (22%) patients againwith progressive symptoms prior to re-intervention.

Failure of radiologi!=al Intervention
As most reports consist of one or two patients, there is little mention of failed radiological intervention in the literature.
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Radiological Intervention and the Budd-Ch iari Syndrome
Radiological intervention failed in 5 out of 18 of our patients, principally during the earlier years of the study.' Three of these patients failed early: recurrent thrombolysis( n=l]; failure to recanahse lVC ocdusion(n=l); and failure to reeanalise hepatic vein ocdusion( n= 1). Two late failuresoccurred (restenosis,n=2). Oflate, better patient selection, use of a combined transhepatic-transjugular route andstentinghave lead to animprovedsuccess rate. Should radiological intervention fail, patients can still proceed to surgical shunting or transplantation. Moreover, a limited response to radiological intervention in a patient with severe hepatic failure, may make subsequent surgery less hazardous.

TIPS
When the main hepatic veins are completely occluded TIPS have been successfully performed (usually through an occluded RHV sinus) asan alternative to surgicalportosystemic shunting=" to relieve portal hypertension and decrease hepatic congestion. Whilst contraindicated in the presence of a concomitant severe upper NC stenosis, TIPS,asopposed to mesocaval shunting, can be considered when severe caudate lobe hypertrophy exists and does not interfere with subsequent liver transplantation. As venous drainagethrough the hepatic veins isnot restored, TIPS carry an inherent risk of portal-systemic encephalopathy although the incidence of this, following surgical portosystemic shunting for Budd-Chiari, is 10w: 39