Patency and reintervention rates during routine TIPSS surveillance

CardioVascular and Interventional Radiology

�9 Spdnger-Verlag New York, Inc. 1998 Cardiovasc Intervent Radio[ (1998) 21:234--239

Patency and Reintervention Rates During Routine TIPSS Surveillance Joanne Latimer, 1 Sadeeq M. Bawa, 2 Colin J. Rees, 2 Mark Hudson, 2 John D.G. Rose 1

~Department of Radiology, Freeman Hospital, Newcastle upon Tyne NE7 7DN, UK 2Liver Unit, Freeman Hospital, Newcastle upon Tyne NE7 7DN, UK

Abstract

Purpose: To assess the medium-term outcome of transjugular intrahepatic portosystemic stent shunts (TIPSS) by mea- suring the incidence of shunt obstruction or failure during routine surveillance and the number of interventions performed. Methods:This is a retrospective study covering a 4-year period, from 1992 to 1996, during which 102 TIPSS procedures were performed. Indications for treatment were variceal bleeding (76%) and refractory ascites (24%). Follow-up protocol after TIPSS included transfemoral or transjugular portal venography and measurement of portosystemic pressure gradient (PPG) at 3 months, 12 months, and then at yearly intervals. The results of the first 155 venograms on 62 patients (mean follow-up 14 months) have been reviewed and Kaplan-Meier analysis performed. Results: One hundred and thirty-seven of 155 (88%) examinations showed patent shunts. Fifty-six of 137 (41%) of the patent TIPSS had elevated PPG with signs of stenosis. The majority (41/56) of shunt stenoses with elevated pressure gradients were related to neointimal hyperplasia in the hepatic venous aspect of the shunt. Interventions used to reduce the pressure gradient or to restore patency included: angioplasty (62/102 interventions), additional stents (21/102), a second TIPSS procedure (2/102), and thrombolysis or thrombectomy (4/102). The primary patency rate was 66% at 1 year (52% at 2 years). Primary assisted patency was 72% at 1 year (58% at 2 years). Secondary patency was 86% at 1 year (63% at 2 years). Conclusion: The majority of TIPSS shunts will remain patent when regular portal venography, with appropriate intervention, is undertaken. Although there is a high reintervention rate this mainly takes the form of balloon angioplasty.

Key words: Shunts, portosystemic--kiver, interventional procedure--Hypertension, portal--Liver, cirrhosis

Correspondence to: Dr. J.D.G. Rose, FRCP, FRCR

The transjugular intrahepatic portosystemic stent shunt (TIPSS) is an artificial communication created between the portal vein and an hepatic vein. It thus reduces the pressure gradient between the portal and systemic venous systems. The shunt traverses hepatic parenchyma and is maintained by the use of a metal stent.

Although a relatively recent technique [1-4], TIPSS is an accepted treatment for bleeding esophagogastric varices when medical and endoscopic treatments have failed [5, 6]. The transjugular shunt has proved lifesaving in the acute situation, with success rates for control of acute variceal bleeding of between 81% and 94% [6-10]. Questions remain as to the morbidity due to the reduction in total hepatic blood flow and the long-term effect on patient survival. There are further concerns about the patency rates of TIPSS.

A wide variation in the incidence of TIPSS stenosis has been reported in the literature, with dysfunction rates quoted from 12.3% [11] to 80% [12]. This probably reflects differences in the methods of assessing shunt dysfunction and in the follow-up intervals. Some centers employ Doppler ultrasound for assessing shunt function, others prefer portal venography and many use a combination of the two.

Definitions of shunt dysfunction have been proposed that rely on changes in flow velocity detected by ultrasound, by angiographic measurements, and pressure manometry during venography [12-15]. The most important definition is that of a rise in pressure gradient measured during venography. The normal portosystemic pressure gradient (PPG) is less than 4 mmHg. Previous studies of the relationship between portal hypertension and variceal bleeding have shown that the risk of bleeding is reduced when the PPG is less than 12 mmHg [16, 17]. Thus we attempt to reduce PPG to 12 mmHg (or less) at all our primary TIPSS procedures. However, at routine (asymptomatic) follow-up, elevation of the PPG to 14 mmHg is accepted and 15 mmHg is used as the threshold for intervention as suggested by other authors [18, 19].

The purpose of this study was to examine the medium- term outcome of TIPSS, including patency rates and the

J. Latimer et al.: TIPSS Patency 235

amount of intervention required to maintain a functional

shunt.

Materials and Methods Over a 4-year period, from August 1992 to July 1996, 102 TIPSS procedures were performed on 100 patients by a single operator at Freeman Hospital. Shunts were successfully completed in 97 of 102 procedures (95%).

The stents inserted were Wallstents (82/97), Memotherm (10/ 97) and Palmaz stents (5/97). The choice of stent was partly related to the availability of each type and size at the time of the procedure. The Wallstent superseded the Palmaz stent because of the more appropriate length achieved with a single device. Memotherm stents were tried for a short period because of the perceived advantage of a stent that would not shorten significantly after deployment. However, in practice this advantage was outweighed by consider- ations of cost and by the ease of deployment of the Wallstent.

The 62 patients included in this study are those who were subjected to follow-up portal venography, whether or not they subsequently went on to orthotopic liver transplantation or died within 30 days. Thirty-five patients who have not undergone por- tography, because their TIPSS was inserted within 3 months of the end of the study period or because of death, non-compliance, or overseas residence, have been excluded from analysis. The mean follow-up period was 14 months (range 1-39 months, median 13 months). In all, 62 patients underwent portal venography on at least one occasion and there were a total of 155 examinations.

The patient group consisted of 36 men (58%) and 26 women (42%) with a mean age of 54 years (range 28-74 years).

The etiology of the underlying liver disease was alcoholic cirrhosis in 42 (68%), primary biliary cirrhosis in 8 (13%), cryp- togenic cirrhosis in 6 (10%), and other causes in 6 (10%) patients. The severity of patients' liver disease, as indicated by Child-Pugh grade, was grade A in 12 (19%), grade B in 27 (44%), and grade C in 23 (37%).

The primary indication for TIPSS was active variceal bleeding in 28 (45%), previous variceal bleeding in 19 (31%), and refractory ascites in 15 (24%) patients.

The protocol for the management of patients with acutely bleeding esophageal varices in our unit indicates TIPSS for cases refractory to two episodes of endoscopic intervention (either variceal sclerotherapy, banding, or both) in combination with supportive medical management including somatostatin analogues (octreotide) or terlipressin (Glypressin). There is a lower threshold for the use of TIPSS to control bleeding from gastric or duodenal varices.

The follow-up protocol included both ultrasound and portal venography via the TIPS& Ultrasound was routinely performed prior to discharge, within 3 days of the procedure, in order to detect early shunt occlusion. Color Doppler examination of the whole shunt was performed and measurements of peak-flow velocity were taken at or close to either end of the shunt. Further Doppler studies and measurement of peak-flow velocities were performed in the outpatient clinic at regular intervals.

Portal venography was routinely performed at 3 and 12 months after placement of a TIPSS via the transjugular or more usually the transfemoral approach. Additional examinations were performed with a low threshold for clinical suspicion of possible shunt dysfunction.

Portal venograms were performed under local anesthetic using a 5 Fr cobra or sidewinder catheter. The PPG was measured on each

occasion, taking readings from the portal vein and inferior vena cava. The PPG was considered unacceptable if it was 15 mmHg or greater, and balloon angioplasty was performed regardless of the degree of stenosis determined angiographically. In cases of severe intractable ascites angioplasty was occasionally performed when the PPG was between 10 and 14 mmHg in an attempt to further increase flow across the (patent) shunt.

Definitions

The classification of TIPSS patency was described by LaBerge et al. [14] and based on criteria set out by Rutherford and Becker [20] for evaluating arterial patency as follows:

Primary patency. Continuous unaided patency of the shunt with a PPG < 15 mmHg. This ends with any intervention to maintain the PPG < 15 mmHg or with shunt occlusion. Primary assisted patenc~;. Continuous patency of the shunt, with or without intervention. This ends with occlusion of the shunt. Secondary patency. Continuous patency, with or without previous occlusion of the shunt.

Statistics

The cumulative survival, shunt patency, and Child-Pugh grades were analyzed by the Kaplan-Meier method [21] and survival curves plotted. Censored events were death or liver transplantation.

Results Overall Surveillance Data

Sixty-two patients underwent 155 separate portal

venograms, ranging from one to nine examinations per pa-

tient. Of these 155 examinations, 81 (52%) showed patent

TIPSS with PPG < 15 mmHg, 56 (36%) showed a stenosis with raised PPG and 18 (12%) revealed an occluded shunt.

Short-Term Complications

Short-term complications refer to events occurring before the first routine follow-up portal venogram at 3 months. These are summarized in Table 1.

Two patients were known to have hepatocellular carci-

noma (HCC) prior to TIPSS. The justification for inserting

the TIPSS in one case was the palliation of severe intractable ascites due to tumor compressing the portal vein. The other

patient had been treated over a 4-year period with intraarte- rial l ipiodol and doxorubicin and a TIPSS was inserted

because of recurrent bleeding varices. Both patients bene-

fited significantly, in terms of quality of life, from the extra

time spent at home as a result of the TIPSS.

Ou~ome

During the follow-up period 12 patients (19%) died. Mean

time to death was 229 days, range 10-540 days, median 180

days. The 12 deaths included 1 patient with Chi ld ' s grade A,

236 d. Latimer et al.: TIPSS Patency

Table 1, Short-term complications of TIPSS

Event no. Time Shunt Rebleed PPG Intervention Outcome

1 3 days Occluded No Covered stent (fistula) 2 3 days Thrombosis PV + stent Yes >15 mmHg Lysis + stent 3 4 days Patent Yes 14 mmHg Embolization 4 1 week Thrombosis PV + stent Yes Occluded Thrombectomy + stent 5 2 weeks Patent Yes 18 mmHg Embolization + stent 6 2 weeks Patent Yes 4 mmHg Embolization 7 2 weeks Thrombosis HCC No Thrombectomy + stent 8 3 weeks Stent shortened No Stent 9 3 weeks Occluded No Angioplasty

10 6 weeks Ingrowth HCC No Angioplasty 11 6 weeks Stent shortened Yes > 15 mmHg Stent

2nd TIPSS at 2 months Death at 10 days Transplant at 15 months Transplant at 4 months Well at 15 months Well at 19 months Death at 4 months Transplant at 33 months 2nd TIPSS at 27 months Death at 3 months Well at 4 months

PV = portal vein; HCC = hepatocellular carcinoma; PPG = portosystemic pressure gradient

Table 2. Patency rates

At 1 year At 2 years

Primary patency 66% 52% Primary assisted patency 72% 58% Secondary patency 86% 63% Primary assisted patency: Child B 73% 48%" Primary assisted patency: Child C 72% 72%"

"Did not reach statistical significance

7 patients with grade B, and 4 patients with grade C liver disease.

Nine patients (15%) underwent orthotopic liver transplantation, which took place between 60 and 990 days after TIPSS placement (mean 350 days, median 270 days). At the time of liver transplantation all explanted livers were exam- ined histologically and shown to have patent TIPSS. Al- though this does not necessarily mean that the TIPSS were hemodynamically effective, none of these patients had a rebleed prior to surgery. Outcome following liver transplantation is not included in this study.

Of the 41 surviving, non-transplanted patients, 36 (88%) have a functioning TIPSS, 2 have a patent second TIPSS, and 3 patients survive with an occluded shunt. Cumulative shunt survival was 76% at 1 year and 58% at 2 years.

Patency Rates

Shunt patency is shown in Figure 1. The 1-year and 2-year patency rates are recorded in Table 2. These rates are derived using the Kaplan-Meier method of analysis of incomplete data sets [21].

Primary patency is compared with the severity of liver disease (as expressed by Child's grade) in Table 2. Only Child's B and C patients are shown because the number with Child's A disease is too small for meaningful analysis.

Patency was not re-established in 8 of 18 occluded TIPSS. Three patients with occluded shunts died prior to reintervention at 10, 80, and 80 days respectively; 2 had advanced HCC and 1 died after a cerebrovascular accident. Two patients with recurrent shunt occlusions and eventual

failed recanalizations had demonstrable biliary fistulae. Both these patients underwent a second TIPSS procedure at 2 and 27 months respectively following the original procedure. The 3 other patients with failed recanalizations have had no rebleeding episodes. One of these had a non-Hodgkin's lymphoma and further intervention was felt to be inappro- priate. The other 2 patients remain alive and asymptomatic at 20 and 23 months respectively. In both patients the indication for the primary TIPSS was acute variceal bleeding and therefore further intervention has been postponed until clin- ically indicated.

Rebleeding

There were 13 episodes of rebleeding in 11 (18%) patients in total, 10 (14.5%) in the first year and 13 (18%) within 2 years. Six of 7 early rebleeds (within 6 weeks of TIPSS) are summarized in Table 1. The seventh patient had a patent shunt but rebled because of liver failure and disseminated intravascular coagulation. The six episodes of late rebleeding occurred at 9, 9, 10, 17, 18, and 27 months after TIPSS respectively. In all six events, in 4 patients, there was evi- dence of shunt stenosis and the PPG was in the range 20-40 mmHg, with a mean of 27 mmHg. Of these 4 patients, 3 were treated successfully by balloon dilatation of the TIPSS. A single patient underwent a second (parallel) TIPSS procedure because of recurrent shunt occlusion secondary to a biliary fistula.

Site of Stenosis

The majority of lesions were in the proximal aspect of the shunt, either in the hepatic vein or in the upper end of the stent (Table 3).

Interventions

Interventions are summarized in Table 4. The majority of interventions required to maintain TIPSS patency and a PPG < 15 mmHg were simple balloon angioplasties. Four patients had dilatation of their shunts performed even though

J. La t imer et al.: T IPSS Patency 237

0.6 n

" 0.5 o

o 0.4 .o n 0.3

1,0 ' '% 0.9~-~'~] 0.8 . . . . . . . . .

0.71 ~ ; . . . . ~":t":'7"':}.,,,.~ ..........................................................................................................

0.2

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I D Q S 6 . . . . . . . . . O i m B Q 0 0

Primary .... Primary Assisted ..... Secondary

12 Duration in Months

24 Fig. 1. Kaplan-Meier estimates of shunt patency.

Table 3. Site of shunt stenosis

Site No. %

Proximal: hepatic vein + proximal stent 41 55 Midpoint of stent 10 14 Distal stent 5 9 Occlusion 18 23

Table 4. Interventions

Intervention No. %

Angioplasty 62 61 Additional stent 21 20 Embolization 8 8 Lysis/Clotbuster 4 4 Failed recanalization 5 5 Second TIPSS 2 2 Total 102 100

the PPG was < 15 mmHg in the absence of significant stenosis. Three of these interventions were undertaken to achieve a greater reduction in PPG in an attempt to treat intractable ascites. In these patients the initial PPG was 14, 12, and 10 mmHg and was reduced to 7, 10, and 5 mmHg respectively. A single patient with a history of bleeding varices and a PPG of 14 mmHg was subjected to angioplasty because of residence abroad and poor compliance with the follow-up protocol. In all four cases it may have been that the stents (Wallstent, Palmaz, and Memotherm) were "over- dilated," but more likely that apparently insignificant intra- mural layers of neointimal hyperplasia were disrupted. No focal lesion was visible in any case.

Additional stents were placed if the PPG could not be lowered sufficiently by angioplasty alone and in particular if there was residual stenosis, especially in the hepatic venous inflow tract. One patient who developed severe encephalop- athy had three additional coaxial stents placed within the shunt to reduce the internal diameter. The same patient later

had placement of a Memotherm TIPSS reduction stent (ex- ternal diameter 14 mm, internal diameter 5 mm; Angiomed, Bard UK, London, UK), but the TIPSS remained hemodynamically significant. Embolization of varices was found to be useful in the small number of cases where rebleeding appeared to be associated with a PPG < 15 mmHg.

Two patients had a second TIPSS procedure after occlusion of the original shunt. Biliary puncture at the time of the first procedure possibly contributed to the severe repeated obstructions that subsequently developed [22].

D i s c u s s i o n

Estimation of the viability of the intrahepatic portacaval shunt in the medium term is complicated by the random decay in patient numbers due to death or liver transplantation. Most patients referred for TIPSS have severe chronic liver disease and indeed more than 80% in this study were Child's grade B or C. Thus some account has to be taken of the sporadic reduction in the number of shunts that remain available for study. As suggested by LaBerge et al. [14], we have approached this problem by the use of the Kaplan- Meier method of analysis. The cumulative shunt survival rates of 76% at 1 year and 58% at 2 years compare with those found by LaBerge of 60% and 51% respectively.

Disappointing primary patency rates for TIPSS have been apparent since the early reports of this procedure [23-26]. However, this is countered by assisted patency rates that, in our series, are in excess of 70% at 1 year. The diminishing figure at 2 years reflects the depletion of patient numbers as well as shunts.

Irremediable occlusion of the TIPSS is a relatively infre- quent event, secondary patency remaining at 63% up to 2 years after the procedure. Thus valuable time can be bought through routine surveillance and interval angioplasty or stenting. Nine of our 62 patients subsequently proceeded to successful liver transplantation at a mean of approximately 1 year after TIPSS insertion.

238 J. Latimer et al.: TIPSS Patency

It has been suggested that a marked reduction in liver function can be related to improved long-term patency of TIPSS and that this may be due in some way to impaired blood coagulation [27]. Our results have not confirmed a relationship between liver function and shunt patency, but show a trend in that direction which does not reach statistical significance.

The frequency of TIPSS dysfunction quoted in the literature varies between 12% and 80% [11, 12, 18, 19]. These large differences may be explained by variations in follow-up methods, such as the use of ultrasound surveillance alone and underutilization of venography and portal manometry. Color Doppler ultrasound is an extremely useful tool for excluding early shunt occlusion but, in our unit, the onset of neointimal hyperplasia in the proximal part of the shunt can be overlooked. This may be due to the unfavorable anatomy of the cephalad aspect of many TIPSS. Unfortu- nately the hepatic vein was the site of 55% of the stenotic lesions in this series and has also been highlighted as a problem area by other authors [10, 12, 24]. This predomi- nance of problems at the proximal end of the shunt may be due in part to stent shortening, particularly when the Wall- stent is used [7] and early in the "learning curve" of TIPSS experience. However, we have noted a similar distribution of stenotic lesions during follow-up of the other stent types. Unfortunately our data contain too few observations of Palmaz and Memotherm stents to enable any useful or ac- curate comparison.

It has been demonstrated previously that almost all episodes of variceal bleeding after TIPSS insertion are related to shunt dysfunction [6, 14, 28]. This concurs with our experience but it is also clear that most TIPSS stenoses found on interval portograms will be asymptomatic. By intervening at the time of routine follow-up studies we hope to keep shunts patent for longer and reduce the rebleeding rate. Thus there is a high rate of reintervention in our series (80 of 155 examinations). These interventions largely take the form of simple balloon angioplasty (61% of interventions). Despite the high intervention rate, medium-term patency has been maintained. Of 41 patients remaining alive, 36 (88%) have a patent primary TIPSS, two have a "parallel" second shunt, and only 3 have an occluded shunt.

The rebleeding rate following insertion of a TIPSS lies between 7% and 38%, with a mean in the larger series of around 18% [28]. Our rate for rebleeding is similar, with a rate of 14.5% at 1 year and 18% at 2 years. Early rebleeds occurred in 2 of our patients, despite the reduction in PPG to levels below 15 mmHg (4 and 14 mmHg). As suggested by Rossle et al. [10], our experience supports the view that the embolization of persistently opacified varices may be useful, after satisfactory reduction of the PPG, in emergency procedures undertaken for acute bleeding. This approach has also been advocated after surgical partial portal decompression [29] and may be particularly appropriate when treating patients with sclerotherapy-induced ulceration [30]. In addi- tion it is possible that occluding collateral vessels may im-

prove shunt patency by increasing blood flow through the stent.

In conclusion, we have found that TIPSS patency and function can be maintained in the medium term in the majority of patients. Although a high proportion of TIPSS may require reintervention to maintain a reduced protosys- temic gradient, angioplasty will suffice in most instances, tn the future, further sophistication of magnetic resonance an- giography (MRA) may help to reduce the need for invasive procedures in the assessment of TIPSS patency and function [31]. Prospective studies comparing portal venography with MRA are needed.

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Patency and reintervention rates during routine TIPSS surveillance

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