Portal vein arterialization: a salvage procedure for a totally de-arterialized liver. The Paul Brousse Hospital experience

Abstract

Background

Portal vein arterialization (PVA) has been used as a salvage inflow technique when hepatic artery (HA) reconstruction is deemed impossible in liver transplantation (LT) or hepatopancreatobiliary (HPB) surgery. Outcomes and the management of possible complications have not been well described.

Methods

The present study analysed outcomes in 16 patients who underwent PVA during the period from February 2005 to January 2011 for HA thrombosis post-LT (n = 7) or after liver resection (n = 1), during curative resection for locally advanced HPB cancers (requiring HA interruption) (n = 7) and for HA resection without reconstruction (n = 1). In addition, a literature review was conducted.

Results

Nine patients were women. The median age of the patients was 58 years (range: 30–72 years). Recovery of intrahepatic arterial signals and PVA shunt patency were documented using Doppler ultrasound until the last follow-up (or until shunt thrombosis in some cases). Of five postoperative deaths, two occurred as a result of haemorrhagic shock, one as a result of liver ischaemia and one as a result of sepsis. The fifth patient died at home of unknown cause. Three patients (19%) had major bleeding related to portal hypertension (PHT). Of these, two underwent re-exploration and one underwent successful shunt embolization to control the bleeding. Four patients (25%) had early shunt thrombosis, two of whom underwent a second PVA. After a median follow-up of 13 months (range: 1–60 months), 10 patients (63%) remained alive with normal liver function and one submitted to retransplantation.

Conclusions

Portal vein arterialization results in acceptable rates of survival in relation to spontaneous outcomes in patients with completely de-arterialized livers. The management of complications (especially PHT) after the procedure is challenging. Portal vein arterialization may represent a salvage option or a bridge to liver retransplantation and thus may make curative resection in locally advanced HPB cancers with vascular involvement feasible.

Introduction

A totally de-arterialized liver is an organ which, in addition to hepatic artery (HA) ligation or resection, is subjected to the complete interruption of all collateral sources of arterial inflow (interlobar hepatic arteries, peribiliary plexus, collaterals in triangular ligaments and lesser omentum).^1–6 This may occur in patients with HA thrombosis (HAT) after liver transplantation (LT), in which a totally de-arterialized liver graft to which the HA is the only arterial inflow vessel is implanted, and in some instances of major liver resection which involve HA resection, in which the liver is completely mobilized from its attachments and skeletonization of the porta with division of the biliary tree is performed in order to achieve oncological clearance.^7,8 In these situations, if the HA is not reconstructed, biliary ischaemia and necrosis are inevitable, and liver necrosis and fatal liver failure are possible. However, ischaemic cholangitis and bile duct necrosis do not occur in all patients with a de-arterialized liver. This may in part reflect the rapid development of collaterals after the complete interruption of the HA (as in some cases of late HAT^9,10).

Portal vein arterialization (PVA) is a salvage technique used in a de-arterialized liver to establish arterial inflow when all other possible strategies for the reconstruction of the artery have been ruled out.¹¹ The procedure increases the oxygen saturation of portal vein (PV) blood significantly, prevents hepatic necrosis and insufficiency, and promotes liver regeneration.^12,13 It will also alleviate the ischaemic state of bile ducts because the terminal PV tributaries form anastomoses with the arterial peribiliary plexus.^3,12,14

Reported experiences with PVA in completely de-arterialized livers are limited and consist only of case reports or small series. These do not detail the mid- or longterm outcomes of the procedure or describe possible consequences, particularly in relation to the development of portal hypertension (PHT) and liver fibrosis.

The aim of the present study was to evaluate results achieved with salvage PVA in 16 patients in a single centre over a 6-year period, with particular emphasis on longterm results. In addition, the published literature was reviewed for relevant studies on the utility of PVA and subsequent outcomes.

Materials and methods

Patient selection

Between February 2005 and June 2011, 16 patients with totally de-arterialized livers in which HA reconstruction was impossible underwent PVA at the Hepatobiliary Centre, Paul Brousse Hospital (Villejuif, France).

Portal vein arterialization was performed in the setting of LT in seven patients (Table 1) and hepatopancreatobiliary (HPB) surgery in nine patients (Table 2).

Table 1.

Main characteristics of seven liver transplant patients submitted to portal vein arterialization (PVA) at Paul Brousse Hospital

Patient	Age, years/sex	Liver transplant or hepatobiliary surgery		Portal vein arterialization
		Indication for surgery	Primary procedure	Indication for PVA (timing)	Type	Interposed vein/prosthetic graft used
1	60/M	NASH-related cirrhosis	DDLT	HAT (2 days)	RGEA to RGEV	No
2	56/M	Alcoholic cirrhosis with HCC	DDLT	HAT (39 days)	HA to PV	No
3	59/M	Alcoholic cirrhosis	DDLT	HAT (17 days) → revascularization → re-HAT with biliary stricture (77 days)	Left genital artery to IMV	No
4	30/M	HBV cirrhosis with HCC	DDLT	HAT (35 days)	LCA to LCV	No
5	30/F	Secondary biliary cirrhosis	Domino LT	HAT with GI bleed (graft → duodenal fistula) (20 months)	LCA to ICV (first PVA)	No
6	65/M	Haemochromatosis with HCC	Domino LT	HAT with GI bleed (graft → duodenal fistula), false aneurysm LHA (29 months)	RIA to SMV	Yes
7	49/F	Acute liver failure (paracetamol poisoning)	DDLT	HAT with biliary fistula (106 days) → revascularization → rupture of HA at 130 days	RGEA to RGEV	No

Patient	Age, years/sex	Postoperative course			Delayed complications	Survival outcomes (follow-up period)	Cause of death
		Significant complications	PVA thrombosis/manner of detection	Re-intervention
1	60/M	Ascites, encephalopathy	No	No	–	Alive (12 months)	–
2	56/M	Ascites	No	No	–	Alive (11 months)	–
3	59/M	No	No	No	Biliary stenosis managed successfully with metallic stent	Alive (23 months)	–
4	30/M	Intra-abdominal bleed with haemorrhagic shock	No	Laparotomy with abdominal packing for intra-abdominal bleed	–	Death (71 days after DDLT)	Haemorrhagic shock with multi-organ failure
5	30/F	–	Yes/detected on Doppler imaging (5 days)	Second PVA (RCIA to MCV) with interposition Gore-Tex® graft	Recurrent cholangitis: retransplanted	Alive (12 months)	–
6	65/M	Intra-abdominal bleed caused by extension of and bleed from LHA pseudoaneurysm	Yes/detected on Doppler imaging (13 days)	Embolization of LHA pseudoaneurysm No re-PVA in view of good collaterals	–	Alive (12 months)	–
7	49/F	Cholangitis	No	Retransplantation at 8.5 months	–	Death (10 months after first DDLT)	Abdominal sepsis with multi-organ failure after re-LT

DDLT, deceased donor liver transplantation; F, female; GI, gastrointestinal; HA, hepatic artery; HAT, hepatic artery thrombosis; HBV, hepatitis B virus; HCC, hepatocellular carcinoma; ICV, inferior colic vein; IMV, inferior mesenteric vein; LCA, left colic artery; LCV, left colic vein; LHA, left hepatic artery; LT, liver transplant; M, male; MCV, middle colic vein; NASH, non-alcoholic steatohepatitis; PV, portal vein; RCIA, right common iliac artery; RGEA, right gastroepiploic artery; RGEV, right gastroepiploic vein; RIA, right iliac artery; SMV, superior mesenteric vein.

Table 2.

Main characteristics of nine hepatopancreatobiliary surgery patients submitted to portal vein arterialization (PVA) at Paul Brousse Hospital

Patient	Age, years/sex	Liver transplant or hepatobiliary surgery		Portal vein arterialization
		Indication for surgery	Primary procedure	Indication for PVA and timing	Type	Interposed vein/prosthetic graft used
8	36/F	Intrahepatic cholangiocarcinoma	Ex situ right extended hepatectomy (including segments I and IV) with partial resection of segments II and III	For curative resection (contralateral artery involvement)	CHA to PV	No
9	61/M	Hilar cholangiocarcinoma (Klatskin type IIIB)	Left extended hepatectomy (including segments I, V, VIII)	For curative resection (RHA involvement)	CHA to PV	No
10	57/M	Gallbladder cancer with invasion of PV, HA, CBD	Left extended hepatectomy (including segment V)/PD, resection and reconstruction of PV, ligation of HA	For curative resection	Aorta to IMV	Yes (6-mm Gore-Tex®)
11	40/F	Schwannoma of hepatic pedicle	Resection of schwannoma/PV/HA/main bile duct PV reconstruction with Gore-Tex® graft, HJ	For curative resection	IMA to IMV	No
12	70/F	Multiple aneurysms coeliac trunk to HA	Aneurysm resection/CHA + SA + LGA ligation	CHA ligation for aneurysm	CA to PV	Yes (6-mm Gore-Tex®)
13	46/F	Large HCC in a non-cirrhotic liver	RH (VE preserving the caval flow, hypothermic perfusion)	HA injury with intraoperative ligation (no arterial inflow to remnant left liver)	SA to PV trunk with IMA graft on PoD 1	Yes
14	72/F	Synchronous colorectal liver metastases with HA infusion catheter in situ (post-systemic chemotherapy)	Left hepatectomy	Intraoperative detection of thrombosed RHA secondary to HA catheter	ICA to IMV	No
15	60/F	Pancreatic adenocarcinoma	Pancreaticoduodenectomy with PV resection (for tumoral invasion)	Absence of arterial intrahepatic flow on intraoperative Doppler US	SA to PV with cadaveric arterial iliac graft	No
16	67/F	Pancreatic adenocarcinoma	Pancreaticoduodenectomy with PV resection (for tumoral invasion)	HAT (2 days)	Aorta to IMV	Yes

Patient	Age, years/sex	Postoperative course			Delayed complications	Survival outcomes (follow-up period)	Cause of death
		Significant complications	PVA thrombosis/manner of detection	Re-intervention
8	36/F	No	Yes/transaminitis (7 days)	Second PVA (aorta to MCV with interposition graft)	–	Died 29 days after resection	Multi-organ failure
9	61/M	Massive ascites, four episodes of variceal bleed, hyperbilirubinaemia (2 months)	No	TAE of shunt caused by portal hypertensive bleed (2.5 months postoperatively)	–	13 months, lost to follow-up	–
10	57/M	Three episodes of intra-abdominal bleeding with haemorrhagic shock	No	Multiple laparotomies with packing and finally ligation of the shunt as a result of recurrent intra-abdominal bleeding	–	Died at 14 days	Haemorrhagic shock with multi-organ failure
11	40/F	Ascites, oesophageal varices and portal vein thrombosis at 3 months	No	TAE of the shunt as a result of portal hypertension at 4.5 months.	–	Alive at 24 months	–
12	70/F	No	Yes/transaminitis (2 days)	No re-PVA in view of good collaterals	–	Alive at 12 months	–
13	46/F	No	No	No	–	Alive at 60 months	–
14	72/F	No	No	No	–	Alive at 12 months/lymph node recurrence	–
15	60/F	Ischaemic necrosis of the right liver, lactic acidosis, cardiac arythmia	No	No	–	Died 3 days after resection	Multi-organ failure.
16	67/F	No	No	TAE of the shunt ‘de principe’ at 40 days	Biliary fistula	Died 2.5 months after resection	NA

CA, coeliac artery; CHA, common hepatic artery; CBD, common bile duct; F, female; HA, hepatic artery; HAT, hepatic artery thrombosis; HJ, hepaticojejunostomy; NA, not available; IMA, inferior mesenteric artery; IMV, inferior mesenteric vein; ICA, ileocolic artery; LGA, left gastric artery; M, male; MCV, middle colic vein; PoD, postoperative day; PV, portal vein; RH, right hepatectomy; RHA, right hepatic artery; SA, splenic artery; TAE, transarterial embolization; US, ultrasonography; VE, vascular exclusion.

In the LT setting, all instances of PVA were performed in emergency contexts for HAT. Four patients suffered early HAT that occurred within the first 2 months after LT and three experienced late HAT in which no arterial collateral inflow to the liver was demonstrable at the time of presentation.

In the setting of HPB surgery, PVA was performed either in an emergency (for HAT or HA injury) or as an elective procedure for curative surgery in locally advanced malignancies. It was performed immediately during resection for planned curative surgery (involving HA resection as a result of tumour invasion) in patients with HPB malignancy (n = 4), or during HA ligation for multiple symptomatic arterial aneurysms (n = 1), or in response to HA injury detected during surgery (n = 3), or as a salvage procedure in the event of HAT (n = 1) after hepatectomy.

Surgical strategy

Salvage PVA was discussed only after Doppler ultrasound (US) and a multidetector computed tomography (MDCT) angiogram before planned surgery had confirmed the absence of intrahepatic arterial signals and a patent PV. The absence of arterial signals was reconfirmed using Doppler US in the operating room, as was the non-feasibility of arterial reconstruction. During the study period, the centre's surgical team performed microvascular surgery including arterial reconstructions (under the microscope) in living related donor LT (>100 patients), split liver transplantation (>100 patients) and liver resection surgery (12 patients). The decision to proceed with PVA was always taken only after all options for arterial reconstruction (including microvascular surgery) had been explored and were considered impossible.

The present group preferred to use the coeliac trunk, HA or splenic artery (SA) as the inflow vessel, provided the operative field was favourable (i.e. that it allowed for easy dissection and did not feature severe adhesions or either proven or suspected local infectious foci, such as a biliary fistula). In other situations, the shunt was performed in the infra-mesocolic compartment using different vessels as detailed in Tables 1 and 2. A palpable thrill on the PV wall and a PVA-type intrahepatic PV flow pattern on Doppler US were considered to indicate the successful creation of the shunt. No prophylactic procedures for postoperative PHT, such as PVA calibration, were performed. Perioperative mortality was defined as mortality occurring within 3 months after PVA or during the same hospitalization.

Postoperative assessment and longterm follow-up

The standard postoperative protocols for the follow-up of LT recipients or liver resection patients were used. Doppler US was performed daily in the intensive care unit (ICU) and twice weekly once the patient had been moved to the ward to confirm the patency of the PVA. Contrast CT angiography was performed before discharge to check the patency of the shunt and/or collateral inflow to the liver. No anticoagulation or anti-platelet treatment other than that included within the normal post-LT protocol was given.

After discharge, patients were examined for signs of PHT [ascites or varices on upper gastrointestinal (GI) endoscopy], abdominal pain, diarrhoea and encephalopathy. The patency of the PVA was confirmed on Doppler US and/or MDCT. This evaluation was performed at 1, 3 and 6 months, and then yearly after discharge.

Results

Operative details and the postoperative courses of all patients are summarized in Tables 1 and 2. Portal vein arterialization was feasible in all attempts.

Portal vein arterialization in the setting of LT

In the setting of LT (Table 1), the first four patients underwent emergency PVA for early HAT. None had intrahepatic collaterals on preoperative MDCT. Patients 1 and 2 had portal hypertensive ascites in the postoperative period, which resolved spontaneously. The PVA was patent in all patients until the last follow-up and there were no residual signs of PHT in the three patients who remained alive with good liver function. On postoperative day (PoD) 35 after initial LT, Patient 4 demonstrated thrombosis in the Gore-Tex® interposition graft used for arterial reconstruction, with no intrahepatic flow on MDCT and Doppler US. A PVA [left colic artery to left colic vein, draining into the inferior mesenteric vein (IMV)] was performed. The patient underwent three re-laparotomies in the postoperative period for diffuse intra-abdominal bleeding (clot evacuation and packing were performed) in which no definite site of bleeding was identified. The patient died 2 months after LT as a result of multi-organ failure following haemorrhagic shock.

Three other patients presented with late HAT. Patients 5 and 6 presented with a GI bleed; on investigation both were found to have developed an arterial graft-to-duodenal fistula. Patient 5 had HA stenosis at 14 months after LT and underwent successful HA stenting. Six months later, she had a GI bleed which was found to have been caused by the erosion of the iliac artery graft (used for arterial reconstruction during LT) into the duodenum. The bleed was initially controlled by endoscopic clip application and adrenaline injection. A covered stent placed in the iliac artery graft at the site of the leak thrombosed within a few hours. An initial attempt at thrombolysis also failed. No intrahepatic arterial signal was detected. A left colic artery-to-ileocolic vein shunt was performed. The shunt thrombosed after 5 days with no intrahepatic arterial signal. The patient underwent a second PVA (right iliac artery to middle colic vein using an interposition Gore-Tex® graft). Good intrahepatic flow was demonstrated. This patient required retransplantation 5 months later as a result of recurrent ischaemic cholangitis. She is presently doing well. Patient 6, who presented 29 months after LT, underwent emergency surgery with ligation of the distal end of the iliac graft and overrunning of the bleeding duodenal ulcer. The arterial supply to the graft via the left hepatic artery (LHA) was preserved. Two months later, a 2-cm pseudoaneurysm was detected at the origin of the LHA in the absence of an intrahepatic arterial flow signal. It was decided that arterial inflow to the graft should be established via a PVA. An anastomosis between the right iliac artery and superior mesenteric vein was performed using an interposition Gore-Tex® graft (Fig. 1a, b). In the postoperative period, the patient suffered an intra-abdominal bleed with haemorrhagic shock. Angiography revealed that the pseudoaneurysm had progressed proximally to the coeliac trunk. Therapeutic embolization was performed. On day 13 after the PVA, a thrombosis of the interposed Gore-Tex graft was noted; however, good collaterals, including hepatopetal flow and good intrahepatic arterial flow signals, were observed. No further intervention was carried out. The patient is doing well 12 months after the PVA.

Figure 1.

Portal vein arterialization for hepatic artery thrombosis post-liver transplantation in Patient 6, demonstrated as (a) an intraoperative view and (b) in postoperative multidetector computed tomography showing the complexity of the arteriovenous shunt between the right iliac artery (RIA) and the superior mesenteric vein (SMV) using an interposed Gore-Tex® [polytetrafluoroethylene (PTFE)] graft measuring 6 mm in diameter

Patient 7 developed a biliary fistula post-LT; later HAT was detected on PoD 106. The graft was revascularized using a saphenous vein graft conduit. However, 2 weeks later (PoD 130), the patient exhibited intra-abdominal bleeding secondary to HA rupture. An exploratory laparotomy with haemostasis, ligation of the HA and a PVA (right gastroepiploic artery to vein anastomosis) was performed. This patient required retransplantation at 8.5 months for ischaemic cholangitis. Postoperatively, he developed intra-abdominal sepsis and died of multi-organ failure at 10 months after the first LT.

Portal vein arterialization in the setting of HPB surgery

Immediate PVA (during surgery) after HA resection or ligation for oncological clearance during curative surgery

In four patients (Patients 8–11), the HA was infiltrated by the tumour and thus its resection was necessary to ensure curative surgery (Table 2). Hepatic artery reconstruction after resection was technically impossible and thus PVA was used to provide arterial inflow to the remnant liver.

In Patient 8, the first PVA thrombosed; a second PVA was performed with an interposition graft, but the patient died soon after surgery as a result of multi-organ failure. The PVA shunt was patent on Doppler US until just before the patient's death. Patient 9 showed signs of PHT in the form of massive ascites and variceal bleed after PVA; the PVA shunt was found to be embolized (Fig. 2). This patient has since done well and has demonstrated normal liver function and no further sequelae of PHT. Patient 10, who had undergone radical surgery for carcinoma of the gallbladder, submitted to three re-explorations for intra-abdominal bleeding and haemorrhagic shock. The PVA shunt was ligated and packing performed. However, the patient died at 14 days after the index surgery as a result of multi-organ failure. In the postoperative period, Patient 11 developed ascitis and endoscopy revealed grade III oesophageal varices (non-bleeding). In addition, portal vein thrombosis (PVT) that was well compensated by a large portal cavernoma was detected at 3 months after the index procedure. The patient underwent an embolization of the PVA at 4.5 months as a result of PHT. At 24 months after resection, the patient continues to progress and maintains normal liver function.

Figure 2.

Computed tomography (CT) images in Patient 9, who underwent left hepatectomy extended to segments I, V and VIII for hilar cholangiocarcinoma with arterioportal anastomosis between the hepatic artery and portal vein. (a) A CT angioscan at 5 days after portal vein arterialization (PVA) shows the patency of the surgical shunt between the hepatic artery and the portal vein. (b) At 5 months after PVA, the arteriovenous shunt is occluded by three concentric stents (white arrow) positioned in the hepatic artery because of recurrent episodes of variceal bleeding

Immediate PVA for multiple arterial aneurysms

Patient 12 had idiopathic symptomatic aneurysms (severe abdominal pain, fever, weight loss) of the coeliac trunk branches including the common hepatic artery (CHA). Preoperative imaging showed collateral pathways to the liver developed by way of the pancreaticoduodenal arcades and the gastroduodenal artery. The patient submitted to elective surgery in which the ligation of all aneurysms was planned. After ligation of the CHA, SA and left gastric artery, intraoperative Doppler US failed to show intrahepatic arterial flow. The surgical team administered local papaverine and waited an adequate length of time to rule out spasm of the collateral hilar vessels. However, when no intrahepatic arterial signals were detected, a PVA between the coeliac trunk and PV using a Gore-Tex® prosthetic interposition graft was performed (Fig. 3a–d). Shunt patency was demonstrated by routine daily Doppler US until post-PVA day 7. Doppler US on PoD 12 revealed a thrombosis of the PVA. However, good intrahepatic arterial signals through collaterals were obtained and hence no further intervention was performed. The patient's liver function stabilized and she was discharged from hospital on PoD 15. She continues to progress 1 year after the procedure.

Figure 3.

Multidetector computed tomography (MDCT) with arterial contrast in Patient 12. (a, b) Preoperative images show the common hepatic artery (thin white arrow) and coeliac trunk (thick white arrow) aneurysms. (c, d) Postoperative images with arterial contrast at 2 days after the ligation of aneurysms and common hepatic artery ligation with portal vein arterialization show that (c) the arteriovenous shunt between the coeliac trunk and the portal vein is thrombosed, but good collateral inflow is apparent, and (d) the collateral arterial supply to the liver arises from the gastroduodenal artery

Immediate PVA for HA injury during surgery or intraoperative detection of HAT/no intrahepatic flow on Doppler US

Portal vein arterialization was performed as an immediate salvage procedure for HA injury or HAT detected during surgery in three patients (Patients 13–15).

In Patient 13, a PVA was performed by creating a shunt between the colic artery and colic vein intraoperatively because no arterial flow in the remnant left liver was observed. On PoD 1, the patient demonstrated raised levels of transaminases (>2000 IU/l) and high arterial ammonia. In addition, some hypovascular areas of ischaemia were noted in the remnant liver on CT scan, with no intrahepatic arterial flow. The patient underwent an SA-to-PV shunt using an interposition cadaveric internal mammary artery (IMA) graft. The patient continues to do well at 5 years after the index surgery and demonstrates shunt patency and no signs of PHT.

Patient 15 underwent a pancreaticoduodenectomy with PV resection (as a result of tumour involvement) for a pancreatic adenocarcinoma. Intraoperatively, Doppler US revealed the absence of good intrahepatic arterial signals. An SA-to-PV shunt was created using a cadaveric iliac artery graft as a conduit. In the postoperative period, the patient developed ischaemic necrosis of the right liver, severe lactic acidosis and cardiac arrhythmias, and died on day 3 after resection as a result of multi-organ failure.

Delayed PVA for HAT after HPB surgery

Patient 16 had undergone pancreaticoduodenectomy and PV resection for a pancreatic adenocarcinoma. This patient developed HAT on PoD 2 and demonstrated transaminase levels of >5000 IU/ml. A PVA was performed by anastomosing the aorta to the IMV using an interposition Gore-Tex® graft. The patient progressed well in the immediate postoperative period, showing no signs of PHT and no thrombosis of the shunt. A ‘de principe’ embolization of the shunt was performed at 40 days after the PVA. The patient developed a biliary fistula, which was managed with stenting. The patient died at home, 2.5 months after the resection, of unknown causes.

Complications

There were five postoperative deaths among the patients in this series. Two patients died as a result of haemorrhagic shock. One patient died from liver ischaemia and one patient died from sepsis. The fifth patient died at home of unknown cause.

In the present series, seven patients (44%) had some form of PHT-related complication. Four patients developed significant ascites in the postoperative period and three had significant bleeding (either intra-abdominal or variceal). Two of these three patients submitted to re-exploration with the aim of controlling bleeding and one underwent successful radiological PVA shunt embolization. Two of these patients died as a result of haemorrhagic shock.

Early PVA shunt thrombosis was documented in four (25%) of the 16 patients. One patient from the LT group, who later required a retransplantation for recurrent cholangitis, and one patient from the HPB surgery group underwent re-PVA. The other two patients were not submitted to re-PVA because good collateral inflow had developed.

Therapeutic embolization or ligation of the arterioportal shunt was performed in four patients (25%), either as an emergency procedure in response to bleeding (n = 2) or electively (n = 2).

Two patients required retransplantation as a result of recurrent cholangitis.

Two patients developed infective complications following PVA, which included liver necrosis and cholangitis.

Discussion

In the present series of 16 patients submitted to PVA in a totally de-arterialized liver, in a single study centre, the recovery of intrahepatic arterial signals and PVA patency (or shunt thrombosis or embolization in some patients) were documented until the last follow-up using Doppler US and/or MDCT. After a median follow-up of 13 months, 10 patients (63%) remained alive with good liver function; one of these patients had undergone retransplantation for recurrent cholangitis during this period.

Human PVA in a de-arterialized liver was first reported in 1992 by Iseki et al., who performed PVA in a patient in whom HA ligation following arterial rupture and haemorrhage after a Whipple procedure was required.¹¹ Subsequently, the use of PVA has been reported in LT and in HPB surgery primarily for HAT. Incidences of early and late HAT after LT are estimated to be around 4.4% and 1.7%, respectively.^15,16 The natural history of early HAT is massive liver necrosis and/or bile duct necrosis, frequently followed by uncontrollable sepsis and, ultimately, death.¹⁵ Revascularization attempts are successful in only 50% of patients because of the absence of a suitable inflow vessel, and urgent re-LT, which may be considered the standard of care in such patients, is not always possible because of the paucity of donors. In late HAT, 55% of patients present with liver abscesses, 36% with biliary tree necrosis and others with biliary complications such as leak or fistula.¹⁶ In this scenario, even if re-LT is performed immediately, the success rate is 50%, and deaths occur primarily as a result of sepsis.^16,17 Waiting for a suitable donor also delays a re-LT. Portal vein arterialization has been used in the emergency setting to re-establish arterial inflow to the liver when thrombolysis by interventional radiology has failed and there is no other option for the reconstruction of the HA. Usually, it serves as a bridge to retransplantation and avoids the risk for massive hepatic necrosis subsequent to the complete interruption of arterial inflow. The patient can then be submitted to elective retransplantation, which has better outcomes than emergency re-LT. In five of the seven post-LT patients (71%) who underwent salvage PVA in the emergency setting, PVA proved to be either life- or graft-saving, either temporarily (as a bridge to retransplantation) (n = 1) or for a prolonged period (n = 4).

In HPB surgery, in addition to HAT, one of the key indications for PVA is the need for a salvage procedure in patients with HPB cancers who require HA ligation or resection in order to ensure curative surgery. In this context, the rationale for the procedure is to provide inflow to a de-arterialized liver and to restore biliary arterial flow through the arterioportal shunt in order to prevent the occurrence of ischaemia-related biliary complications.¹⁴ Of course, the potential risks and benefits must be balanced in such patients before any major or extended resection is undertaken with the aim of achieving cure. The option of preoperative selective embolization of the HA proper (distal to the origin of the gastroduodenal artery) has been described in such patients.¹⁸ This procedure is performed with the aim of facilitating the development of arterial inflow collaterals to the liver from the diaphragm, which will then compensate for the resected HA. However, this strategy can be applied only in those patients in whom it is possible to leave the diaphragmatic attachments of the liver untouched during the planned surgery (such as in a Whipple pancreaticoduodenectomy that requires HA resection).

Literature review

As part of the present study, a literature search of the PubMed database (1993–2012) using the key terms ‘de-arterialized liver/arterioportal shunt/portal vein arterialization’ and ‘liver transplantation/liver resection/pancreatic surgery/biliary surgery’ was performed. This exercise sought relevant studies on indications for and outcomes of PVA in LT and HPB surgery published in English over the last two decades. Subsequently, the references in the articles identified in the search were examined to identify any further series of patients submitted to PVA. The use of PVA in LT and HPB surgery was reported in 61 patients in 26 relevant studies (excluding the present series of 16 patients) between 1993 and mid-2012, each of which referred to one to six patients.^19–44 Studies that referred to those patients submitted to PVA and to arterial reconstruction, in whom physiological arterial inflow was thus maintained (25 patients in the LT setting and none in the HPB setting) were excluded.^{19–28,43–45} In these patients, PVA was used to optimize or augment portal inflow into the transplanted liver in patients with either pre-LT PVT^19–25 or post-LT PVT,^19,22,26 or in the settings of auxiliary LT,^22,27,28 paediatric LT,⁴⁵ and acute liver failure (Table 3).⁴⁶ Portal vein arterialization has also been described as an adjunct, in which HA reconstruction is indeed performed after major liver resection, but PVA is added to augment PV flow and to promote the regeneration of a small remnant liver.^47,48 The literature also includes a report of the use of PVA in patients with anatomic variations such as the absence of portal and mesenteric veins.⁴⁵ These cases were also excluded.

Table 3.

Use of portal vein arterialization (PVA) in portal vein thrombosis and auxiliary liver transplantation

Authors, year	Age, years	Liver transplantation		Portal vein arterialization
		Indication	Procedure	Indications	Timing	Type	Interposed vein or prosthetic graft
Erhard et al. (1995)19	29	NA	NA	Post-LT PVT	NA	Recipient aorta to graft PV (with calibration)	Yes
Erhard et al. (1995)19	47	NA	NA	Pre-LT PVT	During LT	Recipient aorta to graft PV (with calibration)	Yes
Aspinall et al. (1996)26	53	Hepatitis B cirrhosis	DDLT	Post-LT PVT	2 days after LT	Recipient aorta to graft PV	Yes
Neelamekam et al. (1997)20	55	Autoimmune chronic hepatitis	DDLT	Pre-LT PVT	During LT	Recipient HA to graft PV	Yes
Erhard et al. (1998)27	49	Acute liver failure	Auxiliary LT	–	During LT	NA	NA
Erhard et al. (1998)27	18	Acute liver failure	Auxiliary LT	–	During LT	Recipient iliac artery to graft PV	Yes
Erhard et al. (1998)27	25	Acute liver failure	Auxiliary LT	–	During LT	NA	NA
Erhard et al. (1998)27	20	Acute liver failure	Auxiliary LT	–	During LT	Recipient iliac artery to graft PV	Yes
Margarit et al. (2000)28	25	Acute liver failure	Auxiliary LT	–	During LT	Recipient iliac artery to graft PV	Yes
Stange et al. (2001)43 Settmacher et al. (2003)21	53	HCC/hepatitis C cirrhosis	DDLT	Pre LT PVT	During LT	Recipient HA to graft PV (with calibration)	No
Stange et al. (2001)43 Settmacher et al. (2003)21	35	Budd–Chiari syndrome	DDLT	Pre-LT PVT	During LT	Recipient HA to graft PV	No
Stange et al. (2001)43 Settmacher et al. (2003)21	55	Hepatitis B cirrhosis retransplant	DDLT	Pre LT PVT	During LT	Recipient aorta to graft PV (with calibration)	Yes
Charco et al. (2001)22	66	Hepatitis C cirrhosis	DDLT	Pre-LT PVT	Pre LT	Recipient HA to graft PV	No
Charco et al. (2001)22	12	Biliary atresia	DDLT	Post-LT PVT	3 days after LT	Recipient aorta to graft PV	Yes
Ott et al. (2003)23	35	Alcoholic cirrhosis	DDLT	Post-LT PVT requiring emergency re-LT	5 weeks post LT	Recipient aorta to graft PV	Yes (donor iliac artery)
Ott et al. (2003)23	57	Hepatitis B cirrhosis	DDLT	Post LT PVT requiring emergency re-LT	2 months after LT	Recipient aorta to graft PV	Yes (donor iliac artery)
Ott et al. (2003)23	54	Hepatitis B cirrhosis	DDLT	Pre-LT PVT	During LT	Recipient HA to PV	No
Ott et al. (2003)23	68	Hepatitis B cirrhosis	DDLT	Intraoperative detection of PVT	During LT	Recipient aorta to graft PV	Yes (donor iliac artery)
Nivatvongs et al. (2004)24	70	Hepatitis C cirrhosis	DDLT	Pre-LT PVT	During LT	Recipient HA to graft PV	No
Bonnet et al. (2010)25	47	Alcoholic cirrhosis	DDLT	Pre-LT PVT	During LT	Recipient SA to graft PV (with calibration)	No

Authors, year	Age, years	Postoperative course			Survival outcomes	Causes of death
		PHT and other complications	PVA thrombosis/clinical presentation	Embolization or ligature of the shunt
Erhard et al. (1995)19	29	Uneventful	No	No	Alive at 10 months	–
Erhard et al. (1995)19	47	PHT, acute renal failure	No	No	Alive at 12 months	–
Aspinall et al. (1996)26	53	Encephalopathy, septicaemia	No	No	Died at 2 months	Septic shock
Neelamekam et al. (1997)20	55	Ascitis, pseudoaneurysm of PV	No	No	NA, alive	–
Erhard et al. (1998)27	49	None	No	No	Died at 17 days	Septic shock
Erhard et al. (1998)27	18	None	No	No	Alive at 12 months	–
Erhard et al. (1998)27	25	None	No	No	Died at 3 months	CMV pneumonia
Erhard et al. (1998)27	20	None	No	No	Alive at 10 months (retransplanted)	–
Margarit et al. (2000)28	25	Renal failure	NA	No	Alive at 6 months	–
Stange et al. (2001)43 Settmacher et al. (2003)21	53	None	No	No	Alive at 36 months	–
Stange et al. (2001)43 Settmacher et al. (2003)21	35	Right heart failure	No	Elective coil embolization of HA, SA due to PHT (3 months)	Alive at 36 months	–
Stange et al. (2001)43 Settmacher et al. (2003)21	55	Biliary stricture	No	No	Alive at 30 months	–
Charco et al. (2001)22	66	Severe graft dysfunction needing retransplantation	No	Emergency closure by TAE due to PHT (14 months)	Alive at 24 months	–
Charco et al. (2001)22	12	Bile leak	NA	Multi-organ failure	Died at 4 months post re-Tx	Multi-organ failure
Ott et al. (2003)23	35	Laparotomy for bile leak, intra abdominal bleeding	Yes, and PVT	No	Died at 2 months	PVT and liver failure
Ott et al. (2003)23	57	Right heart failure, acute renal failure	No	No	Died at 11 months	HBV recurrence, liver fibrosis
Ott et al. (2003)23	54	–	NA	No	Alive at 36 months, (retransplant for chronic rejection)	–
Ott et al. (2003)23	68	Right heart failure, ascites, recurrent bleeding from persisting retroperitoneal collaterals	NA	No	Died at 19 days	Intra-abdominal bleeding
Nivatvongs et al. (2004)24	70	None	NA	No	Alive at 20 months (biliary stricture)
Bonnet et al. (2010)25	47	Diffuse aneurysmal dilatation of portal branches	No	No	Alive at 72 months

CMV, cytomegalovirus; DDLT, deceased donor liver transplant; GDA, gastroduodenal artery; HA, hepatic artery; HAT, hepatic artery thrombosis; HCC, hepatocellular carcinoma; LT, liver transplant; NA, not available; PHT, portal hypertension; PV, portal vein; PVT, portal vein thrombosis; SA, splenic artery; TAE, transarterial catheter embolization.

Finally, a total of seven patients (19%) submitted to salvage PVA in the LT setting (Table 4) and 29 (81%) patients submitted to PVA in the HPB setting (Table 5 ) were identified.

Table 4.

Systematic review of reports analysing the outcomes of portal vein arterialization (PVA) in seven patients submitted to liver transplantation

Authors, year	Age, years/sex	Liver transplantation		Portal vein arterialization
		Indication	Primary surgery	Indication for PVA and timing	Type	Interposed vein/prosthetic graft used
Cavallari et al. (2001)39	40/M	HBV and HCV cirrhosis	DDLT	HAT (7 days)	Recipient HA to graft PV	No
Shimizu et al. (2000)13	27/F	Biliary atresia (post-Kasai)	LDLT (right lobe)	HAT (during LT)	Arterioportal shunt in the mesenteric vascular (MV) branches	No
Maggi et al. (2010)40	52/M	Alcoholic cirrhosis with HCC	DDLT	HAT (10 days)	Recipient HA to PV	No
Housari et al. (2011)41	66/F	Acute liver failure	DDLT	Massive HA arteriosclerosis (during LT)	Recipient GDA to graft PV	No
Hayashi et al. (2012)42	1/M	Post-BMT GVHD	LDLT (reduced LLS)	HAT (10 days)	Arterioportal shunt in the MV branches	No
Hayashi et al. (2012)42	19/M	Biliary atresia post-Kasai	LDLT (left lobe)	HAT (4 days)	Arterioportal shunt in the MV branches	No
Hayashi et al. (2012)42	57/F	HCV cirrhosis	LDLT (right lobe)	HAT (9 days)	Arterioportal shunt in the MV branches	No

Authors, year	Age, years/sex	Postoperative course			Survival outcomes	Cause of death
		Significant complications	PVA thrombosis/manner of detection	Re-intervention
Cavallari et al. (2001)39	40/M	None	No	No	Died 3 months after re-LT as a result of ischaemic cholangitis	Multi-organ failure and pneumonia
Shimizu et al. (2000)13	27/F	None	Yes, 1.5 months (hepatopetal arterial collaterals)	No	Alive at 14 months	–
Maggi et al. (2010)40	52/M	None	No	Retransplanted	Alive at 16 months	–
Housari et al. (2011)41	66/F	Diffuse aneurysmal dilatation of portal branches, ischaemic cholangitis	No	Re-LT for ischaemic cholangitis	Alive at 9 months	–
Hayashi et al. (2012)42	1/M	Lung GVHD	No	No	Died 12 days after PVA	Lung GVHD with haematologic disorder
Hayashi et al. (2012)42	19/M	Peritonitis, severe acute cellular rejection	No	No	Died 43 days after PVA	Sepsis
Hayashi et al. (2012)42	57/F	Massive ascites, pleural effusion (3 months)	No	Surgical ligation of shunt for to PHT symptoms	Alive	–

BMT, bone marrow transplant; DDLT, deceased donor liver transplantation; F, female; GDA, gastroduodenal artery; GVHD, graft versus host disease; HA, hepatic artery; HAT, hepatic artery thrombosis; HBV, hepatitis B virus; HCC, hepatocellular carcinoma; HCV, hepatitis C virus; LT, liver transplant; LDLT, living donor liver transplant; LLS, left lateral segment; M, male; PHT, portal hypertension; PV, portal vein.

Table 5.

Systematic review of reports analysing the outcomes of hepatopancreatobiliary (HPB) surgery with portal vein arterialization (PVA) in 29 patients

Authors, year	Age, years/sex	HPB surgery		Portal vein arterializations
		Indication	Primary surgery	Indication	Timing	Type	Interposed vein/prosthetic graft
Ozeki et al. (1997)29	NA	NA	LR	For curative surgery	During LR	ICA to ICV	No
Ozeki et al. (1997)29	NA	NA	LR	Inadequate collateral formation after HA ligation	Post-LR	ICA to ICV	No
Ozeki et al. (1997)29	NA	NA	LR	For curative surgery	During LR	ICA to ICV	No
Iseki et al. (1998)30	64/M	Hilar CC	Extended left LR + PD with RHA excision/reconstruction	Post op HAT in reconstructed artery	1 day post LR	Mesenteric vascular branches (ileal)	No
Iseki et al. (1998)30	72/F	Hilar CC	Extended right LR	Postoperative ligation of CHA following HAP rupture (day 6) causing massive liver necrosis	7th day after major liver resection	First PVA – mesenteric vascular branches (ileocaecal)	No
Iseki et al. (1998)30	67/M	Intrahepatic CC	Extended left LR (stenosis of right and left HA post intra-arterial chemotherapy)	Stenosis of right PV, branches with massive liver necrosis	1 day post LR	Mesenteric vascular branches (ileocaecal)	No
Iseki et al. (1998)30	52/M	Pancreatic head cancer	PD, excision of CHA and HAP, PV resection/reconstruction	For curative surgery (pre-emptive shunt)	1 day before major resection	Mesenteric vascular branches (jejunal)	No
Iseki et al. (1998)30	68/M	Gallbladder cancer	PD, LR, excision of HAP, CHA	For curative surgery	During major resection	Mesenteric vascular branches (ileal)	No
Iseki et al. (1998)30	65/M	Hilar CC	PD, extended left LR, excision of anterior branch RHA	For curative surgery (pre-emptive shunt)	5 days before major resection	Mesenteric vascular branches (ileal)	No
Tanabe et al. (1999)31	53/M	IHC	Left extended LR	Post op HAT (pseudoaneurysm with HA stenosis) on POD 6	9 days post LR	Mesenteric vascular branches	No
Inoue et al. (2000)32	NA	Hilar CC	Left extended LR with HAP excision	Curative surgery	During LR	GDA to PV	No
Kondo et al. (2004)33 (n = 10)	56–81 (median 69)	Biliary cancer (6 bile duct and 4 gallbladder)	Major liver resection with en bloc HA resection	For curative surgery	During LR	GDA or CHA to PV	No
Teramoto et al. (2003)34	70/M	Lower CBD CC	PD	HA embolization (bleeding after PD)	1 month	Mesenteric vascular branches	No
Nakamura et al. (2008)35	60/M	Hilar liver metastases	LR	HA ligation	3 days	Mesenteric vascular branches	No
Young et al. (2008)36	54/M	Hilar CC	LR	Curative	During LR	GDA to PV	No
Young et al. (2008)36	51/F	Hilar CC	LR	Curative	During LR	RHA to PV	No
Chen et al. (2010)37 (n = 3)	50–54 (median 52)	Hilar CC	LR	Curative	During LR	HA to PV (with calibration)	No
Qiu et al. (2012)38	55/M	Hilar CC	LR	Curative	During LR	GDA to PV	No

Authors, year	Age, years/sex	Postoperative course			Survival outcomes	Causes of death
		PHT and other significant complications	PVA thrombosis/clinical presentation	Closure of the shunt
Ozeki et al. (1997)29	NA	None	Yes, at 43 days	No	NA/alive	–
Ozeki et al. (1997)29	NA	None	NA	No	In-hospital death	Pulmonary oedema
Ozeki et al. (1997)29	NA	None	No	No	NA/alive	–
Iseki et al. (1998)30	64/M	None	No	No	Died at 4 months	Recurrence
Iseki et al. (1998)30	72/F	None	Yes, day 2, requiring new PVA (SA to PV with interposition femoral vein graft)	No	In-hospital death at 8 days	Reperfusion injury leading to acute renal failure
Iseki et al. (1998)30	67/M	None	Yes, day 2	No	Died at 11 months	Recurrence
Iseki et al. (1998)30	52/M	Hyperbilirubinaemia/right liver abscess	No	No	Died at 6 months	Recurrence
Iseki et al. (1998)30	68/M	Hyperbilirubinaemia	No	Elective by TAE (11 months)	Alive at 60 months	–
Iseki et al. (1998)30	65/M	Hyperbilirubinaemia	No	Elective by TAE (8 months)	Alive at 30 months	Recurrence
Tanabe et al. (1999)31	53/M	None	Yes, 20 days	No	NA, alive	–
Inoue et al. (2000)32	NA	None	No	No	Alive at 1 month	–
Kondo et al. (2004)33 (n = 10)	56–81 (median 69)	Bile leak (n = 2) Liver abscess (n = 1)	Yes, n = 3	Elective shunt closure (n = 7) after documenting collaterals	Four died at 1, 11, 21, 23 months Six alive at a median of 10 months	Recurrence in 3 cases, unknown cause in 1.
Teramoto et al. (2003)34	70/M	Liver abscess	NA	No	Alive at 69 days	–
Nakamura et al. (2008)35	60/M	Variceal bleeding	No	Emergency closure for PHT	Died at 4 months	Haemorrhagic shock
Young et al. (2008)36	54/M	Hyperbilirubinaemia	No	No	Died at 23 months	Recurrence
Young et al. (2008)36	51/F	Bile leak, intra-abdominal bleed, PV pseudoaneurysm	No	Emergency closure for intra-abdominal bleed (12 days)	Alive at 6 months	–
Chen et al. (2010)37 (n = 3)	50–54 (median 52)	None	No	No	One patient died at 7 months	Liver abscess, pneumonia
Qiu et al. (2012)38	55/M	Hyperbilirubinaemia	No	No	Alive at 12 months	–

CC, cholangiocarcinoma; CBD, common bile duct; CHA, common hepatic artery; F, female; GDA, gastroduodenal artery; HA, hepatic artery; HAP, hepatic artery proper; HAT, hepatic artery thrombosis; ICA, ileocolic artery; ICV, ileocolic vein; IHC, intrahepatic cholangiocarcinoma; LR, liver resection; M, male; NA, not available; PD, pancreaticoduodenectomy; PHT, portal hypertension; PV, portal vein; RHA, right hepatic artery; SA, splenic artery; TAE, transarterial embolization.

All seven of the LT patients underwent emergency procedures for HAT or massive HA arteriosclerosis precluding arterial reconstruction detected during LT. Of the 29 patients submitted to resectional surgery for diseases of the liver, biliary tract or pancreas, 24 underwent immediate PVA for curative surgery which necessitated HA resection or ligation, or because of the non-visualization of a good intrahepatic arterial signal intraoperatively, and five patients underwent PVA for HAT or arterial ligation or rupture with bleeding after resection.

An arterioportal shunt was feasible in all attempts. In the transplant recipients, an arterioportal shunt was performed using the HA to provide inflow in two patients (29%), the mesenteric vessels in four patients (57%), and the gastroduodenal artery in one patient (14%). Among the 29 resected patients, the HA or gastroduodenal artery was used in 17 patients (59%) and the mesenteric arteries in 12 patients (41%).

The overall incidence of perioperative mortality was 14% (five of 36 patients). Two patients died after an emergency PVA for post-LT HAT. Three perioperative deaths occurred in the setting of HPB surgery, involving one patient who died when emergency PVA was performed for HA rupture and ligation, one who died after emergency PVA performed because no intrahepatic arterial flow was detected intraoperatively, and one patient who died following elective HA ligation and PVA for curative surgery. Death was related to PVA thrombosis and acute renal failure in one patient, to lung graft versus host disease (GVHD) and a haematological disorder in one patient, to sepsis and multi-organ failure in one patient, and to pulmonary oedema in one patient. The cause was unknown in the remaining patient.

Overall, 20 patients (56%) were reported to remain alive at the end of the respective study periods. Sixteen patients, including the five who died perioperatively, were deceased. Eight patients died late after hepatectomy as a result of tumour recurrence, one as a result of sepsis and multi-organ failure after re-LT, and one as a result of haemorrhagic shock secondary to severe PHT and variceal bleed late after resection. In one patient the cause of death was unknown.

Dealing with PHT and liver fibrosis

In the present series, complications related to PHT occurred in up to 44% of patients submitted to PVA. To prevent PHT and its related complications, some authors have suggested calibrating the arterial inflow.^25,37 Early experimental studies in dogs⁴⁹ and later clinical studies⁵⁰ demonstrated the benefits of pressure- and volume-controlled partial PVA on liver function and regeneration. Shunt calibration is thought to preserve adequate portal flow, yet to prevent PHT and hyperoxygenation of the liver. Chen et al.³⁷ reported the use of a silicon tube to restrict arterial flow to prevent PHT in four patients in whom PVA was performed after HA resection for hilar cholangiocarcinoma. No postoperative complications and no signs of PHT were observed in any patient during the 1-year follow-up period.³⁷ Another purported advantage of calibrated PVA is that it prevents thrombosis from developing at the site of anastomosis as a result of the difference in pressure between the artery and the PV (although this is uncommon). Embolization of the shunt once adequate arterial collaterals with hepatopetal flow have developed may also prevent PHT in the long term.⁵¹

Experimental animal studies and clinical data have implicated the prolonged ‘over-arterialization’ of portal blood flow in causing hyperbilirubinaemia, liver fibrosis and progressive dilatation of the intrahepatic portal branches, if the shunt does not close within a few weeks.^22,23,52 Animal experiment results demonstrated the occurrence of structural changes in the liver parenchyma and vessel tissue, such as necrotizing vasculitis, intimal fibrosis of the PV and periportal fibrosis.⁵² Flow- and pressure-adapted PVA has been shown in animal models to reduce these adverse effects and to improve early graft function. These effects were not significant when only the portal blood flow was reduced.^49,50 Thus, arterial calibration of the shunt or the use of smaller vessels may be assumed to help by reducing portal pressure, while allowing a satisfactory hepatic arterial inflow.

A practical approach to PVA

The potential problems of PHT and possible fibrosis after PVA raise issues in relation to the calibration of shunts to regulate the amount of inflow, the choice of the site (inflow arterial vessel) at which the PVA should ideally be performed, and the possible need for the prophylactic closure of shunts after a certain period of time.

In the present study, prophylactic shunt calibration was not used in any patient. Instead, as the study group's concomitant experience with caval inflow to the graft in transplantation indicates, good results were achieved by the prophylactic eradication of varices by pre-transplant sclerotherapy and band ligation.⁵³ In the post-PVA period, a strict surveillance protocol using upper GI endoscopy was followed and patients with varices were managed by prophylactic endoscopic band ligation.

Logically, all patients in whom PVA is performed should undergo a preventive occlusion of the shunt in order to avoid PHT-induced GI bleeding once collateral arterial pathways to the liver have developed. In the current study, therapeutic shunt embolization was performed in patients with signs of severe PHT using interventional radiology (Fig. 3). In patients in whom this was not possible, a non-absorbable ligature was placed surgically around the arterial side to calibrate but not fully ligate the arterioportal shunt.

In order to offset the potentially harmful consequences of PVA, some technical modifications to these shunts are proposed.

1. It is preferable to use medium-sized arterial inflow vessels to ensure good liver oxygenation in the first instance, to prevent over-arterialization and to provide good short- and medium-term patency.

2. If possible, choose an end vessel for arterial inflow so that using this vessel for PVA will in no way compromise the arterial supply of surrounding viscera. In the event that the shunt must be embolized in the future, this will ensure that the blood supply to the surrounding viscera is not compromised.

3. The choice of abdominal incision and the choice of the site of the arterioportal shunt are also dictated to some extent by the context in which PVA is to be performed (LT or HPB surgery, emergency or elective). In LT recipients, particularly with late HAT, a midline incision may be preferred to avoid abdominal adhesions, and a PVA between the iliac artery or its branches and the mesenteric vein or its tributaries with or without the use of a jump graft may be created. The main goal of PVA in this context is to serve as a bridge to re-LT and thus the hilum can be left untouched. Further, dissection of the graft hilar structures is difficult and sometimes impossible, and may even prove dangerous in patients who have undergone previous surgery or have extensive variceal collaterals often associated with HAT or PVT. Ease of access for the possible future embolization of the shunt is also a consideration.

In the setting of liver resection, the main goal of PVA is to restore the biliary arterial supply in the remnant liver. The policy of the present group is to perform, if possible, an anastomosis between the HA and PV. When the HA is thrombosed, or the HA stump is too small or when the stump lies deep in the hilum, PVA can be performed using the SA or mesenteric arterial branches as the arterial inflow vessel.

There is no published literature or experimental data to demonstrate the time interval required for irreversible biliary ischaemia to occur after HA interruption. However, the consequences of HAT in a totally de-arterialized liver are much more severe as there are no collaterals with which to salvage the bile ducts. As Mays and Wheeler⁵⁴ have demonstrated, selective arteriography shows retrohepatic arterial flow as early as 10 h after the interruption of hepatic arteries. Therefore, if high-quality MDCT does not show good collaterals with hepatic inflow, PVA should be undertaken as early as possible in order to avoid irreversible biliary ischaemia. The present group does not consider PVA in patients with late HAT in whom biliary ischaemia is already evident. Instead, these patients are considered to be candidates for re-LT once concurrent sepsis (which is inevitable in these cases) is controlled.

Conclusions

For now, PVA should continue to be considered as a salvage technique to restore arterial inflow to a totally de-arterialized liver when no other form of arterial reconstruction is possible. The procedure prevents the occurrence of hepatic necrosis, which is inevitable following complete arterial interruption, and in some instances, such as in patients with HAT after LT, acts as a bridge to retransplantation, which can then be performed electively, with better results. In locally advanced malignancies of the liver, biliary tract and pancreas, PVA may help to increase the possibility of a curative (R0) resection in patients who are otherwise deemed inoperable. Although these ‘extreme surgeries’, like ex situ, ex vivo resections, carry a higher risk for perioperative mortality, they may be justified in young patients with advanced malignancies who otherwise will have very grim prognoses. Similarly, PVA may also represent the last option in emergency situations such as in intraoperative injury to the HA, post-resection HAT or arterial rupture, when no other form of arterial reconstruction is feasible.

Strict surveillance and management of PHT (and its complications), and the occasional occlusion of the arterioportal shunt are vital after PVA to prevent or manage life-threatening bleeding. Indeed, these factors are key to reducing perioperative or delayed mortality. Early thrombosis of the PVA may lead to fatal liver ischaemia, whereas a late occlusion is often well tolerated because of the prior development of hepatopetal arterial collaterals.

Despite its applicability, feasibility, theoretical appeal and acceptable outcomes, many unanswered questions discourage the liberal use of salvage PVA. Portal vein arterialization remains an infrequently used surgical technique, and larger series with longer follow-up, as well as experimental models on liver regeneration after PVA, are required to provide greater insight into the outcomes of this technique.

Conflicts of interest

None declared.