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ECR 2019 / C-2984
Imaging Findings, Diagnostic and Treatment Options of Post-transplant Non-occlusive Hepatic Artery Hypoperfusion (Splenic Steal) Syndrome
Congress: ECR 2019
Poster No.: C-2984
Type: Educational Exhibit
Keywords: Transplantation, Ischaemia / Infarction, Haemodynamics / Flow dynamics, Embolisation, Contrast agent-intravenous, Arterial access, Ultrasound-Colour Doppler, Percutaneous, Catheter arteriography, Spleen, Liver, Interventional vascular
Authors: D. Vas, Á. García-Criado, F. M. Gómez, M. Barrufet, M. Burrel; Barcelona/ES
DOI:10.26044/ecr2019/C-2984

Findings and procedure details

 

Postoperative Doppler-US

 

•    After LT a routine Doppler-ultrasound (US) should be performed in the following 24-48 h in order to:

– confirm vascular permeability (HA, PV, hepatic veins, IVC)

– detect flow in the common hepatic artery and main intrahepatic branches

– determine waveform and Resistive Index (RI) (peak systolic velocity– end-     diastolic velocity/peak systolic velocity)

– measure portal flow

– rule out other complications

 

•   During the first post-transplantation days elevated RI (>0,80) is relatively common without any pathologic relevance.  Doppler US follow-up should be performed daily in cases of RI=1 or systolic peaks, until waveform normalization (see diagnostic algorithm Fig. 1Fig. 2Fig. 3 Fig. 4

 

Arteriographic diagnostic criteria 

 

– augmented splenic artery diameter ( > 4 mm or 150% of HA calibre)

– late or lack of filling of the intrahepatic branches of the HA

– early filling of the splenic artery (or GDA) with delayed HA filling

– contrast enhancement of PV and HA at the same time

Fig. 5

 

• Although these radiologic findings in the adequate clinical context are highly suspicious of SSS, the diagnostic confirmation is established posteriorly, after normalization of angiogram and enzyme levels

 

• Asymptomatic LT patients may present non-specific US changes, and arteriography may reveal other arterial pathology (e.g. SA aneurysm)

 

Potential pre-transplant risk factors:

 

• Previous studies describe splenomegaly (SM) (>829 mL) with hypersplenism and increased splenic/hepatic volume ratio or >6 mm difference between splenic and hepatic artery diameters as potential predictors of future non-occlusive hepatic artery hypoperfusion.

 

• Although these changes are common in patients with portal hypertension, only few of them develop steal syndromes: further studies are required to determine significance

 

 Treatment

 

 

Splenic vascular anatomy with rich collaterals permits the exclusion of the SA proximally from the celiac axis and decrease the preferential flow to the SA.

 

  1. Intraoperative prophylactic splenic artery banding or ligation is described in “risk-patients” but no clear recommendations are established due to uncertain predictive factors
  2. If available, transcatheter splenic artery embolization (SAE) is the preferred treatment. (Minimally invasive intervention and  in the same setting offers diagnostic information and therapeutic option) Fig. 6 Fig. 7 Fig. 8 Fig. 9
  3. Particulate embolization by reducing splenic volume requires weeks or months to influence arterial flow
  4. Confirmed splenic steal syndrome can be treated surgically with ligation or banding of the splenic artery if endovascular treatment is not possible. Splenectomy is only recommended if concomitant pathology is present (e.g. aneurysm)
  5. GDA-steal is less frequent and can occur with or without SMA ostial stenosis. In case of stenosis, SMA stenting and GDA embolization is preferred.
  6. Other prophylactic surgical technique is the anastomosis of the donor HA directly with the recipient’s aorta or with interposition of an iliac artery graft excluding the CT.

 

 

Technique

 

• Proximal splenic artery embolization is the preferred treatment of splenic steal syndrome. In order to minimize post embolization complication rate, embolic agent should be deployed proximally but distal to the origin of the pancreatic branches, independently of the embolic agent.

 

• Thus splenic parenchyma is irrigated through short gastric collaterals. Much higher complication rate was observed in distal embolization due to collateral occlusion. Infarct, abscess, multiple organ failure can lead to severe morbidity or mortality.

 

• Successful embolization can be obtained either by coils or Amplatzer vascular plug (AVP).

 

Embolic agent

Occlusion time

Material required

Precise deployment

Vessel calibre

Radiation during procedure

Delivery system

Coil

+++

Multiple

-

Small

+++

microcatheter

AVP

++

Single device

+

Median and large

+/++

guiding catheter

 

In our experience:

 

• Due to patient characteristics (previous portal hypertension with large splenomegaly and SA), AVP should be considered as the first-choice for the endovascular treatment. Only if SA catheterization is impossible with the 5F guiding catheter (due to vessel tortuosity etc. ) start with coil embolization. Additional coils may be necessary to complete vessel occlusion.

 

• AVP size should be overestimated at least 50% according to vessel diameter

 

• If the control angiogram shows significantly increased HA flow, achieve complete occlusion of the SA is not necessary

 

 

Complications

 

Advances in interventional radiology has led to a decrease of complication rate and transcatheter embolization is considered a safe and effective treatment. 

 

• Vascular access

 - Haemorrhage/hematoma

 - Pseudoaneurysm

 - Iliac artery/CT dissection

 

• Embolization

 - Splenic infarction

 - Abscess

 - Paralytic ileus

 - Pancreatitis

 

 

Controversies

 

Controversial issues on non-occlusive hepatic artery hypoperfusion syndrome are highlighting the need for further studies 

 

  • Not well understood, probably multifactorial pathomechanism
  • No established, widely accepted diagnostic criteria
  • Patients with characteristic radiologic findings may be asymptomatic
  • Uncertain pre-transplant risk factors
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