Portal Venous Interventions: How to Recognize, Avoid, or Get Out of Trouble in Transjugular Intrahepatic Portosystemic Shunt (TIPS), Balloon Occlusion Sclerosis (ie, BRTO), and Portal Vein Embolization (PVE)

Imaging-guided interventions modulating portal venous flow: evidence and controversies

Portal hypertension is defined by an increase in the portosystemic venous gradient. In most cases, increased resistance to portal blood flow is the initial cause of elevated portal pressure. More than 90% of cases of portal hypertension are estimated to be due to advanced chronic liver disease or cirrhosis. Transjugular intrahepatic portosystemic shunts, a non-pharmacological treatment for portal hypertension, involve the placement of a stent between the portal vein and the hepatic vein or inferior vena cava which helps bypass hepatic resistance. Portal hypertension may also be a result of extrahepatic portal vein thrombosis or compression. In these cases, percutaneous portal vein recanalisation restores portal trunk patency, thus preventing portal hypertension-related complications. Any portal blood flow impairment leads to progressive parenchymal atrophy and triggers hepatic regeneration in preserved areas. This provides the rationale for using portal vein embolisation to modulate hepatic volume in preparation for extended hepatic resection. The aim of this paper is to provide a comprehensive evidence-based review of the rationale for, and outcomes associated with, the main imaging-guided interventions targeting the portal vein, as well as to discuss the main controversies around such approaches.

Relevance of Spontaneous Portosystemic Shunts Detected with CT in Patients with Cirrhosis

Background Cirrhosis leads to portal hypertension and to the consequent formation of spontaneous portosystemic shunts (SPSSs), leading to complications related to the diversion of portal blood into the systemic circulation, which is called portosystemic shunt syndrome. Purpose To investigate the characteristics of patients with cirrhosis and an SPSS and secondarily to assess the prognostic impact of SPSSs on portal hypertension-related complications and transplant-free survival. Materials and Methods A retrospective database review of patients with cirrhosis (observed from March 2015 to July 2019) was performed to identify patients with CT imaging and outcomes data. For each patient, clinical and biochemical data were collected, and the presence, types, and sizes of SPSSs were investigated with CT. Patients were followed for a mean of 27.5 months ± 22.8. Multivariable logistic analysis was used to identify the clinical characteristics associated with the presence of SPSSs (any size) and presence of SPSSs 1 cm or larger. Competitive risk analysis (Fine and Gray model) was used to identify the association between SPSSs and complications and mortality. Results Two hundred twenty-two patients with cirrhosis (157 male, 65 female; mean age, 62 years ± 12 [standard deviation]) were evaluated. An SPSS was found in 141 of 222 patients (63.5%), and 40 of 222 (18%) had a shunt diameter of at least 1 cm. At presentation, variables independently associated with the presence of SPSSs (any size) were portal vein thrombosis (odds ratio, 5.5; P = .008) and Child-Pugh class C (odds ratio, 3.0; P = .03). Previous hepatic encephalopathy (odds ratio, 4.4; P = .001) and portal vein thrombosis (odds ratio, 5.3; P = .001) were the only variables associated with SPSSs larger than 1 cm. Patients with SPSSs of any size had higher mortality (subdistribution hazard ratio, 1.9; P < .001) and higher frequency of hepatic encephalopathy (subdistribution hazard ratio, 2.3; P = .023), gastrointestinal bleeding (subdistribution hazard ratio, 2.9; P = .039), and portal vein thrombosis (subdistribution hazard ratio, 7.6; P = .005). Conclusion The presence of spontaneous portosystemic shunts on CT images in patients with cirrhosis was associated with higher mortality and complications, including portal vein thrombosis, hepatic encephalopathy, and gastrointestinal bleeding. © RSNA, 2021 See also the editorial by Reeder in this issue.

Balloon-occluded Retrograde Transvenous Obliteration Versus Transjugular Intrahepatic Portosystemic Shunt for Gastric Varices: A Meta-Analysis

INTRODUCTION

Balloon-occluded retrograde transvenous obliteration (BRTO) and transjugular intrahepatic portosystemic shunt (TIPS) are well-validated techniques in the management of portal hypertensive gastric variceal bleeding when medical management alone is not sufficient. However, despite their effectiveness, the adverse effects from both procedures make each technique more suitable to different cohorts of patient's depending on presence or lack of certain comorbidities. This study aims to compare clinical outcomes of patients who have undergone both procedures for portal hypertensive gastric variceal bleeding.

MATERIALS AND METHODS

We conducted a search of electronic databases from their establishment to April 2019. The goal was to compare the efficacy of BRTO and TIPS in preventing variceal rebleeding and the risk of adverse events such as ascites and hepatic encephalopathy. Predictors of overall survival and rebleeding were also analyzed. Meta-analysis was performed with STATA 15.1.

RESULTS

Five randomized controlled trials and retrospective cohort studies were included in our meta-analysis. The number of patients who underwent BRTO and TIPS were 308 and 127, respectively. BRTO and TIPS have similar technical success rates (91.4% vs. 89.7%, P=0.995) and immediate bleeding control rates (97.7% vs. 95.9%, P=0.836). However, compared with TIPS, BRTO has lower likelihood of future cumulative rebleeding (10.6% vs. 18.7%, P=0.027) and hepatic encephalopathy (0.00% vs. 23.1%, P<0.001) but is more likely to aggravate ascites (22.4% vs. 4.3%, P=0.009). Serum albumin level and presence of hepatocellular carcinoma are both independent predictors of increased likelihood of rebleeding and overall survival (P<0.001).

CONCLUSIONS

Both BRTO and TIPS are safe and effective interventions in the management algorithm of portal hypertensive gastric variceal bleeding. Although BRTO may be more effective at the prevention of future variceal rebleeding, the choice of BRTO versus TIPS should be tailored according to patient's comorbidities.

Balloon-Assisted Percutaneous Transhepatic Antegrade Embolization with 2-Octyl Cyanoacrylate for the Treatment of Isolated Gastric Varices with Large Gastrorenal Shunts

Aims

To evaluate the safety and effectiveness of percutaneous transhepatic antegrade embolization (PTAE) with 2-octyl cyanoacrylate assisted with balloon occlusion of the left renal vein or gastrorenal shunts (GRSs) for the treatment of isolated gastric varices (IGVs) with large GRSs.

Methods

Thirty patients with IGVs associated with large GRSs who had underwent PTAE assisted with a balloon to block the opening of the GRS in the left renal vein were retrospectively evaluated and followed up. Clinical and laboratory data were collected to evaluate the technical success of the procedure, complications, changes in the liver function using Child-Pugh scores, worsening of the esophageal varices, the rebleeding rate, and survival. Laboratory data obtained before and after PTAE were compared (paired-sample t-test).

Results

PTAE was technically successful in all 30 patients. No serious complications were observed except for one nonsymptomatic pulmonary embolism. During a mean follow-up of 30 months, rebleeding was observed in 4/30 (13.3%) patients, worsening of esophageal varices was observed in 4/30 (13.3%) patients, and newly developed or aggravated ascites were observed on CT in 3/30 (10%) patients. Significant improvement was observed in Child-Pugh scores (p=0.009) and the international normalized ratio (INR) (p=0.004) at 3 months after PTAE. The cumulative survival rates at 1, 2, 3, and 5 years were 96.3%, 96.3%, 79.9%, and 79.9%, respectively.

Conclusion

Balloon-assisted PTAE with 2-octyl cyanoacrylate is technically feasible, safe, and effective for the treatment of IGV associated with a large GRS.