Date

9-2014

Document Type

Thesis

Degree Name

M.P.H.

Department

Dept. of Public Health and Preventive Medicine

Institution

Oregon Health & Science University

Abstract

Introduction

: Hepatic encephalopathy (HE) is a frequent consequence of transjugular intrahepatic portosystemic shunt (TIPS) placement and a major cause of morbidity, mortality and healthcare utilization in cirrhotic patients. The prevention of post-TIPS HE is mainly achieved by a careful selection of patients before the procedure. A relationship between the occurrence of HE and a low post-TIPS hepatic venous pressure gradient (HVPG) has been shown, suggesting that a large diversion of the blood from the liver poses as a risk factor for this complication. However, no studies have investigated the association between degree of HVPG reduction and development of post-TIPS HE. This study proposes to address a void for predicting post-TIPS HE. We hypothesize that there exists a relative magnitude in the reduction of HVPG after TIPS placement in cirrhotic patients with complications of portal hypertension that is associated with increased risk of post-TIPS HE. The aim of the present study is to determine (1) the prevalence of post-TIPS HE among patients who have undergone TIPS procedure at Oregon Health & Science University (OHSU) from 2002-2012, (2) the degree of HPVG reduction post-TIPS that is associated with an increased risk of HE, and (3) other factors associated with post-TIPS HE.

Methods

: This is a retrospective cohort study, and data are obtained through chart reviews of the electronic medical record, EPIC. Subjects are drawn from a group of cirrhotic patients who underwent TIPS procedure at OHSU as documented by Department of Interventional Radiology between June 2003 and October 2012. The outcome of interest is the frequency of clinically evident HE within 30 days after TIPS placement. Demographic, clinical, biochemical and hepatic hemodynamic characteristics of all subjects were analyzed. The effect measure for degree of HVPG reduction on post-TIPS HE was calculated using multivariable logistic regression analysis, adjusting for potential confounding variables and effect modifiers. Critical threshold for the percent reduction of HVPG was determined by generating ROC curve with the largest AUC and goodness-of-fit test.

Results:

The prevalence of post-TIPS HE was 31% in the study population. Percentage of HVPG reduction adjusted for age, sex, indication, etiology of liver disease, history of pre-TIPS HE, pre-TIPS serum albumin and MELD score was found to be a significant predictor for development of post-TIPS HE (p = 0.01) in multivariate analysis. Other independent predictors of post-TIPS HE include sex, history of pre-TIPS HE, serum albumin and INR. The OR for development of post-TIPS HE was 6.58 when HVPG was decreased by at least 50% (p < 0.01, 95% CI: 1.63 - 26.6). The ROC curve generated to predict the percent of reduction in HVPG leading to HE demonstrated an AUC of 0.77. The absolute value of the post-TIPS HVPG was not found to be a significant predictor of post-TIPS HE in the multivariate analysis. Subjects who underwent TIPS for the indications of recurrent variceal bleed and refractory ascites were found to demonstrate significant differences in their MELD (12.7 vs. 14.1; p = 0.03) and Child-Pugh (7.78 vs. 9.05; p < 0.01) scores, creatinine (0.83 vs. 1.51; p < 0.01) and bilirubin (2.06 vs. 1.39; p < 0.01).

Conclusions:

The percent of reduction in HVPG is a significant predictor for development of post-TIPS HE and a superior predictor compared to post-TIPS HVPG. Specifically, we noted that at least 50% reduction in HVPG identifies patients at highest risk for post-TIPS HE. Our results agree with prior studies and identified additional variables that demonstrated a significant association for development of post-TIPS HE in multivariate analysis, including lowered albumin and history of pre-TIPS HE. Our findings suggest that cirrhotic patients who have >50% reduction in HVPG post-TIPS should be monitored closely for post-TIPS HE and may benefit from medication prophylaxis for development of HE.

Identifier

doi:10.6083/M4NK3CR4

School

School of Medicine

Available for download on Saturday, September 16, 2017

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