Effect of Breath Holding on Spleen Volume Measured by Magnetic Resonance Imaging

Objective

Ultrasonographic studies have demonstrated transient reduction in spleen volume in relation to apnea diving. We measured spleen volume under various respiratory conditions by MR imaging to accurately determine the influence of ordinary breath holding on spleen volumetry.

Materials and Methods

Twelve healthy adult volunteers were examined. Contiguous MR images of the spleen were acquired during free breathing and during respiratory manipulations, including breath holding at the end of normal expiration, breath holding at deep inspiration, and the valsalva maneuver, and spleen volume was measured from each image set based on the sum-of-areas method. Acquisition during free breathing was performed with respiratory triggering. The duration of each respiratory manipulation was 30 s, and five sets of MR images were acquired serially during each manipulation.

Results

Baseline spleen volume before respiratory manipulation was 173.0 ± 79.7 mL, and the coefficient of variance for two baseline measures was 1.4% ± 1.6%, suggesting excellent repeatability. Spleen volume decreased significantly just after the commencement of respiratory manipulation, remained constant during the manipulation, and returned to the control value 2 min after the cessation of the manipulation, irrespective of manipulation type. The percentages of volume reduction were 10.2% ± 2.9%, 10.2% ± 3.5%, and 13.3% ± 5.7% during expiration breath holding, deep-inspiration breath holding, and the valsalva maneuver, respectively, and these values did not differ significantly.

Conclusions

Spleen volume is reduced during short breath-hold apnea in healthy adults. Physiological responses of the spleen to respiratory manipulations should be considered in the measurement and interpretation of spleen volume.

Natural history of cirrhosis

Significant strides have been made in the last few years in advancing our knowledge of the natural history of cirrhosis. These include (1) a better understanding of prognosis in compensated and decompensated cirrhosis, (2) improved estimates of the natural course of variceal bleeding in patients receiving standard of care therapy, (3) recognition of renal failure and infection as important determinants of mortality in the clinic course, (4) realization of the importance of hepatic venous pressure gradient as a marker of prognosis, progression, and treatment response, and (5) evolution of noninvasive studies of liver stiffness as potential predictors of decompensation. Further studies identifying cirrhotics at highest risk of transitioning from a compensated state to a decompensated state will be important in order to alter the natural history of cirrhosis.

Natural history of cirrhosis

Significant strides have been made in the last few years in advancing our knowledge of the natural history of cirrhosis. These include (1) a better understanding of prognosis in compensated and decompensated cirrhosis, (2) improved estimates of the natural course of variceal bleeding in patients receiving standard of care therapy, (3) recognition of renal failure and infection as important determinants of mortality in the clinic course, (4) realization of the importance of hepatic venous pressure gradient as a marker of prognosis, progression, and treatment response, and (5) evolution of noninvasive studies of liver stiffness as potential predictors of decompensation. Further studies identifying cirrhotics at highest risk of transitioning from a compensated state to a decompensated state will be important in order to alter the natural history of cirrhosis.

Hepatocellular carcinoma in patients with chronic hepatitis C virus infection in the Asia-Pacific region

Hepatocellular carcinoma (HCC) is the third-leading cause of cancer-related mortality worldwide. Although hepatitis B still remains the most common risk factor worldwide, chronic hepatitis C virus (HCV) infection is the driving force for the increased incidence of HCC especially in Western countries and Japan. In hepatitis B virus (HBV)-endemic areas, after successful vaccination programs against HBV, chronic HCV infection is now emerging as an important cause of chronic liver diseases. Unlike patients with chronic hepatitis B, those with chronic hepatitis C (CHC) develop HCC in the presence of established cirrhosis in most cases. However, a significant minority of CHC develops HCC in the absence of cirrhosis. Although HCV is a RNA virus with little potential for integrating its genetic material into host genome, various HCV proteins, including core, envelope, and nonstructural proteins, have oncogenic properties by inducing oxidative stress, disturbing cellular regulatory pathways associated with proliferation and apoptosis, and suppressing host immune responses. Overall, a combination of virus-specific, host genetic, environmental, and immune-related factors are likely to determine progression to HCC. Strategies aimed at eliminating the virus may provide opportunities for effective prevention of the development of HCC. Pegylated interferon plus ribavirin therapy appears to be effective at reducing the risk of HCC in patients who achieve sustained virologic responses. In summary, with the emerging importance of CHC, mechanisms of HCV-associated hepatocellular carcinogenesis should be clarified to provide insight into advanced therapeutic and preventive approaches, which eventually decrease the incidence and mortality of HCC.

Ultrasonic characterization of the nonlinear properties of canine livers by measuring shear wave speed and axial strain with increasing portal venous pressure

Elevated hepatic venous pressure is the primary source of complications in advancing liver disease. Ultrasound imaging is ideal for potential noninvasive hepatic pressure measurements as it is widely used for liver imaging. Specifically, ultrasound based stiffness measures may be useful for clinically monitoring pressure, but the mechanism by which liver stiffness increases with hepatic pressure has not been well characterized. This study is designed to elucidate the nonlinear properties of the liver during pressurization by measuring both hepatic shear wave speed (SWS) and strain with increasing pressure. Tissue deformation during hepatic pressurization was tracked in 8 canine livers using successively acquired 3-D B-mode volumes and compared with concurrently measured SWS. When portal venous pressure was increased from clinically normal (0-5mmHg) to pressures representing highly diseased states at 20mmHg, the liver was observed to expand with axial strain measures up to 10%. At the same time, SWS estimates were observed to increase from 1.5-2m/s at 0-5mmHg (baseline) to 3.25-3.5m/s at 20mmHg.

Clinical application of liver stiffness measurement using transient elastography in chronic liver disease from longitudinal perspectives

Accurate determination of the presence and degree of fibrosis in liver is of great importance, because the prognosis and management strategies for chronic liver disease depend mainly on these factors. To date, liver biopsy (LB) remains the "gold standard" for assessing the severity of liver fibrosis; however, LB is often limited by its invasiveness, sampling error, and intra/inter-observer variability in histological interpretation. Furthermore, repeated LB examinations within a short time interval are indeed ineligible in a real clinical practice. Thus, due to the pressing need for non-invasive surrogates for liver fibrosis, transient elastography (TE), as a novel ultrasound based technology, has allowed a noninvasive measurement of liver stiffness and has gained in popularity over recent years. In the past few years, additional roles for transient TE beyond the initial purpose of a non-invasive surrogate for LB have included the prediction of the most two critical consequences of fibrosis progression: the development of portal hypertension-related complications and hepatocellular carcinoma. This indicates that the role of transient TE is not merely limited to reducing the need for LB, but transient TE can enable the establishment of tailored management strategies by providing more detailed prognostic information. In particular, under the concept in which the clinical course of liver fibrosis is dynamic and bidirectional, especially when appropriate intervention is commenced, transient TE can be used to track the dynamic changes in fibrotic burden during antiviral or antifibrotic treatment. This review discussed extended applications of transient TE in prediction of the development of real clinical endpoints from a longitudinal perspective.

Effect of meal ingestion on liver stiffness in patients with cirrhosis and portal hypertension

BACKGROUND AND AIMS

Liver stiffness is increasingly used in the non-invasive evaluation of chronic liver diseases. Liver stiffness correlates with hepatic venous pressure gradient (HVPG) in patients with cirrhosis and holds prognostic value in this population. Hence, accuracy in its measurement is needed. Several factors independent of fibrosis influence liver stiffness, but there is insufficient information on whether meal ingestion modifies liver stiffness in cirrhosis. We investigated the changes in liver stiffness occurring after the ingestion of a liquid standard test meal in this population.

METHODS

In 19 patients with cirrhosis and esophageal varices (9 alcoholic, 9 HCV-related, 1 NASH; Child score 6.9±1.8), liver stiffness (transient elastography), portal blood flow (PBF) and hepatic artery blood flow (HABF) (Doppler-Ultrasound) were measured before and 30 minutes after receiving a standard mixed liquid meal. In 10 the HVPG changes were also measured.

RESULTS

Post-prandial hyperemia was accompanied by a marked increase in liver stiffness (+27±33%; p<0.0001). Changes in liver stiffness did not correlate with PBF changes, but directly correlated with HABF changes (r = 0.658; p = 0.002). After the meal, those patients showing a decrease in HABF (n = 13) had a less marked increase of liver stiffness as compared to patients in whom HABF increased (n = 6; +12±21% vs. +62±29%,p<0.0001). As expected, post-prandial hyperemia was associated with an increase in HVPG (n = 10; +26±13%, p = 0.003), but changes in liver stiffness did not correlate with HVPG changes.

CONCLUSIONS

Liver stiffness increases markedly after a liquid test meal in patients with cirrhosis, suggesting that its measurement should be performed in standardized fasting conditions. The hepatic artery buffer response appears an important factor modulating postprandial changes of liver stiffness. The post-prandial increase in HVPG cannot be predicted by changes in liver stiffness.

Determination of reliability criteria for liver stiffness evaluation by transient elastography

Liver stiffness evaluation (LSE) is usually considered as reliable when it fulfills all the following criteria: ≥10 valid measurements, ≥60% success rate, and interquartile range / median ratio (IQR/M) ≤0.30. However, such reliable LSE have never been shown to be more accurate than unreliable LSE. Thus, we aimed to evaluate the relevance of the usual definition for LSE reliability, and to improve reliability by using diagnostic accuracy as a primary outcome in a large population. 1,165 patients with chronic liver disease from 19 French centers were included. All patients had liver biopsy and LSE. 75.7% of LSE were reliable according to the usual definition. However, these reliable LSE were not significantly more accurate than unreliable LSE with, respectively: 85.8% versus 81.5% well-classified patients for the diagnosis of cirrhosis (P = 0.082). In multivariate analyses with different diagnostic targets, LSE median and IQR/M were independent predictors of fibrosis staging, with no significant influence of ≥10 valid measurements or LSE success rate. These two reliability criteria determined three LSE groups: "very reliable" (IQR/M ≤0.10), "reliable" (0.10< IQR/M ≤0.30, or IQR/M >0.30 with LSE median <7.1 kPa), and "poorly reliable" (IQR/M >0.30 with LSE median ≥7.1 kPa). The rates of well-classified patients for the diagnosis of cirrhosis were, respectively: 90.4%, 85.8%, and 69.5% (P < 10(-3) ). According to these new reliability criteria, 9.1% of LSE were poorly reliable (versus 24.3% unreliable LSE with the usual definition, P < 10(-3) ), 74.3% were reliable, and 16.6% were very reliable.

CONCLUSION

The usual definition for LSE reliability is not relevant. LSE reliability depends on IQR/M according to liver stiffness median level, defining thus three reliability categories: very reliable, reliable, and poorly reliable LSE. (HEPATOLOGY 2013).

Staging of hepatic fibrosis: comparison of magnetic resonance elastography and shear wave elastography in the same individuals

Objective

To cross-validate liver stiffness (LS) measured on shear wave elastography (SWE) and on magnetic resonance elastography (MRE) in the same individuals.

Materials and Methods

We included 94 liver transplantation (LT) recipients and 114 liver donors who underwent either MRE or SWE before surgery or biopsy. We determined the technical success rates and the incidence of unreliable LS measurements (LSM) of SWE and MRE. Among the 69 patients who underwent both MRE and SWE, the median and coefficient of variation (CV) of the LSM from each examination were compared and correlated. Areas under the receiver operating characteristic curve in both examinations were calculated in order to exclude the presence of hepatic fibrosis (HF).

Results

The technical success rates of MRE and SWE were 96.4% and 92.2%, respectively (p = 0.17), and all of the technical failures occurred in LT recipients. SWE showed 13.1% unreliable LSM, whereas MRE showed no such case (p < 0.05). There was moderate correlation in the LSM in both examinations (r = 0.67). SWE showed a significantly larger median LSM and CV than MRE. Both examinations showed similar diagnostic performance for excluding HF (Az; 0.989, 1.000, respectively).

Conclusion

MRE and SWE show moderate correlation in their LSMs, although SWE shows higher incidence of unreliable LSMs in cirrhotic liver.

Assessing portal hypertension in liver diseases

Portal hypertension is a common complication of chronic liver diseases and is responsible for most clinical consequences of cirrhosis, which represent the more frequent causes of death and liver transplantation in these patients. This review is aimed at clarifying the state-of-the art assessment of portal hypertension and at discussing recent developments in this field. Particular attention is paid to new noninvasive techniques that will be soon available for potential routine use.

Spleen stiffness and splenoportal venous flow: assessment before and after transjugular intrahepatic portosystemic shunt placement

OBJECTIVES

To prospectively assess changes in spleen stiffness and splenoportal venous flow before and after transjugular intrahepatic portosystemic shunt (TIPS) placement.

METHODS

We prospectively evaluated spleen stiffness measured by the mean shear wave velocity with acoustic radiation force impulse imaging and the splenoportal venous velocity with color Doppler sonography in 12 patients (mean age ± SD, 42.6 ± 11.0 years; range, 29-65 years) who underwent TIPS placement for portal hypertension and gastroesophageal bleeding. The mean shear wave velocity and angle-corrected splenoportal venous velocity at the main portal and splenic veins were measured 1 day before and 3 to 9 days after TIPS placement (mean interval, 6.0 ± 1.95 days; range, 4-10 days) and were compared with portal vein pressure measured during the procedure.

RESULTS

There was a significant difference in portal vein pressure before and after TIPS (25.34 ± 6.21 versus 15.66 ± 6.07 mm Hg; P = .0005). After TIPS, the mean shear wave velocity decreased significantly in all 12 cases (3.50 ± 0.46 versus 3.15 ± 0.39 m/s before and after TIPS; P = .00015). The flow velocity at the main portal vein increased significantly after TIPS (22.21 ± 4.13 versus 47.25 ± 12.37 cm/s; P = .0000051). The splenic vein velocity and spleen index measured 25.57 ± 6.98 cm/s and 55.99 ± 21.27 cm(2), respectively, before TIPS and 35.72 ± 11.10 cm/s and 50.11 ± 21.12 cm(2) after TIPS (P = .0004 and .003).

CONCLUSIONS

A significant decrease in the mean shear wave velocity and increase in the splenoportal venous velocity occurred with reduced portal vein pressure after TIPS placement. Hence, both parameters can be used as noninvasive quantitative markers for monitoring TIPS function after placement.

Elastography, spleen size, and platelet count identify portal hypertension in patients with compensated cirrhosis

BACKGROUND & AIMS

Noninvasive methods are needed to identify clinically significant portal hypertension (CSPH) and esophageal varices (EVs) in patients with compensated cirrhosis. We looked for markers of the presence of CSPH and EVs in patients with cirrhosis.

METHODS

We performed a cross-sectional study that included a training set of 117 patients with compensated cirrhosis, confirmed by histology, from a tertiary referral center. Spleen diameter was measured by ultrasound, and liver stiffness (LS) was measured by transient elastography; endoscopy was used as the standard for detection of EVs, and measurements of hepatic venous pressure gradient were used as the standard for identifying CSPH. We assessed the ability of platelet count, spleen diameter, LS, and combinations of these factors (ie, ratio of platelet count to spleen size, and LS × spleen size/platelet count [LSPS]) to identify patients with CSPH and EV. The analysis included 2 new statistical models: the PH risk score and the varices risk score. Results were validated using an independent series of 56 patients with compensated patients from another center.

RESULTS

LS was the best single noninvasive variable for identifying patients with CSPH (area under the receiver operating characteristic, 0.883; 95% confidence interval [CI], 0.824-0.943; P < .0001). The area under the receiver operating characteristic value increased when LS was combined with platelet count and spleen size, either as LSPS (0.918; 95% CI, 0.872-0.965; P < .0001) or PH risk score (0.935; 95% CI, 0.893-0.977; P < .0001). More than 80% of patients were accurately classified using LSPS and PH risk score. Analyses of the varices risk score and LSPS were superior to all other noninvasive tests for identifying patients with EVs (area under the receiver operating characteristic, 0.909; 95% CI, 0.841-0.954 and 0.882; 95% CI, 0.810-0.935, respectively); they correctly classified 85% of patients in the training set and 75% in the validation set.

CONCLUSIONS

Combined data on LS, spleen diameter, and platelet count can be used to identify patients with compensated cirrhosis most likely to have CSPH and EV.

Measurement of spleen stiffness by acoustic radiation force impulse imaging identifies cirrhotic patients with esophageal varices

BACKGROUND & AIMS

We evaluated whether spleen stiffness (SS), measured by acoustic radiation force impulse imaging, can identify patients who have esophageal varices (EVs); those without EVs would not require endoscopic examination.

METHODS

In a prospective study, we measured SS and liver stiffness (LS) in 340 patients with cirrhosis undergoing endoscopic screening for EVs and 16 healthy volunteers (controls) at the Kurashiki Central Hospital in Okayama, Japan. The diagnostic accuracy of SS for the presence of EVs was compared with that of other noninvasive parameters (LS, spleen diameter, and platelet count). Optimal cutoff values of SS were chosen to confidently rule out the presence of varices.

RESULTS

Patients with cirrhosis had significantly higher SS and LS values than controls (P < .0001 and P < .0001, respectively). Levels of SS were higher among patients with EVs (n = 132) than controls, and values were highest among patients with high-risk EVs (n = 87). SS had the greatest diagnostic accuracy for the identification of patients with EVs or high-risk EVs compared with other noninvasive parameters, independent of the etiology of cirrhosis. An SS cutoff value of 3.18 m/s identified patients with EVs with a 98.4% negative predictive value, 98.5% sensitivity, 75.0% accuracy, and 0.025 negative likelihood ratio. An SS cutoff value of 3.30 m/s identified patients with high-risk EVs with a 99.4% negative predictive value, 98.9% sensitivity, 72.1% accuracy, and 0.018 negative likelihood ratio. SS values less than 3.3 m/s ruled out the presence of high-risk varices in patients with compensated or decompensated cirrhosis. SS could not be measured in 16 patients (4.5%).

CONCLUSIONS

Measurements of SS can be used to identify patients with cirrhosis with EVs or high-risk EVs. A cutoff SS was identified that could rule out the presence of varices and could be used as an initial noninvasive screening test; UMIN Clinical Trials Registry number, UMIN000004363.

Transient elastography: a meta-analysis of diagnostic accuracy in evaluation of portal hypertension in chronic liver disease

OBJECTIVES

Transient elastography (TE), as a non-invasive method, has been studied for evaluation of portal hypertension in patients with chronic liver diseases (CLD) with variable results. We studied the performance of TE for detection of significant portal hypertension, oesophageal varices and large oesophageal varices using meta-analysis.

METHODS

PubMed, the Cochrane Library, EMBASE and ISI web of Knowledge were searched. The studies published in English relating to the diagnostic value of TE for significant portal hypertension, oesophageal varices and large oesophageal varices in patients with CLD were collected.

RESULTS

A total of 18 studies, which included 3644 patients were analysed. Summary sensitivity and specificity were 0.90 (95% confidence interval (CI), 0.81-0.95) and 0.79 (95% CI, 0.58-0.91) for significant portal hypertension, and 0.87 (95% CI, 0.80-0.92) and 0.53 (95% CI, 0.36-0.69) for oesophageal varices and 0.86 (95% CI, 0.71-0.94) and 0.59 (95% CI, 0.45-0.72) for large oesophageal varices respectively. The HSROCs were 0.93 for significant portal hypertension, 0.84 for oesophageal varices and 0.78 for large oesophageal varices respectively. TE was very informative with 81% probability of correctly detection significant portal hypertension following a 'positive' measurement (over the threshold value) and lowering the probability of disease to as low as 11% when 'negative' measurement (below the threshold value) when pre-test probability was 50% whereas, for oesophageal varices or large oesophageal varices, the probability of a correct diagnosis following a 'positive' measurement did not exceeded 70%.

CONCLUSIONS

TE could be used as a good screening tool for significant portal hypertension, but only moderate diagnostic utility for the prediction of oesophageal varices or large oesophageal varices.

Transjugular intrahepatic portosystemic shunt placement for refractory ascites: a single-centre experience

BACKGROUND

The presence of refractory ascites is a common indication for transjugular intrahepatic portosystemic shunt (TIPS). Different models have been proposed for the prediction of survival after TIPS. The aim of this study was to evaluate the predictive factors associated with patients' survival after TIPS placement for refractory ascites.

METHODS

Data from all consecutive patients undergoing TIPS placement in our center for refractory ascites between February 2003 and January 2008 were prospectively recorded.

RESULTS

Seventy-three patients (52M/21F; 57 ± 10 years) met the inclusion criteria; mean follow-up was 17 ± 2 months. Mean MELD value, before TIPS placement, was 15.7 ± 5.3. TIPS placement led to an effective resolution of refractory ascites in 54% of patients (n = 40) with no significant increase in severe portosystemic encephalopathy. The 1-year survival rate observed was 65.7%, while the overall mortality was 23.3% (n = 17) with a mean survival of 17 ± 14 months. MELD score (B = 0.161, p = 0.042), basal AST (B = 0.020, p = 0.090), and pre-TIPS HVPG (B = 0.016, p = 0.093) were independent predictors of overall mortality, while MELD (B = 0.419, p = 0.018) and HVPG (B = 0.223, p = 0.060) independently predicted 1-year survival. ROC curves identified MELD ≥ 19 and HVPG ≥ 25 mmHg as the best cut-off points for the prediction of 1-year mortality.

CONCLUSIONS

TIPS is an effective treatment for refractory ascites in cirrhotic patients, leading to an effective ascites control in more than half patients. Improvement in patients' selection criteria could lead to better outcome and survival after this procedure. Liver function (MELD), presence of active necroinflammation (AST), and portal hypertension (HVPG) are independent predictors of patients' outcome after TIPS.

The accuracy of noninvasive methods in the prediction of clinically relevant outcomes in patients with chronic liver disease

The prognosis of chronic liver diseases, which represent a major public health problem, is mainly linked to the extent and progression of liver fibrosis and the subsequent risk of developing cirrhosis and related complications, mainly hepatocellular carcinoma. The article reviewed here reports on the prognostic role of liver stiffness as measured by transient elastography and other noninvasive methods in the prediction of clinical decompensation and hepatocellular carcinoma in patients with chronic hepatitis B. From the results of the study, liver stiffness measurement, as obtained using transient elastography and other noninvasive tests used to assess liver fibrosis, can accurately predict the development of hepatocellular carcinoma and variceal bleeding in patients with chronic hepatitis B.

Checkmate to liver biopsy in chronic hepatitis C?

Liver biopsy (LB) has traditionally been considered the gold standard for pretreatment evaluation of liver fibrosis in patients with chronic hepatitis C (CHC). However, LB is an invasive procedure with several shortcomings (intra- and interobserver variability of histopathological interpretation, sampling errors, high cost) and the risk of rare but potentially life-threatening complications. In addition, LB is poorly accepted by patients and it is not suitable for repeated evaluation. Furthermore, the prevalence of CHC makes LB unrealistic to be performed in all patients with this disease who are candidates for antiviral therapy. The above-mentioned drawbacks of LB have led to the development of noninvasive methods for the assessment of liver fibrosis. Several noninvasive methods, ranging from serum marker assays to advanced imaging techniques, have proved to be excellent tools for the evaluation of liver fibrosis in patients with CHC, whereas the value of LB as a gold standard for staging fibrosis prior to antiviral therapy has become questionable for clinicians. Despite significant resistance from those in favor of LB, noninvasive methods for pretreatment assessment of liver fibrosis in patients with CHC have become part of routine clinical practice. With protease inhibitors-based triple therapy already available and substantial improvement in sustained virological response, the time has come to move forward to noninvasiveness, with no risks for the patient and, thus, no need for LB in the assessment of liver fibrosis in the decision making for antiviral therapy in CHC.

Hemosuccus pancreaticus: a rare cause of gastrointestinal bleeding

BACKGROUND

Hemosuccus pancreaticus (HP) is defined as upper gastrointestinal (GI) hemorrhage from the papilla of Vater via the pancreatic duct and is a rare cause of digestive bleeding.

DATA SOURCE

A PubMed search of relevant articles published from January 1967 to September 2011 was performed to identify current information about HP in terms of its etiology, pathophysiology, clinical presentation, diagnosis and management.

RESULTS

A variety of etiological factors, most commonly chronic pancreatitis but also tumors and vascular diseases, can lead to this condition. Appropriate endoscopic or radiologic procedures should be chosen to establish a precise diagnosis for patients, especially those with a known history of pancreatic disorders, who present with abdominal pain, GI hemorrhage and hyperamylasemia. There are two main therapeutic options for this condition: angiographic embolotherapy and surgery. Both treatments can stop bleeding, but angiographic embolotherapy is the treatment of choice for stable patients. Recently, new and less invasive treatments have emerged to treat this condition.

CONCLUSIONS

Because of its rarity and broad spectrum of causes, HP is difficult to diagnose accurately. However, appropriate endoscopic and radiologic procedures are extremely helpful for establishing a correct diagnosis. Both angiographic embolotherapy and surgery are reliable treatment options for this condition, and transcatheter intervention is the treatment of choice for clinically stable patients. Additional innovative treatments have emerged, but their effectiveness and safety must be confirmed.

Noninvasive assessment of liver fibrosis via spleen stiffness measurement using acoustic radiation force impulse sonoelastography in patients with chronic hepatitis B or C

Portal hypertension and splenomegaly are common in patients with cirrhosis. However, there is limited previous in vivo research on the correlation between spleen stiffness and stages of liver fibrosis. This study aimed to evaluate the diagnostic value of spleen stiffness measurement (SSM), using acoustic radiation force impulse (ARFI) technology, for liver fibrosis assessment. Eligible patients with chronic hepatitis B or C (n = 163) underwent concurrent liver stiffness measurement (LSM), SSM and percutaneous liver biopsy. Receiver operating characteristic curves estimated the diagnostic performance of SSM, with multiple linear regression models for LSM and SSM determining the significance of explanatory factors. Results indicated significant correlation between LSM and SSM (R(2) = 0.574, P < 0.0001). Using SSM to classify METAVIR fibrosis (METAVIR F) scores, the areas under curves were 0.839 (95% CI: 0.780-0.898) for METAVIR F1 vs F2-4, 0.936 (95% CI: 0.898-0.975) for F1-2 vs F3-4 and 0.932 (95% CI: 0.893-0.971) for F1-3 vs F4, all P < 0.001. Multiple linear regression models identified BMI, spleen stiffness, METAVIR F3 and F4, serum alanine aminotransferase, international normalized ratio of prothrombin time, sodium and platelet count as significant independent explanatory factors for liver stiffness (adjusted R(2) = 0.724, P < 0.001). Male gender, liver stiffness, METAVIR F2, F3 and F4 also significantly and independently explained spleen stiffness (adjusted R(2) = 0.647, P < 0.001). ARFI SSM is potentially useful as a single or adjunct predictor of stages of liver fibrosis.

Measurement of spleen stiffness to evaluate portal hypertension and the presence of esophageal varices in patients with HCV-related cirrhosis

BACKGROUND & AIMS

The hepatic vein pressure gradient (HVPG) is the standard used to determine the degree of portal hypertension (PH) and an important prognostic factor for patients with cirrhosis; HVPG values correlate with the presence of esophageal varices (EV). However, HVPG can only be accurately determined at specialized centers; noninvasive methods are needed to predict HVPG values and the presence of EV. We compared the diagnostic performance of spleen stiffness (SS) measurement by transient elastography with that of liver stiffness (LS) and of other recently proposed noninvasive tests.

METHODS

We measured SS and LS in 100 consecutive patients with hepatitis C virus-induced cirrhosis. Patients were also assessed by FibroScan, HVPG, esophagogastroduodenoscopy, and liver biopsy. We also analyzed LS-spleen diameter to platelet ratio score and platelet count to spleen diameter.

RESULTS

SS and LS were more accurate than other noninvasive parameters in identifying patients with EV and different degrees of PH. A linear model that included SS and LS accurately predicted HVPG values (R(2) = 0.85). The results were internally validated using bootstrap analysis.

CONCLUSIONS

Measurement of SS can be used for noninvasive assessment and monitoring of PH and to detect EV in patients with hepatitis C virus-induced cirrhosis.

Liver and spleen stiffness measured by acoustic radiation force impulse elastography for noninvasive assessment of liver fibrosis and esophageal varices in patients with chronic hepatitis B

OBJECTIVES

To evaluate the performance of liver and spleen stiffness measured by acoustic radiation force impulse (ARFI) elastography for noninvasive assessment of liver fibrosis and esophageal varices in patients with chronic hepatitis B virus.

METHODS

Two hundred sixty-four participants, of whom 60 were healthy volunteers (classified as stage 0), 66 were patients with chronic hepatitis B who had undergone liver biopsy, and 138 were patients with hepatitis B-related cirrhosis, were enrolled in this study. Median liver and spleen stiffness values (meters per second) from 10 successful measurements per participant were obtained. Patients with cirrhosis were examined by upper endoscopy.

RESULTS

Significant linear correlations were found between liver (Spearman ρ = 0.87; P < .001) and spleen (Spearman ρ = 0.76; P < .001) stiffness and the fibrosis stage. Liver and spleen stiffness values increased as fibrosis progressed; however, overlaps in liver stiffness were detected in stages 0 and 1 and 1 and 2, and overlaps in spleen stiffness were observed in stages 0 and 1, 1 and 2, and 2 and 3. Liver stiffness cutoff values were 1.69 m/s for predicting stage 3 or greater (area under the receiver operating characteristic curve [AUROC] = 0.99) and 1.88 m/s for stage 4 (AUROC = 0.97). The spleen stiffness cutoff value was 2.72 m/s for stage 4 (AUROC = 0.96). Liver stiffness was not correlated with the varix grade, whereas a significant linear correlation (Spearman ρ = 0.65; P < .001) between spleen stiffness and the varix grade was found. The optimal spleen stiffness cutoff value for predicting varices was 3.16 m/s (AUROC = 0.83).

CONCLUSIONS

Liver and spleen stiffness values measured by ARFI elastography are reliable predictors of liver fibrosis. Spleen stiffness measured by ARFI can be used as a non-invasive method for determining the presence and severity of esophageal varices; however, evidence to support a similar role for liver stiffness is lacking.

The stiffness of the liver and spleen on ARFI Imaging pre and post TIPS placement: a preliminary observation

PURPOSE

To prospectively assess the stiffness of the liver and spleen with acoustic radiation force impulse (ARFI) imaging pre and post transjugular intrahepatic portosystemic shunt (TIPS) placement.

MATERIAL AND METHODS

Between February, 2011 and September, 2011, we prospectively measured stiffness of the liver and spleen with mean shear wave velocity (MSV, m/s) on ARFI imaging in 10 healthy volunteers (mean age 32.2 ± 10.3 years, age range 23-53 years) and 10 patients (mean age, 38.6 ± 6.4 years, age range 30-48 years) who underwent TIPS placement for treatment of portal hypertension (PHTN). The portal vein pressure was measured while placing the TIPS. To assess the changes in the stiffness of the liver and spleen following TIPS placement, we measured MSV of the liver and spleen one day before TIPS insertion and 4-9 days after TIPS placement (mean interval 5.9 ± 2.0 days, interval range 5 to 10 days).

RESULTS

There was significant difference in portal vein pressure pre (27.67 ± 5.86 mmHg) and post (18.00 ± 6.93 mmHg) TIPS insertion (P<.01). The MSV of the liver in healthy subjects, patients with PHTN pre TIPS and patients with PHTN post TIPS measured 1.16 ± 0.06 m/s, 2.48 ± 0.39 m/s, and 2.37 ± 0.28 m/s, respectively. The MSV of the spleen in healthy subjects, patients with PHTN pre TIPS and patients with PHTN post TIPS measured 2.22 ± 0.22 m/s, 3.65 ± 0.32 m/s, and 3.27 ± 0.30 m/s, respectively. There were significant differences in MSV of the liver and spleen between healthy subjects and patients with PHTN (all P<.001). There was no significant difference in MSV of the liver pre and post TIPS placement (P>.05). However, a statistically significant difference in MSV of the spleen pre and Post TIPS placement (P<.001) was demonstrated. In addition, we observed a significant difference in spleen index between healthy subjects and patients with PHTN (P<.001), as well as between pre and post TIPS placement (P<.01).

CONCLUSION

The MSV of the spleen measured with ARFI correlates well with portal vein pressure. Hence, the spleen stiffness by means of MSV on ARFI imaging can be used as a quantitative marker in monitoring the portal vein pressure as the function of the TIPS.

Can ARFI elastography predict the presence of significant esophageal varices in newly diagnosed cirrhotic patients?

AIM

To establish an algorithm which includes the liver stiffness (LS) and/or spleen stiffness (SS) assessed by ARFI for the prediction of significant esophageal varices-EV (at least grade 2).

MATERIAL AND METHODS

Our study included 145 newly diagnosed cirrhotic patients admitted in our Department between September 2009-August 2011. 62 patients (42.7%) had significant EV. We performed 10 ARFI measurements in each patient, both in the liver and in the spleen; median values were calculated, expressed in meters/second. In 24 consecutive newly diagnosed cirrhotic patients admitted between September 2011-December 2011, we prospectively analyzed the value of the new score for predicting significant EV.

RESULTS

The LS and SS assessed by ARFI elastography, and the percentage of patients with ascites were stastically significant higher in patients with significant EV as compared with those without EV or grade 1 EV. By multiple regression analysis we obtained the following formula for predicting significant EV: prediction of significant EV (Pred EV(2-3)) score: -0.572 + 0.041 x LS (m/s) + 0.122 x SS (m/s) + 0.325 x ascites (1-absent, 2-present). The best Pred EV(2-3) cut-off value for predicting significant EV was > 0.395 (AUROC = 0.721, accuracy = 69.6%). The accuracy in the group of patients in which the value of this score was prospectively analyzed was similar with that obtained in the first cohort of patients (70.8 vs. 69.6%). In conclusion, the proposed Pred EV(2-3) score had a enough good value for predicting significant EV.

Performance of platelet count/spleen diameter ratio for diagnosis of esophageal varices in cirrhosis: a meta-analysis

BACKGROUND

Platelet count/spleen diameter ratio (PSR) is a non-invasive method for the assessment of esophageal varices (EV), developed as an alternative to endoscopy.

AIM

To assess the performance of PSR for diagnosis of EV using meta-analysis.

METHODS

PubMed, EMBASE, the Cochrane Library, ISI web of Knowledge, China National Knowledge Infrastructure, and article references were searched. We included studies using endoscopy as a reference standard, with the data necessary to calculate the true and false positive, true and false negative diagnostic results of PSR for EV. The quality of the studies was rated with the QUADAS tool. The hierarchical summary receiver operating characteristic (HSROC) was used to examine the PSR accuracy for the diagnosis of EV. Heterogeneity was explored using meta-regression. Clinical utility of PSR for EV was evaluated by a Fagan plot.

RESULTS

In 20 studies (n = 3,063), the HSROC of the PSR for EV was 0.95 at various thresholds. At the threshold of 909, the summary sensitivities and specificities were 0.92 (95% CI, 0.79-0.97) and 0.87 (95% CI, 0.76-0.93), respectively. The HSROC was also 0.95 at the threshold of 909. If PSR was below 909 for EV ("positive" result), the post-test probability (if pre-test probability was 50%) was 87%, while if PSR was at or over 909 ("negative" result), the post-test probability was only 9%. PSR also had a high accuracy in diagnosis of EV in patients with compensated cirrhosis.

CONCLUSIONS

PSR can identify EV in cirrhosis with a high accuracy. Application of this index may decrease the need for endoscopy among cirrhotic patients.

Diagnosing and monitoring cirrhosis: Liver biopsy, hepatic venous pressure gradient and elastography

In this review we summarize the role of liver biopsy, transient elastography and hepatic venous pressure gradient (HVPG) in the diagnosis and monitoring of patients with liver cirrhosis. Transient elastography is useful for the non-invasive diagnosis of cirrhosis, but relevant information is lost if it is used as a dichotomous test. The development of clinically significant portal hypertension (defined as a hepatic venous pressure gradient ≥ 10 mmHg) is associated with the development of varices and decompensation and it is something that it is worth testing for. Transient elastography has some value for the prediction of clinically significant portal hypertension, but a large proportion of patients have non-diagnostic values. It has also some value for the diagnosis of varices, but non-invasive markers cannot substitute endoscopic screening in cirrhosis. Better dynamic, easily repeatable non-invasive tools are needed to monitor compensated cirrhosis.

Noninvasive methods to assess liver disease in patients with hepatitis B or C

The prognosis and management of patients with chronic viral hepatitis B and C depend on the amount and progression of liver fibrosis and the risk for cirrhosis. Liver biopsy, traditionally considered to be the reference standard for staging of fibrosis, has been challenged over the past decade by the development of noninvasive methodologies. These methods rely on distinct but complementary approaches: a biologic approach, which quantifies serum levels of biomarkers of fibrosis, and a physical approach, which measures liver stiffness by ultrasound or magnetic resonance elastography. Noninvasive methods were initially studied and validated in patients with chronic hepatitis C but are now used increasingly for patients with hepatitis B, reducing the need for liver biopsy analysis. We review the advantages and limitations of the noninvasive methods used to manage patients with chronic viral hepatitis B or C infection.

Comparison of acoustic radiation force impulse imaging with transient elastography for the detection of complications in patients with cirrhosis

BACKGROUND

Acoustic radiation force impulse (ARFI) imaging is a new non-invasive, ultrasound-based method for the evaluation of liver fibrosis and cirrhosis.

AIM

To determine the diagnostic accuracy of ARFI imaging, transient elastography (TE) and Fibrotest for the evaluation of complications in patients with cirrhosis.

METHODS

A total of 166 patients (109 male, mean age: 54 ± 11 years) with chronic liver disease and established cirrhosis were included in this study. ARFI-imaging of the liver and spleen, TE and Fibrotest were performed in all patients. In addition, clinical, laboratory and morphological parameters, including MELD/Child-Pugh scores, presence of oesophageal varices and hepatocellular carcinoma, history of variceal bleeding and history of hepatic encephalopathy were recorded.

RESULTS

Acoustic radiation force impulse liver was significantly correlated with ARFI spleen (r = 0.48, P < 0.001), TE (r = 0.75, P < 0.001) and Fibrotest (r = 0.21, P = 0.006). The diagnostic accuracy (AUROC) for the diagnosis of large oesophageal varices was 0.58 (95% CI: 0.48-0.67), 0.58 (0.49-0.67), 0.53 (0.44-0.63) and 0.50 (0.41-0.59) for ARFI liver, spleen, TE and Fibrotest respectively (P > 0.20). The AUROC for the detection of hepatocellular carcinoma (HCC) was 0.54 (0.39-0.70), 0.58 (0.44-0.73), 0.56 (0.40-0.73) and 0.72 (0.60-0.84) respectively (P > 0.20). Multiple logistic regression analysis showed that ARFI spleen better predicted the presence of large oesophageal varices and HCC compared with ARFI liver.

CONCLUSIONS

The diagnostic accuracy of ARFI liver and spleen was comparable to TE and Fibrotest for the detection of complications in patients with cirrhosis.

Liver and spleen stiffness in patients with extrahepatic portal vein obstruction

PURPOSE

To evaluate liver stiffness (LS) and spleen stiffness (SS) in patients with extrahepatic portal vein obstruction (EHPVO).

MATERIALS AND METHODS

Institutional research board approval and informed consent were obtained. LS and SS were measured in 65 consecutive patients with EHPVO. Patients underwent endoscopy, liver biopsy, liver function tests, abdominal ultrasonography, a detailed history, and examination. LS and SS measurements were also obtained in 50 age-matched healthy control subjects. Comparisons were made by using the Student t test, Mann-Whitney test for quantitative data, and χ(2) or Fisher exact test for qualitative data.

RESULTS

Sixty-five patients with EHPVO (with a bleed, n = 45; without a bleed, n = 20; mean age, 25.4 years ± 10.7 [standard deviation]; 29 men, 36 women) were enrolled. Twenty-two (34%) had hypersplenism. LS (P = .001) and SS (P = .01) were higher in patients with EHPVO (6.7 kPa ± 2.3 and 51.7 kPa ± 21.5, respectively) than in control subjects (4.6 kPa ± 0.7 and 16.0 kPa ± 3.0, respectively). Patients who had a bleed had higher SS than did those without a bleed (60.4 kPa ± 5.4 vs 30.3 kPa ± 14.2, P = .01). There was no significant difference in age (26.7 years ± 10.4 vs 22.5 years ± 9.8, P = .8) and median duration of disease (4.5 years [range, 1-26 years] vs 6.0 years [range, 1-22 years], P = .23) in patients with a bleed versus those without. With a cutoff of 5.9 kPa for LS, sensitivity and specificity for detection of a variceal bleed were 67% and 75%, respectively. An SS cutoff of 42.8 kPa yielded sensitivity and specificity of 88% and 94%, respectively.

CONCLUSION

LS and SS were higher in patients with EHPVO than in control subjects, and patients with a history of a bleed had a higher SS than did those without a bleed.

Hepatic venous pressure gradient in the assessment of portal hypertension before liver resection in patients with cirrhosis

BACKGROUND

Preoperative measurement of hepatic venous pressure gradient (HVPG) is not performed routinely before hepatectomy in patients with cirrhosis, although it has been suggested to be useful. This study investigated whether preoperative HVPG values and indirect criteria of portal hypertension (PHT) predict the postoperative course in these patients.

METHODS

Between January 2007 and December 2009, consecutive patients with resectable hepatocellular carcinoma (HCC) in a cirrhotic liver were included in this prospective study. PHT was assessed by transjugular HVPG measurement and by classical indirect criteria (oesophageal varices, splenomegaly and thrombocytopenia). The main endpoints were postoperative liver dysfunction and 90-day mortality.

RESULTS

Forty patients were enrolled. A raised HVPG was associated with postoperative liver dysfunction (median 11 and 7 mmHg in those with and without dysfunction respectively; P = 0·017) and 90-day mortality (12 and 8 mmHg in those who died and survivors respectively; P = 0·026). Oesophageal varices, splenomegaly and thrombocytopenia were not associated with any of the endpoints. In multivariable analysis, body mass index, remnant liver volume ratio and preoperative HVPG were the only independent predictors of postoperative liver dysfunction.

CONCLUSION

An increased HVPG was associated with postoperative liver dysfunction and mortality after liver resection in patients with HCC and liver cirrhosis, whereas indirect criteria of PHT were not. This study suggests that preoperative HVPG measurement should be measured routinely in these patients.

Non invasive evaluation of portal hypertension using transient elastography

The development of portal hypertension is a common consequence of chronic liver diseases leading to the formation of esophageal and gastric varices responsible for variceal bleeding, associated with a high mortality rate, as well as other severe complications such as portosystemic encephalopathy and sepsis. Measurement of hepatic venous pressure gradient (HVPG) and upper GI endoscopy are considered the gold standards for portal hypertension assessment in patients with cirrhosis. However, both types of investigation are invasive and HVPG measurement is routinely available and/or performed with adequate standards only in expert centres. There is thus a need for non invasive methods able to predict, with acceptable diagnostic accuracy, the progression of portal hypertension toward the levels of clinically significant (i.e. HVPG ≥ 10 mmHg) and severe (HVPG ≥ 12 mmHg) as well as the presence and the size of oesophageal varices. Transient elastography (TE) is a novel non invasive technology that allows measuring liver stiffness and that has gained popularity over the past few years. Although TE has been initially proposed to assess liver fibrosis, a good correlation has been reported between liver stiffness values and HVPG as well as the presence of oesophageal varices, suggesting that it could be an interesting tool for the non invasive evaluation of portal hypertension. This review is aimed at discussing the advantages and limits of TE and the perspectives for its rationale use in clinical practice for the management of patients with portal hypertension.

Minimal hepatic encephalopathy in patients with cirrhosis by measuring liver stiffness and hepatic venous pressure gradient

BACKGROUND/AIM

Transient elastography (TE) of liver and hepatic venous pressure gradient (HVPG) allows accurate prediction of cirrhosis and its complications in patients with chronic liver disease. There is no study on prediction of minimal hepatic encephalopathy (MHE) using TE and HVPG in patients with cirrhosis.

PATIENTS AND METHODS

Consecutive cirrhotic patients who never had an episode of hepatic encephalopathy (HE) were enrolled. All patients were assessed by psychometry (number connection test (NCT-A and B), digit symbol test (DST), serial dot test (SDT), line tracing test (LTT)), critical flicker frequency test (CFF), TE by FibroScan and HVPG. MHE was diagnosed if there were two or more abnormal psychometry tests (± 2 SD controls).

RESULTS

150 patients with cirrhosis who underwent HVPG were screened; 91 patients (61%, age 44.0 ± 11.4 years, M:F:75:16, Child's A:B:C 18:54:19) met the inclusion criteria. Fifty three (58%) patients had MHE (Child A (7/18, 39%), Child B (32/54, 59%) and Child C (14/19, 74%)). There was no significant difference between alanine aminotranferease (ALT), aspartate aminotransferase (AST) and total bilirubin level in patients with MHE versus non MHE. Patients with MHE had significantly lower CFF than non MHE patients (38.4 ± 3.0 vs. 40.2 ± 2.2 Hz, P = 0.002). TE and HVPG in patients with MHE did not significantly differ from patients with no MHE (30.9 ± 17.2 vs. 29.8 ± 18.2 KPas, P = 0.78; and 13.6 ± 2.7 vs. 13.6 ± 3.2 mmHg, P = 0.90, respectively).There was significant correlation of TE with Child's score (0.25, P = 0.01), MELD (0.40, P = 0.001) and HVPG (0.72, P = 0.001) while no correlation with psychometric tests, CFF and MHE.

CONCLUSION

TE by FibroScan and HVPG cannot predict minimal hepatic encephalopathy in patients with cirrhosis.

Assessment of portal hypertension by transient elastography in patients with compensated cirrhosis and potentially resectable liver tumors

BACKGROUND & AIMS

Patients with cirrhosis and small hepatocellular carcinoma with normal bilirubin and hepatic venous pressure gradient (HVPG) <10 mm Hg have >70% 5-year survival after hepatic resection. On the contrary, patients with HVPG ≥10 mm Hg (clinically significant portal hypertension, CSPH) frequently develop decompensation following surgery, with around 50% 5-year survival. Liver stiffness (LS) evaluation by transient elastography might non-invasively identify CSPH. We investigated the usefulness of LS predicting CSPH in patients with compensated cirrhosis and potentially resectable liver tumors.

METHODS

Ninety-seven consecutive Child-Pugh A patients with potentially resectable liver tumors referred for HVPG measurement were prospectively evaluated. In fasting conditions LS was measured before the hemodynamic study.

RESULTS

HVPG could be measured in all patients, whereas LS could not be measured in 18 (18.5%) obese patients. In the 79 patients with valid LS, 32 (40.5%) had CSPH; mean HVPG was 8.8±4.7 mm Hg. Mean LS was 18.4±12.3 kPa. LS showed a moderate correlation with HVPG (r=0.552; p<0.001). LS<13.6 kPa had high sensitivity (91%) but low specificity (57%) excluding CSPH. Conversely, LS>21 kPa had low sensitivity (53%) and high specificity (91%) predicting CSPH. 35% of patients had LS between 13.6 and 21 kPa ("grey zone").

CONCLUSIONS

These data suggest that in real-life scenarios half of patients with potentially resectable liver nodules can be non-invasively classified as having or not CSPH by LS. However, in the remaining half, LS is either not applicable or inaccurate. In this last population HVPG is still a non replaceable method to detect CSPH.

Noninvasive evaluation of portal hypertension: emerging tools and techniques

Portal hypertension is the main cause of complications in patients with cirrhosis. However, evaluating the development and progression of portal hypertension represents a challenge for clinicians. There has been considerable focus on the potential role of noninvasive markers of portal hypertension that could be used to stratify patients with respect to the stage of portal hypertension and to monitor disease progression or treatment response in a longitudinal manner without having to undertake repeated invasive assessment. The pathogenesis of portal hypertension is increasingly understood and emerging knowledge of the vascular processes that underpin portal hypertension has paved the way for exploring novel biomarkers of vascular injury, angiogenesis, and endothelial dysfunction. In this paper we focus on the pathogenesis of portal hypertension and potential non-invasive biomarkers with particular emphasis on serum analytes.

Towards noninvasive detection of oesophageal varices

Current guidelines recommend that all cirrhotic patients should undergo screening endoscopy at diagnosis to identify patients with varices at high risk of bleeding who will benefit from primary prophylaxis. This approach places a heavy burden upon endoscopy units and the repeated testing over time may have a detrimental effect on patient compliance. Noninvasive identification of patients at highest risk for oesophageal varices would limit investigation to those most likely to benefit. Upper GI endoscopy is deemed to be the gold standard against which all other tests are compared, but is not without its limitations. Multiple studies have been performed assessing clinical signs and variables relating to liver function, variables relating to liver fibrosis, and also to portal hypertension and hypersplenism. Whilst some tests are clearly preferable to patients, none appear to be as accurate as upper GI endoscopy in the diagnosis of oesophageal varices. The search for noninvasive tests continues.

The impact of hepatic pressurization on liver shear wave speed estimates in constrained versus unconstrained conditions

Increased hepatic venous pressure can be observed in patients with advanced liver disease and congestive heart failure. This elevated portal pressure also leads to variation in acoustic radiation-force-derived shear wave-based liver stiffness estimates. These changes in stiffness metrics with hepatic interstitial pressure may confound stiffness-based predictions of liver fibrosis stage. The underlying mechanism for this observed stiffening behavior with pressurization is not well understood and is not explained with commonly used linear elastic mechanical models. An experiment was designed to determine whether the stiffness increase exhibited with hepatic pressurization results from a strain-dependent hyperelastic behavior. Six excised canine livers were subjected to variations in interstitial pressure through cannulation of the portal vein and closure of the hepatic artery and hepatic vein under constrained conditions (in which the liver was not free to expand) and unconstrained conditions. Radiation-force-derived shear wave speed estimates were obtained and correlated with pressure. Estimates of hepatic shear stiffness increased with changes in interstitial pressure over a physiologically relevant range of pressures (0-35 mmHg) from 1.5 to 3.5 m s(-1). These increases were observed only under conditions in which the liver was free to expand while pressurized. This behavior is consistent with hyperelastic nonlinear material models that could be used in the future to explore methods for estimating hepatic interstitial pressure noninvasively.

Increased liver stiffness denotes hepatic dysfunction and mortality risk in critically ill non-cirrhotic patients at a medical ICU

INTRODUCTION

Hepatic dysfunction is a common finding in critically ill patients on the ICU and directly influences survival. Liver stiffness can be measured by the novel method of transient elastography (fibroscan) and is closely associated with hepatic fibrosis in patients with chronic liver disease, but also is increased in patients with acute hepatitis, acute liver failure and cholestasis. We investigated liver stiffness as a potentially useful tool for early detection of patients with hepatic deterioration and risk stratification with respect to short- and long-term mortality.

METHODS

We prospectively evaluated 108 consecutive critically ill patients at our medical intensive care unit (ICU) with subsequent longitudinal liver stiffness measurements (admission, Day 3, Day 7 and weekly thereafter) during the course of ICU treatment. Outcome was followed after discharge (median observation time 237 days).

RESULTS

Liver stiffness could be reliably measured in 71% of ICU patients at admission (65% at Day 3, 63% at Day 7). Critically ill patients (n = 108) had significantly increased liver stiffness compared to sex- and age-matched standard care patients (n = 25). ICU patients with decompensated cirrhosis showed highest liver stiffness, whereas other critical diseases (for example, sepsis) and comorbidities (for example, diabetes, obesity) did not impact stiffness values. At admission to the ICU, liver stiffness is closely related to hepatic damage (liver synthesis, cholestasis, fibrosis markers). During the course of ICU treatment, fluid overload (renal failure, volume therapy) and increased central venous pressure (mechanical ventilation, heart failure) were major factors determining liver stiffness. Liver stiffness values > 18 kilopascal (kPa) at ICU admission were associated with increased ICU and long-term mortality, even in non-cirrhotic patients.

CONCLUSIONS

Considering that liver stiffness cannot be validly measured in about 30% of ICU patients, transient elastography performed at ICU admission might be a useful tool to early identify liver dysfunction and predict mortality in critically ill patients at a medical ICU.