Guest guest Posted May 8, 2007 Report Share Posted May 8, 2007 Anyone who has had a chance to examine their old liver after transplant knows how stiff and hard it is compared to cow liver in the butcher shop. This stiffness has been found to correlate with portal hypertension. Portal hypertension is elevated pressure in certian blood vessels leading to the liver and the cause of leathal bleeding in liver failure. It looks like there is finally a good non-invasive way to measure the pressure. This could lead to better evaluation of treatments of portal hypertension. Perhaps Losartan is better than inderol at treating portal hypertensionbut it is hard to compare the two with invasive testing but should be easy to compare with ultrasound. Liver Stiffness Measurement May Predict Severe Portal Hypertension CME News Author: Laurie Barclay, MD CME Author: Désirée Lie, MD, MSEd Disclosures Release Date: May 7, 2007; Valid for credit through May 7, 2008 Credits Available Physicians - maximum of 0.25 AMA PRA Category 1 Credit(s)™ for physicians; Family Physicians - up to 0.25 AAFP Prescribed credit(s) for physicians May 7, 2007 — Transient elastography may predict severe portal hypertension in patients with hepatitis C virus (HCV)–related cirrhosis, according to the results of a study reported in the May issue of Hepatology. " Measurement of hepatic venous pressure gradient (HVPG) is a standard method for the assessment of portal pressure and correlates with the occurrence of its complications, " write Francesco Vizzutti, from the Università degli Studi di Firenze/Azienda Ospedaliero Universitaria Careggi in Firenze, Italy, and colleagues. " Liver stiffness measurement (LSM) has been proposed as a noninvasive technique for the prediction of the complications of cirrhosis. " The investigators evaluated the ability of liver stiffness measurement to predict severe portal hypertension compared with that of HVPG in 61 consecutive patients with chronic HCV-related liver disease. In the overall population, there was a strong relationship between liver stiffness measurement and HVPG measurements (r = 0.81; P < .0001). The correlation was excellent for HVPG values less than 10 or 12 mm Hg (r = 0.81; P = .0003 and r = 0.91; P < .0001, respectively). However, linear regression analysis was not optimal for HVPG values of 10 mm Hg or greater (r2 = 0.35; P < .0001) or 12 mm Hg or greater (r2 = 0.17; P = .02). The areas under the receiver operating characteristic curves were 0.99 for the prediction of HVPG of 10 mm Hg or greater and 0.92 for the prediction of 12 mm Hg or greater. At liver stiffness measurement cutoff values of 13.6 and 17.6 kPa, sensitivity was 97% and 94%, respectively. In patients with cirrhosis, liver stiffness measurement positively correlated with the presence of esophageal varices (P = .002). However, there was no apparent correlation between liver stiffness measurement and size of esophageal varices. Area under the receiver operating characteristic curve for the prediction of esophageal varices was 0.76, and at a liver stiffness measurement cutoff value of 17.6, kPa sensitivity was 90%. " LSM represents a non-invasive tool for the identification of chronic liver disease patients with clinically significant or severe portal hypertension and could be employed for screening patients to be subjected to standard investigations including upper GI endoscopy and hemodynamic studies, " the authors conclude. " Measurement of liver stiffness by transient elastography may represent a reliable non- invasive methodology for the prediction of clinically significant and severe portal hypertension, although not good enough to replace endoscopy for the detection of varices. " The Italian MIUR, the University of Florence, and the Italian Liver Foundation supported this study. The authors have disclosed no relevant financial relationships. Hepatology. 2007;45:1290-1297. Clinical Context According to the authors of the current study, progression of liver disease to cirrhosis occurs in successive stages of liver fibrosis and noninvasive tests are needed to assess progression of liver fibrosis and portal hypertension to optimize management. HVPG has been used as a gold standard for the evaluation of portal hypertension to assess the benefit of antiviral therapy, but it is invasive and costly and available only at major centers, whereas transient elastography is an emerging noninvasive method that has potential for predicting hepatic fibrosis in patients with chronic HCV-related hepatitis. Transient elastography relies on a novel ultrasound-based technology in which the tip of an ultrasound transducer probe is placed between 2 intercostal spaces at the level of the right liver lobe and transmits a low frequency to the liver, inducing an elastic shear wave that propagates through liver tissue and is then measured to reflect liver stiffness. This is a study of patients with chronic HCV-related hepatitis conducted using HVPG as a gold standard to examine the predictive value of transient elastography for portal hypertension and varices. Study Highlights Included were 61 consecutive patients (39 men) with histopathologically determined chronic HCV infection who underwent HVPG measurement. Patients had a hemodynamic study to obtain baseline assessment of portal pressure before starting & #946;-blockers. 16 patients had cirrhosis, and 14 patients had advanced hepatic fibrosis. Excluded were patients with body mass index of 35 kg/m2 or higher, ascites, overt complications such as renal or cardiovascular problems, hepatocellular carcinoma, or coinfection with other viruses or those receiving antiviral therapy. After overnight fasting, patients underwent complete upper abdomen ultrasound followed by transient elastography using the Fibroscan (Echosens, Paris, France) apparatus with a 5-MHz transducer probe. An elastic shear was produced by low-amplitude vibrations, and liver stiffness measurement was determined in a cylinder of hepatic tissue 1 cm by 2 to 4 cm. The clinician operator had prior experience with at least 100 liver stiffness measurement procedures. After liver stiffness measurement was determined, HVPG (portal pressure gradient) and transjugular liver biopsy were performed using local anesthesia. The operator was unaware of patient's liver disease status. Clinically significant portal hypertension was defined as an HVPG of 10 mm Hg or greater. Mean age was 56 years, 64% were men, mean body mass index was 23 kg/m2, 34% had no esophageal varices, and 38% had large varices. Among 47 patients with cirrhosis, 60% were classified as Child-Pugh class A, 30% as class B, and 10% as class C. 9% had no portal hypertension, 13% had preclinical portal hypertension, and 77% had clinically significant portal hypertension of whom 57% had severe portal hypertension. Esophageal varices were present in 30 of 47 patients with cirrhosis, gastroesophageal varices in 4, and isolated gastric varices in 1. Patients with cirrhosis showed significantly higher HVPG and liver stiffness vs those with advanced fibrosis (P < .0001 for both). There was a significant correlation between HVPG and liver stiffness measurement (r = 0.81; P < .0001). Liver stiffness was significantly higher in patients with an HVPG of 10 mm Hg or greater and 12 mm Hg or greater than in those with that of less than 10 mm Hg and less than 12 mm Hg (P < .0001). Based on receiver operating characteristic curves, different cutoff values for liver stiffness measurement were determined. A liver stiffness measurement of 13.6 kPa or greater had a negative predictive value of 92% and a sensitivity of 97% for the prediction of patients with HVPG of 10 mm Hg or greater. A liver stiffness measurement of 17.6 kPa or greater had a negative predictive value of 91% and a sensitivity of 94% for the prediction of patients with HVPG of 12 mm Hg or greater. However, using a cutoff value of 17.6 kPa or greater for liver stiffness measurement, the negative predictive value and positive predictive value for the prediction of varices were only 66% and 77%, respectively. There was no correlation between liver stiffness measurement and the size of esophageal varices. The authors concluded that measurement of liver stiffness by transient elastography represents a reliable and noninvasive method for the prediction of clinically severe portal hypertension but is not good enough to replace endoscopy for the detection of varices. The authors suggest larger studies to collaborate these findings. Quote Link to comment Share on other sites More sharing options...
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