Assessment of a biofluid mechanics-based model for calculating portal pressure in canines.

BACKGROUND: Portal hypertension is a severe complication caused by various chronic liver diseases. The standard methods for detecting portal hypertension (hepatic venous pressure gradient and free portal pressure) are available in only a few hospitals due to their technical difficulty and invasiveness; thus, non-invasive measuring methods are needed. This study aimed to establish and assess a novel model to calculate free portal pressure based on biofluid mechanics. RESULT: Comparison of each dog's virtual and actual free portal pressure showed that a biofluid mechanics-based model could accurately predict free portal pressure (mean difference: -0.220, 95% CI: - 0.738 to 0.298; upper limit of agreement: 2.24, 95% CI: 1.34 to 3.14; lower limit of agreement: -2.68, 95% CI: - 3.58 to - 1.78; intraclass correlation coefficient: 0.98, 95% CI: 0.96 to 0.99; concordance correlation coefficient: 0.97, 95% CI: 0.93 to 0.99) and had a high AUC (0.984, 95% CI: 0.834 to 1.000), sensitivity (92.3, 95% CI: 64.0 to 99.8), specificity (91.7, 95% CI: 61.5 to 99.8), positive likelihood ratio (11.1, 95% CI: 1.7 to 72.8), and low negative likelihood ratio (0.08, 95% CI: 0.01 to 0.6) for detecting portal hypertension. CONCLUSIONS: Our study suggests that the biofluid mechanics-based model was able to accurately predict free portal pressure and detect portal hypertension in canines. With further research and validation, this model might be applicable for calculating human portal pressure, detecting portal hypertensive patients, and evaluating disease progression and treatment efficacy.

Assessment of contrast-enhanced ultrasonography of the hepatic vein for detection of hemodynamic changes associated with experimentally induced portal hypertension in dogs.

OBJECTIVE To assess the use of contrast-enhanced ultrasonography (CEUS) of the hepatic vein for the detection of hemodynamic changes associated with experimentally induced portal hypertension in dogs. ANIMALS 6 healthy Beagles. PROCEDURES A prospective study was conducted. A catheter was surgically placed in the portal vein of each dog. Hypertension was induced by intraportal injection of microspheres (10 to 15 mg/kg) at 5-day intervals via the catheter. Microsphere injections were continued until multiple acquired portosystemic shunts were created. Portal vein pressure (PVP) was measured through the catheter. Contrast-enhanced ultrasonography was performed before and after establishment of hypertension. Time-intensity curves were generated from the region of interest in the hepatic vein. Perfusion variables measured for statistical analysis were hepatic vein arrival time, time to peak, time to peak phase (TTPP), and washout ratio. The correlation between CEUS variables and PVP was assessed by use of simple regression analysis. RESULTS Time to peak and TTPP were significantly less after induction of portal hypertension. Simple regression analysis revealed a significant negative correlation between TTPP and PVP. CONCLUSIONS AND CLINICAL RELEVANCE CEUS was useful for detecting hemodynamic changes associated with experimentally induced portal hypertension in dogs, which was characterized by a rapid increase in the intensity of the hepatic vein. Furthermore, TTPP, a time-dependent variable, provided useful complementary information for predicting portal hypertension. IMPACT FOR HUMAN MEDICINE Because the method described here induced presinusoidal portal hypertension, these results can be applied to idiopathic portal hypertension in humans.

Three-dimensional multislice helical computed tomography techniques for canine extra-hepatic portosystemic shunt assessment.

The purpose of the present study was to investigate the feasibility and usefulness of three-dimensional (3D) multislice computed tomography (CT) angiography with maximum intensity projection (MIP) and volume rendering (VR) in six dogs with clinical and sonographic findings suggestive of portosystemic shunt. Furthermore, we aimed to estimate the diameter of the portal vein and shunt vessels. MIP and VR reconstructions were performed for each patient and the origin and insertion of all shunt vessels were detected. In addition, 3D reconstructions allowed excellent depiction of vascular morphology and topography. All diagnoses and vessel measurements were confirmed by surgery. 3D multidetector CT angiography is a promising, noninvasive, and accurate method of evaluating dogs with suspected portosystemic shunts.