Patient-Caregiver Portal System in Palliative Oncology: Assessment of Usability and Perceived Benefit.

BACKGROUND: The engagement of family caregivers in oncology is not universal or systematic. OBJECTIVE: We implemented a process intervention (ie, patient-caregiver portal system) with an existing patient portal system to (1) allow a patient to specify their caregiver and communication preferences with that caregiver, (2) connect the caregiver to a unique caregiver-specific portal page to indicate their needs, and (3) provide an electronic notification of the dyad's responses to the care team to inform clinicians and connect the caregiver to resources as needed. METHODS: We assessed usability and satisfaction with this patient-caregiver portal system among patients with cancer receiving palliative care, their caregivers, and clinicians. RESULTS: Of 31 consented patient-caregiver dyads, 20 patients and 19 caregivers logged in. Further, 60% (n=12) of patients indicated a preference to communicate equally or together with their caregiver. Caregivers reported high emotional (n=9, 47.3%), financial (n=6, 31.6%), and physical (n=6, 31.6%) caregiving-related strain. The care team received all patient-caregiver responses electronically. Most patients (86.6%, 13/15 who completed the user experience interview) and caregivers (94%, 16/17 who completed the user experience interview) were satisfied with the system, while, of the 6 participating clinicians, 66.7% agreed "quite a bit" (n=1, 16.7%) or "very much" (n=3, 50%) that the system allowed them to provide better care. CONCLUSIONS: Our findings demonstrate system usability, including a systematic way to identify caregiver needs and share with the care team in a way that is acceptable to patients and caregivers and perceived by clinicians to benefit clinical care. Integration of a patient-caregiver portal system may be an effective approach for systematically engaging caregivers. These findings highlight the need for additional research among caregivers of patients with less advanced cancer or with different illnesses.

Assessment of portal system hemodynamics for the prediction of portal vein thrombosis in cirrhosis-A systematic review and meta-analysis.

BACKGROUND: The pathogenesis of portal vein thrombosis (PVT) in cirrhosis is multifactorial, with altered hemodynamics being proposed as a possible contributor. The present systematic review was conducted to study the role of assessment of portal hemodynamics for the prediction of PVT in patients with cirrhosis. METHODS: Three databases (Medline, Embase, and Scopus) were searched from inception to February 2023 for studies comparing portal venous system parameters in patients with cirrhosis developing PVT with those not. Results were presented as mean difference (MD) or odds ratio (OR) with their 95% confidence intervals (CIs). RESULTS: A total of 31 studies (patients with cirrhosis: 19 studies, patients with cirrhosis undergoing splenectomy: 12 studies) were included. On pooling the data from multivariable analyses of the included studies, a larger portal vein diameter was a significant predictor of PVT in patients with cirrhosis without or with splenectomy with OR 1.74 (1.12-2.69) and OR 1.55 (1.26-1.92), respectively. On the other hand, a lower portal vein velocity (PVV) was a significant predictor of PVT in cirrhotics without or with splenectomy with OR 0.93 (0.91-0.96) and OR 0.71 (0.61-0.83), respectively. A PVV of <15 cm/s was the most commonly used cut-off for the prediction of PVT. Patients developing PVT also had a significantly higher splenic length, thickness, and splenic vein velocity. CONCLUSION: The assessment of portal hemodynamic parameters at baseline evaluation in patients with cirrhosis may predict the development of PVT. Further studies are required to determine the optimal cut-offs for various parameters.

Endoscopic ultrasound-guided sampling and profiling of portal circulation in human patients for metabolic research studies and biomarker assessment.

Portal and hepatic circulation can now be safely accessed using endoscopic ultrasound (EUS). EUS-guided needle access of the portal vein is performed clinically at select tertiary centers for measurement of portal pressure gradients in patients with chronic liver disease and sampling of portal venous thrombus to diagnose malignancy. We propose that this novel clinical technique can be applied in research studies to allow blood collection from and profiling of portal and hepatic circulation. In this technical report, we present and highlight the technical aspects, feasibility, and safety of EUS: guided portal venous blood collection. As a proof of the concept and the utility of this technique in metabolic research and biomarker assessment and discovery, we present a pilot metabolite profiling study of portal venous blood in a small cohort of patients with cirrhosis and a comparison with a group without cirrhosis. Despite the very small diameter of the endoscopic needle used for the blood collection, the portal samples have the same quality as those collected from systemic circulation, and they can be used for the same downstream applications. Finally, we propose an analytical workflow to screen for promising metabolites that could qualify for further studies to determine their utility as sensitive, early candidate biomarkers of hepatic fibrosis, portal shunt, and hypertension. We hope that this report could stimulate and facilitate the widespread use of EUS-guided techniques for the profiling of portal circulation, which could potentially open a new field of scientific inquiry.NEW & NOTEWORTHY The technical aspects, feasibility, and safety of endoscopic ultrasound (EUS)-guided needle access for portal venous blood collection are presented in this technical report. Despite the very small diameter of the endoscopic needle, portal blood samples have the same quality as those collected from systemic circulation. As a proof of the concept and the utility of this technique in metabolic research and biomarker assessment and discovery, we present a pilot metabolite profiling study of portal venous blood in a small cohort of patients with cirrhosis and a comparison with a group without cirrhosis.

Effect of prophylactic treatment with levetiracetam on the incidence of postattenuation seizures in dogs undergoing surgical management of single congenital extrahepatic portosystemic shunts.

OBJECTIVE: To report the incidence of postattenuation seizures (PAS) in dogs that underwent single congenital extrahepatic portosystemic shunt (cEHPSS) attenuation and to compare incidence of PAS in dogs that either did or did not receive prophylactic treatment with levetiracetam (LEV). STUDY DESIGN: Multi-institutional retrospective study. POPULATION: Nine hundred forty dogs. METHODS: Medical records were reviewed to identify dogs that underwent surgical attenuation of a single cEHPSS from January 2005 through July 2017 and developed PAS within 7 days postoperatively. Dogs were divided into 3 groups: no LEV (LEV-); LEV at ≥15 mg/kg every 8 hours for ≥24 hours preoperatively or a 60 mg/kg intravenous loading dose perioperatively, followed by ≥15 mg/kg every 8 hours postoperatively (LEV1); and LEV at <15 mg/kg every 8 hours, for <24 hours preoperatively, or continued at <15 mg/kg every 8 hours postoperatively (LEV2). RESULTS: Seventy-five (8.0%) dogs developed PAS. Incidence of PAS was 35 of 523 (6.7%), 21 of 188 (11.2%), and 19 of 228 (8.3%) in groups LEV-, LEV1, and LEV2, respectively. This difference was not statistically significant (P = .14). No differences between groups of dogs that seized with respect to investigated variables were identified. CONCLUSION: The overall incidence of PAS was low (8%). Prophylactic treatment with LEV according to the protocols that were investigated in our study was not associated with a reduced incidence of PAS. CLINICAL SIGNIFICANCE: Prophylactic treatment with LEV does not afford protection against development of PAS. Surgically treated dogs should continue to be monitored closely during the first 7 days postoperatively for seizures.

Ultrasonography for Noninvasive Assessment of Portal Hypertension.

Portal hypertension is a major pathophysiology in patients with cirrhosis. Portal pressure is the gold standard to evaluate the severity of portal hypertension, and radiological intervention is the only procedure for pressure measurement. Ultrasound (US) is a simple and noninvasive imaging modality available worldwide. B-mode imaging allows broad applications for patients to detect and characterize chronic liver diseases and focal hepatic lesions. The Doppler technique offers real-time observation of blood flow with qualitative and quantitative assessments, and the application of microbubble-based contrast agents has improved the detectability of peripheral blood flow. In addition, elastography for the liver and spleen covers a wider field beyond the original purpose of fibrosis assessment. These developments enhance the practical use of US in the evaluation of portal hemodynamic abnormalities. This article reviews the recent progress of US in the assessment of portal hypertension.

Histological and immunohistochemical assessment of liver biopsies in morbidly obese patients.

AIMS: To study liver lesions in morbidly obese patients who underwent liver biopsy at the time of bariatric surgery to define histological lesions, especially inflammatory infiltrate, diagnostic categories and the possible influence of gender in this respect. METHODS AND RESULTS: 110 biopsies (36 males-M- and 76 females -F-) were evaluated and categorised, according to the NAS (NAFLD -non alcoholic fatty liver disease- Activity Score) system and other criteria, as non-NAFLD (15.5%, F predominance), non-alcoholic steatohepatitis (NASH) (16.5%, M predominance), non-alcoholic hepatosteatosis (NAHS) (21%, F predominance) and, the most numerous group, NASH-borderline (NASH-BORD) (47%), with three subgroups, characterised by centrozonal lesions, portal area preferential involvement or affecting both areas. The predominant form of hepatocytesteatosis was mixed with a multivesicular component that was present in most cases with fibroinflammatory portal involvement. Nuclear glycogenosomes were found in greater number of biopsies in patients in the third and sixth decades. Portal inflammation was present in a large number of cases (M predominance); the application of immunohistochemical techniques (myeloperoxidase and CD68 antibodies) to evaluate lobular inflammation revealed "surgical hepatitis" in one third of the cases, and the presence of microgranulomas (CD68+) (M predominance), which were more abundant with increasing lesion severity. CONCLUSIONS: Portal inflammation and multivesicular hepatocytesteatosis are highly prevalent in morbidly obese patients. This study identifies a new subtype of NASH-BORD characterized by centrizonal and porto-periportal area involvement and the existence of liver biopsies without steatosis. CD68+ microgranulomas constitute an unequivocal marker of lobular inflammation in surgical biopsies and of lesion severity, which is gender-related.

A pictorial review of benign hepatocellular nodular lesions: comprehensive radiological assessment incorporating the concept of anomalous portal tract syndrome.

BACKGROUND/PURPOSE: Although the pathological categorization system advocated by the International Working Party (IWP) on Terminology has been helpful in categorizing benign hepatocellular lesions, the diverse clinicopathological features of the lesions still cause confusion of diagnosis in clinical settings. Recently, an integrated disease concept termed "anomalous portal tract syndrome" (APTS) has been proposed as a congenital anomaly of the portal tract, being a single unifying etiological factor underlying the disorder. In this article, we discuss the radiological features of benign nodular hepatocellular lesions incorporated in the concept of APTS. METHODS: We systematically reviewed the literature on benign hepatocellular lesions based on the concept of APTS, as well as standard IWP terminology. For this pictorial review, we selected six representative cases and assessed the radiological features of the cases based on the concept of APTS. RESULTS: The comprehensive assessment based on APTS enabled the systematic categorization of benign hepatocellular lesions, including nodular regenerative hyperplasia, large regenerative nodules, partial nodular transformation, focal nodular hyperplasia, and hepatocellular adenoma, and was helpful in understanding the overlapping features of these lesions. CONCLUSIONS: Although the disease concept of APTS is still evolving, it is nonetheless helpful in comprehensively understanding the clinicopathological and radiological features of various benign hepatocellular lesions.

Hemodynamic assessment of the development of portal-systemic collaterals in portal hypertensive rats.

BACKGROUND: Portal hypertension induced the formation of portal-systemic collaterals. Revealing the developmental change of portal-systemic collaterals is important for future therapy. METHODS: We observed the evolution of an accessible shunting vessel, the spleno-renal shunt (SRS), in rats after induction of portal hypertension by partial portal vein ligation (PVL). The hemodynamic and histological assessments of SRS were performed by transit time ultrasound and immunohistochemical studies. RESULTS: The portal pressure of PVL rats surged to 16.5 ± 1.1 mmHg on day 1 after ligation surgery and was maintained at a significantly higher level (13.0 ± 0.4 mmHg) to day 14 when compared to sham rats (p < 0.05). The size or flow of SRS in PVL rats did not change immediately after portal pressure surge. Instead, they increased rapidly on day 4, peaked on day 7, and stabilized thereafter. The size and flow were greater and the resistance of SRS was lower in PVL rats after day 7 (p < 0.05). The anti-Ki67 immunohistochemical study demonstrated positive staining of endothelium in SRS and negative in portal vein or aorta of PVL rats. In addition, the endothelial cells of SRS were stained positive for CD31 and KLF5. CONCLUSIONS: We concluded that the pressure-induced opening of pre-existing vessels was not the primary underlying mechanism in the formation of SRS. Endothelial proliferating and vascular remodeling process participated actively during the development of SRS. These observations can be used for studying the pathogenesis and developing more effective anti-portal hypertensive therapy in the future.

Systematic review: endoscopic and imaging-based techniques in the assessment of portal haemodynamics and the risk of variceal bleeding.

BACKGROUND: Invasive measurement of the hepatic venous pressure gradient (HVPG) is regarded as the gold standard for risk stratification and the evaluation of pharmaceutical agents in patients with portal hypertension. AIM: To review the techniques for endoscopic and imaging-based assessment of portal haemodynamics, with particular emphasis on trials where the results were compared with HVPG or direct portal pressure measurement. METHODS: Systematic search of the MEDLINE electronic database with keywords: portal hypertension, variceal bleeding, variceal pressure, endoscopic ultrasound, Doppler ultrasonography, magnetic resonance angiography, CT angiography, hepatic venous pressure gradient. RESULTS: Computed tomography angiography and endoscopic ultrasound (EUS) have been both employed for the diagnosis of complications of portal hypertension and for the evaluation of the efficacy of endoscopic therapy. Colour Doppler ultrasonography and magnetic resonance angiography has given discrepant results. Endoscopic variceal pressure measurements either alone or combined with simultaneous EUS, correlate well with HVPG and risk of variceal bleeding and have a low interobserver variability. CONCLUSIONS: Endoscopic and imaging-based measurements of portal haemodynamics provide an alternate means for the assessment of complications of portal hypertension. Further studies are required to validate their use in risk stratification and the evaluation of drug therapies in patients with portal hypertension.

Nutrient net absorption across the portal-drained viscera of forage-fed beef steers: Quantitative assessment and application to a nutritional prediction model.

This study aimed to establish the relationship between ME intake and energy and nutrient absorption across the portal-drained viscera (PDV) of forage-fed beef steers. Eight Angus (328 +/- 40 kg of BW) steers were surgically fitted with portal, mesenteric arterial, and mesenteric venous catheters, and were fed alfalfa cubes in a replicated 4 x 4 Latin square design with 4 levels of energy intake between 1 and 2 times maintenance energy requirements. On d 28 of each experimental period, p-aminohippuric acid was infused to measure blood and plasma flow across the PDV, and blood samples (1 every hour, for 6 h) were collected simultaneously from arterial and venous catheters for net absorption measurements. Oxygen utilization, and therefore energy utilization, increased (P < 0.05) linearly in relation to ME intake. Glucose net uptake was unaffected, but lactate net release increased linearly in response to ME intake (P < 0.05). Net absorption of all AA except tryptophan, glutamate, and glutamine increased linearly with ME intake (P < 0.05). The constant net absorption of glutamate and glutamine indicated increased net utilization of these AA when dietary supply was increased. These data provide quantitative measures of the PDV effects on energy and AA availability for productive tissues, and suggest that the greater net utilization of some AA when ME intake is increased could relate to their catabolism for energy production. Prediction estimates of small intestinal AA absorption, based on the Cornell Net Carbohydrate and Protein System (CNCPS), exceeded observed net AA PDV absorption. Mean bias represented the greatest proportion (87 to 96%) of the deviation between individual AA absorption and observed net AA PDV absorption, suggesting that the CNCPS model may be used to predict AA net absorption when factors describing AA utilization by the PDV are applied to model predictions.

Hepatic radionuclide angiography and Doppler ultrasonography in the detection and assessment of vascular disturbances in the portal system.

BACKGROUND/AIMS: The aim of the study was evaluation of the morphology of the blood vessels, blood flow velocity and direction with Doppler ultrasound (D-US) and correlation with the relative liver parenchymal perfusion assessed by hepatic radionuclide angiography (HRA). METHODOLOGY: Real-time, D-US and HRA were performed in 108 patients. RESULTS: In patients with portal venous aneurysm, hepatopetal blood flow was increased, while portal perfusion did not differ from controls. In portal hypertensive patients, D-US detected dilatation of the portal system veins, with decreased blood flow. In comparison to the portal perfusion in controls and portal venous aneurysm, values were significantly (p < 0.01) lower in chronic active hepatitis and liver cirrhosis and differed between themselves (p < 0.01). In the groups of cirrhotic patients with esophageal varices, sclerosed esophageal varices, recanalized umbilical vein, partial portal thrombosis and cavernous portal vein with hepatofugal, hyperkinetic or slow blood flow, and very low velocities beside the thrombi, portal perfusion was lower (p < 0.01) than in controls, portal venous aneurysm, chronic active hepatitis and liver cirrhosis without collaterals. In complete thrombosis, minimal collateral flow was found with D-US, while HRA proved no portal supply. CONCLUSIONS: D-US and HRA are complementary for the estimation of various liver vascular disorders.

Assessment of the regularity of hepatic arterio-portal anastomosis exploiting in vivo microscopy.

PURPOSE: To determine the regularity of hepatic arterio-portal anastomosis (i.e., does every branch of the portal system receive a tributary from the hepatic arterial system and, if so, does it occur at a constant level?). MATERIALS AND METHODS: Ten male Wistar mice weighing 50 g each were divided into two groups. The first group underwent portal vein ligation, and the second group underwent ligation of the portal vein, aorta, and inferior vena cava simultaneously. Fluorescence and heparin were injected prior to ligation, via the jugular vein. The liver surface circulation was monitored, using in vivo microscopy before and after ligation. RESULTS: Prior to ligation, two kinds of blood flow were noticed, fast and slow, regardless of the position of the examined site on the liver surface, in the distributing venules, terminal portal venules, and sinusoids. Following ligation, results were similar in both groups with four types of blood flow: (1) complete cessation of blood flow; (2) respiration-related blood movement; (3) slow blood flow, starting either in the distributing venules, terminal portal venules, or sinusoids; (4) fast blood flow, starting either in the distributing venules, or terminal portal venules or sinusoids. CONCLUSION: The presence of two types of blood flow, before ligation, and the presence of four types of blood flow after ligation, starting at different levels, lead to the conclusion that arterio-portal anastomosis does not follow a regular pattern in the peripheral zone. That is to say, a 1-to-1 ratio does not exist, and, where it exists, it does not occur at a constant level of the vascular tree.

Per-rectal portal scintigraphy is complementary to ultrasonography and endoscopy in the assessment of portal hypertension in children with chronic cholestasis.

UNLABELLED: We evaluated the clinical usefulness of 99mTc-pertechnetate per-rectal portal scintigraphy (PPS) in the assessment of portal circulation in children with chronic cholestasis. METHODS: PPS percentage shunt index (%SI) (the amount of radionuclide that shunts the liver and reaches the systemic blood after injection in the rectum) was measured in 22 children (mean age, 7.2 +/- 4.9 y) and compared with established clinical, laboratory, and endoscopic and imaging parameters of portal hypertension (PH). Fourteen children had surgically treated biliary atresia, and 8 had chronic intrahepatic cholestasis. Six clinically well children served as control subjects. RESULTS: The %SI was 14.3 +/- 3.1 and 34.7 +/- 18.8 in controls and in patients, respectively (P < 0.01). A cutoff of 19% correctly allocated 100% of controls and 86% of patients. Mean %SI values were significantly higher in patients with biliary atresia, a high risk of pretransplantation death, esophageal varices (EV) at endoscopy, and an abnormal value for the ratio of lesser omentum thickness to abdominal aorta diameter (LO/Ao) at ultrasonography. Correlations between %SI values and several ultrasonographic continuous variables were statistically significant only for LO/Ao ratios (r = 0.51; P = 0.005) and spleen longitudinal diameters (r = 0.53; P = 0.01). The presence of EV could correctly be predicted only when values of %SI were greater than 30% (100% specificity; 56% sensitivity). Endoscopic and PPS findings agreed for a diagnosis of PH with EV in 3 of 7 patients with normal or borderline ultrasonographic LO/Ao ratios. PPS patterns and %SI values became normal in 3 children who underwent liver transplantation. CONCLUSION: In children with chronic cholestasis, PPS may be an advantageous, minimally invasive tool complementary to ultrasonography and endoscopy for better assessment and follow-up of PH before and after liver transplantation.

Assessment of tumor hemodynamics in small hepatocellular carcinoma: comparison of Doppler ultrasonography, angiography-assisted computed tomography, and pathological findings.

AIM: We evaluated the usefulness of Doppler ultrasonography (DUS) for the analysis of tumor hemodynamics in small hepatocellular carcinoma (HCC). METHODS: We compared Doppler ultrasound (DUS) findings with angiography-assisted computed tomography (Angio-CT) such as CT during arterial portography and during hepatic arteriography in the evaluation of the intratumoral hemodynamics, and with pathologic findings in 45 small HCC nodules (< or =3.0 cm in diameter) of 43 patients. DUS flow pattern of each nodule was categorized into three types: afferent continuous flow (Type 1), afferent pulsatile flow with afferent continuous flow (Type 2), and afferent pulsatile flow without afferent continuous flow (Type 3). Intratumoral blood supply was determined by Angio-CT, and pathologic findings were evaluated on resected or biopsied specimen. RESULTS: Based on Angio-CT findings, Type 1 nodules showed decreased arterial blood supply (ABS) without decreased portal blood supply (PBS). Type 2 nodules showed unchanged ABS but decreased PBS. Type 3 nodules showed both increased ABS and decreased PBS. DUS findings well represented blood supply of HCC evaluated by Angio-CT. In addition, all Type 1 and 2 nodules were well-differentiated HCC, and all Type 3 nodules were moderately or poorly differentiated HCC; DUS findings well reflected differentiation of HCC. CONCLUSIONS: DUS is a non-invasive imaging method and can be used for the evaluation of the stage of malignancy of small HCC.

Inhalation of insulin in dogs: assessment of insulin levels and comparison to subcutaneous injection.

Pulmonary insulin delivery is being developed as a more acceptable alternative to conventional subcutaneous administration. In 15 healthy Beagle dogs (average weight 9.3 kg), we compared insulin distribution in arterial, deep venous, and hepatic portal circulation. Dogs received 0.36 units/kg s.c. regular human insulin (n = 6) or 1 mg (2.8 units/kg) or 2 mg (5.6 units/kg) dry-powder human inhaled insulin (n = 3 and 6, respectively). Postinhalation of inhaled insulin (1 or 2 mg), arterial insulin levels quickly rose to a maximum of 55 +/- 6 or 92 +/- 9 microU/ml, respectively, declining to typical fasting levels by 3 h. Portal levels were lower than arterial levels at both doses, while deep venous levels were intermediate to arterial and portal levels. In contrast, subcutaneous insulin was associated with a delayed and lower peak arterial concentration (55 +/- 8 microU/ml at 64 min), requiring 6 h to return to baseline. Peak portal levels for subcutaneous insulin were comparable to those for 1 mg and significantly less than those for 2 mg inhaled insulin, although portal area under the curve (AUC) was comparable for the subcutaneous and 2-mg groups. The highest insulin levels with subcutaneous administration were seen in the deep venous circulation. Interestingly, the amount of glucose required for maintaining euglycemia was highest with 2 mg inhaled insulin. We conclude that plasma insulin AUC for the arterial insulin level (muscle) and hepatic sinusoidal insulin level (liver) is comparable for 2 mg inhaled insulin and 0.36 units/kg subcutaneous insulin. In addition, arterial peak concentration following insulin inhalation is two times greater than subcutaneous injection; however, the insulin is present in the circulation for half the time.

Ultrasonographic assessment of hemodynamic changes in the portal vein during surgical attenuation of congenital extrahepatic portosystemic shunts in dogs.

OBJECTIVE: To determine portal hemodynamic changes associated with surgical shunt ligation and establish ultrasonographic criteria for determining the optimal degree of shunt narrowing and predicting outcome. DESIGN: Case series. ANIMALS: 17 dogs, each with a single congenital extrahepatic portosystemic shunt. PROCEDURE: Pre- and postligation flow velocities and flow directions were determined by Doppler ultrasonography intraoperatively in the shunt and in the portal vein cranial and caudal to the shunt origin. Outcome was evaluated 1 month after surgery by measuring blood ammonia concentration and performing abdominal ultrasonography. RESULTS: Hepatofugal flow was detected in 9 of 17 dogs before shunt attenuation in the portal segment that was between the shunt origin and the entering point of the gastroduodenal vein. If hepatofugal flow became hepatopetal after shunt ligation, hyperammonemia resolved. Hepatofugal portal flow was caused by blood that flowed from the gastroduodenal vein toward the shunt. Shunt attenuation converted hepatofugal flow to hepatopetal in the shunt in 12 of 17 dogs. Chronic portal hypertension developed or perioperative death occurred when the portal congestion index caudal to the shunt origin increased by > 3.6 times. CONCLUSIONS AND CLINICAL RELEVANCE: After hepatopetal flow in the cranial portal vein and the shunt is established, further shunt narrowing is contraindicated. Increase of the portal congestion index caudal to the shunt > 3.5 times should be avoided. Poor outcome because of severe hypoplasia of the portal branches can be expected if the flow direction remains hepatofugal after shunt occlusion cranial to the shunt origin.

Assessment of vascular physiology of tumorous livers: comparison of two different methods.

RATIONALE AND OBJECTIVES: To evaluate liver and liver tumor perfusions by using two different modelling methods: gamma-variate fitting and a single-compartment model. MATERIALS AND METHODS: 5 New Zealand White rabbits with VX2 tumor implanted into the liver via portal injections were studied. Contrast-enhanced functional CT (fCT) examinations with temporal resolution of 200-500 milliseconds were conducted before tumor inoculation. Thereafter, two or three follow-up studies were conducted. A gamma-variate fitting method was used to determine fractional blood volumes (BV), and a single-compartment model method was used to determine fractional blood volumes (BV), blood flows (BF), and mean transit times (MTT) for normal and tumorous liver regions. RESULTS: For tumorous regions in liver, the gamma-variate fitting and the single-compartment model methods showed statistically significant increases in arterial perfusions (P < 0.01) and decreases in portal perfusions (P < 0.01 with single-compartment model, and P < 0.05 with gamma-variate fitting) when compared with normal liver regions. The single-compartment model showed statistically significant increases (P < 0.01) in MTTs in tumorous regions. In normal liver regions, portal BFs decreased and MTTs increased after tumor inoculation, but the changes were statistically not significant. CONCLUSION: The gamma-variate fitting and the single-compartment model methods showed definite differences in perfusions between normal and tumorous regions in liver. The single-compartment model showed slightly more distinction and was faster. More importantly, both methods can easily be applied in the clinical environment in the assessment of liver perfusion.

Multislice computed tomography in the preoperative assessment of adult-to-adult living donor liver transplantation: personal results.

PURPOSE: To evaluate the possible role of multislice spiral computed tomography (MSCT) as the sole imaging examination in the preoperative assessment of potential donors undergoing adult-to-adult living donor liver transplantation (LDLT). MATERIALS AND METHODS: Fifteen patients underwent MSCT with 0.5-second gantry rotation time. Pre- (4 X 2.5 mm collimation) and post-contrast (4 X 1 mm collimation) acquisitions during arterial and portal venous phases were performed after intravenous administration of 140 ml of non ionic contrast agent at 4-5 ml/s, with a delay time of 25 and 60 seconds, respectively. Pre-contrast scans with 80 and 140 kVp were acquired at the same level used to assess liver density. Real-time interaction with the post-contrast 3D data set was performed on a dedicated workstation to determine total and lobar liver volume, and to assess arterial and venous vascular anatomy. RESULTS: Steatosis was found in three patients, who as a consequence were excluded as possible candidates. MSCT correctly identified five cases of arterial anatomical variations: two cases of the right hepatic artery arising from the superior mesenteric artery, two cases of the common hepatic artery arising from the superior mesenteric artery and one case of the left hepatic artery arising from left gastric artery. In two cases portal trifurcation was considered a criterion for exclusion. A 4% error in the liver volume calculation was found at surgery, in no case considered significant. Two patients underwent surgery and three have been short-listed. CONCLUSIONS: MSCT enables complete preoperative evaluation of potential donors undergoing LDLT. Total and lobar volume determination provided accurate and reproducible information. MSCT enabled correct surgical planning without intra-operative complications. One of the limits of the technique was the poor visualization of the biliary anatomy with the need to perform an intraoperative cholangiography in all the patients.

Direct assessment and distribution of regional portal blood flow in the pig by means of fluorescent microspheres.

Measurement of regional organ blood flow by means of fluorescent microspheres (FM) is an accepted method. However, determination of regional portal blood flow (RPBF) cannot be performed by microspheres owing to the entrapment of the spheres in the upstream capillary bed of the splanchnic organs. We hypothesized that an adequate experimental setting would enable us to measure RPBF by means of FM and to analyze its distribution within the pig liver. A mixing chamber for the injection of FM was developed, and its capability to distribute FM homogeneously in the blood was evaluated in vitro. The chamber was implanted into the portal vein of six anesthetized pigs (23.5 +/- 2.9 kg body wt). Three consecutive, simultaneous injections of FM of two different colors into the chamber were performed. Reference portal blood samples were collected by means of a Harvard pump. At the end of the experiment, the liver was explanted and fixed in formalin before dissection. FM were isolated from the tissue samples by an automated process, and fluorescence intensity was determined. Comparison of 5,458 single RPBF values, determined by simultaneously injected FM, revealed good agreement (bias 2.5%, precision 12.7%) and high correlation (r = 0.97, r2 = 0,95, slope = 1.04, intercept = 0.05). Median RPBF was 1.07 +/- 0.78 ml x min(-1) x g(-1). Allocation of the blood flow values to the anatomic regions of the liver revealed a significantly higher RPBF (P = 0.01) in the liver tissue located close to the diaphragm compared with the rest of the organ and a significantly lower RPBF (P = 0.01) in the left liver lobe compared with the median and right lobes. The results show that the model presented makes it possible to measure RPBF by means of FM reliably and that RPBF is distributed heterogeneously in the porcine liver.

The high metabolic cost of a functional gut.

BACKGROUND & AIMS: Animal studies have shown that more than half of the dietary protein intake is used by the gut and that a large proportion of this utilization is devoted to (glyco-)protein synthesis. Recycling of these secretions may play a critical role in the regulation of overall dietary amino acid bioavailability. METHODS: Four piglets (age 32 days, 8-10 kg) bearing portal, arterial, and duodenal catheters and a portal flow probe were infused with a complete diet via the duodenum for 12 hours, followed by 12 hours of fasting. The portal balance of glucose and amino acids was measured throughout the 24-hour period. The animals also received duodenal and intravenous infusions of different lysine and threonine tracers. Measurements of intestinal tracer utilization and reappearance in the portal blood were used to calculate intestinal amino acid utilization and recycling. RESULTS: From 0 to 6 hours, one third of the protein intake appeared in the portal blood. As feeding continued, the portal glucose balance (60% of intake) was constant, but the net amino acid portal balance became progressively more positive. Significant net amino acid absorption continued for at least 6 hours after the cessation of feeding. Over 24 hours, 52% of the dietary protein intake appeared in the circulation and one third of this derived from recycled intestinal secretions. CONCLUSIONS: Intestinal recycling of amino acids contributes significantly to their systemic availability and may be a critical factor in amino acid nutrition.