Portal venous arterialization resulting in increased portal inflow and portal vein wall thickness in rats

AIM： To explore the influence of portal vein hemodynamic changes after portal venous arterialization （PVA） on peribiliary vascular plexus （PVP） morphological structure and hepatic pathology, and to establish a theoretical basis for the clinical application of PVA. METHODS： Sprague-Dawley rats were randomly divided into control and PVA groups. After PVA, hemodynamic changes of the portal vein and morphological structure of hepatohilar PVP were observed using Doppler ultrasound, liver function tests, ink perfusion transparency management and three-dimensional reconstruction of computer microvisualization, and pathological examination was performed on tissue from the bile duct wall and the liver. RESULTS： After PVA, the cross-sectional area and blood flow of the portal vein were increased, and the increase became more significant over time, in a certain range. If the measure to limit the flow in PVA was not adopted, the high blood flow would lead to dilatation of intrahepatic portal vein and its branches, increase in collagen and fiber degeneration in tunica intima. Except glutamic pyruvic transaminase （GPT）, other liver function tests were normal. CONCLUSION： Blood with a certain flow and oxygen content is important for filling the PVP and meeting the oxygen requirement of the bile duct wall. After PVA, It is the anatomic basis to maintain normal morphology of hepatohilar bile duct wall that the blood with high oxygen content and high flow in arterialized portal vein may fill PVP by collateral vessel reflux. A adequate measure to limit blood flow is necessary in PVA.

Effects of portal venous arterialization on acute occlusion of hepatic artery in rats

Background A fatal complication after liver transplantation is anastomotic embolization of the hepatic artery. In order to solve this problem, the portal venous arterialization （PVA） is used to reconstruct the hepatic arterial blood flow. The purpose of this study was to investigate the influence of PVA on rats with acute occlusion of hepatic artery. Methods Rat PVA models were established and then randomly divided into Group 1 （control group）, Group 2 （jaundice group）, Group 3 （bile duct recanalization group）, and Group 4 （portal vein arterilization group）. Recanalization of the common bile duct and PVA were performed 5 days after bile duct ligation in the rats. The influence of the PVA on general conditions, hepatic changes of structure and function, portal vein pressure and hepatic micrangium were observed for one month. Results Five days after common bile duct ligation the serum bilirubin, transaminase and alkaline phosphatase levels were significantly increased. Compared with group 1, there was a statistically significant difference （P 〈0.01）. These rats then underwent bile duct recanalization and PVA. After a month, the liver functions and microscopic structures completely returned to normal and, compared with group 1, there was no statistically significant difference in portal vein pressure （P 〉0.05）. Vascular casting samples showed that hepatic sinusoids were slightly thicker and more filled than normal ones and although they had some deformations, the hepatic sinusoids were still distributed around the central vein in radial form. Conclusion Within a month after operation, bile duct recanalization and PVA do not show obvious adverse effects on liver hemodynamics and hepatic micrangium, and the liver function and microscopic structure can return to normal.

Immuohistochemical study on smooth muscle cell proliferation, pheno-typic modulation, and extracellular matrix accumulation in venous arterial grafts in rabbits

Objective: To study the kinetics and distribution of smooth muscle cell (SMC) proliferation, phe-notypic modulation, and various extracellular matrix (ECM) components accumulation during vein graft remodeling. Methods: Normal vein and vein graft in carotid arteries were examined on d 4, d 7, d 14, d 60 and d180 after bypass grafting with immunohistochemical markers of cellular proliferation (proliferating cell nuclear antigen, PCNA), cytoskeletal protein production (a-actin SMC), myosin heavy chain (MHO iso-forms, ECM proteins, and histochemistry (hematoxylin eosin and Elastica-van Gieson stain). Results: Normal veins demonstrated an extremely low level of cellular proliferation and expressed as adult phenotype SM-Cs in media. After bypass grafting, medial SMCs in the graft appeared to be damaged and began to proliferate on d 4, and subsequently migrated and formed the neointima on d 7. Thereafter, the neointima thickened throughout the 180-day period of the experiment, although the neointimal SMC proliferation decreased after d 14. Meanwhile SMCs underwent a distinct phenotypic change from normal adult type to embryonic type. On d 60, embryonic phenotype SMCs began to return to the adult phenotype, but remain to be present in the neointima for as long as 180 d. ECM components including type I collagen, heparin sulfate proteoglucan (HSPG), and dermatan sulfate proteoglcan (decorin) were detected within the neointima on d 7. Thereafter, the accumulation of ECM increased progressively with time. On d 180, a large amount of ECM components were found in the neointima. HSPG mainly accumulated in the superficial and cellular region of the neointima , decorin, on other hand, located in hypocellular area deep in neointima. Type I collagen scatted in both regions. The elastic fibers became rich and arranged continuously in the neointima. Conclusion: The neointima of vein graft was initially formed by proliferation of the embryonic-type SMCs and then thickened infinitely due to ECM accumulation. Prolonged existence of the embryonic-type SMCs in the neointima may contribute to ECM accumulation and increase in the neointima thickness infinitely, which may predispose accelerated stenosis in the vein graft.

Off-pump sequential bilateral internal mammary artery grafting combined with selective arterialization of the coronary venous system

Background Off-pump coronary artery bypass surgery （OPCAB） has been widely applied in recent years as a less invasive method of myocardial revascularization. This study evaluated the sequential bilateral internal mammary artery grafting combined with selective arterialization of the coronary venous system during OPCAB.Methods From April 2004 to August 2010, patients with diffuse right coronary lesions were studied retrospectively and divided into two groups. Group 1 included seventeen patients who underwent this surgery while group 2 included twenty-one patients without right coronary artery surgical therapy. All patients presented with symptoms of angina. Blood flow of bridged vessels was measured. The perioperative ventricular parameters including left ventricular ejection fraction and end diastolic diameter were compared. During follow-up, myocardial nuclide imaging and coronary angiography were carried out.Results Off-pump coronary artery bypass was performed with an average of 3.6 grafts per patient. Hospital mortality was zero. At the time of follow-up, the patients in group 1 recovered better than in group 2 （P〈0.05）. In both groups, the mean New York Heart Association （NYHA） class and ejection fraction increased significantly （P〈0.001） and the mean left ventricular end-diastolic diameter decreased significantly （P 〈0.05）. Myocardial blood supply of inferior wall in group 1 was obviously improved by myocardial nuclide imaging. Coronary angiography for eight patients in group 1 verified that there was blood flow to myocardium in the arterialized vein.Conclusions Sequential bilateral internal mammary artery grafting combined with selective arterialization of the coronary venous system can be performed during OPCAB. A postoperative improvement in the cardiac functions and the quality of life was documented, increasing our expectation for extensive application.

A case with insulinoma localized by combined use of various means

A patient with insulinoma diagnosed by clinical features and localized preoperatively using a combination of contrast-enhanced ultrasonography （CEUS）, dual phase contrast enhanced spiral computed tomography （DPSCT） and arterial stimulation and venous sampling （ASVS） was reported. A 37-year-old man was admitted to our hospital because of hypoglycemic attacks, palpitations, and muscular weakness. Fajans＇ ratio reported to be an index for insulinoma was positive. Transabdominal computed tomography and ultrasonography failed to detect any abnormalities. CEUS showed a small low echoic lesion in the pancreatic body with blood flow and the early arterial phase of DPSCT revealed a small strengthening focus, which mimicked a pancreatic tumor in the pancreatic body. ASVS showed that the insulin levels in the hepatic vein were extremely increased by calcium injection to the gastroduodenal artery. An open intra-abdominal operation was performed and an insulinoma was confirmed in the pancreatic body. Enucleation of tumor was undertaken and histopathological examination showed an adenoma, insulin expression was positive in immunofluorescence staining.Symptomatic hypoglycemia never happened even without glucose infusion since the operation. His blood glucose level improved to within the normal range.