Implantable Micropump System for Augmented Liver Perfusion

Marseille, O; Habib, Nagy; Reul, H.; Rau, G.

doi:10.1046/j.1525-1594.1998.06097.x

Cited by 12 publications

(12 citation statements)

References 5 publications

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“…40 To augment portal inflow, a miniature portal pump was used, which has been designed for human implantation. 19 Because the PV is larger in humans than the rabbit (average diameter 4 mm), the pump was placed in a viscoelastic cannula inserted into the proximal and distal portions of the PV. By using a Transonic flowmeter system, the portal inflow was monitored continuously to ensure a constant flow throughout the period of portal pumping.…”

Section: Discussionmentioning

confidence: 99%

“…After baseline readings in the hepatic fibrosis group, the animals were anticoagulated with 1,000 units of heparin intravenously. A miniature impeller pump as described previously 19 was placed in a viscoelastic cannula with ends tailed to 4 mm in diameter on either side. The cannula ends were inserted into the proximal and distal portions of the PV as shown schematically in Fig.…”

Section: Methodsmentioning

confidence: 99%

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The effect of mechanically enhancing portal venous inflow on hepatic oxygenation, microcirculation, and function in a rabbit model with extensive hepatic fibrosis

et al. 1999

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Enhancing the portal venous blood flow (PVBF) has been shown to reduce portal pressure and intrahepatic vascular resistance and to improve liver function in isolated cirrhotic rodent livers in vitro. The aim of this study was to assess the short-term effect of mechanically pumping the portal inflow on hepatic microcirculation (HM), oxygenation, and function in an animal model of extensive hepatic fibrosis. New Zealand white rabbits underwent laparotomy and exposure of the liver: group 1 (n ‫؍‬ 7) were normal controls; group 2 (n ‫؍‬ 7) had hepatic fibrosis. Total hepatic blood flow (THBF) and HM was measured along with continuous monitoring of intrahepatic tissue oxygenation using near infrared spectroscopy (NIRS). Baseline hepatic hemodynamics and liver function were measured in both groups. PVBF was then increased by 50% over a 3-hour period in the hepatic fibrosis group using a miniature portal pump designed for human implantation, and the hemodynamics were monitored continuously. Liver function tests were repeated after portal pumping. In comparison with normal controls, animals with hepatic fibrosis had a higher portal pressure (13.0 ؎ 3.6 vs. 3.7 ؎ 1.4 mm Hg, P F .001, mean ؎ SD vs. controls), reduced PVBF (52.4 ؎ 24.6 vs. 96.9 ؎ 21.1 mL/min, P ‫؍‬ .003), and increased portal vascular resistance (P ‫؍‬ .001). THBF and flow in the HM was lower than in controls, and liver function tests were abnormal. After a 3-hour period of enhanced portal flow in animals with hepatic fibrosis, the portal pressure greatly reduced (13.0 ؎ 3.6 to 2.5 ؎ 1.1 mm Hg, P F .001) as did the intrahepatic portal resistance ( Current aims in the management of portal hypertension are to reduce portal venous pressure (PVP), to increase blood flow through hepatic parenchyma, 1 and to decompress esophageal and gastric varices. 2,3 Reduction of PVP minimizes the risk of bleeding from varices, the likelihood of hepatic encephalopathy and problems relating to first pass uptake of drugs. 4 Reduced portal pressure also decreases intestinal venous congestion and could increase blood flow through the hepatic parenchyma and hence increase liver function. 5 In 1991, Habib et al. 6 first introduced the concept of mechanical pumping of portal blood to enhance hepatic portal inflow. Since then, we have seen a number of publications in this field. 7-10 Cardoso et al. [7][8][9] showed that augmenting portal inflow to isolated perfused cirrhotic rat and human livers decreased intrahepatic resistance without a change in intrahepatic shunting and resulted in liver function improvement. Bernadich et al. 10 found that in rats with portal hypertension owing to portal vein stenosis, mechanical portal pumping decreased portal pressure and portal-systemic shunting without having a significant effect on systemic hemodynamics. In cirrhosis, several early studies provided evidence that it was vasoactive mediators coupled with the extensive destruction of hepatocytes and nodular regeneration that contributed to the pathogenesis of portal hypertension. [11][12][13]...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

The effect of mechanically enhancing portal venous inflow on hepatic oxygenation, microcirculation, and function in a rabbit model with extensive hepatic fibrosis

et al. 1999

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“…A micropump for an implantable blood pump is a typical example of important micro mechanical systems applicable to bio-related fields. Of course, micropump systems are widely expected to apply for a variety of fields such as cooling pump for CPU generating a large amount of heat, fuel supplying pump for small fuel cells, medical fluid transportation pump and so on [3,4].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of microinducer by 5-axis control ultraprecision micromilling

et al. 2011

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“…The concept of placing a microaxial rotary blood pump within the portal vein of a cirrhotic patient has been previously reported (1)(2)(3)(4). The IMALP (Implantable Microsystems for Augmented Liver Perfusion) pump was developed via a project involving multi-partners in Europe funded by EEC (ESPRIT III IMALP project, No.…”

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confidence: 99%

Investigation of Materials for Blood‐Immersed Bearings in a Microaxial Blood Pump

Mahmood¹,

Kerkhoffs²,

Schumacher³

et al. 2003

Artificial Organs

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Rotary blood pumps are gaining popularity among cardiothoracic surgeons. This article presents an in vitro investigation for choosing a suitable mechanical bearing system in a medium-long term microaxial pump. Different metallic, polymeric, and ceramic components are introduced. Polymers displayed mechanical insufficiency for the application, whereas certain ceramics displayed an inconsistent pattern of failure. We are in search of a compromise in properties that would favor a durable material combination.

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Implantable Micropump System for Augmented Liver Perfusion

Cited by 12 publications

References 5 publications

The effect of mechanically enhancing portal venous inflow on hepatic oxygenation, microcirculation, and function in a rabbit model with extensive hepatic fibrosis

The effect of mechanically enhancing portal venous inflow on hepatic oxygenation, microcirculation, and function in a rabbit model with extensive hepatic fibrosis

Fabrication of microinducer by 5-axis control ultraprecision micromilling

Investigation of Materials for Blood‐Immersed Bearings in a Microaxial Blood Pump

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