Publications by authors named "Michael D Rizzari"

Background: Recent trials in liver machine perfusion (MP) have revealed unique challenges beyond those seen in most clinical studies. Correct trial design and interpretation of data are essential to avoid drawing conclusions that may compromise patient safety and increase costs.

Methods: The International Liver Transplantation Society, through the Special Interest Group "DCD, Preservation and Machine Perfusion," established a working group to write consensus statements and guidelines on how future clinical trials in liver perfusion should be designed, with particular focus on relevant clinical endpoints and how different techniques of liver perfusion should be compared.

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Background: Portal vein thrombosis (PVT) makes the technical aspect of liver transplantation challenging and also affects outcomes. Our aim was to study impact of PVT grade and postreperfusion portal flow on posttransplant outcomes.

Methods: Patients who underwent transplantation with PVT between January 2007 and May 2017 were selected (n = 126).

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Appropriate graft regeneration after living donor liver transplantation (LDLT) is crucial to avoid small-for-size syndrome. We enrolled 44 recipients who underwent ABO-identical/compatible LDLT from December 2007 to August 2016 and determined possible factors associated with low graft regeneration after LDLT. Liver regeneration was calculated by the ratio of the graft size on postoperative day (POD) 7 ± 1 day (calculated by CT volumetry) to the size of the donated liver at implant.

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Background: Adenoviruses are double-stranded DNA viruses that typically cause mild self-limiting respiratory, ocular, and gastrointestinal infections. In immunocompromised patients, especially transplant recipients, the infection can be severe, with dissemination and multiorgan failure. In intestinal transplant recipients, the incidence is as high as 57%.

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Biliary stricture is a common cause of morbidity after liver transplantation (LT). This study aimed to determine the risk factors for post-transplant biliary anastomotic strictures (BAS), focusing on perioperative platelet counts. We enrolled 771 consecutive recipients who underwent ABO-identical/compatible deceased donor LT with duct-to-duct biliary reconstruction from January 2000 to June 2012.

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Background: The positive impact of platelets has been recently implicated in liver transplantation (LT). The aim of this study was to determine the risk factors for graft loss and mortality after LT, focusing on perioperative platelet counts.

Methods: We reviewed all deceased donor LT from 2000 to 2012 and enrolled 975 consecutive recipients.

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Islet transplantation (ITx) is an emerging and promising therapy for patients with uncontrolled type 1 diabetes. The islet isolation and purification processes require exposure to extended cold ischemia, warm-enzymatic digestion, mechanical agitation, and use of damaging chemicals for density gradient separation (DG), all of which reduce viable islet yield. In this paper, we describe initial proof-of-concept studies exploring quadrupole magnetic separation (QMS) of islets as an alternative to DG to reduce exposure to these harsh conditions.

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Objective: The objective of this study was to determine the fate of patients who attempted to donate organs after circulatory death (DCD) using a standardized DCD protocol.

Background: Successful donation is not always possible after attempted DCD.

Methods: Data were collected for all DCD donors between 1/2011 and 9/2014.

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Porcine islet xenotransplantation is a promising alternative to human islet allotransplantation. Porcine pancreas cooling needs to be optimized to reduce the warm ischemia time (WIT) following donation after cardiac death, which is associated with poorer islet isolation outcomes. This study examines the effect of four different cooling Methods on core porcine pancreas temperature (n = 24) and histopathology (n = 16).

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Hypertension (HTN) is common in pediatric recipients following kidney transplantation (KT). We retrospectively assessed the impact of HTN on long-term (>10-yr) outcomes in pediatric KT recipients (aged < 18 yr) at our center. Two hundred and ninety-three pediatric KT recipients (83% living donor [LD]) with graft survival (GS) for ≥5 yr were studied.

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Persufflation (PSF; gaseous oxygen perfusion) is an organ preservation technique with a potential for use in donor heart preservation. Improved heart preservation with PSF may improve outcomes by maintaining cardiac tissue quality in the setting of longer cold ischemia times and possibly increasing the number of donor hearts available for allotransplant. Published data suggests that PSF is able to extend the cold storage times for porcine hearts up to 14 hours without compromising viability and function, and has been shown to resuscitate porcine hearts following donation after cardiac death.

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Background: Gaseous insufflation of oxygen via the venous vascular system has proven to be an effective tool for preventing anoxic tissue injury after extended time periods of ischemic liver preservation. Most experimental studies so far have been undertaken in rat models and include a series of pinpricks into postsinusoidal venules as an outlet for the insufflated gas. Here, we describe a simplified technique for minimally invasive liver oxygenation in porcine grafts, representing a hassle-free access to organ oxygenation without vascular lesions.

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Improved preservation techniques have the potential to improve transplant outcomes by better maintaining donor organ quality and by making more organs available for allotransplantation. Persufflation, (PSF, gaseous oxygen perfusion) is potentially one such technique that has been studied for over a century in a variety of tissues, but has yet to gain wide acceptance for a number of reasons. A principal barrier is the perception that ex vivo PSF will cause in vivo embolization post-transplant.

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Background And Objectives: Rapid discontinuation of prednisone after kidney transplantation potentially allows for minimization of steroid-related side effects. Although intermediate-term data with rapid discontinuation of prednisone have been promising, concern still exists regarding long-term outcomes. The 10-year experience is reported herein.

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Individuals with kidneys having ≥ 2 arteries appear to have an increased incidence of hypertension. Whether kidney donors in whom the remaining kidney has ≥ 2 arteries are at increased risk of hypertension is unknown. Therefore, we studied 3685 kidney donors to determine whether donors left with a kidney having ≥ 2 arteries were at increased risk of hypertension, impaired renal function, or death.

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Background: Paramagnetic microparticles (MPs) may be useful in pancreatic islet purification, in particular purification of porcine islets as a potential xenotransplantation product. We assessed whether MPs affect islet function or induce an adverse effect following implantation.

Methods: Porcine islets were co-cultured with 0, 500, and 1500 MPs per islet equivalent (IE) for 1 day and with 0 and 1500 MPs/IE for 7 days.

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Background: Defining living donor (LD)-related risk factors affecting kidney transplant outcome will allow better donor selection and more educated informed consent when there is more than one potential donor. We studied risk factors in a large cohort at a single institution.

Methods: We reviewed 1632 recipients who underwent LD kidney transplantation at the University of Minnesota between January 1, 1990, and October 1, 2009.

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