title: Chronic in vivo testing of the Penn State infant ventricular assist device.
abstract: The Penn State Infant Ventricular Assist Device (VAD) is a 12-14 ml stroke volume pneumatically actuated pump, with custom Björk-Shiley monostrut valves, developed under the National Heart, Lung, and Blood Institute Pediatric Circulatory Support program. In this report, we describe the seven most recent chronic animal studies of the Infant VAD in the juvenile ovine model, with a mean body weight of 23.5 ± 4.1 kg. The goal of 4-6 weeks survival was achieved in five of seven studies, with support duration ranging from 5 to 41 days; mean 26.1 days. Anticoagulation was accomplished using unfractionated heparin, and study animals were divided into two protocol groups: the first based on a target activated partial thromboplastin time of 1.5-2 times normal, and a second group using a target thromboelastography R-time of two times normal. The second group required significantly less heparin, which was verified by barely detectable heparin activity (anti-Xa). In both groups, there was no evidence of thromboembolism except in one animal with a chronic infection and fever. Device thrombi were minimal and were further reduced by introduction of the custom valve. These results are consistent with results of adult VAD testing in animals and are encouraging given the extremely low levels of anticoagulation in the second group.
authors.affiliation: Department of Surgery, Penn State College of Medicine, Hershey, Pennsylvania, USA. bweiss@psu.edu
authors.forename: William J
authors.initials: WJ
authors.lastname: Weiss
authors.forename: Elizabeth L
authors.initials: EL
authors.lastname: Carney
authors.forename: J Brian
authors.initials: JB
authors.lastname: Clark
authors.forename: Rebecca
authors.initials: R
authors.lastname: Peterson
authors.forename: Timothy K
authors.initials: TK
authors.lastname: Cooper
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Nifong
authors.forename: Christopher A
authors.initials: CA
authors.lastname: Siedlecki
authors.forename: Dennis
authors.initials: D
authors.lastname: Hicks
authors.forename: Bradley
authors.initials: B
authors.lastname: Doxtater
authors.forename: Branka
authors.initials: B
authors.lastname: Lukic
authors.forename: Eric
authors.initials: E
authors.lastname: Yeager
authors.forename: John
authors.initials: J
authors.lastname: Reibson
authors.forename: Joshua
authors.initials: J
authors.lastname: Cysyk
authors.forename: Gerson
authors.initials: G
authors.lastname: Rosenberg
authors.forename: William S
authors.initials: WS
authors.lastname: Pierce
mesh_terms: D000818:Animals; D000925:Anticoagulants / Q000627:therapeutic use; D002309:Cardiology / Q000295:instrumentation*; D002908:Chronic Disease; D005334:Fever; D019918:Heart Valve Prosthesis Implantation; D006353:Heart-Assist Devices; D006493:Heparin / Q000627:therapeutic use; D008422:Materials Testing; D023421:Models, Animal; D010314:Partial Thromboplastin Time; D011474:Prosthesis Design; D012756:Sheep; D016896:Treatment Outcome
chemical_list: D000925:Anticoagulants; D006493:Heparin