Thrombogenic performance of a st. Jude bileaflet mechanical heart valve in a sheep model.
The sheep model is preferred for chronic evaluation of prosthetic heart valves, surgical techniques, and endocardiographic studies. A bileaflet mechanical heart valve (MHV) was implanted into a sheep model to study its in vivo performance and to evaluate the thrombogenic potential of the valve. Transesophageal echocardiography and transcranial Doppler ultrasonography measurements were conducted before and after the valve implantation. Platelet activity state (PAS) assay measurements were also conducted before and after the implantation surgery. After sheep euthanasia, the MHV was explanted and scanning electron microscopy (SEM) was performed on the explanted valve to examine changes to the MHV surface. Tissue blocks were taken from the sheep brain, left ventricle, aorta, spleen, and lung lobes for histological examination. Our results indicated that after the MHV implantation, more embolic signals were detected in the sheep carotid artery, increasing monotonously as a function of implantation time. Echocardiographic parameters including blood aortic velocity, transvalvular pressure gradient, and velocity time integral increased. PAS increased significantly after valve implantation. SEM pictures demonstrated calcium and phosphate deposition on the valve surfaces. Histological examination demonstrated hemorrhage in the lung tissue, pulmonary thrombosis, and osteogenesis in heart tissue.
Yin
Wei
W
Department of Biomedical Engineering, Division of Hematology, Stony Brook University, Stony Brook, NY, USA.
Krukenkamp
Irvin B
IB
Saltman
Adam E
AE
Gaudette
Glenn
G
Suresh
Krishnamurthy
K
Bernal
Oscar
O
Jesty
Jolyon
J
Bluestein
Danny
D
D000818:Animals; D001011:Aorta / Q000503:physiopathology; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000601:surgery; D001783:Blood Flow Velocity; D001792:Blood Platelets / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002339:Carotid Arteries / Q000503:physiopathology; D017548:Echocardiography, Transesophageal; D005260:Female; D005500:Follow-Up Studies; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects*; D008855:Microscopy, Electron, Scanning; D010710:Phosphates / Q000378:metabolism; D015539:Platelet Activation; D011474:Prosthesis Design; D012756:Sheep; D013927:Thrombosis / Q000209:etiology* / Q000473:pathology; D013997:Time Factors; D016896:Treatment Outcome; D017585:Ultrasonography, Doppler, Transcranial
D010710:Phosphates; D002118:Calcium