Biomaterial Database

Haemodynamic consequences of arterial replacement with a synthetic graft. 1986

R F Appleyard, and L R Sauvage

Because of structural differences between a synthetic graft and the natural artery, a graft would be expected to alter the haemodynamics of the vessel which is bypassed. To examine this, a segment of the lower descending thoracic aorta in six calves was removed and replaced with a Dacron graft. The gradients in pressure and flow across this segment were calculated from simultaneous measurements of pressure and flow made at both ends. From these, the longitudinal (Zl) and transverse (Zt) impedance of the segment was computed. In three animals pressure and flow were measured in the ascending aorta so that the systemic input impedance (Zi) could also be computed. Neither the magnitude nor phase of Zl was affected by the graft. However, the magnitude of Zt was approximately five times higher at all frequencies above DC following insertion of the graft. The characteristic impedance (Zo) was computed from Zl and Zt. Zo for the aortic segment remained approximately constant between 20 and 40 Pa X s X cm-3 for the first 10 harmonics. In contrast, Zo for the graft was strongly frequency dependent, and progressively increased in magnitude up through the tenth harmonic. The input impedance at the entrance to the segment (Zx) was strongly influenced by Zo. As a result, the higher frequency components of Zx were increased following insertion of the graft. In spite of these local changes in impedance, Zi was not affected by the graft. This was probably due to effective filtering by the healthy, compliant aorta left intact between the graft and the left ventricle.

UI	MeSH Term	Description	Entries
D008297	Male		Males
D001783	Blood Flow Velocity	A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.	Blood Flow Velocities,Flow Velocities, Blood,Flow Velocity, Blood,Velocities, Blood Flow,Velocity, Blood Flow
D001794	Blood Pressure	PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.	Systolic Pressure,Diastolic Pressure,Pulse Pressure,Pressure, Blood,Pressure, Diastolic,Pressure, Pulse,Pressure, Systolic,Pressures, Systolic
D002417	Cattle	Domesticated bovine animals of the genus Bos, usually kept on a farm or ranch and used for the production of meat or dairy products or for heavy labor.	Beef Cow,Bos grunniens,Bos indicus,Bos indicus Cattle,Bos taurus,Cow,Cow, Domestic,Dairy Cow,Holstein Cow,Indicine Cattle,Taurine Cattle,Taurus Cattle,Yak,Zebu,Beef Cows,Bos indicus Cattles,Cattle, Bos indicus,Cattle, Indicine,Cattle, Taurine,Cattle, Taurus,Cattles, Bos indicus,Cattles, Indicine,Cattles, Taurine,Cattles, Taurus,Cow, Beef,Cow, Dairy,Cow, Holstein,Cows,Dairy Cows,Domestic Cow,Domestic Cows,Indicine Cattles,Taurine Cattles,Taurus Cattles,Yaks,Zebus
D006439	Hemodynamics	The movement and the forces involved in the movement of the blood through the CARDIOVASCULAR SYSTEM.	Hemodynamic
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D001013	Aorta, Thoracic	The portion of the descending aorta proceeding from the arch of the aorta and extending to the DIAPHRAGM, eventually connecting to the ABDOMINAL AORTA.	Aorta, Ascending,Aorta, Descending,Aortic Arch,Aortic Root,Arch of the Aorta,Descending Aorta,Sinotubular Junction,Ascending Aorta,Thoracic Aorta,Aortic Roots,Arch, Aortic,Ascending Aortas,Junction, Sinotubular,Root, Aortic,Sinotubular Junctions
D014655	Vascular Resistance	The force that opposes the flow of BLOOD through a vascular bed. It is equal to the difference in BLOOD PRESSURE across the vascular bed divided by the CARDIAC OUTPUT.	Peripheral Resistance,Total Peripheral Resistance,Pulmonary Vascular Resistance,Systemic Vascular Resistance,Peripheral Resistance, Total,Resistance, Peripheral,Resistance, Pulmonary Vascular,Resistance, Systemic Vascular,Resistance, Total Peripheral,Resistance, Vascular,Vascular Resistance, Pulmonary,Vascular Resistance, Systemic
D019736	Prostheses and Implants	Artificial substitutes for body parts, and materials inserted into tissue for functional, cosmetic, or therapeutic purposes. Prostheses can be functional, as in the case of artificial arms and legs, or cosmetic, as in the case of an artificial eye. Implants, all surgically inserted or grafted into the body, tend to be used therapeutically. IMPLANTS, EXPERIMENTAL is available for those used experimentally.	Implants, Artificial,Prostheses and Implant,Prosthesis,Prosthetic Implant,Endoprostheses,Endoprosthesis,Prostheses,Prosthetic Implants,Artificial Implant,Artificial Implants,Implant and Prostheses,Implant, Artificial,Implant, Prosthetic,Implants and Prostheses,Implants, Prosthetic