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Titolo:
TURBULENT STRESSES DOWNSTREAM OF 3 MECHANICAL AORTIC-VALVE PROSTHESESIN HUMAN-BEINGS
Autore:
NYGAARD H; PAULSEN PK; HASENKAM JM; PEDERSEN EM; ROVSING PE;
Indirizzi:
AARHUS UNIV HOSP,SKEJBY SYGEHUS,DEPT CARDIOTHORAC SURG DK-8200 AARHUSN DENMARK AARHUS UNIV HOSP,SKEJBY SYGEHUS,DEPT THORAC & CARDIOVASC SURG AARHUS DENMARK AARHUS UNIV HOSP,COLL ENGN AARHUS DENMARK AARHUS UNIV,INST EXPTL CLIN RES AARHUS DENMARK AARHUS UNIV,CARDIOVASC RES CTR AARHUS DENMARK
Titolo Testata:
Journal of thoracic and cardiovascular surgery
fascicolo: 2, volume: 107, anno: 1994,
pagine: 438 - 446
SICI:
0022-5223(1994)107:2<438:TSDO3M>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
PULSATILE FLOW; SHEAR-STRESS; HEART-VALVES; INVITRO; VELOCITY; VICINITY; REPLACEMENT; AGGREGATION; HEMOLYSIS; STENOSIS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
39
Recensione:
Indirizzi per estratti:
Citazione:
H. Nygaard et al., "TURBULENT STRESSES DOWNSTREAM OF 3 MECHANICAL AORTIC-VALVE PROSTHESESIN HUMAN-BEINGS", Journal of thoracic and cardiovascular surgery, 107(2), 1994, pp. 438-446

Abstract

High levels of turbulent stresses resulting from disturbed blood flowmay cause damage to red blood cells and platelets. The purpose of this study was to evaluate the spatial distribution and temporal development of turbulent stresses downstream of three mechanical aortic valve prostheses in human subjects: the St. Jude Medical, the CarboMedics, and the Starr-Edwards silicone rubber ball. Blood velocity measurementswere taken at 17 measuring points in the cross-sectional area of the ascending aorta 5 to 6 sm downstream of the aortic anulus with the useof a perivascular pulsed Doppler ultrasound system. Turbulence analysis was done for each of the 17 measuring points by calculating the radial Reynolds normal stresses within 50 msec overlapping time windows during systole. By coordinating the calculated Reynolds normal stress values for each time window and for all measuring points, computerized two-dimensional color-coded mapping of the turbulent stress distribution during systole was done. For the St. Jude Medical valves the highest Reynolds normal stress (27 to 63 N/m(2)) were found along the central slit near the vessel walls. The temporal development and spatial distribution of Reynolds normal stresses for the CarboMedics valves were quite similar to those of the St. Jude Medical valves with maximum Reynolds normal stress values ranging from 19 to 72 N/m(2). The typical Reynolds normal stress distribution for the Starr-Edwards silicone rubber ball valves was asymmetric, revealing the highest Reynolds normal stresses, (11 to 56 N/m(2)) at various locations in the annular region between the ball and the vessel wall. The spatial distribution and temporal development of turbulent stresses downstream of the three investigated mechanical aortic valve prostheses correlated well with the superstructure of the valves. The maximum Reynolds normal stresses for the three valve types were in the same order of magnitude with exposure times sufficient to cause sublethal damage to red blood cells and platelets.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/09/20 alle ore 08:00:32