Aortic Root Compliance Influences Hemolysis in Mechanical Heart Valve Prostheses: An In-Vitro Study

• Published in: International journal of artificial organs Vol. 35; no. 7; pp. 495 - 502
• Main Authors: Linde, Torsten, Hamilton, Kathrin F., Navalon, Elena Cuenca, Schmitz-Rode, Thomas, Steinseifer, Ulrich
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01-07-2012; Wichtig
• Subjects: Acoustics; Aging; Animals; Aorta - physiopathology; Aortic Valve - physiopathology; Biological and medical sciences; Compliance; Heart Valve Prosthesis - adverse effects; Heart Valve Prosthesis Implantation - instrumentation; Hemolysis; Materials Testing; Medical sciences; Prosthesis Design; Sound Spectrography; Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases; Surgery of the heart; Swine; Time Factors; Vascular Stiffness; Hemolysis; Heart valve prosthesis; Windkessel; In-vitro testing; Valve dynamics; Cavitation; Mechanical prosthesis; Heart valve; In vitro; Artery; Pig; Biomechanics; Vertebrata; Compliance (volume pressure); Mammalia; Blood vessel; Animal; Aorta; Complication; Stiffness; Circulatory system; Artiodactyla; Ungulata; Comparative study
• ISSN: 0391-3988; 1724-6040
• DOI: 10.5301/ijao.5000108

Mechanical heart valve prostheses are known to activate coagulation and cause hemolysis. Both are particularly dependent on the leaflet dynamics, which in turn depends on the flow field in the aortic root influenced by the aortic root geometry and its compliance. Compliance reduction of large vessels occurs in aging patients, both in those who have atherosclerotic diseases and those who do not. In this study we investigated the correlation between hemolysis and the compliance of the proximal aorta in a novel, pulsatile in vitro blood tester using porcine blood. Two mechanical heart valves, the St Jude Medical (SJM) bileaflet valve and a trileaflet valve prototype (Triflo) were tested for hemolysis under physiological conditions (120/80 mm Hg, 4.5 l/min, 70 bpm) and using two different tester setups: with a stiff aorta and with a compliant aorta. Valve dynamics were subsequently analyzed via high-speed videos. In the tests with the Triflo valve, the free plasma hemoglobin increased by 13.4 mg/dl for the flexible and by 19.3 mg/dl for the stiff setup during the 3-hour test. The FFT spectra and closing speed showed slight differences for both setups. Free plasma hemoglobin for the SJM valve was up by 22.2 mg/dl in the flexible and 42.7 mg/dl in the stiff setup. Cavitation induced by the higher closing speed might be responsible for this, which is also indicated by the sound spectrum elevation above 16 kHz.