Development of Smaller Artificial Ventricles and Valves Made by Vacuum Forming

Gm, Pantalos; By, Chaing; Dn, Bishop; Pa, Perkins; Ls, Yu; Jansen, J.A.; Pa, Socha; Marks, John D.; Jb, Riebman; Gl, Burns

doi:10.1177/039139888801100512

Cited by 9 publications

(3 citation statements)

References 5 publications

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“…The ventricle was fabricated with Pellethane (Dow Chemical Corp., D. S. Gilmore Laboratories, North Haven, collection port 4 valves + diaphragm + CT, U.S.A.) by vacuum-forming techniques (2), and the joints were sealed by radiofrequency welding (3). Scaled-down-version valves to fit in the small ventricle were also fabricated by the vacuumforming technique (2). The ventricle was connected to the blood reservoir by a quick-connect system previously developed in this laboratory (4).…”

Section: Methodsmentioning

confidence: 99%

Loss of Anticoagulant Effect of Heparin During Circulation of Human Blood In Vitro

et al. 1990

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Device‐induced thrombogenesis was studied in an in vitro model using human blood circulated through an artificial ventricle. A new constant pressure filtration technique was used to detect circulating microemboli, the activated partial thromboplastin time (APTT) test was used to monitor the blood for the presence of anticoagulant activity of heparin, and hemolysis was quantified by measuring the plasma free hemoglobin level. Circulation of blood through a 20‐ml stroke volume pneumatically driven ventricle for 6‐9 h resulted in a significant reduction of APTT, indicating the loss of the anticoagulant effect of heparin. Microemboli concentration was minimal until the APTT decreased below 125 s, at which time the microemboli concentration increased rapidly. This was presumed to be due to the formation of thrombi following a decrease in heparin activity. A significant increase in hemolysis was also noted when blood was pumped. None of these changes was noted in the nonpumped control blood. Spontaneous loss of heparin activity in blood circulated by a pneumatically driven pump may have clinical implications and may help understanding of the problems associated with device‐induced thrombogenesis.

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Section: Methodsmentioning

confidence: 99%

Loss of Anticoagulant Effect of Heparin During Circulation of Human Blood In Vitro

et al. 1990

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“…The base was covered by a semirigid polymer dome 20-mm high, with mounts for inflow (mitral) and outflow (aortic) prosthetic valves. The ventricular model 10 was fitted with a flexible polyurethane trileaflet inflow valve and a rigid tilting disc outflow valve (Medtronic Hall 25 mm, Medtronic, Inc., Minneapolis, MN), so that the predominant feature of the acceleration signal would be the outflow valve closing spike. 11 The downstream valve ring incorporated a short cylindrical section and a barb for connecting 25 mm Tygon tubing.…”

Section: Mock Circulationmentioning

confidence: 99%

The Influence of Mock Circulation Input Impedance on Valve Acceleration During In Vitro Cardiac Device Testing

Sharp¹,

Richards²,

Gillars³

et al. 2008

ASAIO Journal

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For a mechanical heart valve, a strong spike in pressure during closing is associated with valve wear and erythrocyte damage; thus, for valid in vitro testing, the mock circulation system should replicate the conditions, including pressure spikes, expected in vivo. To address this issue, a study was performed to investigate how mock circulation input impedance affects valve closure dynamics. A left ventricular model with polyurethane trileaflet inflow valve and tilting disc outflow valve was connected to a Louisville mock circulation system, which incorporates 2 adjustable flow resistors and 2 compliances. In the study, 116 cases matched zero frequency modulus well (982-1147 dyn x s/cm), but higher harmonics were purposely varied. Acceleration measured at the outflow valve ring (42.4-89.4 milli-Gs) was uncorrelated with impedance error (74.1-237 dyn x s/cm relative to target impedance), but was correlated with end-systolic impedance (1082-1319 dyn x s/cm) for cases with high zero frequency modulus, which exhibited just less than full ejection. These differences demonstrate that mock circulation response affects the magnitude of the closing spike, indicating that control of this parameter is necessary for authentic testing of valves. Correlation of acceleration to end-systolic impedance was weak for low zero frequency modulus, which tended toward full or hyperejection, reinforcing common laboratory observations that valve closing also depends on ventricular operating conditions.

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“…The Japanese are small in stature as compared to Europeans (1–4). The ventricular assist devices (VADs) presently available are designed in accordance with the physique of Europeans and Americans and are too large and heavy for the Japanese (5–9).…”

mentioning

confidence: 99%

Development of the Pulsation Device for Rotary Blood Pumps

et al. 2005

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A rotary blood pump (RP) is desirable as a small ventricular assist device (VAD). However, an RP is nonpulsatile. We tried to develop a device that attaches a pulse to the RP. We also tried to develop a pulse-generating equipment that was not air-pressure driven. The ball screw motor was considered a candidate. The application of a small-sized shape memory alloy was also attempted. An electrohydraulic system was adopted, and actuator power was connected to the diaphragm. The diaphragm was placed on the outer side of the ventricle. Most RPs that have been developed all over the world drain blood from the ventricle. The wave of a pulse should be generated if a pulse is added by the drawn part. The output assistance from the outer side of the ventricle was attempted in animal experiments, and the device operated effectively. This device can be used during implantable operation of RP. This may serve as an effective device in patients experiencing problems in peripheral circulation and in the function of internal organs.

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Development of Smaller Artificial Ventricles and Valves Made by Vacuum Forming

Cited by 9 publications

References 5 publications

Loss of Anticoagulant Effect of Heparin During Circulation of Human Blood In Vitro

Loss of Anticoagulant Effect of Heparin During Circulation of Human Blood In Vitro

The Influence of Mock Circulation Input Impedance on Valve Acceleration During In Vitro Cardiac Device Testing

Development of the Pulsation Device for Rotary Blood Pumps

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