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Lemos BLHD, Bortolin VAA, de Lima Amaral R, Mazzetto M, Cestari IA, Meneghini JR. Effect of the bileaflet inlet valve angle on the flow of a pediatric ventricular assist device: experimental analysis. Artif Organs 2022; 46:1833-1846. [PMID: 35524699 DOI: 10.1111/aor.14282] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Revised: 03/29/2022] [Accepted: 04/29/2022] [Indexed: 12/01/2022]
Abstract
BACKGROUND Mechanical heart valves (MHV) and its fluid dynamics inside a pulsatile pediatric ventricular assist device (PVAD) can be associated with blood degradation. In this paper, flow structures are analyzed and compared by an experimental investigation on the effect of bileaflet MHV positioned at varying angles in the inlet port orifice of a PVAD. METHODS Time-resolved particle image velocimetry (TR-PIV) was applied to characterize the internal flow of the device. St Jude Medical bileaftlet valves were used on the inlet orifice and positioned at 0°, 15°, 30°, 45°, 60°, and 90° in relation to the centerline of the device. Three planes with bidimensional velocity magnitude fields were considered in the analysis with visualization of diastolic jets, device wall washing patterns and flow circulation during emptying or systole of the pump. Also, the washing vortex area, and vertical velocity probabilities of regurgitant flows in the inlet valve were evaluated. RESULTS The results show that a variation in the angle of the MHV at the inlet port produced distinct velocities, fluid structures, and regurgitant flow probabilities within the device. MHV positioned at an angle of 0° generated the strongest inlet jet, larger vortex area during filling, more prominent outgoing flow, and less regurgitation compared to the angles studied. The presence of unfavorable fluid structures, such as small vortices, and/or sudden flow structure interruption, and/or regurgitation, were identified at 45° and 90° angles. CONCLUSIONS The 0° inlet angle had better outcomes than other angles due to its consistency in the multiple parameters analyzed.
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Affiliation(s)
| | | | - Rodrigo de Lima Amaral
- Escola Politécnica da Universidade de São Paulo (EP USP), Av. Prof. Mello Moraes 2231, São Paulo, Brazil
| | - Marcelo Mazzetto
- Bioengineering Laboratory, Heart Institute, Hospital das Clínicas, HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, Av. Dr. Enéas Carvalho de Aguiar 44, São Paulo, Brazil
| | - Idágene Aparecida Cestari
- Bioengineering Laboratory, Heart Institute, Hospital das Clínicas, HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, Av. Dr. Enéas Carvalho de Aguiar 44, São Paulo, Brazil
| | - Julio Romano Meneghini
- Escola Politécnica da Universidade de São Paulo (EP USP), Av. Prof. Mello Moraes 2231, São Paulo, Brazil
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Bazan O, Ortiz JP. Duration of Systole and Diastole for Hydrodynamic Testing of Prosthetic Heart Valves: Comparison Between ISO 5840 Standards and in vivo Studies. Braz J Cardiovasc Surg 2016; 31:171-3. [PMID: 27556318 PMCID: PMC5062727 DOI: 10.5935/1678-9741.20160036] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 04/25/2016] [Indexed: 11/22/2022] Open
Abstract
Objective To complement the ISO 5840 standards concerning the duration of left
ventricular systole and diastole as a function of changes in heart rates
according to in vivo studies from the physiologic literature review. Methods The systolic and diastolic durations from three in vivo
studies were compared with the durations of systole proposed by the ISO
5840:2010 and ISO 5840-2:2015 for hydrodynamic performance assessment of
prosthetic heart valves. Results Based on the in vivo studies analyzed, the systolic
durations proposed by the ISO 5840 standard seemed consistent for 45 and 120
beats per minute (bpm), and showed diverse results for the 70 bpm
condition. Conclusion Information on the realistic validation of the operation of left ventricular
models for different heart rates were obtained.
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Affiliation(s)
- Ovandir Bazan
- Department of Mechanical Engineering, Escola Politécnica, University of São Paulo, Brazil
| | - Jayme Pinto Ortiz
- Department of Mechanical Engineering, Escola Politécnica, University of São Paulo, Brazil
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Malota Z, Sadowski W, Krzyskow M, Stolarzewicz B. The Application of Bileaflet Mechanical Heart Valves in the Polish Ventricular Assist Device: Physical and Numerical Study and First Clinical Usage. Artif Organs 2015; 40:252-60. [DOI: 10.1111/aor.12554] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
| | | | - Marek Krzyskow
- Foundation for Cardiac Surgery Development; Zabrze Poland
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Numerical Washout Study of a Pulsatile Total Artificial Heart. Int J Artif Organs 2014; 37:241-52. [DOI: 10.5301/ijao.5000306] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/27/2013] [Indexed: 11/20/2022]
Abstract
Purpose For blood pumps with long term indication, blood stagnation can result in excessive thromboembolic risks for patients. This study numerically investigates the washout performance of the left pump chamber of a pulsatile total artificial heart (TAH) as well as the sensitivity of the rotational orientation of the inlet bileaflet mechanical heart valve (MHV) on blood stagnation. Methods To quantitatively evaluate the washout efficiency, a fluid-structure interaction (FSI) simulation of the artificial heart pumping process was combined with a blood washout model. Four geometries with different orientations (0°, 45°, 90° and 135°) of the inlet valve were compared with respect to washout performance. Results The calculated flow field showed a high level of agreement with particle image velocimetry (PIV) measurements. Almost complete washout was achievable after three ejection phases. Remains of old blood in relation to the chamber volume was below 0.6% for all configurations and were mainly detected opposite to the inlet and outlet port at the square edge where the membrane and the pump chamber are connected. Only a small variation in the washout efficiency and the general flow field was observed. An orientation of 0° showed minor advantages with respect to blood stagnation and recirculation. Conclusions Bileaflet MHVs were demonstrated to be only slightly sensitive to rotation regarding the washout performance of the TAH. The proposed numerical washout model proved to be an adequate tool to quantitatively compare different configurations and designs of the artificial organ regarding the potential for blood stagnation where experimental measurements are limited.
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Hemodynamic influence of tilting disc valve type on pump performance with the NIPRO-ventricular assist device. J Artif Organs 2011; 15:134-9. [DOI: 10.1007/s10047-011-0616-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Accepted: 10/31/2011] [Indexed: 10/15/2022]
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Akagawa E, Lee H, Tatsumi E, Homma A, Tsukiya T, Taenaka Y. Flow visualization for different port angles of a pulsatile ventricular assist device. J Artif Organs 2011; 15:119-27. [PMID: 22038496 DOI: 10.1007/s10047-011-0614-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Accepted: 10/10/2011] [Indexed: 10/15/2022]
Abstract
The "washout effect" inside a blood pump may depend in part on the configuration of the blood pump, including its "port angle." The port angle, which is primarily decided based on anatomical considerations, may also be important from the rheological viewpoint. In our department, a next-generation diaphragm-type blood pump is being developed. In this study, we examined the influence of the port angle on flow conditions inside our new blood pump. Acrylic resin mock pumps with three different port angles (0°, 30°, and 45°) were prepared for flow visualization. Mechanical monoleaflet valves were mounted on the inlet and outlet ports of the mock pumps. Flow conditions within the mock pumps were visualized by means of particle image velocimetry during a half stroke. As a result, a high flow velocity region was seen along the main circular flow from the inlet to the outlet port. This circular flow was almost uniform and parallel to the plane of the diaphragm-housing junction (DhJ) when viewed from the inlet and outlet sides. Moreover, the proportion of high flow velocity vectors in the plane in the vicinity of the DhJ decreased as the degree of the port angle increased. In conclusion, we found that the flow behavior in the plane in the vicinity of the DhJ changed with the port angle, and that a port angle of 0° may be suitable for our diaphragm-type blood pump in view of the washout effect.
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Affiliation(s)
- Eiki Akagawa
- Department of Artificial Organs, Research Institute, National Cerebral and Cardiovascular Center, 5-7-1 Fujishiro-dai, Suita, Osaka, 565-8565, Japan.
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Flow Visualization of the Penn State Pulsatile Pediatric Ventricular Assist Device Cannulae and Change in Outlet Valve Placement. Cardiovasc Eng Technol 2011. [DOI: 10.1007/s13239-011-0062-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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A parametric study of valve orientation on the flow patterns of the Penn State pulsatile pediatric ventricular assist device. ASAIO J 2010; 56:356-63. [PMID: 20559131 DOI: 10.1097/mat.0b013e3181e3cb22] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Because of the shortage of organs for transplant in pediatric patients with end-stage heart failure, Penn State is developing a pneumatically driven 12 cc pulsatile pediatric ventricular assist device (PVAD). A major concern is the flow field changes related to the volume decrease and its effect on device thrombogenicity. Previous studies of similar devices have shown that changes in the orientation of the inlet valve can lead to improvement in the flow field. Herein, the fluid dynamic effects of orientation changes at both the inlet and outlet valves are studied. Using two-dimensional particle image velocimetry, we examine the flow field in vitro using an acrylic model of the PVAD in a mock circulatory loop. Regardless of valve orientation, the overall flow pattern inside the PVAD remains similar, but important differences were seen locally in the wall shear rates, which is notable because shear rates >500 s may prevent thrombus formation. As the inlet valve was rotated toward the fluid side of the PVAD, we observed an increase in inlet jet velocity and wall shear rates along the inlet port wall. A corresponding rotation of the outlet valve increases the wall shear rate along the outer wall near the device outlet. Wall shear rates were all higher when both valves were rotated toward the fluid side of the device, with the best rates found at orientations of +15 degrees for both the inlet and outlet valves. Overall, orientations of +15 degrees or +30 degrees of both the inlet and outlet valve resulted in an increase in wall shear rates and could aid in the reduction of thrombus formation inside the PVAD.
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Flow Visualization of A Monoleaflet and Bileaflet Mechanical Heart Valve in A Pneumatic Ventricular Assist Device Using A PIV System. ASAIO J 2010; 56:186-93. [DOI: 10.1097/mat.0b013e3181d68f83] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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Experimental Study on the Reynolds and Viscous Shear Stress of Bileaflet Mechanical Heart Valves in a Pneumatic Ventricular Assist Device. ASAIO J 2009; 55:348-54. [DOI: 10.1097/mat.0b013e3181a793e0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Lee H, Ikeuchi Y, Akagawa E, Tatsumi E, Taenaka Y, Yamamoto T. Effects of leaflet geometry on the flow field in three bileaflet valves when installed in a pneumatic ventricular assist device. J Artif Organs 2009; 12:98-104. [PMID: 19536626 DOI: 10.1007/s10047-009-0453-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2008] [Accepted: 03/01/2009] [Indexed: 11/26/2022]
Abstract
Our group is currently developing a pneumatic ventricular assist device (PVAD). In this study, in order to select the optimal bileaflet valve for our PVAD, three kinds of bileaflet valve were installed and the flow was visualized downstream of the outlet valve using the particle image velocimetry (PIV) method. To carry out flow visualization inside the blood pump and near the valve, we designed a model pump that had the same configuration as our PVAD. The three bileaflet valves tested were a 21-mm ATS valve, a 21-mm St. Jude valve, and a 21-mm Sorin Bicarbon valve. The mechanical heart valves were mounted at the aortic position of the model pump and the flow was visualized by using the PIV method. The maximum flow velocity was measured at three distances (0, 10, and 30 mm) from the valve plane. The maximum flow velocity of the Sorin Bicarbon valve was less than that of the other two valves; however, it decreased slightly with increasing distance it the X-Y plane in all three valves. Although different bileaflet valves are very similar in design, the geometry of the leaflet is an important factor when selecting a mechanical heart valve for use in an artificial heart.
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Affiliation(s)
- Hwansung Lee
- Department of Artificial Organs, Research Institute, National Cardiovascular Center, Suita, Osaka, Japan.
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Effects of the driving condition of a pneumatic ventricular assist device on the cavitation intensity of the inlet and outlet mechanical heart valves. ASAIO J 2009; 55:328-34. [PMID: 19506466 DOI: 10.1097/mat.0b013e3181a8d84f] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Our group is currently developing a pneumatic ventricular assist device (PVAD), and in previous studies, we reported the mechanical heart valve (MHV) cavitation intensity at the inlet valve in the PVAD only. In this study, we investigated the effect of the running conditions on the cavitation intensity both for the inlet and outlet valve in the PVAD using an acoustic signal. A 23-mm Medtronic Hall valve with an opening angle of 70 degrees was mounted in the inlet and outlet port of the PVAD after removing the sewing ring. A mini pressure sensor with high frequency was mounted 15 mm downstream from the inlet valve and downstream from the outlet valve. The pressure signal was band-pass filtered between 35 and 500 kHz using a digital filter. The band-pass filtered root mean squared (RMS) pressure was used as an index of the cavitation intensity. The RMS pressure of the inlet valve was higher than that of the outlet valve. Even if the outlet valve has a lower RMS pressure than the inlet valve, cavitation occurs. In case of a full-filling and full-ejection condition, the RMS pressure of the inlet valve was higher than that of the partial-filling and partial-ejection condition. This means that a partial-filling and partial-ejection condition is best to prevent the hemolysis caused by the cavitation phenomenon and the damage to the valve surface in our PVAD system.
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Homma A, Taenaka Y, Tatsumi E, Akagawa E, Lee H, Nishinaka T, Takewa Y, Mizuno T, Tsukiya T, Kakuta Y, Katagiri N, Shimosaki I, Hamada S, Mukaibayashi H, Iwaoka W. Development of a compact wearable pneumatic drive unit for a ventricular assist device. J Artif Organs 2009; 11:182-90. [PMID: 19184282 DOI: 10.1007/s10047-008-0433-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2008] [Accepted: 08/30/2008] [Indexed: 11/28/2022]
Abstract
The purpose of this study was to develop a compact wearable pneumatic drive unit for a ventricular assist device (VAD). This newly developed drive unit, 20 x 8.5 x 20 cm in size and weighing approximately 1.8 kg, consists of a brushless DC motor, noncircular gears, a crankshaft, a cylinder-piston, and air pressure regulation valves. The driving air pressure is generated by the reciprocating motion of the piston and is controlled by the air pressure regulation valves. The systolic ratio is determined by the noncircular gears, and so is fixed for a given configuration. As a result of an overflow-type mock circulation test, a drive unit with a 44% systolic ratio connected to a Toyobo VAD blood pump with a 70-ml stroke volume achieved a pump output of more than 7 l/min at 100 bpm against a 120 mmHg afterload. Long-term animal tests were also performed using drive units with systolic ratios of 45% and 53% in two Holstein calves weighing 62 kg and 74 kg; the tests were terminated on days 30 and 39, respectively, without any malfunction. The mean aortic pressure, bypass flow, and power consumption for the first calf were maintained at 90 x 13 mmHg, 3.9 x 0.9 l/min, and 12 x 1 W, and those for the second calf were maintained at 88 x 13 mmHg, 5.0 x 0.5 l/min, and 16 x 2 W, respectively. These results indicate that the newly developed drive unit may be used as a wearable pneumatic drive unit for the Toyobo VAD blood pump.
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Affiliation(s)
- Akihiko Homma
- The Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan.
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Lee H, Akagawa E, Tatsumi E, Taenaka Y. Characteristics of cavitation intensity in a mechanical heart valve using a pulsatile device: synchronized analysis between visual images and pressure signals. J Artif Organs 2008; 11:60-6. [DOI: 10.1007/s10047-008-0408-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2007] [Accepted: 02/23/2008] [Indexed: 10/21/2022]
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Lee H, Taenaka Y. Characteristics of Mechanical Heart Valve Cavitation in a Pneumatic Ventricular Assist Device. Artif Organs 2008; 32:453-60. [DOI: 10.1111/j.1525-1594.2008.00564.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Effect of systolic duration on mechanical heart valve cavitation in a pneumatic ventricular assist device: using a monoleaflet valve. ASAIO J 2008; 54:25-30. [PMID: 18204312 DOI: 10.1097/mat.0b013e318161d71c] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
The cavitation intensity of a mechanical heart valve (MHV) may differ according to the geometry of the blood pump and driving mechanism. Our group is currently developing a pneumatic ventricular assist device (VAD), and the effects of different operating conditions on MHV cavitation in our pneumatic VAD were investigated. Tests were conducted under physiological pressure at heart rates ranging from 60 to 90 beats/min and at a systolic duration ranging from 38% to 43%. The valve-closing velocity was measured using a charge-coupled device (CCD) laser displacement sensor, and images of MHV cavitation were recorded using a high-speed video camera. A miniature pressure sensor was mounted 10 mm away from the inlet valve surface. The data were stored at a 1-MHz sampling rate using a digital oscilloscope. The pressure signal was band-pass filtered between 35 and 200 kHz using a digital filter. The cavitation bubbles were concentrated at the inlet valve stop, and were caused mainly by the squeeze flow. The band-pass filtered root mean squared (RMS) pressure and cavitation cycle duration increased with the closing velocity of the inlet valve. At a low heart rate and low systolic duration, the inlet valve closed before the outlet valve opened, which caused no cavitation bubbles to form around the valve stop.
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