A Novel Miniature Ventricular Assist Device for Hemodynamic Support

Takagaki, Masami; Rottenberg, D; McCarthy, Patrick M.; Smedira, Nicholas G.; Dessoffy, Raymond; Al-Ahmadi, Mamdouh; Shoshani, David; Fukamachi, Kiyotaka

doi:10.1097/00002480-200107000-00022

Cited by 5 publications

(6 citation statements)

References 11 publications

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“…6) to the measured data of several other studies (Takagaki et al, 2001;Rich et al, 2000;Segers et al, 2001;Slama et al, 2000;Bauer et al, 2002;Pagani et al, 1979;Wells et al, 1998). Figure 7A compares P-V loops constructed from measured data (Segers et al, 2001) to a model-generated loop.…”

Section: Model Behavior In the Reclining Positionmentioning

confidence: 91%

“…Because it is docile, large, and has a cardiac output similar to the human, the sheep serves as a good animal model for developing and testing ventricular assist devices (Kono et al, 2000;Takagaki et al, 2001), pulmonary assist devices and for simulating human cardiopulmonary diseases (Rich et al, 2000;Segers et al, 2001;Slama et al, 2000;Sugi et al, 1991). A mathematical model of the sheep's cardiovascular system (CVS) and its interaction with these devices and diseases is highly desirable, as it might help us understand them, and it would reduce the time and expense of animal experimentation.…”

Section: Introductionmentioning

confidence: 99%

“…Measured indices fromTakagaki et al (2001),Rich et al (2000),Segers et al (2001),Slama et al (2000),Bauer et al (2002),Pagani et al (1979), andWells et al (1998).…”

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confidence: 99%

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An Integrative Cardiovascular Model of the Standing and Reclining Sheep

Qian

Ware

et al. 2005

Cardiovasc Eng

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We have developed an integrative model of the ovine cardiovascular system that simulates the effects of posture and ventricular function to help design the circulatory and pulmonary assist devices often tested in conscious sheep that stand and recline during chronic experiments. Our present focus is the simulation itself and not the evaluation of specific assist devices. Adjusted parameters of the model provide good fits to in vivo experimental data and can describe the hemodynamic changes that follow balloon occlusion of the inferior vena cava and standing. Since circulatory assist devices are often tested in animal preparations of left heart failure, we extended the model to study the effects that standing and inferior vena cava occlusion would have in sheep with primarily systolic left heart dysfunction. We also developed an elastance-based formulation for ventricular muscular work and a sensitivity analysis of the autonomic reflexes affecting blood pressure. The model can analyze the biophysical mechanisms underlying the responses to orthostatic stress and left ventricular dysfunction and should help improve the development and testing of assist devices. NOMENCLATUREa min constant (dimensionless) A i parameter of activation function of the heart (dimensionless) B i parameter of activation function of the heart (s) C i parameter of activation function of the heart (s) CBO caval balloon occlusion CO cardiac output D 0 volume parameter (mL) e(t) time-varying activation function (mmHgmL −1 ) E(t) time-varying elastance function (mmHgmL −1 ) E ES end-systolic elastance (mmHgmL −1 ) EDPVR end-diastolic pressure-volume relationship ESPVR end-systolic pressure-volume relationship ε E energy stored by elastance element (erg) ε M muscular energy provided to ventricle by metabolic energy (erg) F CON normalized sympathetic efferent discharge frequency controlling contractility (dimensionless) F HRS normalized sympathetic controlling heart rate frequency (dimensionless) F HRV normalized vagal controlling heart rate frequency (dimensionless) 53 1567-8822/05/0600-0053/0 C 2005 Springer Science+Business Media, Inc. 54 Ha, Qian, Ware, Zwischenberger, Bidani, and Clark F VASO normalized sympathetic efferent discharge frequency controlling vasomotor tone (dimensionless) FLV failing left ventricle h 1 -h 6 constants (bpm) HR heart rate (beats per minute, bpm) IVC inferior vena cava K a scaling parameter (mmHg) K p1 constant scaling parameter (mmHg) K p2 constant scaling parameter (mmHg) K r constant scaling parameter (mmHg) LA left atrium LV left ventricle LVMW left ventricular muscular work λ diastolic elastance coefficient (dimensionless) MAP mean arterial pressure NLV normal left ventricle P a ar systemic arterial pressure in the active state (fully constricted) (mmHg) P p ar systemic arterial pressure in the passive state (relaxed) (mmHg) P ED (V ) end-diastolic pressure (mmHg) P ES (V ) end-systolic pressure (mmHg) P LA left atrial pressure (mmHg) P LV left ventricular pressure (mmHg) P 0 diastolic pressure parameter (mmHg)...

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Section: Model Behavior In the Reclining Positionmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

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An Integrative Cardiovascular Model of the Standing and Reclining Sheep

Qian

Ware

et al. 2005

Cardiovasc Eng

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“…The purpose is to assess hemodynamic performance and the ability of the pump to support life and maintain the integrity of the cardiovascular system. Researchers typically select sheep (ovine), cows (bovine), pig (porcine), and nonsurvival dog (canine) models for artificial blood pump testing (39–42). Research institutes choose a certain animal based on the belief that physiologic data obtained from the experiment will provide the most valuable insight into pump performance.…”

Section: Methods Of Failure Evaluationmentioning

confidence: 99%

Methods of Failure and Reliability Assessment for Mechanical Heart Pumps

et al. 2005

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Artificial blood pumps are today's most promising bridge-to-recovery (BTR), bridge-to-transplant (BTT), and destination therapy solutions for patients suffering from intractable congestive heart failure (CHF). Due to an increased need for effective, reliable, and safe long-term artificial blood pumps, each new design must undergo failure and reliability testing, an important step prior to approval from the United States Food and Drug Administration (FDA), for clinical testing and commercial use. The FDA has established no specific standards or protocols for these testing procedures and there are only limited recommendations provided by the scientific community when testing an overall blood pump system and individual system components. Product development of any medical device must follow a systematic and logical approach. As the most critical aspects of the design phase, failure and reliability assessments aid in the successful evaluation and preparation of medical devices prior to clinical application. The extent of testing, associated costs, and lengthy time durations to execute these experiments justify the need for an early evaluation of failure and reliability. During the design stages of blood pump development, a failure modes and effects analysis (FMEA) should be completed to provide a concise evaluation of the occurrence and frequency of failures and their effects on the overall support system. Following this analysis, testing of any pump typically involves four sequential processes: performance and reliability testing in simple hydraulic or mock circulatory loops, acute and chronic animal experiments, human error analysis, and ultimately, clinical testing. This article presents recommendations for failure and reliability testing based on the National Institutes of Health (NIH), Society for Thoracic Surgeons (STS) and American Society for Artificial Internal Organs (ASAIO), American National Standards Institute (ANSI), the Association for Advancement of Medical Instrumentation (AAMI), and the Bethesda Conference. It further discusses studies that evaluate the failure, reliability, and safety of artificial blood pumps including in vitro and in vivo testing. A descriptive summary of mechanical and human error studies and methods of artificial blood pumps is detailed.

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“…Due to its large size and cardiac output similar to man, the sheep can serve as a useful animal model for the study of the hemodynamic efficacy of ventricular assist devices (Kono et al, 2000;Takagaki et al, 2001), pulmonary assist devices (Cook et al, 1996;Haft et al, 2001;Lick et al, 2001a;b;Zwischenberger et al, 2002), and cardiopulmonary diseases (Rich et al, 2000;Segers et al, 2001;Slama et al, 2000). This study focuses primarily on the attachment of pulmonary assist devices to the pulmonary circulation.…”

Section: Introductionmentioning

confidence: 99%

Hemodynamic Analysis and Design of a Paracorporeal Artificial Lung Device

Wang

Zwischenberger

et al. 2006

Cardiovasc Eng

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We have extended our model of the ovine pulmonary circulation to include a model of a paracorporeal artificial lung (AL) and its attachments to the natural pulmonary circulation in two configurations: in series and in parallel. Our model of the natural lung (NL) circulation is first shown to be in agreement with hemodynamic and input impedance data from the open literature. We then study design efficacy of the AL in terms of its housing and attachments. A sensitivity analysis of the modified pulmonary circulation model reveals that there are three key parameters: inlet graft length (IGL) and the compliances of the inlet compliance chamber (CC) and housing of the artificial lung. Based on literature reports, we assume the right ventricle is well-matched to the impedance of the natural pulmonary circulation and adjust the parameters of the modeled AL circuit to achieve the best least-squares fit to natural pulmonary input impedance data. Best-fit parameters produce impedance curves that fit natural impedance well, particularly below 3 Hz, where both compliance and graft length have their largest effects. Of these parameters, the impedance profile is most sensitive to IGL. However, the compliances are important, as well, particularly at low frequencies.

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A Novel Miniature Ventricular Assist Device for Hemodynamic Support

Cited by 5 publications

References 11 publications

An Integrative Cardiovascular Model of the Standing and Reclining Sheep

An Integrative Cardiovascular Model of the Standing and Reclining Sheep

Methods of Failure and Reliability Assessment for Mechanical Heart Pumps

Hemodynamic Analysis and Design of a Paracorporeal Artificial Lung Device

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