1
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Wu EL, Maw M, Stephens AF, Stevens MC, Fraser JF, Tansley G, Moscato F, Gregory SD. Estimation of Left Ventricular Stroke Work for Rotary Left Ventricular Assist Devices. ASAIO J 2023; 69:817-826. [PMID: 37191479 DOI: 10.1097/mat.0000000000001972] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/17/2023] Open
Abstract
Continuous monitoring of left ventricular stroke work (LVSW) may improve the medical management of patients with rotary left ventricular assist devices (LVAD). However, implantable pressure-volume sensors are limited by measurement drift and hemocompatibility. Instead, estimator algorithms derived from rotary LVAD signals may be a suitable alternative. An LVSW estimator algorithm was developed and evaluated in a range of in vitro and ex vivo cardiovascular conditions during full assist (closed aortic valve [AoV]) and partial assist (opening AoV) mode. For full assist, the LVSW estimator algorithm was based on LVAD flow, speed, and pump pressure head, whereas for partial assist, the LVSW estimator combined the full assist algorithm with an estimate of AoV flow. During full assist, the LVSW estimator demonstrated a good fit in vitro and ex vivo (R 2 : 0.97 and 0.86, respectively) with errors of ± 0.07 J. However, LVSW estimator performance was reduced during partial assist, with in vitro : R 2 : 0.88 and an error of ± 0.16 J and ex vivo : R 2 : 0.48 with errors of ± 0.11 J. Further investigations are required to improve the LVSW estimate with partial assist; however, this study demonstrated promising results for a continuous estimate of LVSW for rotary LVADs.
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Affiliation(s)
- Eric L Wu
- From the Innovative Cardiovascular Engineering and Technology Laboratory (ICETLAB), Critical Care Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia
- School of Medicine, The University of Queensland, Queensland, Brisbane, Australia
| | - Martin Maw
- Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
| | - Andrew F Stephens
- Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Australia
- Cardio-Respiratory Engineering and Technology Laboratory, Baker Heart and Diabetes Institute, Alfred Hospital, Melbourne, Australia
| | - Michael C Stevens
- From the Innovative Cardiovascular Engineering and Technology Laboratory (ICETLAB), Critical Care Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia
- Graduate School of Biomedical Engineering, Faculty of Engineering, University of New South Wales, Sydney, New South Wales, Australia
| | - John F Fraser
- From the Innovative Cardiovascular Engineering and Technology Laboratory (ICETLAB), Critical Care Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia
- School of Medicine, The University of Queensland, Queensland, Brisbane, Australia
| | - Geoffrey Tansley
- From the Innovative Cardiovascular Engineering and Technology Laboratory (ICETLAB), Critical Care Research Group, The Prince Charles Hospital, Chermside, Queensland, Australia
- School of Engineering and Built Environment, Griffith University, Gold Coast, Australia
| | - Francesco Moscato
- Ludwig Boltzmann Institute for Cardiovascular Research, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, Vienna, Austria
| | - Shaun D Gregory
- Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, Australia
- Cardio-Respiratory Engineering and Technology Laboratory, Baker Heart and Diabetes Institute, Alfred Hospital, Melbourne, Australia
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2
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(Physiology of Continuous-flow Left Ventricular Assist Device Therapy. Translation of the document prepared by the Czech Society of Cardiology). COR ET VASA 2022. [DOI: 10.33678/cor.2022.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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3
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Rosenbaum AN, Antaki JF, Behfar A, Villavicencio MA, Stulak J, Kushwaha SS. Physiology of Continuous-Flow Left Ventricular Assist Device Therapy. Compr Physiol 2021; 12:2731-2767. [PMID: 34964115 DOI: 10.1002/cphy.c210016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The expanding use of continuous-flow left ventricular assist devices (CF-LVADs) for end-stage heart failure warrants familiarity with the physiologic interaction of the device with the native circulation. Contemporary devices utilize predominantly centrifugal flow and, to a lesser extent, axial flow rotors that vary with respect to their intrinsic flow characteristics. Flow can be manipulated with adjustments to preload and afterload as in the native heart, and ascertainment of the predicted effects is provided by differential pressure-flow (H-Q) curves or loops. Valvular heart disease, especially aortic regurgitation, may significantly affect adequacy of mechanical support. In contrast, atrioventricular and ventriculoventricular timing is of less certain significance. Although beneficial effects of device therapy are typically seen due to enhanced distal perfusion, unloading of the left ventricle and atrium, and amelioration of secondary pulmonary hypertension, negative effects of CF-LVAD therapy on right ventricular filling and function, through right-sided loading and septal interaction, can make optimization challenging. Additionally, a lack of pulsatile energy provided by CF-LVAD therapy has physiologic consequences for end-organ function and may be responsible for a series of adverse effects. Rheological effects of intravascular pumps, especially shear stress exposure, result in platelet activation and hemolysis, which may result in both thrombotic and hemorrhagic consequences. Development of novel solutions for untoward device-circulatory interactions will facilitate hemodynamic support while mitigating adverse events. © 2021 American Physiological Society. Compr Physiol 12:1-37, 2021.
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Affiliation(s)
- Andrew N Rosenbaum
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,William J von Liebig Center for Transplantation and Clinical Regeneration, Mayo Clinic, Rochester, Minnesota, USA
| | - James F Antaki
- Meinig School of Biomedical Engineering, Cornell University, Ithaca, New York, USA
| | - Atta Behfar
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,William J von Liebig Center for Transplantation and Clinical Regeneration, Mayo Clinic, Rochester, Minnesota, USA.,VanCleve Cardiac Regenerative Medicine Program, Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | | | - John Stulak
- Department of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Sudhir S Kushwaha
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, Minnesota, USA.,William J von Liebig Center for Transplantation and Clinical Regeneration, Mayo Clinic, Rochester, Minnesota, USA
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4
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Kado Y, Smith WA, Miyamoto T, Adams J, Polakowski AR, Dessoffy R, Horvath DJ, Fukamachi K, Karimov JH. Use of a Virtual Mock Loop model to evaluate a new left ventricular assist device for transapical insertion. Int J Artif Organs 2020; 43:677-683. [PMID: 32089074 DOI: 10.1177/0391398820907104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We are developing a novel type of miniaturized left ventricular assist device that is configured for transapical insertion. The aim of this study was to assess the performance and function of a new pump by using a Virtual Mock Loop system for device characterization and mapping. The results, such as pressure-flow performance curves, from pump testing in a physical mock circulatory loop were used to analyze its function as a left ventricular assist device. The Virtual Mock Loop system was programmed to mimic the normal heart condition, systolic heart failure, diastolic heart failure, and both systolic and diastolic heart failure, and to provide hemodynamic pressure values before and after the activation of several left ventricular assist device pump speeds (12,000, 14,000, and 16,000 r/min). With pump support, systemic flow and mean aortic pressure increased, and mean left atrial pressure and pulmonary artery pressure decreased for all heart conditions. Regarding high pump-speed support, the systemic flow, aortic pressure, left atrial pressure, and pulmonary artery pressure returned to the level of the normal heart condition. Based on the test results from the Virtual Mock Loop system, the new left ventricular assist device for transapical insertion may be able to ease the symptoms of patients with various types of heart failure. The Virtual Mock Loop system could be helpful to assess pump performance before in vitro bench testing.
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Affiliation(s)
- Yuichiro Kado
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Takuma Miyamoto
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Joseph Adams
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Anthony R Polakowski
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Raymond Dessoffy
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | | | - Kiyotaka Fukamachi
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
| | - Jamshid H Karimov
- Department of Biomedical Engineering, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA
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5
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In vivo tissue reaction within the outflow conduit in patients supported by HeartWare HVAD. Cardiovasc Pathol 2020; 44:107156. [DOI: 10.1016/j.carpath.2019.107156] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/23/2019] [Accepted: 09/24/2019] [Indexed: 11/23/2022] Open
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6
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Jain P, Shehab S, Muthiah K, Robson D, Granegger M, Drakos SG, Jansz P, Macdonald PS, Hayward CS. Insights Into Myocardial Oxygen Consumption, Energetics, and Efficiency Under Left Ventricular Assist Device Support Using Noninvasive Pressure-Volume Loops. Circ Heart Fail 2019; 12:e006191. [DOI: 10.1161/circheartfailure.119.006191] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background:
Assessment of left ventricular (LV) recovery under continuous-flow LV assist device therapy is hampered by concomitant pump support. We describe derivation of noninvasive pressure-volume loops in continuous-flow LV assist device patients and demonstrate an application in the assessment of recovery.
Methods and Results:
Using pump controller parameters and noninvasive arterial pressure waveforms, central aortic pressure, outflow conduit pressure gradient, and instantaneous LV pressure were calculated. Instantaneous LV volumes were calculated from echocardiographic LV end-diastolic volume accounting for the integral of pump flow with respect to time and aortic ejection volume derived from the pump speed waveform. Pressure-volume loops were derived during pump speed adjustment and following bolus intravenous milrinone to assess changes in loading conditions and contractility, respectively. Fourteen patients were studied. Baseline noninvasive LV end-diastolic pressure correlated with invasive pulmonary arterial wedge pressure (
r
2
=0.57, root mean square error 5.0 mm Hg,
P
=0.003). Measured noninvasively, milrinone significantly increased LV ejection fraction (40.3±13.6% versus 36.8±14.2%,
P
<0.0001), maximum dP/dt (623±126 versus 555±122 mm Hg/s,
P
=0.006), and end-systolic elastance (1.03±0.57 versus 0.89±0.38 mm Hg/mL,
P
=0.008), consistent with its expected inotropic effect. Milrinone reduced myocardial oxygen consumption (0.15±0.06 versus 0.16±0.07 mL/beat,
P
=0.003) and improved myocardial efficiency (43.7±14.0% versus 41.2±15.5%,
P
=0.001). Reduced pump speed caused increased LV end-diastolic volume (190±80 versus 165±71 mL,
P
<0.0001) and LV end-diastolic pressure (14.3±10.2 versus 9.9±9.3 mm Hg,
P
=0.024), consistent with a predictable increase in preload. There was increased myocardial oxygen consumption (0.16±0.07 versus 0.14±0.06 mL O
2
/beat,
P
<0.0001) despite unchanged stroke work (
P
=0.24), reflecting decreased myocardial efficiency (39.2±12.7% versus 45.2±17.0%,
P
=0.003).
Conclusions:
Pressure-volume loops are able to be derived noninvasively in patients with the HeartWare HVAD and can detect induced changes in load and contractility.
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Affiliation(s)
- Pankaj Jain
- Cardiology Department, St Vincent’s Hospital, Sydney, Australia (P.J., S.S., K.M., D.R., P.J., P.S.M., C.S.H.)
| | - Sajad Shehab
- Cardiology Department, St Vincent’s Hospital, Sydney, Australia (P.J., S.S., K.M., D.R., P.J., P.S.M., C.S.H.)
| | - Kavitha Muthiah
- Cardiology Department, St Vincent’s Hospital, Sydney, Australia (P.J., S.S., K.M., D.R., P.J., P.S.M., C.S.H.)
| | - Desiree Robson
- Cardiology Department, St Vincent’s Hospital, Sydney, Australia (P.J., S.S., K.M., D.R., P.J., P.S.M., C.S.H.)
| | - Marcus Granegger
- Institute for Imaging Science and Computational Modelling in Cardiovascular Medicine, Charitè Universitätsmedizin, Berlin, Germany (M.G.)
| | | | - Paul Jansz
- Cardiology Department, St Vincent’s Hospital, Sydney, Australia (P.J., S.S., K.M., D.R., P.J., P.S.M., C.S.H.)
| | - Peter S. Macdonald
- Cardiology Department, St Vincent’s Hospital, Sydney, Australia (P.J., S.S., K.M., D.R., P.J., P.S.M., C.S.H.)
| | - Christopher S. Hayward
- Cardiology Department, St Vincent’s Hospital, Sydney, Australia (P.J., S.S., K.M., D.R., P.J., P.S.M., C.S.H.)
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