Exercise Hemodynamics During Extended Continuous Flow Left Ventricular Assist Device Support: The Response of Systemic Cardiovascular Parameters and Pump Performance

Martina, Jerson R.; Jonge, Nicolaas de; Rutten, Marcel; Kirkels, J. H.; Klöpping, C.; Rodermans, Ben F.M.; Sukkel, E.; Hulstein, Nelienke; Mol, Bas A. J. M. de; Lahpor, Jaap R.

doi:10.1111/aor.12151

Cited by 59 publications

(46 citation statements)

References 38 publications

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“… EmaxL : among all the investigated parameters, EmaxL is one of the most important in assuring a higher TCO at exercise. These results are in line with previous clinical studies evidencing the crucial role of the residual LV function in eliciting a higher TCO and exercise capacity . Noor et al observed that patients with a residual LV contractility are able to better accommodate an increase in TCO, resulting in higher exercise capacities.…”

Section: Discussionsupporting

confidence: 91%

“…Current LVADs work at a constant pump speed and do not embed physiological controllers to adapt the support to body needs at exercise. Therefore, patients mainly rely on their remaining cardiac function to increase TCO by the output through the aortic valve (Q AV ) and achieve higher peak VO 2 levels . Dependencies between low LVAD speed (below baseline value) and reduced exercise capacities were found in the previous clinical studies .…”

Section: Introductionmentioning

confidence: 93%

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LVAD speed increase during exercise, which patients would benefit the most? A simulation study

et al. 2019

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Patients supported with a left ventricular assist device (LVAD) have impaired cardiovascular adaptations during exercise, resulting in reduced total cardiac output and exercise intolerance. The aim of this study is to report associations among these impaired cardiovascular parameters and exercise hemodynamics, and to identify in which conditions an LVAD speed increase can provide substantial benefits to exercise. A cardiorespiratory simulator was used to reproduce the average hemodynamics of LVAD patients at exercise. Then, a sensitivity study was conducted where cardiovascular parameters were changed individually ±20% of their baseline value at exercise (heart rate, left/right ventricular contractility, total peripheral resistance, and valve pathologies). Simulations were performed at a baseline LVAD speed of 2700 rpm and repeated at 3500 rpm to evaluate the benefits of a higher LVAD support on hemodynamics. Total cardiac output (TCO) was mostly impaired by a poor left ventricular contractility or vasodilation at exercise (−0.6 L/min), followed by a poor chronotropic response (−0.3 L/min) and by a poor right ventricular contractility (−0.2 L/min). LVAD speed increase better unloads the left ventricle and improves total cardiac output in all the simulated conditions. The most substantial benefits from LVAD speed increase were observed in case of poor left ventricular contractility (TCO + 1.6 L/min) and vascular dysfunction (TCO + 1.4 L/min) followed by lower heart rate (TCO + 1.3 L/min) and impaired right ventricular contractility (TCO + 1.1 L/min). Despite the presence of the LVAD, exercise hemodynamic is strongly depending on the ability of the cardiovascular system to adapt to exercise. A poor left ventricular inotropic response and a poor vascular function can strongly impair cardiac output at exercise. In these conditions, LVAD speed increase can be an effective strategy to augment total cardiac output and unload the left ventricle. These results evidence the need to design a physiological LVAD speed controller, tailored on specific patient’s needs.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 93%

LVAD speed increase during exercise, which patients would benefit the most? A simulation study

et al. 2019

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“…The key determinates for a decreased pump head are increasing venous return and LV contractility or reducing afterload, for example, due to vasodilation. These effects occur as a cardiovascular response during exercise depending on exercise intensity and duration .…”

Section: Discussionmentioning

confidence: 99%

LVAD Pump Flow Does Not Adequately Increase With Exercise

Gross

Marko²,

Mikl³

et al. 2018

Artificial Organs

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Left ventricular assist devices (LVADs) restore cardiovascular circulatory demand at rest with a spontaneous increase in pump flow to exercise. The relevant contribution of cardiac output provided by the LVAD and ejected through the aortic valve for exercises of different intensities has been barely investigated in patients. The hypothesis of this study was that different responses in continuous recorded pump parameters occur for maximal and submaximal intensity exercises and that the pump flow change has an impact on the oxygen uptake at peak exercise (pVO ). Cardiac and pump parameters such as LVAD flow rate (Q ), heart rate (HR), and aortic valve (AV) opening were analyzed from continuously recorded LVAD data during physical exercises of maximal (bicycle ergometer test) and submaximal intensities (6-min walk test and regular trainings). During all exercise sessions, the LVAD speed was kept constant. Cardiac and pump parameter responses of 16 patients for maximal and submaximal intensity exercises were similar for Q : +0.89 ± 0.52 versus +0.59 ± 0.38 L/min (P = 0.07) and different for HR: +20.4 ± 15.4 versus +7.7 ± 5.8 bpm (P < 0.0001) and AV-opening with 71% versus 23% of patients (P < 0.0001). Multi-regression analysis with pVO (R = 0.77) showed relation to workload normalized by bodyweight (P = 0.0002), HR response (P = 0.001), AV-opening (P = 0.02), and age (P = 0.06) whereas the change in Q was irrelevant. Constant speed LVADs provide inadequate support for maximum intensity exercises. AV-opening and improvements in HR show an important role for higher exercise capacities and reflect exercise intensities. Changes in pump flow do not impact pVO and are independent of AV-opening and response in HR. An LVAD speed control may lead to adequate left ventricular support during strenuous physical activities.

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“…(18,22–24) By 6 months, peak VO 2 ranged from 12.7 to 18.7 mL/kg/min. (21,24–26) Percentage of predicted norms reflected these increases with percentages increasing from 48–61% at 1 month to 42–66% at 12 months. (24–28) These large improvements illustrated that patients function better after LVAD, however function remained significantly below age-adjusted norms.…”

Section: Describing Functional Progressmentioning

confidence: 94%

Functional Status in Left Ventricular Assist Device–Supported Patients: A Literature Review

Abshire

Himmelfarb

Russell

2014

Journal of Cardiac Failure

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The prevalence of advanced heart failure (HF) is increasing due to the aging population and improvements in HF management strategies. Left Ventricular Assist Device (LVAD) technology and management continue to advance rapidly and it is anticipated that the number of LVAD implants will increase. LVADs have been demonstrated to extend life and improve outcomes in patients with advanced HF. The purpose of this article is to review and synthesize the evidence on impact of LVAD therapy on functional status. Significant functional gains were demonstrated in patients supported by LVAD throughout the first year with most improvement in distance walked and peak oxygen consumption demonstrated in the first 6 months. Interventions to enhance exercise performance have had inconsistent effects on functional status. Poor exercise performance was associated with increased risk of adverse events. Functional status improved with LVAD therapy, though performance remained substantially reduced compared to age adjusted norms. There is tremendous need to enhance our understanding of factors influencing functional outcomes in this high-risk population.

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Exercise Hemodynamics During Extended Continuous Flow Left Ventricular Assist Device Support: The Response of Systemic Cardiovascular Parameters and Pump Performance

Cited by 59 publications

References 38 publications

LVAD speed increase during exercise, which patients would benefit the most? A simulation study

LVAD speed increase during exercise, which patients would benefit the most? A simulation study

LVAD Pump Flow Does Not Adequately Increase With Exercise

Functional Status in Left Ventricular Assist Device–Supported Patients: A Literature Review

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