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Flow Modulation Algorithms for Continuous Flow Left Ventricular Assist Devices to Increase Vascular Pulsatility: A Computer Simulation Study

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Abstract

Continuous flow (CF) left ventricular assist devices (LVAD) support diminishes vascular pressure pulsatility. Despite its recent clinical success CF LVAD support has been associated with a higher incidence of gastrointestinal bleeding, aortic valve dysfunction and hemorrhagic strokes. To overcome this limitation, we are develo** algorithms to provide vascular pulsatility using a CF LVAD. The effects of timing and synchronizing the CF LVAD flow modulation to the native myocardium, modulation amplitude, and modulation widths were studied on the native ventricle and vasculature using a computer simulation model of the circulatory system simulating heart failure. A total of over 150 combinations of varying pulse widths, beat frequencies, time shifts, and amplitudes to modulate CF LVAD flow were tested. All control algorithms maintained a mean CF LVAD flow of 5.0 ± 0.1 L/min (full support) or 2.5 ± 0.1 L/min (partial support). These algorithms resulted in an increased arterial pressure pulsatility of up to 59 mmHg, reduced left ventricular external work (LVEW) by 10–75%, and increased myocardial perfusion by up to 44% from baseline heart failure condition. Importantly, reduction in LVEW and increase in pulsatility may be adjusted to user-defined values while maintaining the same average CF LVAD flow rate. These methods of CF LVAD flow modulation may enable tailored unloading of the native ventricle to provide rest and rehabilitation (maximal unloading to rest followed by gradual reloading to wean), which may promote sustainable myocardial recovery. Further, these LVAD flow modulation patterns may reduce the incidence of adverse events associated with the CF LVAD therapy by increasing vascular pulsatility.

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Acknowledgment

The research was funded by a National Scientist Development Grant from the American Heart Association (0730319N) and by the University of Louisville Clinical and Translational Science Pilot Grant Program award.

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Authors and Affiliations

  1. Department of Bioengineering, Cardiovascular Innovation Institute, University of Louisville, Louisville, KY, 40202, USA

    Mickey Ising, Sean Warren, Mark S. Slaughter & Steven C. Koenig

  2. Department of Surgery, University of Louisville, Louisville, KY, USA

    Michael A. Sobieski, Mark S. Slaughter, Steven C. Koenig & Guruprasad A. Giridharan

Authors
  1. Mickey Ising
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  2. Sean Warren
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  3. Michael A. Sobieski
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  4. Mark S. Slaughter
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  5. Steven C. Koenig
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  6. Guruprasad A. Giridharan
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Correspondence to Guruprasad A. Giridharan.

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Associate Editor John Timothy Baldwin oversaw the review of this article.

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Ising, M., Warren, S., Sobieski, M.A. et al. Flow Modulation Algorithms for Continuous Flow Left Ventricular Assist Devices to Increase Vascular Pulsatility: A Computer Simulation Study. Cardiovasc Eng Tech 2, 90–100 (2011). https://doi.org/10.1007/s13239-011-0042-x

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  • DOI: https://doi.org/10.1007/s13239-011-0042-x

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