Rotary pump speed modulation for generating pulsatile flow and phasic left ventricular volume unloading in a bovine model of chronic ischemic heart failure

Soucy, Kevin G.; Giridharan, Guruprasad A.; Choi, Young Joon; Sobieski, Michael A.; Monreal, Gretel; Cheng, Allen; Schumer, Erin M.; Slaughter, Mark S.; Koenig, Steven C.

doi:10.1016/j.healun.2014.09.017

Cited by 79 publications

(62 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…21,25 In brief, chronic IHF was induced by microsphere injection into the left main coronary artery. Animals were then aggressively medically managed for at least 60 days before LVAD implantation.…”

Section: Animal Modelmentioning

confidence: 99%

“…However, these data are appropriate for demonstrating feasibility of proposed hypotheses (pulsatility, endorgan perfusion), which were tested in a study design (IHF model, sample size n = 10) for demonstrating efficacy and achieving statistical significance. 21 …”

Section: Limitationsmentioning

confidence: 99%

“…[5][6][7][8][9] Augmenting aortic pressure pulsatility via CF LVAD flow and/or motor speed modulation algorithms has been proposed to minimize adverse events, prevent aortic insufficiency, alter ventricular unloading, reduce myocardial oxygen consumption, and improve myocardial recovery. [10][11][12][13][14][15][16][17][18][19][20][21] The potential hemodynamic benefits of CF LVAD modulation evaluated in a computer simulation model with candidate pump speed modulation algorithms identified for feasibility testing. 22 Based on these findings, hemodynamic performance of a clinically approved CF LVAD operated at constant pump speed, and asynchronous, synchronous copulsation, and synchronous counterpulsation modulated pump speed were further investigated in a mock flow loop model, and acutely in a chronic ischemic heart failure (IHF) bovine model (n = 3) to demonstrate feasibility.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Feasibility of Pump Speed Modulation for Restoring Vascular Pulsatility with Rotary Blood Pumps

Ising¹,

Sobieski²,

Slaughter³

et al. 2015

ASAIO Journal

Self Cite

View full text Add to dashboard Cite

Continuous flow (CF) left ventricular assist devices (LVAD) diminish vascular pressure pulsatility, which may be associated with clinically reported adverse events including gastrointestinal bleeding, aortic valve insufficiency, and hemorrhagic stroke. Three candidate CF LVAD pump speed modulation algorithms designed to augment aortic pulsatility were evaluated in mock flow loop and ischemic heart failure (IHF) bovine models by quantifying hemodynamic performance as a function of mean pump speed, modulation amplitude, and timing. Asynchronous and synchronous copulsation (high revolutions per minute [RPM] during systole, low RPM during diastole) and counterpulsation (low RPM during systole, high RPM during diastole) algorithms were tested for defined modulation amplitudes (±300, ±500, ±800, and ±1,100 RPM) and frequencies (18.75, 37.5, and 60 cycles/minute) at low (2,900 RPM) and high (3,200 RPM) mean LVAD speeds. In the mock flow loop model, asynchronous, synchronous copulsation, and synchronous counterpulsation algorithms each increased pulse pressure (ΔP = 931%, 210%, and 98% and reduced left ventricular external work (LVEW = 20%, 22%, 16%). Similar improvements in vascular pulsatility (1,142%) and LVEW (40%) were observed in the IHF bovine model. Asynchronous modulation produces the largest vascular pulsatility with the advantage of not requiring sensor(s) for timing pump speed modulation, facilitating potential clinical implementation.

show abstract

Section: Animal Modelmentioning

confidence: 99%

Section: Limitationsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Feasibility of Pump Speed Modulation for Restoring Vascular Pulsatility with Rotary Blood Pumps

Ising¹,

Sobieski²,

Slaughter³

et al. 2015

ASAIO Journal

Self Cite

View full text Add to dashboard Cite

show abstract

“…Both PF-LVADs and speed modulated CF-LVADs can be configured at a rate independent of the native HR (asynchronous) or equal to native HR (synchronous), with the latter requiring an synchronous triggering source, such as R-wave detection. [42][43][44][45] No matter the ejection time delay of CT-LVAD with respect to the cardiac cycle may be set at a certain phase between zero (co-pulsation) and half a cardiac cycle (counter-pulsation), the TIW achieves its maximum value in Figure 8 when the pump rate is equal to the mock left ventricle rate. This agrees with the previous research, 46 where the authors concluded that when the rotational speed of the CF-LVADs was synchronized to the heart beat, the arterial perfusion was improved.…”

Section: Discussionmentioning

confidence: 99%

Pumping Rate Study of a Left Ventricular Assist Device in a Mock Circulatory System

Zhuang

Yang

et al. 2016

ASAIO Journal

View full text Add to dashboard Cite

The aim of this work was to investigate the hemodynamic influence of the change of pump rate on the cardiovascular system with consideration of heart rate and the resonant characteristics of the arterial system when a reliable synchronous triggering source is unavailable. Hemodynamic waveforms are recorded at baseline conditions and with the pump rate of left ventricular assist device (LVAD) at 55, 60, 66, and 70 beats per minute for four test conditions in a mock circulatory system. The total input work (TIW) and energy equivalent pressure (EEP) are calculated as metrics for evaluating the hemodynamic performance within different test conditions. Experimental results show that TIW and EEP achieve their maximum values, where the pump rate is equal to the heart rate. In addition, it demonstrates that TIW and EEP are significantly affected by changing pump rate of LVAD, especially when the pump rate is closing to the natural frequency of the arterial system. When a reliable synchronous triggering source is not available for LVAD, it is suggested that selecting a pump rate equal to the resonant frequency of the arterial system could achieve better supporting effects.

show abstract

“…Therefore, the end-organ vasculature may not be experiencing any significant differences in flow type when a continuous-flow pump is placed in a patient accustomed to pulsatile physiology. Conversely, a recent study using a chronic ischemic heart failure bovine model found that end organ perfusion was improved when pulsatility was integrated into a continuous-flow LVAD by using variable speeds compared to the use of a constant speed [42]. In summary, what clinical significance, if any, changes to the arterial vasculature signify remains to be seen.…”

Section: Introductionmentioning

confidence: 99%

Physiologic effects of continuous-flow left ventricular assist devices

Healy

McKellar

Drakos

et al. 2016

Journal of Surgical Research

View full text Add to dashboard Cite

Background Within the past ten years, continuous-flow Left Ventricular Assist Devices (LVADS) have replaced pulsatile-flow LVADs as the standard of care for both destination therapy and bridging patients to heart transplantation. Despite the rapid clinical adoption of continuous-flow LVADs, an understanding of the effects of continuous-flow physiology, as opposed to more natural pulsatile-flow physiology, is still evolving. Materials and Methods A thorough review of the relevant scientific literature regarding the physiologic and clinical effects of continuous-flow physiology was performed. These effects were analyzed on an organ system basis and include an evaluation of the cardiovascular, respiratory, hematologic, gastrointestinal, renal, hepatic, neurologic, immunologic, and endocrine systems. Results Continuous-flow physiology is, generally speaking, well tolerated over the long term. Several changes are manifest at the organ system level, however. While many of these changes are without appreciable clinical significance, other changes, such as an increased rate of gastrointestinal bleeding, appear to be associated with continuous-flow physiology. Conclusions Continuous-flow LVADs confer a significant advantage over their pulsatile-flow counterparts with regard to size and durability. From a physiologic standpoint, continuous-flow physiology has limited clinical effects at the organ system level. Though improved over previous generations, challenges with this technology remain. Approaching these problems with a combination of clinical and engineering solutions may be needed to achieve continued progression in the field of durable mechanical circulatory support.

show abstract

Rotary pump speed modulation for generating pulsatile flow and phasic left ventricular volume unloading in a bovine model of chronic ischemic heart failure

Cited by 79 publications

References 23 publications

Feasibility of Pump Speed Modulation for Restoring Vascular Pulsatility with Rotary Blood Pumps

Feasibility of Pump Speed Modulation for Restoring Vascular Pulsatility with Rotary Blood Pumps

Pumping Rate Study of a Left Ventricular Assist Device in a Mock Circulatory System

Physiologic effects of continuous-flow left ventricular assist devices

Contact Info

Product

Resources

About