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. 2016 Mar;5(1):22-29.
doi: 10.1016/j.imr.2016.01.001. Epub 2016 Jan 8.

Mathematical analysis of the effects of valvular regurgitation on the pumping efficacy of continuous and pulsatile left ventricular assist devices

Yoo Seok Kim  1 , Eun-Hye Kim  1 , Hyeong-Gyun Kim  2 , Eun Bo Shim  3 , Kwang-Soup Song  1 , Ki Moo Lim  1
Affiliations

Mathematical analysis of the effects of valvular regurgitation on the pumping efficacy of continuous and pulsatile left ventricular assist devices

Yoo Seok Kim et al. Integr Med Res. 2016 Mar.

Abstract

Background: A left ventricular assist device (LVAD) is normally contraindicated in significant aortic regurgitation (AR) and requires intraoperative valve repair or exclusion. Nevertheless, AR can coexist with an LVAD, so a valid question when asked might still be of clinical significance. The purpose of this study is to analyze the effects of valve regurgitation on the pumping efficacy of continuous and pulsatile LVADs with a computational method.

Methods: A cardiovascular model was developed based on the Windkessel model, which reflects the hemodynamic flow resistance and the blood wall elasticity. Using the Windkessel model, important cardiovascular components, such as the right atrium, right ventricle, pulmonary artery, pulmonary vein, left atrium (LA), left ventricle (LV), aorta, and branching blood vessels, were expressed.

Results: In the case of AR, continuous and pulsatile LVADs improved cardiac output and reduced mechanical load slightly. In the case of mitral regurgitation, the LVADs improved cardiac output (cardiac outputs were about 5 L/min regardless of the severity of regurgitation) and reduced afterload significantly.

Conclusion: AR reduced both continuous and pulsatile LVAD function significantly while mitral regurgitation did not affect their pumping efficacy.

Keywords: Windkessel model; aortic regurgitation; left ventricular assist device; mitral regurgitation; regurgitation severity.

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Figures

Fig. 1
Fig. 1
Schematic drawing of the cardiovascular system model that consists of eight compartments. See Lim et al for the detailed parameter information. SF, scale factor for the leakage resistance.
Fig. 2
Fig. 2
Time-varying compliance of the right and left ventricles. HF, heart failure; NORM, normal condition.
Fig. 3
Fig. 3
Left ventricular assist device (LVAD) flow rate for one pumping cycle. Dashed line, pulsatile LVAD (PLVAD) inflow; dotted line, continuous LVAD (CLVAD) inflow and outflow; solid line, PLVAD outflow.
Fig. 4
Fig. 4
Left ventricular and aortic pressure profiles under the aortic valve regurgitation. (A) Without left ventricular assist device (LVAD) treatment. (B) With continuous LVAD (CLVAD) treatment. (C) With pulsatile LVAD (PLVAD) treatment. AR, aortic regurgitation.
Fig. 5
Fig. 5
Left ventricular and aortic pressure profiles under the mitral valve regurgitation. (A) Without left ventricular assist device (LVAD) treatment. (B) With continuous LVAD (CLVAD) treatment. (C) With pulsatile LVAD (PLVAD) treatment. MR, mitral regurgitation.
Fig. 6
Fig. 6
Pressure-volume loops under the aortic and mitral valve regurgitation conditions (A and B) without left ventricular assist device (LVAD) treatment, (C and D) with continuous LVAD (CLVAD) treatment, and (E and F) with pulsatile LVAD (PLVAD) treatment. AR, aortic regurgitation; MR, mitral regurgitation.
Fig. 7
Fig. 7
Cardiac responses. (A) Cardiac output (CO). (B) Left ventricular stroke work (LV SW). (C) Left ventricular stroke work (LV SW). (D) left ventricular ejection fraction (LV EF). (E) left ventricular peak pressure (LV PP). (F) Under-valve regurgitation by the CLVAD and the PLVAD. AR, aortic regurgitation; CLVAD, continuous left ventricular assist device, MR, mitral regurgitation; PLVAD, pulsatile left ventricular assist device.
See this image and copyright information in PMC

References

    1. Casarotto D., Bottio T., Gambino A., Testolin L., Gerosa G. The last to die is hope: prolonged mechanical circulatory support with a Novacor left ventricular assist device as a bridge to transplantation. J Thorac Cardiovasc Surg. 2003;125:417–418. - PubMed
    1. John R., Kamdar F., Liao K., Colvin-Adams M., Boyle A., Joyce L. Improved survival and decreasing incidence of adverse events with the HeartMate II left ventricular assist device as bridge-to-transplant therapy. Ann Thorac Surg. 2008;86:1227–1234. - PubMed
    1. Daneshmand M.A., Rajagopal K., Lima B., Khorram N., Blue L.J., Lodge A.J. Left ventricular assist device destination therapy versus extended criteria cardiac transplant. Ann Thorac Surg. 2010;89:1205–1209. - PubMed
    1. Uretsky S., Supariwala A., Nidadovolu P., Khokhar S.S., Comeau C., Shubayev O. Quantification of left ventricular remodeling in response to isolated aortic or mitral regurgitation. J Cardiovasc Magn Reson. 2010;12 http://jcmr-online.biomedcentral.com/articles/10.1186/1532-429X-12-32, Article number 32. - DOI - PMC - PubMed
    1. Bryant A.S., Holman W.L., Nanda N.C., Vengala S., Blood M.S., Pamboukian S.V. Native aortic valve insufficiency in patients with left ventricular assist devices. Ann Thorac Surg. 2006;81:6–8. - PubMed

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