0
Technical Briefs

In Vitro Pulsatility Analysis of Axial-Flow and Centrifugal-Flow Left Ventricular Assist Devices

[+] Author and Article Information
J. Ryan Stanfield

Department of Mechanical Engineering,
University of Utah,
50 S Central Campus Dr.,
Rm. 2110, Salt Lake City, UT 84112
e-mail: ryan.stanfield@utah.edu

Craig H. Selzman

Department of Surgery,
Division of Cardiothoracic Surgery,
University of Utah,
30 N 1900 E, SOM 3C127,
Salt Lake City, UT 84132

Contributed by the Bioengineering Division of ASME for publication in the Journal of Biomechanical Engineering. Manuscript received October 6, 2012; final manuscript received January 21, 2013; accepted manuscript posted January 29, 2013; published online February 11, 2013. Assoc. Editor: Ender A. Finol.

J Biomech Eng 135(3), 034505 (Feb 11, 2013) (6 pages) Paper No: BIO-12-1466; doi: 10.1115/1.4023525 History: Received October 06, 2012; Revised January 21, 2013; Accepted January 29, 2013

Recently, continuous-flow ventricular assist devices (CF-VADs) have supplanted older, pulsatile-flow pumps, for treating patients with advanced heart failure. Despite the excellent results of the newer generation devices, the effects of long-term loss of pulsatility remain unknown. The aim of this study is to compare the ability of both axial and centrifugal continuous-flow pumps to intrinsically modify pulsatility when placed under physiologically diverse conditions. Four VADs, two axial- and two centrifugal-flow, were evaluated on a mock circulatory flow system. Each VAD was operated at a constant impeller speed over three hypothetical cardiac conditions: normo-tensive, hypertensive, and hypotensive. Pulsatility index (PI) was compared for each device under each condition. Centrifugal-flow devices had a higher PI than that of axial-flow pumps. Under normo-tension, flow PI was 0.98 ± 0.03 and 1.50 ± 0.02 for the axial and centrifugal groups, respectively (p < 0.01). Under hypertension, flow PI was 1.90 ± 0.16 and 4.21 ± 0.29 for the axial and centrifugal pumps, respectively (p = 0.01). Under hypotension, PI was 0.73 ± 0.02 and 0.78 ± 0.02 for the axial and centrifugal groups, respectively (p = 0.13). All tested CF-VADs were capable of maintaining some pulsatile-flow when connected in parallel with our mock ventricle. We conclude that centrifugal-flow devices outperform the axial pumps from the basis of PI under tested conditions.

FIGURES IN THIS ARTICLE
<>
Copyright © 2013 by ASME
Your Session has timed out. Please sign back in to continue.

References

Wesolowski, S. A., Fisher, J. H., and Welsh, C. S., 1953, “Perfusion of the Pulmonary Circulation by Nonpulsatile Flow,” Surgery, 33(3), pp. 370–375. [PubMed]
Nose, Y., 1992, “Is a Pulsatile Cardiac Prosthesis a Dying Dinosaur?” Artif. Organs, 16(3), pp. 233–234. [CrossRef] [PubMed]
Hindman, B. J., Dexter, F., Ryu, K. H., Smith, T., and Cutkomp, J., 1994, “Pulsatile versus Nonpulsatile Cardiopulmonary Bypass: No Difference in Brain Blood Flow or Metabolism at 27  °C,” Anesthesiology, 80(5), pp. 1137–1147, Available at: http://journals.lww.com/anesthesiology/Abstract/1994/05000/Pulsatile_Versus_Nonpulsatile_Cardiopulmonary.23.aspx
Pagani, F. D., Miller, L. W., Russell, S. D., Aaronson, K. D., John, R., Boyle, A. J., Conte, J. V., Bogaev, R. C., MacGillivray, T. E., Naka, Y., Mancini, D., Massey, H. T., Chen, L., Klodell, C. T., Aranda, J. M., Moazami, N., Ewald, G. A., Farrar, D. J., and Frazier, O. H., 2009, “Extended Mechanical Circulatory Support With a Continuous-Flow Rotary LVAD,” J. Am. Coll. Cardiol., 54(4), pp. 312–321. [CrossRef] [PubMed]
Slaughter, M. S., Rogers, J. G., Milano, C. A., Russell, S. D., Conte, J. V., Feldman, D., Sun, B., Tatooles, A. J., Delgado, R. M., Long, J. W., Wozniak, T. C., Ghumman, W., Farrar, D. J., and Frazier, O. H., 2009, “Advanced Heart Failure Treated With Continuous-Flow LVAD,” New Engl. J. Med., 361, pp. 2241–2251. [CrossRef]
Nose, Y., 1988, “The Need for a Nonpulsatile Pumping System,” Artif. Organs, 12(2), pp. 113–115. [CrossRef] [PubMed]
Unger, F., 1986, “Review Article: Current Status and Use of Artificial Hearts and Circulatory Assist Devices,” Perfusion, 1(3), pp. 155–163. [CrossRef]
Olsen, D. B., 2000, “The History of Continuous-Flow Blood Pumps,” Artif. Organs, 24(6), pp. 401–404. [CrossRef] [PubMed]
Allen, G. S., Murray, K. D., and Olsen, D. B., 1997, “The Importance of Pulsatile and Nonpulsatile Flow in the Design of Blood Pumps,” Artif. Organs, 21(8), pp. 922–928. [CrossRef] [PubMed]
Potapov, E. V., Loebe, M., Nasseri, B. A., Sinawski, H., Koster, A., Kuppe, H., Noon, G. P., DeBakey, M. E., and Hetzer, R., 2000, “Pulsatile Flow in Patients With a Novel Nonpulsatile Implantable VAD,” Circulation, 102(19 Suppl. 3), pp. III183–III187. [CrossRef] [PubMed]
Griffith, B. P., Kormos, R. L., Borovetz, H. S., Litwak, K., Antaki, J. F., Poirier, V. L., and Butler, K. C., 2001, “HeartMate II LVAS: From Concept to First Clinical Use,” Ann. Thorac. Surg., 71(3 Suppl.), pp. S116–S120. [CrossRef] [PubMed]
Choi, S., Antaki, J. F., Boston, J. R., and Thomas, D. A., 2001, “Sensorless Approach to Control of a Turbodynamic LVAS,” IEEE T. Contr. Syst. T., 9(3), pp. 473–482. [CrossRef]
Pantalos, G. M., Koenig, S. C., Gillars, K. J., Giridharan, G. A., and Ewert, D. L., 2004, “Characterization of an Adult Mock Circulation for Testing Cardiac Support Devices,” ASAIO J., 50(1), pp. 37–46. [CrossRef] [PubMed]
Stanfield, J. R., Selzman, C. H., Pardyjak, E. R., and Bamberg, S. M., 2012, “Flow Characteristics of Continuous-Flow LVADs in a Novel Open-Loop System,” ASAIO J., 58(6), pp. 590–596. [CrossRef] [PubMed]
Stanfield, J. R., and Selzman, C. H., 2012, “Pressure Sensitivity of Axial-Flow and Centrifugal-Flow LVADs,” Cardiovasc. Eng. Tech., 3(4), pp. 413–423. [CrossRef]
Choi, S., Boston, J. R., and Antaki, J. F., 2005, “An Investigation of the Pump Operating Characteristics as a Novel Control Index for LVAD Control,” Int. J. Cont. Autom., 3(1), pp. 100–108, Available at: http://bme2.aut.ac.ir/~towhidkhah/BioModelling/Seminar87-1/rohani/An%20investigation%20of%20the%20pump%20operating%20characteristics%20as%20a%20novel%20control%20index%20for%20LVAD%20control.pdf
Choi, S., Boston, J. R., and Antaki, J. F., 2007, “Hemodynamic Controller for LVAD Based on Pulsatility Ratio,” Artif. Organs, 31(2), pp. 114–125. [CrossRef] [PubMed]
Stepanoff, A. J., 2011, Centrifugal and Axial Flow Pumps, 2nd ed., John Wiley & Sons, New York.
Garcia, S., Kandar, F., Boyle, A., Colvin-Adams, M., Lliao, K., Joyce, L., and John, R., 2008, “Effects of Pulsatile- and Continuous-Flow LVADs on Left Ventricular Unloading,” J. Heart Lung Transpl., 27(3), pp. 261–267. [CrossRef]
Klotz, S., Deng, M. C., Stypmann, J., Roetker, J., Wilhelm, M. J., Hammel, D., Scheld, H., H., and Schmid, C., 2004, “Left Ventricular Pressure and Volume Unloading During Pulsatile versus Nonpulsatile LVAD Support,” Ann. Thorac. Surg., 77(1), pp. 143–150. [CrossRef] [PubMed]
Haft, J., Armstrong, W., Dyke, D. B., Aaronson, K. D., Koelling, T. M., Farrar, D. J., and Pagani, F. D., 2007, “Hemodynamic and Exercise Performance With Pulsatile and Continuous-Flow LVADs,” Circulation, 116(11 Suppl.), pp. I8–I15. [CrossRef] [PubMed]
DiGiorgi, P. L., Smith, D. L., Naka, Y., and Oz, M. C., 2004, “In Vitro Characterization of Aortic Retrograde and Antegrade Flow From Pulsatile and Nonpulsatile VADs,” J. Heart Lung Transpl., 23(2), pp. 186–192. [CrossRef]
Nakata, K., Shiono, M., Orime, Y., Hata, M., Sezai, A., Saitoh, T., and Sezai, Y., 1996, “Effect of Pulsatile and Nonpulsatile Assist on Heart and Kidney Microcirculation With Cardiogenic Shock,” Artif. Organs, 20(6), pp. 681–684. [CrossRef] [PubMed]
Amir, O., Radovancevic, B., Delgado, R. M., Kar, B., Radovancevic, R., Henderson, M., Cohn, W. E., and Smart, F. W., 2006, “Peripheral Vascular Reactivity in Patients With Pulsatile vs. Axial Flow LVAD Support,” J. Heart Lung Transpl., 25(4), pp. 391–394. [CrossRef]
Young, J. B., 2001, “Healing the Heart With VAD Therapy: Mechanisms of Cardiac Recovery.” Ann. Thorac. Surg., 71(3 Suppl.), pp. S210–S219. [CrossRef] [PubMed]
Levin, H., Oz, M., Chen, J., Packer, M., Rose, E., and Burkhoff, D., 1995, “Reversal of Chronic Ventricular Dilatation in Patients With End-Stage Cardiomyopathy by Prolonged Mechanical Unloading,” Circulation, 91(11), pp. 2717–2720. [CrossRef] [PubMed]
Farrar, D. J., Bourque, K., Dague, C. P., Cotter, C. J., and Poirier, V. L., 2007, “Design Features, Developmental Status and Experimental Results With the Heartmate III Centrifugal LVAS With Magnetically Levitated Rotor,” ASAIO J., 53(3), pp. 310–315. [CrossRef] [PubMed]

Figures

Grahic Jump Location
Fig. 1

Schematic of mock circulation loop with pulsatile capability. PCC/SCC, pulmonary/systemic compliance chamber(s); LA, left atrium; LV, left ventricle. Not shown: unidirectional pericardial valves at “top” of LV to represent mitral and aortic valves.

Grahic Jump Location
Fig. 2

Baseline oscillating pressure waveforms associated with each simulated cardiac condition: normo-tensive, hypertensive, and hypotensive. AoP, aortic pressure; LVP, left ventricular pressure (mm Hg).

Grahic Jump Location
Fig. 3

Oscillating head and flow coefficient waveforms under all tested conditions for axial (A1, A2) and centrifugal (C1, C2) continuous-flow pumps. φ, flow coefficient; ψ, head coefficient. Left column are waveforms for all pumps under normo-tensive condition, middle column under hypertensive condition, right column under hypotensive condition.

Grahic Jump Location
Fig. 4

Pressure-flow (first column: ΔP-Q; second column: ψ-φ) performance curves for all four devices under the three tested conditions. Q, flow rate (L/min); ΔP, pressure differential (mm Hg); φ, flow coefficient; ψ, head coefficient.

Grahic Jump Location
Fig. 5

Hydraulic power (mW), supplied by each VAD in a typical cycle under the pulsatile cardiac conditions: (1) normo-tensive, (2) hypertensive, and (3) hypotensive

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In