There is increasing evidence for successful management of end-stage heart failure with continuous-flow left ventricular assist device (CF-LVAD) technology. However, passive flow adjustment at fixed CF-LVAD speed is susceptible to flow balancing issues as well as adverse hemodynamic effects relating to the diminished arterial pulse pressure and flow. With current therapy, flow cannot be adjusted with changes in venous return, which can vary significantly with volume status. This limits the performance and safety of CF-LVAD. Active flow adjustment strategies have been proposed to improve the synchrony between the pump and the native cardiovascular system, mimicking the Frank–Starling mechanism of the heart. These flow adjustment strategies include modulation by CF-LVAD pump speed by synchrony and maintenance of constant flow or constant pressure head, or a combination of these variables. However, none of these adjustment strategies have evolved sufficiently to gain widespread attention. Herein we review the current challenges and future directions of CF-LVAD therapy and sensor technology focusing on the development of a physiologic, long-term active flow adjustment strategy for CF-LVADs.
From the *Department of Cardiovascular Surgery, Mayo Clinic, Rochester, Minnesota; †Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada; ‡Department of Surgery, Alameda Health System, Oakland, California; §Faculty of Medicine, University of Sydney, Sydney, Australia; ¶Department of Medicine and Health Sciences, Linkoping University, Linkoping, Sweden; ‖1Department of Mechanical Engineering, Rochester Institute of Technology, Rochester, New York; and #Department of Thoracic and Cardiovascular Surgery, University of Louisville, Louisville, Kentucky.
Submitted for consideration May 2016; accepted for publication in revised form October 2016.
Disclosure: The authors have no conflicts of interest to report.
Correspondence: Vakhtang Tchantchaleishvili, Department of Cardiovascular Surgery, Mayo Clinic, Saint Mary’s Hospital, Joseph 5–200, 200 First Street SW, Rochester, MN 55905. Email: Tchantchaleishvili.Vakhtang@mayo.edu.