HeartWare Left Ventricular Assist Device Exercise Hemodynamics With Speed Adjustment Based on Left Ventricular...

Area of Science:

• Cardiology
• Biomedical Engineering
• Exercise Physiology

Background:

• Heart failure patients with left ventricular assist devices (LVADs) experience limited functional capacity.
• Fixed pump speeds in LVADs hinder adequate left ventricular offloading during exertion.

Purpose of the Study:

• To test if manually adjusting LVAD speed based on pulmonary capillary wedge pressure during exercise enhances cardiac output and maximal oxygen consumption.
• To investigate the impact of dynamic LVAD speed adjustment on hemodynamic parameters during cardiopulmonary stress tests.

Main Methods:

• Two participants with HeartWare LVADs underwent invasive cardiopulmonary stress tests.
• Exercise phases included fixed LVAD speed and adjusted speed, with speed altered based on pulmonary capillary wedge pressure changes.
• Hemodynamic data, including cardiac output and filling pressures, were continuously monitored.

Main Results:

• No significant difference in maximal oxygen consumption was found between fixed and adjusted speed phases.
• A modest increase in total cardiac output was observed during adjusted speed, but filling pressures increased when pump speed reached its maximum (4,000 rpm).
• Blood pressure variability and increased pressure across the LVAD pump (ΔP) were noted with speed adjustment.

Conclusions:

• Manual LVAD speed adjustment during exercise did not improve functional capacity or overall cardiac output as hypothesized.
• The limited native cardiac reserve and baroreceptor responses may influence the variable outcomes.
• Further research is required to understand the complex interactions and optimize LVAD management during physical activity.