Vascular pulsatility in patients with a pulsatile- or continuous-flow ventricular assist device

Area of Science:

• Cardiovascular Physiology
• Medical Device Engineering

Background:

• Heart failure significantly alters ventricular function and vascular hemodynamics.
• Left ventricular assist devices (LVADs) are crucial for end-stage heart failure management.
• Understanding the hemodynamic effects of different LVAD flow types is vital.

Purpose of the Study:

• To compare vascular pulsatility indices between normal ventricular function and heart failure patients.
• To investigate hemodynamic differences between continuous-flow and pulsatile-flow LVADs.
• To assess the impact of LVAD type on vascular input impedance and pulsatility.

Main Methods:

• Studied 8 normal ventricular function patients and 22 heart failure patients.
• Utilized high-fidelity pressure catheters and transit-time flow probes for hemodynamic data acquisition.
• Calculated vascular input impedance, energy-equivalent pressure, and surplus hemodynamic energy across varying device flow rates.

Main Results:

• Pulsatile support restored surplus hemodynamic energy close to normal values, while continuous support drastically reduced it.
• Continuous support at high levels diminished surplus energy by 97%, whereas pulsatile support augmented it by 49%.
• Pulsatile support reduced vascular impedance and maintained vascular compliance, unlike continuous support which increased impedance and indicated stiffening.

Conclusions:

• LVAD type and flow rate significantly influence vascular pulsatility and input impedance.
• These hemodynamic changes may have implications for clinical outcomes in LVAD patients.
• Pulsatile LVAD support appears more favorable for maintaining vascular health compared to continuous-flow support.