Central and peripheral blood flow during exercise with a continuous-flow left ventricular assist device: constant...

Area of Science:

• Cardiovascular Physiology
• Medical Devices
• Exercise Science

Background:

• End-stage heart failure significantly impairs cardiac output and organ blood flow.
• Left ventricular assist devices (LVADs) are used to support circulation in heart failure patients.

Purpose of the Study:

• To assess if cardiac output and peripheral perfusion are maintained during exercise in patients with an axial-flow LVAD.
• To determine if increasing LVAD pump speed enhances organ blood flow during exercise.

Main Methods:

• Eight patients with a HeartMate II LVAD underwent two incremental cycle exercise tests.
• Cardiac output, leg blood flow, and cerebral perfusion were measured under constant and increasing LVAD pump speed conditions.

Main Results:

• At maximal exercise, LVADs supported near-normal increases in cardiac output and leg blood flow.
• Cerebral perfusion was low at rest and unchanged during exercise with constant pump speed.
• Increasing LVAD pump speed significantly augmented cerebral perfusion during exercise.

Conclusions:

• Axial-flow LVADs adequately support cardiac output and leg perfusion during maximal exercise.
• Cerebral perfusion remains suboptimal in LVAD patients during exercise.
• Adjusting LVAD pump speed can improve cerebral blood flow during physical activity.