Pump-Induced Hemolysis of Speed Modulated Axial-Flow Left Ventricular Assist Devices

Area of Science:

• Cardiovascular Engineering
• Biomedical Device Technology
• Hemodynamics

Background:

• Reduced arterial pulsatility during continuous-flow left ventricular assist device (LVAD) support is linked to adverse events.
• Pump speed modulation is a potential strategy to enhance arterial pulsatility.
• Understanding the impact of speed modulation on hemolysis is crucial for LVAD safety.

Purpose of the Study:

• To compare pump-induced hemolysis between constant speed and modulated speed modes for two axial-flow LVADs (Sputnik1 and HeartMate2).
• To evaluate the hemolytic performance differences between the Sputnik1 and HeartMate2 LVADs.

Main Methods:

• Two Sputnik1 and two HeartMate2 (HM2) LVADs were tested in automated hemolysis systems for 6 hours per mode.
• Speed modulation was applied using rectangular patterns at 70 and 140 bpm, achieving head pressures of 80-120 mmHg.
• Plasma-free hemoglobin levels were measured hourly to calculate the modified index of hemolysis (MIH).

Main Results:

• Speed modulation increased hemolysis (MIH) in Sputnik1 LVADs but decreased it in most HeartMate2 (HM2) LVADs compared to constant speed.
• Significant differences in hemolysis due to modulation were only observed in one Sputnik1 LVAD.
• Sputnik1 LVADs demonstrated lower hemolysis levels than HM2 LVADs when operated in constant speed mode.

Conclusions:

• HeartMate2 (HM2) LVADs may be safely operated in speed modulation mode without increased hemolysis risk.
• For Sputnik1 LVADs, the benefits of speed modulation require careful consideration against the potential for increased hemolysis.
• Sputnik1 LVADs appear to have a lower hemolytic profile than HM2 LVADs in the standard constant speed mode.