A comparison of three ventricles used for left ventricular bypass in the calf

Area of Science:

• Biomedical Engineering
• Cardiovascular Surgery
• Materials Science

Background:

• Long-term cardiac support often requires mechanical circulatory assistance.
• Left ventricular assist devices (LVADs) are crucial for managing heart failure.
• Thrombus formation remains a significant challenge in current LVAD designs.

Purpose of the Study:

• To evaluate thrombus formation in different pneumatically powered left ventricular bypass pump designs.
• To identify design features that minimize or eliminate thrombus development.
• To assess the efficacy of anticoagulation and surface coatings in preventing thrombus.

Main Methods:

• Implementation of long-term synchronized left ventricular bypass in calves.
• Utilized three distinct pump designs: sac, longitudinal tethered sac, and transverse tethered sac.
• Fabricated pumps with smooth linings of segmented polyurethane.

Main Results:

• Significant thrombi developed in the apex of sac and longitudinal tethered sac pumps.
• Transverse tethered sac pumps exhibited considerably smaller thrombi, primarily at the inlet flexion point.
• Thrombus formation correlated with areas of low flow velocity, unaffected by anticoagulation or surface coatings.

Conclusions:

• Ventricle design is critical for developing thrombus-free blood pumps.
• Modifications to pump geometry are necessary to reduce or eliminate thrombus formation.
• Further research into flow dynamics and pump design is warranted for improved LVAD safety.