Development status of Terumo implantable left ventricular assist system

Area of Science:

• Biomedical Engineering
• Cardiovascular Devices
• Medical Implants

Background:

• Development of the T-ILVAS (implantable left ventricular assist system) featuring a magnetically suspended centrifugal pump (MSCP) has been ongoing since 1995.
• Early prototypes demonstrated long-term durability, excellent blood compatibility (up to 864 days), and stable magnetic bearing performance.

Purpose of the Study:

• To evaluate the clinical feasibility and performance of a newly devised titanium version of the T-ILVAS (Type IV pump).
• To assess the hydrodynamic performance, blood compatibility, and long-term stability of the implantable assist device in an in vivo model.

Main Methods:

• A titanium Type IV pump (180 ml) with a new position sensor and wearable controller was developed.
• In vitro hydrodynamic performance and hemolysis tests were conducted.
• In vivo evaluation in 6 sheep, with survival up to 6 months, without routine anticoagulation.

Main Results:

• The Type IV pump confirmed suitability for small patients (body surface area as low as 1.3) via cadaver fit study.
• In vitro tests showed excellent hydrodynamic performance and acceptable hemolysis.
• In vivo studies in sheep demonstrated no mechanical failure or thromboembolism, with one instance of mural thrombi around the inflow cannula.

Conclusions:

• The magnetically suspended centrifugal pump (MSCP) mechanism is reliable and feasible for long-term circulatory assist.
• The titanium Type IV T-ILVAS shows promising performance and durability for clinical application.
• Further investigation into inflow cannula design may mitigate localized thrombus formation.