Flexible Anti-thrombotic LVADs

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PROJECT SUMMARY Left ventricular assist device (LVAD) is a promising therapeutic option for end-stage heart failure patients, besides cardiac transplant, which is limited by the number of available donors. However, severe complications, including bleeding and thrombosis, significantly worsen the long-term outcome of the patients. This proposed joint effort aims to solve these problems by reducing blood damage using flexible rotors and dramatically reducing pump thrombosis through novel Slippery Hydrophilic (SLIC) coatings. The objective of this project is to develop a novel LVAD with flexible polymeric rotors and novel anti-thrombotic coatings that can dramatically reduce blood damage and dramatically reduce the risk of pump thrombosis. Development of the flexible anti-thrombotic LVAD requires careful optimization of the flexible rotors and SLIC coatings. In Aim 1, Characterization and Optimization of Flexible Polymeric Rotors to Reduce Blood Damage, we will design, fabricate and test rotors with a wide range of flexibilities. Flexible, water-clear polyurethanes will be used for the rotor, which grants optical access to the rotor passage. Durability will be characterized in this aim through a custom-built accelerated hydrodynamic testing rig. The hemodynamic performance and blood damage potential of the flexible LVAD with SLIC coatings will be characterized in-vitro using 2D and 3D particle image velocimetry. Blood damage caused to the blood cells will be quantified experimentally by evaluating the shear history obtained from 3D time-resolved particle tracking. In Aim 2, Optimize SLIC coatings for Maximum Anti-thrombotic Response, we propose to fabricate SLIC coatings on polymeric surfaces and characterize the physical and chemical inhomogeneities through Atomic Force Microscopy (AFM),contact angle goniometry (advancing and receding angle measurements). X-ray photoelectron spectroscopy (XPS), near-edge x-ray absorption fine structure (NEXAFS), electrostatic force microscopy (EFM), to maximize the anti-thrombotic response. The optimized LVAD with flexible rotors and SLIC coatings will be thoroughly evaluated in-vitro using a blood loop under both quasi-steady and dynamic conditions. Levels of the blood damage and thrombosis potential will be compared with a rigid counterpart with and without SLIC coatings, along with statistical analysis. We hypothesize that through optimized polymeric flexible blade designs and SLIC coatings, LVADs can achieve excellent hemocompatibility, dramatically reducing blood damage and thrombosis. This novel design coupled with the unique SLIC coating has the potential to be used in future generations of LVADs that can provide long-term support to end-stage heart failure patients as a non-inferior alternative to cardiac transplants.