Biofunctional impact of textured coatings in the application of heart assist therapy

Abstract

Due to a lack of organs, cardiac support systems are being implanted in patients with severe congestive heart failure. One of the solutions to overcome complications such as inflow obstruction or pump thrombosis, which may occur in the case of ventricular assist devices, is to modify the surface of cannulas for the controlled blood clotting process. The results obtained up till now for developed surface coatings clearly show the influence of topographical and mechanical parameters of the coatings on cell viability and protein adsorption mechanism. The new coatings should enable the controlled growth of scar tissue, resulting in the limitation of thromboembolic events, and the reduction of cystic tissue growth into the flow lumen. The aim of this study is to evaluate the correlation between surface topography parameters on the susceptibility of cells to grow and adhere to the substrate as a solution with potential for use in MCS (mechanical circulatory support) devices. Research on surfaces used in MCS devices and on inflow cannulas has been carried out for many years, while the novelty of the present solution makes it a milestone within that type of application simultaneously allowing for appropriate selection of process parameters. Surface modification of titanium alloy Ti6Al7Nb was carried out using vacuum powder sintering of CP-Ti (commercially pure titanium) powder with two morphologies (regular spheres and irregular grains). The characterization of coatings obtained with the proposed method and the influence of measured topographic parameters (applying scanning electron microscopy, contact angle measurement and contact profilometry) on the cytotoxicity and susceptibility to protein adsorption were presented. Advanced albumin adsorption studies have fully confirmed the dependence of surface complexity on protein adsorption. The obtained results show a high potential of the produced coatings toward enabling permanent integration at the implant with the soft tissue.

Thrombus formation at the inflow cannula of continuous‐flow left ventricular assist devices—A systematic analysis

“…Some clinical studies (i.e., in vivo investigations) have addressed the subject of thrombus formation depending on specific design aspects or design changes. 16 During the clinical course, thrombi at the inflow cannula cannot be determined directly, thus thromboembolic events like neurologic incidents 24,25 or pump thrombosis 26 are often used as a surrogate.…”

“…13,14 The healing process is influenced by the properties of the surface facing the wound tissue: while the topography of a textured surface promotes adhesion of myocardial cells, 15 a polished surface does not encourage macroscopic anchoring of the tissue to the cannula. 16 Published in silico simulations investigating thrombus formation and thrombus propagation in CF-VADs tend to focus on specific aspects of flow characteristics or geometrical variations. 17,18 The advantage of these simulations is that they can isolate flow-related aspects by excluding superimposing effects.…”

In Vitro and In Vivo Testing of Stereolithography (SLA)-Manufactured Haemocompatible Photopolymers for Blood Pump

“…It will enable an extension of LVADs to broader patient populations [12], including future strategies related to minimally invasive implantable devices inserted through the femoral artery. Taking into account the existing data [13][14][15][16][17][18][19][20][21][22], it is evident that the problem of thrombus formation could be avoided through the use of novel hybrid materials and engineering methods based on so-called additive manufacturing technology [23][24][25][26][27]. It allows almost complete freedom of the geometric design of the rotor shape providing proper long-term contact with the blood [28].…”

Biological Response to Sintered Titanium in Left Ventricular Assist Devices: Pseudoneointima, Neointima, and Pannus

“…Therefore, some manner of surface modification is necessary, most commonly texturing via abrasive blasting, laser ablation, atmospheric plasma spraying, wire wrapping, and vacuum powder sintering. 8,9 However, reported clinical outcomes over the past several decades have been highly variable and apparently unpredictable. Consequently, there is no consensus of best practices or guidelines to optimize endothelialization on sintered titanium.…”