RVEX: Right Ventricular External Device for Biomimetic Support and Monitoring of the Right Heart

Abstract

devices (LVADs) have provided an invaluable alternative for thousands of patients with severe left-sided heart failure. Nevertheless, right ventricular failure is a leading cause of death and morbidity following several cardiothoracic procedures, including implantation of LVAD devices. [1,2] According to Lampert et al., postoperative right ventricular failure, defined as the inability of the right ventricle to maintain enough blood flow through the pulmonary circulation, remains the most frequent and serious complication after LVAD implantation and occurs in up to 35% of LVAD recipients, especially in patients with smaller left ventricular size, such as women. [2][3][4] LVAD implantation requires the right ventricle (RV) to increase its output flow in order to match the LVAD flow, a concept referred to in medical jargon as "hemodynamic adaptation." [5] It is worth noting that failure to adapt to the new hemodynamic requirements manifests acutely in the first few days or weeks following surgical procedures. [5] Limiting LVAD patient selection based on predictive models is an attractive option, but preoperative risk factors of RV failure in LVAD patients are inconsistent and newer deep-learning methods to predict postoperative RV failure have yet to be tested in prospective trials. [6,7] Thus, clinical strategies and devices should be designed to provide adequate protection to the RV and support its adaptation to the new hemodynamic demand. In this context, continuous monitoring over the days following the surgery would be an effective way to track and adjust treatment response.Failure to adapt to new hemodynamic demand can put the RV at a biomechanical disadvantage, characterized by strain concentrations that trigger adverse dilatation (or "remodeling") and, eventually, failure. It has been shown that such dilatation is a well-recognized precursor of heart failure, and is driven by biomechanical perturbations in the passive filling phase of the heart's cycle, such as excessive tissue stresses or strains due to overfilling of the ventricle. [8,9] Previous attempts at mechanically reducing ventricular strain through devices have been referred to as ventricular restraint therapy: a non-transplant surgical treatment mainly investigated in the context of the left ventricular dilation. This strategy was attempted in patients where the left ventricle (LV) had experienced significant dilatation, in an attempt to prevent failure. To limit undesired tissue distention and expansion, the epicardial (outer-most) layer of the heart Right ventricular (RV) failure remains a significant burden for patients with advanced heart failure, especially after major cardiac surgeries such as implantation of left ventricular assist devices. Device solutions that can assist the complex biological function of heart muscle without the disadvantages of bulky designs and infection-prone drivelines remain an area of pressing clinical need, especially for the right ventricle. In addition, devices that incur contact between blood and artificial sur...

Review on structural optimization techniques for additively manufactured implantable medical devices

“…More flexibility, structural design, and compliance attributed to soft functional materials used in the fabrication of these devices make them ideal for delicate tasks in fragile in-body environments. For instance, an implantable elastic sleeve for right ventricular failure and monitoring of hemodynamic conditions was designed by Pirozzi et al (Pirozzi et al, 2022), as seen in Figure 4B. However, the inherent nonlinearity of soft functional materials and their anisotropic actuation in compliant mechanisms present ongoing challenges in performance improvement.…”