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Purpose: Pediatric heart failure patients remain in critical need of a dedicated mechanical circulatory support (MCS) solution as development efforts for specific pediatric devices continue to fall behind those for the adult population. The Inspired Pediatric VAD is being developed as a pediatric specific MCS solution to provide up to 30-days of circulatory or respiratory support in a compact modular package that could allow for patient ambulation during treatment., Methods: Hydrodynamic performance (flows, pressures), impeller/rotor mechanical properties (torques, forces), and flow shear stress and residence time distributions of the latest design version, Inspired Pediatric VAD V3, were numerically predicted and investigated using computational fluid dynamics (CFD) software (SolidWorks Flow Simulator)., Results: Hydrodynamic performance was numerically predicted, indicating no change in flow and pressure head compared to the previous device design (V2), while displaying increased impeller/rotor torques and translation forces enabled by improved geometry. Shear stress and flow residence time volumetric distributions are presented over a range of pump rotational speeds and flow rates. At the lowest pump operating point (3000 RPM, 0.50 L/min, 75 mmHg), 79% of the pump volume was in the shear stress range of 0-10 Pa with < 1% of the volume in the critical range of 150-1000 Pa for blood damage. At higher speed and flow (5000 RPM, 3.50 L/min, 176 mmHg), 65% of the volume resided in the 0-10 Pa range compared to 2.3% at 150-1000 Pa., Conclusions: The initial computational characterization of the Inspired Pediatric VAD V3 is encouraging and future work will include device prototype testing in a mock circulatory loop and acute large animal model., (© 2022. The Author(s) under exclusive licence to Biomedical Engineering Society.)

Inspired Therapeutics (Merritt Island, FL) is developing a mechanical circulatory support (MCS) system designed as a single driver with interchangeable, extracorporeal, magnetically levitated pumps. The NeoMate system design features an integrated centrifugal rotary pump, motor, and controller that will be housed in a single compact unit. Conceptually, the primary innovation of this technology will be the combination of disposable, low-cost pumps for use with a single, multi-functional, universal controller to support multiple pediatric cardiopulmonary indications. In response to the paucity of clinically available pediatric devices, Inspired Therapeutics is specifically targeting the underserved neonate and infant heart failure (HF) patient population first. In this article, we present the development of the prototype Inspired Therapeutics NeoMate System for pediatric left ventricular assist device (LVAD) support, and feasibility testing in static mock flow loops (H-Q curves), dynamic mock flow loops (hemodynamics), and in an acute healthy ovine model (hemodynamics and clinical applicability). The resultant hydrodynamic and hemodynamic data demonstrated the ability of this prototype pediatric LVAD and universal controller to function over a range of rotary pump speeds (500-6000 RPM), to provide pump flow rates of up to 2.6 L/min, and to volume unload the left ventricle in acute animals. Key engineering challenges observed and proposed solutions for the next design iteration are also presented., Competing Interests: This study was supported by a National Institutes of Health SBIR grant 1R43HL144214-01 (PI Dasse). Drs. Monreal, Koenig, and Slaughter were co-investigators on the NIH SBIR phase I grant (1R43HL144214-01) subcontract with Inspired Therapeutics. Dr. Dasse and Mr. Gellman were PI and Co-I, respectively, on the NIH SBIR phase I grant (1R43HL144214-01) and are employed by Inspired Therapeutics. Dr. Monreal is supported in part by a gift from Robert M. Prizant to the Legacy Foundation of Kentuckiana. Dr. Koenig is co-founder of Cor Habere and MAST developing medical devices supported by NIH SBIR phase I grants (R43HL142337-01, R43HL142385-01, R43HL152894-01); however, these affiliations and funded projects are unrelated to the subcontract with Inspired Therapeutics and independent of the work presented in this manuscript. Dr. Slaughter is co-founder of Cor Habere and MAST developing medical devices supported by NIH SBIR phase I grants (R43HL142337-01, R43HL142385-01, R43HL152894-01) and consultant with Magenta Medical; however, these affiliations and funded projects are unrelated to the subcontract with Inspired Therapeutics and independent of the work presented in this manuscript. Mr. Morello was a consultant on the NIH SBIR phase I grant (1R43HL144214-01) subcontract with Inspired Therapeutics and is employed by Veritium Research. Dr. Prina was a consultant on the NIH SBIR phase I grant (1R43HL144214-01) with Veritium Research LLC. Dr. Prina was also a paid consultant of VADovations Inc and Oregon Institute of Technology through his previous company Applimotion. None of these additional affiliations are related to the work presented in this manuscript. Dr. Tompkins was an engineer on the NIH SBIR phase I grant (1R43HL144214-01) as a graduate student at the University of Louisville and is a consultant for Inspired Therapeutics LLC. Additionally, Dr. Tompkins is a co-owner of MAST LLC, engineer with Cor Habere Corp., and consultant with VADovations Inc.; however, none of these additional affiliations are related to the work presented in this manuscript. Dr. Huang has a research grant from Gilead Sciences, serves as a consultant for GE Healthcare, and has ownership at Microsensor Labs and Degranin Therapeutics. Mr. Gellman is a consultant to Paragonix Technologies, Inc.; Vivante Health, Inc.; and Cardiac Assist Holdings, which are unrelated to to work presented in this manuscript. Dr. Dasse is the CEO and co-Founder of Inspired Therapeutics LLC and serves as PI on the NIH SBIR Phase I grant (1R43HL144214-01) that supported prototype development and feasibility testing presented in this manuscript. In addition, Dr. Dasse is a co-investigator on NIH SBIR phase I grant (R43HL142385-01) and consultant on NIH SBIR grant (R43HL158430), which are unrelated to this manuscript. He is also President and COO of VADovations Inc, and serves as a consultant to BiVACOR Inc, CH-Biomedical USA Inc, Jarvik Heart International, and Vortronix Medical, LLC, Teal Health Inc. CAH Holdings LLC, and “The Kidney Project” affiliated with the University of California San Francisco and Vanderbilt University, which are unrelated to this manuscript. Dr. Dasse serves on the Board of Directors for Makana Therapeutics and Artio Medical, which are unrelated to this manuscript.

Purpose: Despite the availability of first-generation extracorporeal mechanical circulatory support (MCS) systems that are widely used throughout the world, there is a need for the next generation of smaller, more portable devices (designed without cables and a minimal number of connectors) that can be used in all in-hospital and transport settings to support patients in heart failure. Moreover, a system that can be universally used for all indications for use including cardiopulmonary bypass (CPB), uni- or biventricular support (VAD), extracorporeal membrane oxygenation (ECMO) and respiratory assist that is suitable for use for adult, neonate, and pediatric patients is desirable. Providing a single, well designed, universal technology could reduce the incidence of human errors by limiting the need for training of hospital staff on a single system for a variety of indications throughout the hospital rather than having to train on multiple complex systems. The objective of this manuscript is to describe preliminary research to develop the first prototype pump for use as a ventricular assist device for pediatric patients with the Inspired Universal MCS technology. The Inspired VAD Universal System is an innovative extracorporeal blood pumping system utilizing novel MagLev technology in a single portable integrated motor/controller unit which can power a variety of different disposable pump modules intended for neonate, pediatric, and adult ventricular and respiratory assistance., Methods: A prototype of the Inspired Pediatric VAD was constructed to determine the hemodynamic requirements for pediatric applications. The magnitude/range of hydraulic torque of the internal impeller was quantified. The hydrodynamic performance of the prototype pump was benchmarked using a static mock flow loop model containing a heated blood analogue solution to test the pump over a range of rotational speeds (500-6000 RPM), flow rates (0-3.5 L/min), and pressures (0 to ~ 420 mmHg). The device was initially powered by a shaft-driven DC motor in lieu of a full MagLev design, which was also used to calculate the fluid torque acting on the impeller., Results: The pediatric VAD produced flows as high as 4.27 L/min against a pressure of 127 mmHg at 6000 RPM and the generated pressure and flow values fell within the desired design specifications., Conclusions: The empirically determined performance and torque values establish the requirements for the magnetically levitated motor design to be used in the Inspired Universal MagLev System. This next step in our research and development is to fabricate a fully integrated and functional magnetically levitated pump, motor and controller system that meets the product requirement specifications and achieves a state of readiness for acute ovine animal studies to verify safety and performance of the system., (© 2021. Biomedical Engineering Society.)

Pediatric heart failure (HF) patients have been a historically underserved population for mechanical circulatory support (MCS) therapy. To address this clinical need, we are developing a low cost, universal magnetically levitated extracorporeal system with interchangeable pump heads for pediatric support. Two impeller and pump designs (pump V1 and V2) for the pediatric pump were developed using dimensional analysis techniques and classic pump theory based on defined performance criteria (generated flow, pressure, and impeller diameter). The designs were virtually constructed using computer-aided design (CAD) software and 3D flow and pressure features were analyzed using computational fluid dynamics (CFD) analysis. Simulated pump designs (V1, V2) were operated at higher rotational speeds (~5,000 revolutions per minute [RPM]) than initially estimated (4,255 RPM) to achieve the desired operational point (3.5 L/min flow at 150 mm Hg). Pump V2 outperformed V1 by generating approximately 30% higher pressures at all simulated rotational speeds and at 5% lower priming volume. Simulated hydrodynamic performance (achieved flow and pressure, hydraulic efficiency) of our pediatric pump design, featuring reduced impeller size and priming volume, compares favorably to current commercially available MCS devices., Competing Interests: Disclosure: The authors have no conflicts of interest to report., (Copyright © ASAIO 2020.)

In the US, the most significant morbidity and mortality associated with non-valvular atrial fibrillation (NVAF) is embolic stroke, with 90% of thrombus originating from the left atrial appendage (LAA). Anticoagulation is the preferred treatment for the prevention of stroke in NVAF patients, but clinical studies have demonstrated high levels of non-compliance and increased risk of bleeding or ineligibility for anticoagulation therapy, especially in the elderly population where the incidence of NVAF is highest. Alternatively, stroke may be preventing using clinically approved surgical and catheter-based devices to exclude or occlude the LAA, but these devices continue to be plagued by peri-device leaks and thrombus formation because of residual volume. To overcome these limitations, Cor Habere (Louisville, KY) and the University of Louisville are developing a LAA closure device (StrokeShield) that completely occludes and collapses the LAA to minimize the risk of stroke. The StrokeShield device is a collapsible occluder (nitinol reinforced membrane) that completely covers the LAA orifice with an expandable conical coil anchor that attaches to the myocardium. The device is designed for catheter-based delivery and expands to completely occlude the LAA orifice and collapse the LAA. The primary advantages of the StrokeShield system are a completely sealed LAA (no peri-device flow or residual space) and smooth endothelialized connection to the left atrial wall with minimal risk of cardiac bleeding and tamponade. We tested proof-of-concept of a prototype StrokeShield device in acute (n = 2) and chronic 60-day (n = 2) healthy canine models. Acute results demonstrated that the conical coil securely attached to the myocardium (5N pull-out force) and the Nitinol umbrella fully deployed and covered the LAA ostium. Results from the chronic implants demonstrated long-term feasibility of device placement with no procedural or device-related intra- or post-operative complications, secure placement and correct positioning of the device with no device migration. The device successfully occluded the LAA ostium and collapsed the LAA with no interference with the mitral valve, circumflex coronary artery, or pulmonary veins. Necropsy demonstrated no gross signs of thrombus or end-organ damage and the device was encapsulated in the LAA. Histology demonstrated mature neointima covering the device with expected foreign body inflammatory response. These early positive results will help to guide the iterative design process for the continued development of the StrokeShield system., Competing Interests: Financial • Two US patents awarded related to the research presented in this manuscript, and a third University of Louisville (UofL) invention disclosure was filed February 1, 2021, but is not presented in this manuscript Slaughter MS, Giridharan GA, Sobieski MA, Soucy KG, and Koenig SC. Atrial appendage closure device and related methods (US Patent 10,531,878 awarded January 14, 2020) Slaughter MS, Giridharan GA, Sobieski MA, Soucy KG, and Koenig SC. Atrial appendage closure device and related methods (US Patent 10,898,202 awarded January 26, 2021) Slaughter MS, Monreal G, Koenig SC, Jimenez J, Tompkins L. Left Atrial Appendage (LAA) device, delivery tool, and related methods (UofL Invention Disclosure no. 21038, filed February 1, 2021) • Research presented in this manuscript was funded as an internal project subaward (PI: Guruprasad Giridharan) from a 5-yr Coulter Foundation grant awarded to University of Louisville (PIs: Robert Keynton, PhD and Mark Slaughter, MD) • Co-authors Jimenez, Koenig, Slaughter are co-founders of Cor Habere (Louisville KY), and are continuing the research and development of the StrokeShield system (LAA device) presented in this manuscript. Note: Cor Habere was founded after the research and development presented in this manuscript had been completed. • Cor Habere was awarded a NIH SBIR phase I grant (R43HL142337-01) to continue development of the StrokeShield system (LAA device, delivery tool) but none of the work supported by the SBIR phase I grant is presented in this manuscript. Co-authors (Giridharan, Koenig, Slaughter) were awarded US Patent 10,531,878 (January 14, 2020) and US Patent 10,898,202 (January 26, 2021). All of the co-authors are continuing with the development of the StrokeShield device and are listed as co-inventors on our recent UofL invention disclosure (no. 21038, filed Feb 1, 2021) and co-investigators of NIH SBIR phase I grant (R43HL142337-01, awarded Sep 30, 2019). This information does NOT alter our adherence to PLOS ONE policies on sharing data and materials.

Compression and cold therapy used separately have shown to reduce negative effects of tissue damage. The combining compression and cold therapy (cryocompression) as a single recovery modality has yet to be fully examined. To examine the effects of cryocompression on recovery following a bout of heavy resistance exercise, recreationally resistance trained men (n =16) were recruited, matched, and randomly assigned to either a cryocompression group (CRC) or control group (CON). Testing was performed before and then immediately after exercise, 60 minutes, 24 hours, and 48 hours after a heavy resistance exercise workout (barbell back squats for 4 sets of 6 reps at 80% 1RM, 90 sec rest between sets, stiff legged deadlifts for 4 sets of 8 reps at 1.0 X body mass with 60 sec rest between sets, 4 sets of 10 eccentric Nordic hamstring curls, 45 sec rest between sets). The CRC group used the CRC system for 20-mins of cryocompression treatment immediately after exercise, 24 hours, and 48 hours after exercise. CON sat quietly for 20-mins at the same time points. Muscle damage [creatine kinase], soreness (visual analog scale, 0-100), pain (McGill Pain Q, 0-5), fatigue, sleep quality, and jump power were significantly (p < 0.05) improved for CRC compared to CON at 24 and 48 hours after exercise. Pain was also significantly lower for CRC compared to CON at 60-mins post exercise. These findings show that cryocompression can enhance recovery and performance following a heavy resistance exercise workout.

Counterpulsation devices (CPDs) require an accurate, reliable electrocardiogram (ECG) waveform for triggering inflation and deflation. Surface electrodes are for short-term use, and transvenous/epicardial leads require invasive implant procedure. A subcutaneous ECG lead configuration was developed as an alternative approach for long-term use with timing mechanical circulatory support (MCS) devices. In this study, efficacy testing was completed by simultaneously recording ECG waveforms from clinical-grade epicardial (control) and subcutaneous (test) leads in chronic ischemic heart failure calves implanted with CPD for up to 30 days. Sensitivity and specificity of CPD triggering by R-wave detection was quantified for each lead configuration. The subcutaneous leads provided 98.9% positive predictive value and 98.9% sensitivity compared to the epicardial ECG leads. Lead migration (n = 1) and fracture (n = 1) were observed in only 2 of 40 implanted leads, without adversely impacting triggering efficacy due to lead redundancy. These findings demonstrate the efficacy of subcutaneous ECG leads for long-term CPD timing and potential use as an alternative method for MCS device timing.