Heartwheels! STEM Mobile Outreach Program.

Heartwheels! STEM Mobile Outreach is a scientist-led collaborative, innovative, and reproducible experiential educational program and mobile lab developed to engage people young and old in the cardiovascular sciences, improve health literacy and awareness of heart-healthy living, and spark curiosity in the science, technology, engineering, and mathematics (STEM) fields. Applied hands-on interactive activities at Heartwheels! events include heart dissection, cardiovascular physiology, and mock flow loops (science), medical devices (technology), instrumentation and sensors (engineering), and calibration and validation methods and models (math). These modules are complementary to school activities and are particularly successful from an educational standpoint because they are fun, interactive, engaging, voluntary, open-ended, not graded or assessed, and can lead participants and their families to develop STEM-positive identities.

Feasibility Testing of the Bionet Sonar Ultrasound Transcutaneous Energy Transmission (UTET) System for Wireless Power and Communication of a LVAD.

Purpose: To address the clinical need for totally implantable mechanical circulatory support devices, Bionet Sonar is developing a novel Ultrasonic Transcutaneous Energy Transmission (UTET) system that is designed to eliminate external power and/or data communication drivelines.

Methods: UTET systems were designed, fabricated, and pre-clinically tested using a non-clinical HeartWare HVAD in static and dynamic mock flow loop and acute animal models over a range of pump speeds (1800, 2400, 3000 RPM) and tissue analogue thicknesses (5, 10, 15 mm).

Results: The prototypes demonstrated feasibility as evidenced by meeting/exceeding function, operation, and performance metrics with no system failures, including achieving receiver (harvested) power exceeding HVAD power requirements and data communication rates of 10kB/s and pump speed control (> 95% sensitivity and specificity) for all experimental test conditions, and within healthy tissue temperature range with no acute tissue damage.

Early-stage Development of the CoRISMA Mechanical Circulatory Support (CMCS) System for Heart Failure Therapy.

Purpose: CoRISMA MCS Systems Inc (Hamden CT) is developing an innovative mechanical circulatory support system (CMCS) as a durable therapeutic option for heart failure (HF) patients. The CMCS system is comprised of an axial flow pump, non-contacting hydrodynamic bearings, and integrated DC motor designed to be fully implantable in a left atrial (LA) to aortic (Ao) configuration; this unloading strategy may be particularly beneficial for HF patients with preserved ejection fraction (HFpEF). The small (5.

Anatomical and Hemodynamic Characterization of Totally Artificial Hearts.

We characterize the anatomy and function of never before studied total artificial hearts (TAHs) using established methods for testing mechanical circulatory support (MCS) devices. A historical review of TAHs is also presented to aid in benchmarking performance metrics. Six TAHs, ranging from spooky Halloween beating hearts to a cute colorful plush heart, were imaged, instrumented (mock flow loops) to measure their pressure, volume, and flow, and qualitatively evaluated by 3rd party cardiac surgeons for anatomical accuracy and surgical considerations.

Feasibility Testing of the RT Cardiac Systems Percutaneous Mechanical Circulatory Support Device.

RT Cardiac Systems (RTCS, Raleigh, NC) is developing an intravascular percutaneous mechanical circulatory support (pMCS) device drive system for use during high-risk percutaneous coronary intervention and emergent cardiogenic shock. The proprietary pMCS device (US patent 10,780,206) consists of a miniaturized axial flow pump with an integrated motor connected via a short flexible drive system. This novel flexible drive system creates a flexible pump that is advantageous for percutaneous placement and conforming to anatomy.

Feasibility testing of the Inspired Therapeutics NeoMate mechanical circulatory support system for neonates and infants.

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.

Demonstration of proof-of-concept of StrokeShield system for complete closure and occlusion of the left atrial appendage for non-valvular atrial fibrillation therapy.

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.

Risk Factors and Outcomes in Redo Coronary Artery Bypass Grafting.

Background: Reoperative coronary artery bypass grafting (redo-CABG) has declined during the last decade, while use of percutaneous coronary intervention (PCI) has increased. The aim of this retrospective study was to evaluate risk factors, in-hospital mortality, and long-term survival between first-time CABG and redo-CABG.

Methods: From January 2009 to December 2015, 2,581 patients underwent first-time CABG procedures while 132 underwent isolated redo-CABG.

Left ventricular assist device explantation after myocardial recovery.

Left ventricular assist device (LVAD) treatment may lead to reverse remodeling in heart failure patients. Selected patients can recover heart function and be eligible for LVAD explantation. Surgical methods for explanting an LVAD have been reported using various surgical accesses and different degrees of retained device material.

Efficacy of Subcutaneous Electrocardiogram Leads for Synchronous Timing During Chronic Counterpulsation Therapy.

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.

Left ventricular assist devices: current controversies and future directions.

Advanced heart failure is a growing epidemic that leads to significant suffering and economic losses. The development of left ventricular assist devices (LVADs) has led to improved quality of life and long-term survival for patients diagnosed with this devastating condition. This review briefly summarizes the short history and clinical outcomes of LVADs and focuses on the current controversies and issues facing LVAD therapy.

Feasibility Study of Pulsatile Left Ventricular Assist Device for Prolonged Ex Vivo Lung Perfusion.

Background: Ex vivo lung perfusion (EVLP) has the potential to increase the donor pool for lung transplantation by facilitating resuscitation and extended evaluation of marginal organs. Current EVLP methodology employs continuous flow (CF) pumps that produce non-pulsatile EVLP hemodynamics. In this feasibility study, we tested the hypothesis that a pulsatile flow (PF) pump will provide better EVLP support than a CF pump through delivery of physiologic hemodynamics.

Left ventricular volume unloading with axial and centrifugal rotary blood pumps.

Axial (AX) and centrifugal (CFG) rotary blood pumps have gained clinical acceptance for the treatment of advanced heart failure. Differences between AX and CFG designs and mechanism of blood flow delivery may offer clinical advantages. In this study, pump characteristics, and acute physiologic responses during support with AX (HeartMate II) and CFG (HVAD) left ventricular assist devices (LVAD) were investigated in mock loop and chronic ischemic heart failure bovine models.

Hemodynamic changes and retrograde flow in LVAD failure.

In the event of left ventricular assist device (LVAD) failure, we hypothesized that rotary blood pumps will experience significant retrograde flow and induce adverse physiologic responses. Catastrophic LVAD failure was investigated in computer simulation with pulsatile, axial, and centrifugal LVAD, mock flow loop with pulsatile (PVAD) and centrifugal (ROTAFLOW), and healthy and chronic ischemic heart failure bovine models with pulsatile (PVAD), axial (HeartMate II), and centrifugal (HVAD) pumps. Simulated conditions were LVAD "off" with outflow graft clamped (baseline), LVAD "off" with outflow graft unclamped (LVAD failure), and LVAD "on" (5 L/min).

Rotary pump speed modulation for generating pulsatile flow and phasic left ventricular volume unloading in a bovine model of chronic ischemic heart failure.

Background: Rotary blood pumps operate at a constant speed (rpm) that diminishes vascular pulsatility and variation in ventricular end-systolic and end-diastolic volumes, which may contribute to adverse events, including aortic insufficiency and gastrointestinal bleeding. In this study, pump speed modulation algorithms for generating pulsatility and variation in ventricular end-systolic and end-diastolic volumes were investigated in an ischemic heart failure (IHF) bovine model (n = 10) using a clinically implanted centrifugal-flow left ventricular assist device (LVAD).

Methods: Hemodynamic and hematologic measurements were recorded during IHF baseline, constant pumps speeds, and asynchronous (19-60 cycles/min) and synchronous (copulse and counterpulse) pump speed modulation profiles using low relative pulse speed (±25%) of 3,200 ± 800 rpm and high relative pulse speed (±38%) of 2,900 ± 1,100 rpm.

Feasibility study of particulate extracellular matrix (P-ECM) and left ventricular assist device (HVAD) therapy in chronic ischemic heart failure bovine model.

Myocardial recovery with left ventricular assist device (LVAD) support is uncommon and unpredictable. We tested the hypothesis that injectable particulate extracellular matrix (P-ECM) with LVAD support promotes cell proliferation and improves cardiac function. LVAD, P-ECM, and P-ECM + LVAD therapies were investigated in chronic ischemic heart failure (IHF) calves induced using coronary embolization.

Early feasibility testing and engineering development of a sutureless beating heart connector for left ventricular assist devices.

APK Advanced Medical Technologies (Atlanta, GA) is developing a sutureless beating heart (SBH) left ventricular assist device (LVAD) connector system consisting of anchoring titanium coil, titanium cannula with integrated silicone hemostatic valve, coring and delivery tool, and LVAD locking mechanism to facilitate LVAD inflow surgical procedures. Feasibility testing was completed in human cadavers (n = 4) under simulated normal and hypertensive conditions using saline to observe seal quality in degraded human tissue and assess anatomic fit; acutely in ischemic heart failure bovine model (n = 2) to investigate short-term performance and ease of use; and chronically for 30 days in healthy calves (n = 2) implanted with HeartWare HVAD to evaluate performance and biocompatibility. Complete hemostasis was achieved in human cadavers and animals at LV pressures up to 170 mm Hg.

Development of an extracellular matrix delivery system for effective intramyocardial injection in ischemic tissue.

Biomaterials with direct intramyocardial injection devices have been developed and are being investigated as a potential cardiac regenerative therapy for end-stage ischemic heart failure. Decellularized extracellular matrix (ECM) has been shown to improve cardiac function and attenuate or reverse pathologic remodeling cascades. CorMatrix Cardiovascular, Inc.

Extended extra-aortic counterpulsation with the C-Pulse device does not alter aortic wall structure.

The C-Pulse System is an implantable, extra-aortic, non-blood-contacting counterpulsation device, investigational in the United States and intended for use as a heart assist device for heart failure (NYHA class III-ambulatory IV) patients. As long-term effects of this implantable extra-aortic counterpulsation device on the aortic wall structure are not well established, we examined the histological and clinical data of a patient supported on the device for 21 months. A 58-year-old woman diagnosed with nonischemic cardiomyopathy (NYHA III) remained symptomatic despite optimal medical therapy and dual chamber pacemaker.

The In Vivo Skills Laboratory in Anesthesiology Residency Training.

Background: Anesthesiologists routinely perform high-risk procedures that are associated with permanent disability or death. Critical perioperative events require that the anesthesiologist perform procedures that are only used intermittently. Teaching these procedures is complicated by their infrequency and pressure to maximize operating room efficiency; therefore we created an annual 1-day anesthesiology skills lab as an innovative method of residency education.

Early feasibility testing and engineering development of the transapical approach for the HeartWare MVAD ventricular assist system.

Implantation of ventricular assist devices (VADs) for the treatment of end-stage heart failure (HF) falls decidedly short of clinical demand, which exceeds 100,000 HF patients per year. Ventricular assist device implantation often requires major surgical intervention with associated risk of adverse events and long recovery periods. To address these limitations, HeartWare, Inc.

Large animal models for left ventricular assist device research and development.

In vivo preclinical testing of left ventricular assist devices (LVADs) warrants a large animal model that faithfully simulates human etiology. Although LVAD recipients are in end-stage heart failure (HF), healthy, young animals have served as the experimental platform for most LVAD research and development (R&D) to demonstrate device safety, reliability, and biocompatibility. The rapidly growing HF epidemic, donor heart shortage, and clinical acceptance of LVAD for bridge-to-transplant therapy (BTT) has led to the expanded role of LVAD for destination therapy and bridge-to-recovery therapy.

Right ventricular remodeling in restrictive ventricular septal defect.

Restrictive ventricular septal defect (rVSD) presents with little/no hemodynamic aberrations despite a patent septal defect. Clinically, these patients are observed with the hope that the defect will functionally close over time without the need for surgical repair and development of heart failure. Without evidence supporting a definitive therapeutic strategy, rVSD patients may have increased risk of a poor outcome.

Cytoskeletal remodeling of desmin is a more accurate measure of cardiac dysfunction than fibrosis or myocyte hypertrophy.

Aims: Fibrosis and myocyte hypertrophy are classical remodeling parameters in heart failure (HF); however, an intriguing possibility is that myocytes undergo intracellular remodeling which decrease compliance, contributing to diastolic dysfunction. The most obvious candidates are cytoskeletal proteins. The cytoskeletal protein desmin reinforces the sarcomeres, enabling force generation.

Teaching the "hybrid approach": a novel swine model of muscular ventricular septal defect.

This report describes a reproducible swine model for creating muscular ventricular septal defects (VSDs). The model not only facilitates the development and modification of hybrid techniques for closing muscular VSDs, but also serves as a teaching tool that allows operators to become accustomed to the specific technical requirements necessary when using the hybrid approach to perform periventricular VSD device closure. The authors' institutional experience using this novel animal model is presented.