Feasibility of an animal model for long-term mechanical circulatory support with Impella 5.5 implanted through carotid artery access in sheep.

Impella is a mechanical circulatory support device of a catheter-based intravascular microaxial pump for left ventricular support and unloading. However, nonclinical studies assessing the effects of the extended duration of left ventricular unloading on cardiac recovery are lacking. An animal model using Impella implanted with a less invasive procedure to enable long-term support is required.

Hemodynamic Evaluation of Asynchronous Speed Modulation of a Continuous-Flow Left Ventricular Assist Device in an Acute-Myocardial Injury Sheep Model.

Asynchronous rotational-speed modulation of a continuous-flow left ventricular assist device (LVAD) can increase pulsatility; however, the feasibility of hemodynamic modification by asynchronous modulation of an LVAD has not been sufficiently verified. We evaluated the acute effect of an asynchronous-modulation mode under LVAD support and the accumulated effect of 6 consecutive hours of driving by the asynchronous-modulation mode on hemodynamics, including both ventricles, in a coronary microembolization-induced acute-myocardial injury sheep model. We evaluated 5-min LVAD-support hemodynamics, including biventricular parameters, by switching modes from constant-speed to asynchronous-modulation in the same animals ("acute-effect evaluation under LVAD support").

Feasibility study of an artificial placenta system consisting of a loop circuit configuration extracorporeal membrane oxygenation with a bridge circuit in the form of the umbilical arterial-venous connection.

We developed a new artificial placenta (AP) system consisting of a loop circuit configuration extracorporeal membrane oxygenation (ECMO) with a bridge circuit designed to be applied to the fetus in the form of an umbilical arterial-venous connection. We aimed to evaluate the feasibility of the AP system by performing a hydrodynamic simulation using a mechanical mock circulation system and fetal animal experiment. The effect of the working condition of the AP system on the fetal hemodynamics was evaluated by hydrodynamic simulation using a mechanical mock circulation system, assuming the weight of the fetus to be 2 kg.

Coronary microembolization sheep model by adjusting the number of microspheres based on coronary blood flow.

Background: A heart failure (HF) model using coronary microembolization in large animals is indispensable for medical research. However, the heterogeneity of myocardial response to microembolization is a limitation. We hypothesized that adjusting the number of injected microspheres according to coronary blood flow could stabilize the severity of HF.

Numerical simulation of the leakage flow of the hydrodynamically levitated centrifugal blood pump for extracorporeal mechanical circulatory support systems.

Extracorporeal centrifugal pumps are widely used in various forms of mechanical circulatory support, including extracorporeal membrane oxygenation and ventricular assist device. A durable centrifugal pump was developed by implementing a new hydrodynamic bearing design that prevents the impeller from touching to the casing wall and provides sufficient washout through the pump to prevent thrombus formation in the pump. The hydrodynamic bearings of the pump are composed of dual annular paths located on both sides of the impeller.

Assessment of ocular blood flow in continuous-flow ventricular assist device by laser speckle flowgraphy.

Although the influence of continuous-flow left ventricular assist device (CF-LVAD) support on peripheral circulation has been widely discussed, its monitoring modalities are limited. The aim of this study was to assess the peripheral circulation using the laser speckle flowgraph (LSFG) which can quantitatively measure the ocular blood flow. We implanted a centrifugal CF-LVAD (EVAHEART; Sun Medical Technology Research Corporation, Nagano, Japan) in five adult goats (body weight 44.

Impact of anatomical position of the inflow cannula on stroke in patients with left ventricular assist devices.

Objectives: Stroke is a substantial complication of left ventricular assist device (LVAD) implantation. The relationship between stroke and the anatomical position of the inflow cannula of patients who underwent LVAD implantation was investigated.

Methods: We enrolled 15 patients with advanced-stage heart failure who underwent implantation of continuous-flow-LVAD.

Bentall and redo-Konno Operation for an Adult With Aortic Paraprosthetic Leak and Root Aneurysm.

We report a case of Bentall and redo-Konno operation. A 39-year-old male with surgical history of Konno operation presented with hemolytic anemia and heart failure. Further evaluations revealed aortic paraprosthetic leak with moderate regurgitation, moderate biventricular outflow tract obstruction, and aortic root aneurysm.

Evaluation of cardiac beat synchronization control for a rotary blood pump on valvular regurgitation with a mathematical model.

We have studied the cardiac beat synchronization (CBS) control for a rotary blood pump (RBP) and revealed that it can promote pulsatility and reduce cardiac load. Besides, patients with LVAD support sometimes suffer from aortic and mitral regurgitation (AR and MR). A control method for the RBP should be validated in wider range of conditions to clarify its benefits and pitfalls prior to clinical application.

Computed tomography perfusion in patients of stroke with left ventricular assist device.

Left ventricular assist devices (LVAD) are widely applied for patients with severe heart failure as a bridge to heart transplantation as well as destination therapy. Patients with implanted LVAD have an increased risk of cerebral thrombosis and computed tomographic perfusion (CTP) has the potential to be performed for early diagnosis and treatment of acute ischemic stroke (AIS), including interventional thrombectomy. Here, we report our series of CTP examination in patients having suspected AIS after LVAD implantation.

Long-Term Clinical Outcomes of Cardiac Surgery for Kidney Transplant Patients.

Purpose: Immunosuppressant and steroid are inevitable for graft survival after renal transplantation, and their usage is known to be a risk factor for mortality and morbidity after cardiac surgery. We evaluated the long-term clinical outcomes in patients who underwent cardiac surgery after renal transplantation.

Methods: We retrospectively reviewed 23 patients who underwent cardiac surgery after renal transplantation with maintained grafts at the time of the cardiac surgery in our institution between June 2000 and June 2018 (19 males, 4 females; mean age, 55 (38-81) years).

The angle of the outflow graft to the aorta can affect recirculation due to aortic insufficiency under left ventricular assist device support.

Aortic insufficiency (AI) is a crucial complication during continuous-flow left ventricular assist device (LVAD) support. Our previous clinical study suggested that a larger angle between the outflow graft and the aorta (O-A angle) could cause AI progression. This study examined the effect of the O-A angle on the hemodynamics of AI under LVAD support in an acute animal experimental model.

Impact of Recurrent Ventricular Tachyarrhythmia on Outcome in Japanese Heart Transplant Candidates With a Left Ventricular Assist Device.

Background: Recurrent ventricular tachyarrhythmias (VTA) are "A factor" modifiers in the Interagency Registry for Mechanically Assisted Circulatory Support profile. The effect of recurrent VTA on clinical outcome, however, is controversial. We evaluated the impact of recurrent VTA on outcome in Japanese heart transplant candidates with a left ventricular assist device (LVAD).

Left heart pressures can be the key to know the limitation of left ventricular assist device support against progression of aortic insufficiency.

Aortic insufficiency (AI) is a worrisome complication under left ventricular assist device (LVAD) support. AI progression causes LVAD-left ventricular (LV) recirculation and can require surgical intervention to the aortic valve. However, the limitations of LVAD support are not well known.

Outflow graft anastomosis site design could be correlated to aortic valve regurgitation under left ventricular assist device support.

Aortic valve regurgitation (AR) is a critical complication during circulatory support with a left ventricular assist device (LVAD). The time-course of AR and related factors, including outflow graft anastomosis site design, were investigated. Twenty-three patients who had continuous-flow LVAD implantation and were supported for more than 6 months were investigated.

Japanese registry for Mechanically Assisted Circulatory Support: First report.

Background: In Japan, ventricular assist devices (VADs) have been used for patients with severe heart failure as a bridge to transplantation (BTT) since 1992. However, it was not until 1997, when the Organ Transplant Law was enacted, that medical devices received approval by the national health insurance system for that use. To encourage research and development of innovative medical devices, the Pharmaceuticals and Medical Devices Agency has established a public-private partnership in collaboration with academic societies, hospitals and manufacturers.

Outcomes in children with advanced heart failure in Japan: importance of mechanical circulatory support.

The Japanese organ transplant law was revised in July 2010 in order to enable children aged <15 years to donate organs. However, the waiting time for orthotopic heart transplantation (HTx) is as long as 636 days in children due to a shortage of organ donors. Ventricular assist devices (VADs) have been widely used as a bridge to transplantation in Western countries, whereas experience with VADs is limited in Japan due to a lack of device availability for small children.

LVAD inflow cannula covered with a titanium mesh induces neointimal tissue with neovessels.

Background: Thrombus formation at the interfaces of inflow cannulas and left ventricular apexes is considered to be one of the predominant sources of thromboembolic complication. Use of a fine titanium mesh-covered inflow cannula is expected to prevent such thrombus formation by inducing neointimal tissue around the cannula.

Methods: Titanium pins (20 mm long, 3 mm diameter) covered with a fine titanium mesh (wire dia.

Ventricular assist device implantation late after double switch operation for L-transposition of the great arteries.

We provided a left ventricular assist device (LVAD) for a 22-year-old man with congenital L-transposition of the great arteries after anatomic repair at the age of 7 years. He was hospitalized for progressive low-output syndrome caused by intractable biventricular failure. He received LVAD in his morphologic left ventricle with a concomitant pulmonary valve replacement.

Post-approval study of a highly pulsed, low-shear-rate, continuous-flow, left ventricular assist device, EVAHEART: a Japanese multicenter study using J-MACS.

Background: The EVAHEART left ventricular assist device was approved in 2010 by the Japanese Pharmaceuticals and Medical Devices Agency (PMDA) for bridge to heart transplantation (BTT). However, its effectiveness has not been evaluated since approval. In this study we evaluated the EVAHEART device in a commercial setting in Japan.

Circadian variation of motor current observed in fixed rotation speed continuous-flow left ventricular assist device support.

The algorithm for the physiological control provided by left ventricular assist devices (LVADs) has been controversial. In particular, little is known about the physiological control algorithm (such as for achieving physiological circadian rhythms) in continuous-flow LVADs. To investigate the existence of circadian variation, we retrospectively evaluated the LVAD flow-correlated motor current of patients supported by continuous-flow LVADs.

Clinical outcomes of pediatric ventricular assist device implantation: a single-institute report from Japan.

Purpose: Numerous difficulties remain associated with pediatric heart transplantation. Therefore, the development of a ventricular assist device (VAD) specific to these cases is extremely important for therapeutic effectiveness. We present 5 cases of severe heart failure that were managed by ventricular assist device implantation, as a bridge to transplantation.