Papers by Tadashi Motomura
Japanese Journal of Cardiovascular Surgery, 2001
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Annals of thoracic and cardiovascular surgery: official journal of the Association of Thoracic and Cardiovascular Surgeons of Asia
ABSTRACT
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The Annals of Thoracic Surgery, 1989
ABSTRACT From 1983 to 1992, 203 patients with chronic congestive heart failure and no angina unde... more ABSTRACT From 1983 to 1992, 203 patients with chronic congestive heart failure and no angina underwent primary coronary artery bypass. This represented 3% of patients undergoing coronary artery bypass grafting. Ninety-two percent of the patients were in New York Heart Association (NYHA) functional class III or IV prior to undergoing coronary artery bypass grafting. Thallium perfusion imaging was performed in 21% of the patients, with a reversible defect present in 88%. An internal mammary artery graft was used in 70% of the patients. The hospital mortality was 6.0% and the actuarial survival at 5 years was 59%. An improvement in NYHA functional class occurred in 75% of the surviving patients with a mean improvement of 1.6 +/- 0.6 functional classes. Univariate analysis identified risk factors for hospital death as emergency operation, recent myocardial infarction (< 30 days), and the need for an intra-aortic balloon pump. A trend emerged for nonuse of an internal mammary artery to predict hospital death. A positive thallium perfusion scan was not a predictor of early or late survival, nor did it influence NYHA functional class. The use of the internal mammary artery significantly enhanced late survival (p = 0.01), however, did not affect the functional class of survivors. We conclude that coronary artery bypass grafting is effective in ameliorating symptoms of chronic congestive heart failure in patients suffering from chronic ischemic cardiomyopathy and can be performed with acceptable early and late mortality.
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History, Development and Promise, 2012
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Kyobu geka. The Japanese journal of thoracic surgery, 2002
We measured the fully carboxylated prothrombin levels using the Carinactivase-1 (CA-1) test and t... more We measured the fully carboxylated prothrombin levels using the Carinactivase-1 (CA-1) test and thus compared prothrombin levels between patients having atrial fibrillation (Af) without pacemaking and those having sick sinus syndrome due to Af with cardiac pacemaker implantation during anticoagulation therapy with warfarin. Total plasma samples were assayed for the CA-1 test, the prothrombin time international normalized ratio (PT-INR) and the thrombotest (TT). This prospective randomized study was carried out on 641 samples obtained at the Fukuoka University Hospital Department of Cardiovascular Surgery between May 1997 and March 1999. The patients were divided into 2 groups consisting of: group A; 144 patients having sick sinus syndrome due to Af implanted with a cardiac pacemaker who were treated with warfarin, group B; 497 patients atrial fibrillation without pacemaking who were treated with warfarin. The prothrombin levels in each group were 65.5 +/- 25.2 and 76.1 +/- 47.7 micr...
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ASAIO Journal, 2011
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ASAIO Journal
Left ventricular assist device (LVAD) inflow cannula malposition is a significant risk for pump t... more Left ventricular assist device (LVAD) inflow cannula malposition is a significant risk for pump thrombosis. Thrombus development is influenced by altered flow dynamics, such as stasis or high shear that promote coagulation. The goal of this study was to measure the intraventricular flow field surrounding the apical inflow cannula of the Evaheart centrifugal LVAD, and assess flow stasis, vortex structures, and pulsatility for a range of cannula insertion depths and support conditions. Experimental studies were performed using a mock loop with a customized silicone left ventricle (LV) and the Evaheart LVAD. A transparent inflow cannula was positioned at 1, 2, or 3 cm insertion depth into the LV and the velocity field in the LV midplane was measured for 2 levels of LVAD support: 1800 and 2300 rpm. The LV velocity field exhibits a diastolic vortex ring whose size, path, and strength are affected by the flow conditions and cannula position. During diastole, the large clockwise midplane vortex grows, but its circulation and kinetic energy are reduced with cannula insertion depth. The counterclockwise vortex is smaller and exhibits more complex behavior, reflecting a flow split at 3 cm. Overall, the 1 cm cannula insertion depth produces the flow pattern that exhibits the least apical flow stasis and greatest pulsatility and should correlate to a lower risk of thrombus formation.
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32nd Aerospace Sciences Meeting and Exhibit, 1994
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Japanese Journal of Thrombosis and Hemostasis, 2001
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Japanese Journal of Cardiovascular Surgery, 2000
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The Journal of Heart and Lung Transplantation, 2012
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The Journal of Heart and Lung Transplantation, 2013
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Artificial Organs, 2001
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Artificial Organs, 2011
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ASAIO Journal, 2004
A newly designed flexible inflow cannula has been developed for a biventricular assist device (BV... more A newly designed flexible inflow cannula has been developed for a biventricular assist device (BVAD). The inflow tip was designed for long-term ventricle drainage. Considering the anatomic differences between the right and left ventricles, a flexible inflow cannula, as a mass production model with a titanium tip, was developed and investigated in chronic BVAD animal experiments using the NEDO permanently implantable centrifugal blood pump. These flexible inflow cannulae consist of flexible plastic tubing with wire supported, titanium left and right tips. The right titanium inflow tip was designed with inner and outer stoppers to be inserted into the right ventricle wall and a beak shape to avoid sucking. The left tip was designed to be inserted into the left ventricle cavity. Five chronic BVAD bovine studies were performed to investigate the new beak shaped titanium tip. In these studies, the new beak shaped titanium tip and cannula prevented stenosis by a proliferation of pseudoneointimal, and supplied adequate blood flow to the pump without sucking. This newly designed inflow cannula with the beak shaped titanium tip was successfully implanted for 90 days.
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ASAIO Journal
The EVAHEART 2 (Sun Medical Technology Research Corporation, Nagano, Japan) is an investigational... more The EVAHEART 2 (Sun Medical Technology Research Corporation, Nagano, Japan) is an investigational centrifugal ventricular assist device in the United States, introduced a new type inflow, named "double cuff tipless" inflow cannula intended to mitigate the risks of cannula malposition and subsequent ischemic stroke events associated with thrombi around the inflow cannula. To achieve these performance benefits of the "tipless" design, however, it is crucial to adhere to the recommended surgical procedure. We introduced a polymer-based patient model that mimics a dilated cardiomyopathy apex for inflow cannula implantation training. Here, we used the model to simulate appropriate and inappropriate techniques for inflow suturing. With the appropriate technique, the inflow ostium is aligned on the endocardial plane, and the cut myocardial surface is not exposed to the bloodstream. By contrast, with the inappropriate technique, which is represented as a worst-case suturing scenario, the inflow ostium is misaligned, thus exposing the cut myocardial cross-section to the bloodstream. This misalignment can predispose to platelet deposition, thrombus formation, and pannus formation with long-term support. Repeated training with this human apex model is important to confirm the inflow position and intraventricular finish before moving on to human cases. Along with rigorous preclinical training, technical adherence will help to ensure better clinical outcomes.
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ASAIO Journal
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ASAIO Journal
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The Annals of thoracic surgery, Jan 4, 2016
Supraphysiologic shear stress from continuous-flow left ventricular assist devices (LVADs) accele... more Supraphysiologic shear stress from continuous-flow left ventricular assist devices (LVADs) accelerates von Willebrand factor (vWF) degradation and predisposes patients to nonsurgical bleeding. It is unknown whether unique design characteristics of LVADs differentially affect vWF degradation. We tested the hypothesis that the centrifugal-flow EVAHEART (Evaheart, Houston, TX) left ventricular assist system (LVAS), which was designed to minimize shear stress (low operational revolutions per minute [rpm], larger flow gaps, low shear stress, flat H-Q curve), reduced vWF degradation versus the axial-flow HeartMate II (Thoratec, Pleasanton, CA) LVAD. Whole human blood was obtained from volunteer donors (n = 22). Blood was circulated for 12 hours in mock circulatory loops through a HeartMate II (n = 10; 11,400 rpm, 6.3 ± 0.8 L/min, 76 ± 2 mm Hg) or an EVAHEART LVAS (n = 12; 2,300 rpm, 5.7 ± 0.1 L/min, 80 ± 1 mm Hg). vWF degradation was characterized with electrophoresis and immunoblotting f...
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Papers by Tadashi Motomura