Abstract:
:As the aortic valve (AV) opens, the pump pressure head remains constant, which is reflected as a "notch/plateau" in pump pressure and flow signals. However, instantaneous flow estimation may be influenced by friction and is particularly difficult in axial pumps. Therefore, a new method to determine the duration of AV opening based on the area under the curve (AUC) of the power spectral density analysis of pump speed signal was developed. Data from patients implanted with HeartWare HVAD left ventricular assist device were studied at different pump speeds, with simultaneous transthoracic echocardiography in two cohorts. In the first group, pump data of 15 patients were used to investigate the ability to discriminate between an open and closed AV. In the second cohort of a further 13 patients, the duration of AV opening was measured from digitized M-mode images, and the relationship between the AV opening time and the new method assessed. In 14 of the initial 15 patients, AV status could be discriminated using only one threshold for all patients. In the second cohort, gradual speed reduction resulted in aortic valve opening in 12 of the 13 patients. The correlation between AV opening duration and AUC was 0.96 ± 0.03. Regression analysis indicated a linear relationship in each of the patients with a small error between the fit and the measured opening time (root mean square error = 11.0 ± 7.6 ms). However, the slopes (69.0 ± 52.8) and intercepts (-31.4 ± 78.0) varied widely between patients. The sensitivity and specificity for the new method using AUC threshold of 0.95 for aortic valve closure was 95% and 91%, respectively. The newly developed method to detect AV opening not only provides information on the AV status during LVAD support (open/closed) but also gives insight into the duration of AV opening. Because the slope of the relationship varies from patient to patient, initial training and adaptation of the method to each patient seems to be required.
journal_name
Artif Organsjournal_title
Artificial organsauthors
Hayward C,Lim CP,Schima H,Macdonald P,Moscato F,Muthiah K,Granegger Mdoi
10.1111/aor.12570subject
Has Abstractpub_date
2015-08-01 00:00:00pages
704-9issue
8eissn
0160-564Xissn
1525-1594journal_volume
39pub_type
杂志文章,多中心研究abstract::Tubular polymer scaffolds based on tissue engineering techniques have been studied as potential alternatives for vascular regeneration implants. The blood vessels of the cardiovascular system are mainly fibrous, composed of collagen (Col) and elastin (El), and its inner layer consists of endothelial cells. In this wor...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/aor.13857
更新日期:2020-11-10 00:00:00
abstract::The flow of blood as a viscous, Newtonian, incompressible liquid in an expanding spherical cavity with a ball-type inlet valve was examined. This type of flow can serve as a model of the phase of ventricular diastole in a sac-type artificial heart. The critical values of Reynolds numbers at which flow interruption beh...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.1983.tb04170.x
更新日期:1983-02-01 00:00:00
abstract::A multi-compartment capillary membrane culture model with independently perfused three-dimensionally woven capillaries was developed for immobilization of hepatocytes in bioreactors. This enables spatial restructuring of cells and enhanced mass transfer performance with more efficient oxygenation and metabolite exchan...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.1994.tb02181.x
更新日期:1994-03-01 00:00:00
abstract::The vibrating flow pump (VFP) can generate high frequency oscillated blood flow. Because of the high frequency driving with short stroke volume, the pump system can be small. The disposable type VFP (D-VFP) was developed for use for extracorporeal circulation. The electromagnetic actuator was detached from the vibrati...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.1997.tb03724.x
更新日期:1997-07-01 00:00:00
abstract::We have made an eccentric roller type total artificial heart (ERTAH). The ERTAH is a positive-displacement device comparable to a DeBakey roller pump. Its left and right outputs are determined by the size of its blood chambers, and the ratio of its left and right output is almost constant. We focused on an interatrial...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1046/j.1525-1594.1999.06414.x
更新日期:1999-08-01 00:00:00
abstract::Creating an interatrial shunt to achieve left-right flow balance and modification of the blood chambers to improve the basic performance of the device were performed in developing an eccentric roller type total artificial heart (ERTAH). Smaller blood chambers reduce friction loss and increase durability and energy eff...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1046/j.1525-1594.2000.06602.x
更新日期:2000-08-01 00:00:00
abstract::In this pilot study, we assessed the feasibility of using positron emission tomography (PET) imaging for in vivo measurement of skeletal muscle ventricle (SMV) tissue blood flow. In 4 dogs, with SMVs prepared from their latissimus dorsi muscle, we quantified SMV tissue blood flow by PET and related it to the tissue fl...
journal_title:Artificial organs
pub_type: 杂志文章
doi:
更新日期:2001-04-01 00:00:00
abstract::By using high speed gel filtration combined with ion exchange gradient elution chromatography, the concentrations of plasma (p) middle molecules (MM) were determined in 126 samples from 90 non-dialyzed azotemic patients and in 210 pre-dialysis samples from 53 regular hemodialysis and 24 intermittent peritoneal dialysi...
journal_title:Artificial organs
pub_type: 杂志文章
doi:
更新日期:1981-01-01 00:00:00
abstract::The weight gain of IVOX devices removed from the first 49 human clinical trials patients after from 1 to 29 days of implantation into the venae caval blood stream has been assessed. Each patient had received sufficient systemic heparin to maintain activated clotting times between 150 and 200 s while the IVOX device wa...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.1994.tb03329.x
更新日期:1994-11-01 00:00:00
abstract::The generation of anaphylatoxins, particularly C5a, is important in extracorporeal circulation therapies such as granulocyte/monocyte apheresis, which activates the complement system and elevates C5a levels. However, no side effects of granulocyte/monocyte apheresis using cellulose acetate beads have been reported. To...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.2009.00995.x
更新日期:2010-12-01 00:00:00
abstract::This paper presents an overview of the U.S. Food and Drug Administration's regulatory requirements for introducing medical device and diagnostic products into commercial distribution in the United States. For any specific product, the requirements vary depending upon the product's associated risks, classification, and...
journal_title:Artificial organs
pub_type: 临床试验,杂志文章
doi:10.1111/j.1525-1594.1982.tb04146.x
更新日期:1982-11-01 00:00:00
abstract::Plasma, in an amount corresponding to 0.05 gm fibrinogen/Kg of body weight, was administered during one hour to defibrinogenated dogs subjected to extracorporeal circulation. Four blood filters included in the extracorporeal circuit were removed one by one at 30-minute intervals. The prefilter pressures rose gradually...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.1979.tb03809.x
更新日期:1979-02-01 00:00:00
abstract::A comparative assessment has been made regarding efficacy and safety of the double filtration plasmapheresis (DFPP), thermofiltration (TFPP), and low-density lipoprotein (LDL) adsorptive (PA) methods by making a crossover test on heterozygous familial hypercholesterolemia patients. Treatments by DFPP, TFPP (secondary ...
journal_title:Artificial organs
pub_type: 临床试验,杂志文章
doi:10.1111/j.1525-1594.1996.tb04448.x
更新日期:1996-04-01 00:00:00
abstract::This is a revision of the IDE Application Form, "How to Comply with the Food and Drug Administration's New 'Investigational Device Exemption (IDE)' Regulations, Including an Application Form" originally published in Artificial Organs, Volume 4, Number 4, November 1980. This publication updates the IDE application form...
journal_title:Artificial organs
pub_type: 杂志文章
doi:
更新日期:1982-02-01 00:00:00
abstract::In patients with reduced respiratory function, lung resection is associated with high risk because separate ventilation is generally needed for safe management. For patients with end-stage emphysema, intraoperative respiratory management is important and particularly difficult because neither incomplete oxygenation no...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1046/j.1525-1594.2000.06339.x
更新日期:2000-01-01 00:00:00
abstract::Since the introduction of high-performance prosthetic heart valves, particularly bileaflet valves and monoleaflet valves with larger opening angles, we have observed in vivo complex leaflet motion which has not been experimentally confirmed yet. We developed a computer-controlled hydraulic mock circulator to study the...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.1997.tb00373.x
更新日期:1997-04-01 00:00:00
abstract::The purpose of this study was to investigate whether an artificial matrix can help neonatal cardiomyocytes restore an injured heart in a rat model of myocardial infarction (MI). The left coronary arteries of female Sprague Dawley (SD) rats were ligated to create MI models. Ventricular cardiomyocytes from 1- to 3-day-o...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.2006.00186.x
更新日期:2006-02-01 00:00:00
abstract::The specific timing for discontinuing renal replacement therapy (RRT) in acute kidney injury (AKI) patients is debatable. The predictive abilities of variables at the time of discontinuation of RRT for the long-term prognoses of patients have not been explored. This study aimed to explore the prognostic factors upon d...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/aor.12927
更新日期:2017-12-01 00:00:00
abstract::Wall shear stress on the pump casing cover was measured using a surface-mounted hot-film sensor. In addition, the shear stress distribution in the pump was qualitatively investigated by means of oil-film visualization. The characteristics of shear stress in the pump are discussed, including the results on the oil-film...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.2007.00421.x
更新日期:2007-07-01 00:00:00
abstract::In this study, a detection algorithm for suction and regurgitation of the centrifugal pump during left heart bypass without relying on external flow or pressure sensors was developed and evaluated in acute studies using adult goats. The detection scheme relies on power spectral density (PSD) analysis of the motor curr...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1046/j.1525-1594.1999.06397.x
更新日期:1999-06-01 00:00:00
abstract::In vitro cardiovascular device performance evaluation in a mock circulation loop (MCL) is a necessary step prior to in vivo testing. A MCL that accurately represents the physiology of the cardiovascular system accelerates the assessment of the device's ability to treat pathological conditions. To serve this purpose, a...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.2010.01088.x
更新日期:2011-04-01 00:00:00
abstract::Atrial connections in a single-unit total artificial heart (TAH) may be difficult to make because of the rigidity of the device and the fixed position of the atrial inlets. We developed a technique to separate the natural atrial borders in an experimental implantation of a unitary TAH. In this technique, the interatri...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.1995.tb02442.x
更新日期:1995-08-01 00:00:00
abstract::Upon introducing off-pump coronary artery bypass grafting (CABG), the indications for CABG were expanded to include patients who previously had no operative indications. For accurate anastomosis, various devices and methods have been developed. Bradycardia is easily induced by drug administration. However, this method...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1046/j.1525-1594.2002.07087.x
更新日期:2002-10-01 00:00:00
abstract::The ventricular assist device inflow cannulation site is the primary interface between the device and the patient. Connecting these cannulae to either atria or ventricles induces major changes in flow dynamics; however, there are little data available on precise quantification of these changes. The objective of this i...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.2010.01093.x
更新日期:2010-09-01 00:00:00
abstract::We recently experienced a case of a female hemodialysis patient with multiple intestinal angiodysplasias. In 2001, she complained of melena, and angiographic embolization halted bleeding from ileum angiodysplasia. In 2002, she again complained of black stool. Abdominal angiography found jejunum angiodysplasia, and pha...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.2004.29003.x
更新日期:2005-01-01 00:00:00
abstract::Neurologic complications during on-pump cardiovascular surgery are often induced by mobilization of atherosclerotic plaques, which is directly related to enhanced wall shear stress. In the present study, we numerically evaluated the impact of dispersive aortic cannulas on aortic blood flow characteristics, with specia...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/aor.12359
更新日期:2015-03-01 00:00:00
abstract::Using an ex vivo model, the effects of membrane composition and surface area on both the complement system (as reflected by plasma C3a levels) and platelets [as indicated by plasma concentrations of thromboxane B2 (TXB2) and platelet factor 4 (PF4)] were studied. In this model, polyacrylonitrile (PAN) was associated w...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/j.1525-1594.1987.tb02648.x
更新日期:1987-04-01 00:00:00
abstract::Continuous hemodiafiltration (CHDF) has been performed for the treatment of severe acute pancreatitis. Phospholipase A2 (PLA2) is one of the important mediators which exacerbate acute pancreatitis, but whether PLA2 can be removed by CHDF is unclear. In this study, the kinetics of group IB and group IIA PLA2 was examin...
journal_title:Artificial organs
pub_type: 临床试验,杂志文章
doi:10.1111/j.1525-1594.2007.00398.x
更新日期:2007-05-01 00:00:00
abstract::We compared in vitro rates of hemolysis for a recently developed centrifugal pump with a conventional roller pump (10-10-00; Stöckert, Munich, Germany). Flow rates of 0.3 L/min and 1 L/min and a pressure of 200 mm Hg were chosen to simulate conditions during neonatal extracorporeal membrane oxygenation (ECMO). There w...
journal_title:Artificial organs
pub_type: 杂志文章
doi:
更新日期:1996-06-01 00:00:00
abstract::Left ventricle (LV) unloading caused by a left ventricular assist device (LVAD) has been shown to enhance reverse LV remodeling in end-stage cardiomyopathy. Several reports consistently suggest that a pulsatile-flow LVAD has more profound effects compared to continuous-flow LVAD, though the responsible mechanisms are ...
journal_title:Artificial organs
pub_type: 杂志文章
doi:10.1111/aor.13348
更新日期:2019-04-01 00:00:00