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PURPOSE: To evaluate the effectiveness and safety of selective ophthalmic arterial injection (SOAI) for retinoblastoma utilizing a microballoon catheter system with an M chamber. STUDY DESIGN: Retrospective analysis. METHODS AND PATIENTS: This study was sanctioned by theNational Cancer Center Hospital' Independent Ethics Committee. The surgeon was a general interventional radiologist. After confirming that the distal internal carotid artery was not delineated by balloon occlusion and the ophthalmic artery was visualized using digital subtraction angiography, melphalan was manually administered. Notably, in cases presenting bilateral retinoblastoma, both eyes received treatment in a singular, low-dose procedure. Between July 2015 and December 2021, 125 patients with retinoblastoma (68 boys and 57 girls) underwent SOAI at our facility. The average age at initial treatment was 19.3 months. The study covered 250 procedures, with patients undergoing an average of 3.7 procedures. RESULTS: The success rate of the procedure was 99.2%, with a mean procedure duration of 18.3 min. Two distinct technical failures were recorded: one attributed to an internal carotid artery having a wide lumen and the other due to the ophthalmic artery remaining undetected on angiography post-balloon occlusion of the internal carotid artery. Adverse events were minimal but included bronchospasm post-procedure and severe orbital inflammation in 0.8% and 0.4% of cases, respectively. CONCLUSION: SOAI using the microballoon catheter with the M chamber is a feasible and safe procedure for the treatment of retinoblastoma. The success rate was 99.2%. This system can be recommended as intra-arterial chemotherapy for retinoblastoma.
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Injeções Intra-Arteriais , Melfalan , Artéria Oftálmica , Neoplasias da Retina , Retinoblastoma , Humanos , Retinoblastoma/terapia , Retinoblastoma/diagnóstico , Retinoblastoma/tratamento farmacológico , Artéria Oftálmica/diagnóstico por imagem , Neoplasias da Retina/terapia , Neoplasias da Retina/tratamento farmacológico , Neoplasias da Retina/diagnóstico , Estudos Retrospectivos , Feminino , Masculino , Lactente , Pré-Escolar , Melfalan/administração & dosagem , Angiografia Digital , Resultado do Tratamento , Seguimentos , Antineoplásicos Alquilantes/administração & dosagem , CriançaRESUMO
OBJECTIVES: For appropriate glucocorticoid (GC) reduction, we investigated the optimal strategy including baseline factors that could reduce GC more than 50% with 96 weeks of belimumab. METHODS: This is a retrospective cohort study of Kakogawa Central City hospital from 2019 to 2023. We identified SLE patients who were receiving 200 mg of belimumab weekly by subcutaneous injection for 96 weeks. The background at baseline, trends in clinical indicators, and factors involved in GC reduction were statistically analyzed. Finally, univariate and multivariate logistic analyses were carried out to identify baseline factors associated ≥50% GC reduction at 96 weeks. RESULTS: Forty-seven patients were enrolled, with a median daily prednisolone of 5 mg. Almost 90% of them received concomitant immunosuppressants and/or hydroxychloroquine. Serological indices, daily GC dose, and SLEDAI-2K scores showed significant improvement in 96 weeks. At baseline, a significant negative correlation has been shown between the daily dose of GC and the duration from onset or last flare, as well as C4 levels. At 96 weeks, GC reduction rate and SLEDAI-2K scores were negatively correlated with duration from onset or last flare to initiation of belimumab. Mycophenolate mofetil use was significantly frequent in patients with lupus nephritis (LN), which also correlated with the frequency of past flares. In addition, LN presence was associated with higher SLEDAI-2K scores at 96 weeks, and baseline SLEDAI-2K ≥10 was associated with significantly higher GC dose at 96 weeks. Univariate analysis of the factor contributing to achieving ≥50% GC reduction at 96 weeks has pointed shorter disease duration and higher daily GC dose at baseline as significant variables. Finally, we performed a multivariate analysis by combining above two items with age, which extracted the higher daily GC dose at baseline as a significant variable (OR (95% CI) 1.25 (1.00 to 1.56), p = .047). CONCLUSIONS: Our study showed that a delay in belimumab initiation led to higher SLEDAI-2K score and difficulty in achieving a 50% GC reduction at 96 weeks. Since GC-related adverse events increase with long-term administration of GC though with small daily doses, we proposed here that belimumab should be started in combination with higher daily prednisolone.
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Anticorpos Monoclonais Humanizados , Lúpus Eritematoso Sistêmico , Nefrite Lúpica , Humanos , Prednisolona/efeitos adversos , Estudos Retrospectivos , Glucocorticoides/efeitos adversos , Resultado do Tratamento , Índice de Gravidade de Doença , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Lúpus Eritematoso Sistêmico/induzido quimicamente , Imunossupressores/efeitos adversos , Nefrite Lúpica/induzido quimicamenteRESUMO
We report the case of a 45-year-old man who was diagnosed with clinically amyopathic dermamyositis (CADM) and interstitial lung disease (ILD) after presenting with skin lesions typical of CADM and testing positive for anti-Melanoma Diferentiation-Associated gene 5 (anti-MDA5) anti-bodies. He was treated with a regimen including steroid pulse therapy, intravenous cyclophosphamide (IVCY), and calcineurin Inhibitor drug, which initially improved his ILD. However, three months post-treatment, the first deterioration of his conditions occurred, necessitating further administration of steroid pulse therapy and IVCY. After eight cycles of IVCY therapy, the serum levels of KL-6 and anti-MDA5 antibodies decreased, and reaching their lowest values. Nevertheless, two years and six months after the first observed deterioration, the second deterioration of his conditions occurred, leading to acute respiratory failure, treated again with steroid pulse therapy and IVCY. This treatment did not result in improvement of respiratory failure, therefore plasma exchange was attempted, which demonstrated a beneficial effect on the ILD for a short time. This case suggests that IVCY and plasma exchange might be effective therapeutic options for CADM with ILD.
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Dermatomiosite , Doenças Pulmonares Intersticiais , Masculino , Humanos , Pessoa de Meia-Idade , Dermatomiosite/complicações , Dermatomiosite/diagnóstico , Dermatomiosite/tratamento farmacológico , Helicase IFIH1 Induzida por Interferon , Doenças Pulmonares Intersticiais/complicações , Doenças Pulmonares Intersticiais/terapia , Ciclofosfamida/uso terapêutico , Esteroides/uso terapêutico , Autoanticorpos/uso terapêuticoRESUMO
OBJECTIVES: To investigate the efficacy of mepolizumab in patients with eosinophilic granulomatosis with polyangiitis (EGPA) and factors contributing to glucocorticoid (GC) discontinuation. METHODS: We retrospectively studied EGPA patients treated with mepolizumab who were on GC at the time of induction of mepolizumab, at Japanese single center as of January 2023. Patients were classified into those who were able to discontinue GC at the time of the investigation (GC-free group) and those who continued (GC-continue group). Patient characteristics at the time of EGPA diagnosis (age, gender, absolute eosinophil counts, serum CRP level, serum IgE level, Rheumatoid factor (RF) / anti-neutrophil cytoplasmic antibody (ANCA) positivity, presence of asthma, affected organ, Five factor score (FFS), Birmingham Vasculitis Activity Score (BVAS) and characteristics at the time of mepolizumab induction (daily prednisolone dose, concomitant immunosuppressive maintenance therapy at the mepolizumab induction, prior history of GC pulse therapy, concomitant immunosuppressive therapy for remission induction,), history of relapse before mepolizumab induction and the duration of mepolizumab treatment were compared. We also followed the clinical indicators (absolute eosinophil counts, CRP and IgE levels, BVAS, Vascular Damage Index (VDI)) and daily prednisolone dosage at the EGPA diagnosis, at the mepolizumab induction and at the survey. RESULTS: Twenty-seven patients were included in the study. At the time of the study, patients had received mepolizumab for median 31 months (IQR, 26 to 40), the daily prednisolone dose was median 1 mg (IQR, 0 to 1.8) and GC-free was achieved in 13 patients (48%). Among clinical indicators that have improved by conventional therapy before the induction of mepolizumab, eosinophil counts, GC doses and BVAS have successively shown significant reductions throughout the observation period both GC-free and GC-continue. Of the GC-free patients, 7 were ANCA positive and 12 had FFS1 or more. Univariate analysis showed that the absolute eosinophil counts at diagnosis was significantly higher in the GC-free group (median 8165/µl (IQR, 5138 to 13,409) vs. 4360/µl (IQR, 151 to 8380), P = 0.037) and significantly fewer patients presented with gastrointestinal lesions (2 (15%) vs. 8 (57%), P = 0.025), while multivariate analysis showed no significant differences. Mepolizumab treatment significantly improved VDI in the GC-continue group (P = 0.004). CONCLUSIONS: After three years of treatment with mepolizumab, approximately 50% of patients with EGPA achieved GC-free status. GC could be discontinued even in severe cases and ANCA-positive cases. Although multivariate analysis did not extract any significant factors contributing to achieving GC-free, we found that improvement in eosinophil counts and BVAS led to GC reduction, resulted in protection of organ damages in both the GC-free and continuation groups. The significance of achieving GC-free remission in EGPA patients was demonstrated.
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Síndrome de Churg-Strauss , Granulomatose com Poliangiite , Humanos , Glucocorticoides/uso terapêutico , Granulomatose com Poliangiite/tratamento farmacológico , Granulomatose com Poliangiite/diagnóstico , Estudos Retrospectivos , Síndrome de Churg-Strauss/tratamento farmacológico , Anticorpos Anticitoplasma de Neutrófilos , Japão , Prednisolona/uso terapêutico , Imunoglobulina ERESUMO
RATIONALE: Chronic eosinophilic pneumonia (CEP) presents eosinophil infiltrations in the lung due to allergic reactions. Most CEP patients continue to take glucocorticoids, and their prolonged use induces various side effects. In this case report, based on the efficacy of baricitinib in patients with rheumatoid arthritis (RA) and CEP, we aimed to show that the administration of Janus kinase (JAK) inhibitors, when RA is complicated by an allergic disease, can stabilize the disease state and help avoid the adverse effects of long-term systemic glucocorticoid administration. PATIENTS CONCERNS: A 56-year-old woman developed RA at the age of 19 years. Treatment of the arthritis was initiated, but the joint destruction had progressed. At the age of 42, she developed eosinophilic pneumonia, which was relieved by glucocorticoid therapy. Since then, maintenance therapy has been continued with the diagnosis of CEP. She was treated with concomitant tacrolimus for persistent arthritis, and the prednisolone (PSL) dose was reduced to 3 mg/day after 10 years. However, around this time, an increase in peripheral blood eosinophil counts and respiratory symptoms was observed. DIAGNOSIS: The peripheral blood eosinophil count was 4000/µL and computed tomography revealed multiple ground-glass opacities in the peripheral lung fields. As interstitial pneumonia due to infection or other causes was ruled out, CEP relapse was diagnosed. INTERVENTIONS: Pneumonia rapidly recovered when the PSL dose was increased to 15 mg/day, and asymptomatic eosinophilic infiltrates reappeared in the lung field along with a relapse of arthritis when the PSL dose was reduced to 5 mg/day. Concomitant use of methotrexate and baricitinib has been introduced to suppress allergic reactions to pneumonia. OUTCOMES: After starting combination therapy with baricitinib and methotrexate, both arthritis and eosinophilia improved, and glucocorticoid-free remission was achieved. LESSONS: Recently, inhibition of IL-5 signaling via JAK2 has been reported to be effective in bronchial asthma and atopic dermatitis. Although complications of RA and CEP are not common, the actions of baricitinib are useful not only in arthritis but also in allergic diseases. The efficacy of some JAK inhibitors should be actively tested in patients with RA and these complications.
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Artrite Reumatoide , Asma , Inibidores de Janus Quinases , Eosinofilia Pulmonar , Feminino , Humanos , Adulto Jovem , Adulto , Pessoa de Meia-Idade , Glucocorticoides/uso terapêutico , Eosinofilia Pulmonar/diagnóstico , Metotrexato/uso terapêutico , Inibidores de Janus Quinases/uso terapêutico , Artrite Reumatoide/complicações , Artrite Reumatoide/tratamento farmacológico , Artrite Reumatoide/diagnóstico , Prednisolona/uso terapêutico , Asma/tratamento farmacológico , RecidivaRESUMO
Pathogens including autoantigens all failed to induce systemic lupus erythematosus (SLE). We, instead, studied the integrity of host's immune response that recognized pathogen. By stimulating TCR with an antigen repeatedly to levels that surpass host's steady-state response, self-organized criticality, SLE was induced in mice normally not prone to autoimmunity, wherein T follicular helper (Tfh) cells expressing the guanine nucleotide exchange factor DOCK8 on the cell surface were newly generated. DOCK8+Tfh cells passed through TCR re-revision and induced varieties of autoantibody and lupus lesions. They existed in splenic red pulp and peripheral blood of active lupus patients, which subsequently declined after therapy. Autoantibodies and disease were healed by anti-DOCK8 antibody in the mice including SLE-model (NZBxNZW) F1 mice. Thus, DOCK8+Tfh cells generated after repeated TCR stimulation by immunogenic form of pathogen, either exogenous or endogenous, in combination with HLA to levels that surpass system's self-organized criticality, cause SLE.
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Low-flow blood pumps rated under 1 L/min are emerging for new medical applications, such as hemofiltration in acute use. In those pumps, platelet adhesion and aggregation have to be carefully considered because of clogging risk in the filter part. To find an acceptable hemocompatibility that can be applied to low-flow centrifugal blood pump design, the platelet aggregation index, clogging on a micromesh filter, and the hemolysis index were investigated using a low-flow blood pump designed for hemofiltration use. We conducted circulation testing in vitro using fresh porcine blood and two centrifugal pumps with different impeller inlet shapes. The Negative Log Platelet Aggregation Threshold Index (NL-PATI), which reflects the ability of residual platelets to aggregate, and flow rate were measured during reflux for 60 min, and the Normalized Index of Hemolysis (NIH (g/20 min)) was calculated. In addition, blood cell clogging after reflux was observed on the micromesh filter by SEM, and the adhesion rate was calculated. Our results showed that the platelet clogging on the micromesh filter occurred when the average NL-PATI was greater than 0.28 and the average NIH (g/20 min) was greater than 0.01. In contrast, platelet clogging on the micromesh was suppressed when NL-PATI was less than 0.17 and the NIH (g/20 min) was less than 0.003. These values might be used as acceptable hemocompatibility of low-flow centrifugal blood pumps with suppressed platelet clogging for hemofiltration pumps.
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Plaquetas , Coração Auxiliar , Animais , Coração Auxiliar/efeitos adversos , Hemólise , Agregação Plaquetária , Testes de Função Plaquetária , SuínosRESUMO
We have developed a hydrodynamically levitated centrifugal blood pump. In the blood pump having hydrodynamic bearings, the narrow bearing gap has a potential for high hemolysis. The purpose of the this study is to improve hemolysis performance in a hydrodynamically levitated centrifugal blood pump by optimizing a shroud size. The impeller was levitated passively at the position where the thrust forces acting on the impeller were balanced. We focused on a size of a bottom shroud with a hydrodynamic bearing that could change the bottom hydrodynamic force to balance the thrust force at the wide bearing gap for reducing hemolysis. Five test models with various shroud size were compared: 989 mm2 (HH-10.5), 962 mm2 (HH-12), 932 mm2 (HH-13.5), 874 mm2 (HH-16), and 821 mm2 (HH-18). A numerical analysis was first performed to estimate the bearing gaps in the test model. The bearing gaps were then measured to validate the numerical analysis. Finally, an in vitro hemolysis test was performed. The numerical analysis revealed that the HH-13.5 model had the widest bearing gap of 129 µm. In the measurement test, the estimation error for the bearing gap was less than 10%. In the hemolysis test, the HH-13.5 model achieved the lowest hemolysis level among the five models. The present study demonstrated that the numerical analysis was found to be effective for determining the optimal should size, and the HH-13.5 model had the optimal shroud size in the developed hydrodynamically levitated centrifugal blood pump to reduce hemolysis.
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Coração Auxiliar , Hemólise , Centrifugação , Desenho de Equipamento , Humanos , Hidrodinâmica , Desenho de PróteseRESUMO
A suitable index is needed for hemolysis tests that use low-flow pumps, such as pediatric blood pumps or blood purification pumps. To create such an index, the present study investigates the change of plasma-free hemoglobin in the pump circuit with time and the change of the hemolysis rate with flow rate and impeller rotational speed. The results show that the hemolysis rate or the increase rate of the total free hemoglobin are suitable measures for hemolysis evaluation for low-flow pumps.
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Coração Auxiliar , Hemólise , Algoritmos , Animais , Bovinos , Hemodinâmica , HemoglobinasRESUMO
PURPOSE: When accidental tumor incision (ATI) has occurred during open partial nephrectomy (PN), scissors can be changed easily. In contrast, during laparoscopic partial nephrectomy (LPN) or robotic partial nephrectomy (RPN), it is time consuming and expensive especially during RPN to change scissors. This study investigates whether tumor cells remain on the surface of scissors after ATI during PN and investigates an alternative way to avoid changing scissors during LPN and RPN. MATERIALS AND METHODS: We subcutaneously injected 786-O renal-cell carcinoma (RCC) cells containing enhanced green fluorescent protein (786-O/EGFP) into six mice. We incised the subsequent tumor with straight or Microline scissors. The scissor surfaces were then examined by microscopy for detection of EGFP immunofluorescence. In addition, the scissor surfaces were treated in three ways: no electrical treatment, electrical treatment of 20 W for 5 seconds, and electrical treatment of 40 W for 5 seconds. RESULTS: Strings or dots of EGFP were detected on every scissor surface, and 786-O/EGFP cells were alive and able to proliferate in medium in 33% of the nonelectrically treated samples. However, no 786-O/EGFP cells treated with monopolar electricity survived. In another experiment, we also found that 100 786-O cells placed on scissor surfaces could not survive after the same electrical treatment. CONCLUSIONS: RCC cells remained on scissors after ATI; however, electrical treatment eliminated tumor cells, possibly preventing recurrence or metastasis after surgery.
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Carcinoma de Células Renais/cirurgia , Contaminação de Equipamentos , Neoplasias Renais/cirurgia , Nefrectomia/métodos , Procedimentos Cirúrgicos Robóticos/métodos , Instrumentos Cirúrgicos , Animais , Linhagem Celular Tumoral , Eletricidade , Feminino , Humanos , Técnicas In Vitro , Laparoscopia/métodos , Camundongos , Camundongos Nus , Recidiva Local de Neoplasia , Transplante de Neoplasias , Estudos Retrospectivos , RobóticaRESUMO
BACKGROUND AND OBJECTIVE: While adult asthma has been shown to be a risk factor for COPD, the effect of remitted childhood asthma on adult lung function has not been clarified. The aim of this study was to examine whether remitted childhood asthma is a risk factor for airflow obstruction in a middle-aged general population. METHODS: A total of 9896 participants (range: 35-60 years) from five healthcare centres were included in the study. The participants were classified into four categories based on the presence or absence of physician-diagnosed childhood/adulthood asthma and asthma symptoms as follows: healthy controls (n = 9154), remitted childhood asthma (n = 287), adulthood-onset asthma (n = 354) and childhood-adulthood asthma (n = 101). RESULTS: The prevalence of respiratory symptoms was similar in both the participants with remitted childhood asthma and healthy controls. The prevalence of airflow obstruction (forced expiratory volume in 1 s (FEV1 )/forced vital capacity (FVC) < 0.7) was significantly higher in the participants with remitted childhood asthma, those with adult-onset asthma and those with childhood-adulthood asthma (5.2%, 14.4% and 16.8%, respectively) compared with healthy controls (2.2%). Multivariate logistic regression showed that remitted childhood asthma was independently associated with airflow obstruction. Among the participants with remitted childhood asthma, ever-smokers had significantly lower FEV1 /FVC than never-smokers. CONCLUSION: Clinically remitted childhood asthma is associated with airflow obstruction in middle-aged adults. Smoking and remitted childhood asthma may be additive factors for the development of airflow obstruction.
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Obstrução das Vias Respiratórias , Asma , Adulto , Idade de Início , Obstrução das Vias Respiratórias/diagnóstico , Obstrução das Vias Respiratórias/epidemiologia , Obstrução das Vias Respiratórias/etiologia , Obstrução das Vias Respiratórias/fisiopatologia , Asma/complicações , Asma/diagnóstico , Asma/epidemiologia , Asma/fisiopatologia , Criança , Feminino , Volume Expiratório Forçado , Humanos , Japão/epidemiologia , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Fumar/epidemiologia , Capacidade VitalRESUMO
A long-term durability test was conducted on a newly developed axial-flow ventricular assist device (VAD) with hydrodynamic bearings. The mock circulatory loop consisted of a diaphragm pump with a mechanical heart valve, a reservoir, a compliance tank, a resistance valve, and flow paths made of polymer or titanium. The VAD was installed behind the diaphragm pump. The blood analog fluid was a saline solution with added glycerin at a temperature of 37 °C. A pulsatile flow was introduced into the VAD over a range of flow rates to realize a positive flow rate and a positive pressure head at a given impeller rotational speed, yielding a flow rate of 5 L/min and a pressure of 100 mmHg. Pulsatile flow conditions were achieved with the diastolic and systolic flow rates of ~0 and 9.5 L/min, respectively, and an average flow rate of ~5 L/min at a pulse rate of 72 bpm. The VAD operation was judged by not only the rotational speed of the impeller, but also the diastolic, systolic, and average flow rates and the average pressure head of the VAD. The conditions of the mock circulatory loop, including the pulse rate of the diaphragm pump, the fluid temperature, and the fluid viscosity were maintained. Eight VADs were tested with testing periods of 2 years, during which they were continuously in operation. The VAD performance factors, including the power consumption and the vibration characteristics, were kept almost constant. The long-term durability of the developed VAD was successfully demonstrated.
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Coração Auxiliar , Fluxo Pulsátil , Pressão Sanguínea , Humanos , Hidrodinâmica , Teste de Materiais , PressãoRESUMO
Plasma skimming is a phenomenon in which discharge hematocrit is lower than feed hematocrit in microvessels. Plasma skimming has been investigated at a bearing gap in a spiral groove bearing (SGB), as this has the potential to prevent hemolysis in the SGB of a blood pump. However, it is not clear whether plasma skimming occurs in a blood pump with the SGB, because the hematocrit has not been obtained. The purpose of this study is to verify plasma skimming in an SGB of a centrifugal blood pump by developing a hematocrit measurement method in an SGB. Erythrocyte observation using a high-speed microscope and a bearing gap measurement using a laser confocal displacement meter was performed five times. In these tests, bovine blood as a working fluid was diluted with autologous plasma to adjust the hematocrit to 1.0%. A resistor was adjusted to achieve a pressure head of 100 mm Hg and a flow rate of 5.0 L/min at a rotational speed of 2800 rpm. Hematocrit on the ridge region in the SGB was measured using an image analysis based on motion image of erythrocytes, mean corpuscular volume, the measured bearing gap, and a cross-sectional area of erythrocyte. Mean hematocrit on the ridge region in the SGB was linearly reduced from 0.97 to 0.07% with the decreasing mean bearing gap from 38 to 21 µm when the rotational speed was changed from 2250 to 3000 rpm. A maximum plasma skimming efficiency of 93% was obtained with a gap of 21 µm. In conclusion, we succeeded in measuring the hematocrit on the ridge region in the SGB of the blood pump. Hematocrit decreased on the ridge region in the SGB and plasma skimming occurred with a bearing gap of less than 30 µm in the hydrodynamically levitated centrifugal blood pump.
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Circulação Assistida/instrumentação , Eritrócitos/citologia , Hematócrito/métodos , Algoritmos , Animais , Bovinos , Centrifugação/instrumentação , Desenho de Equipamento , Índices de Eritrócitos , Hidrodinâmica , Microvasos/fisiologiaRESUMO
An impeller the same geometry as the impeller of a commercial monopivot cardiopulmonary bypass pump was manufactured using 3D printing. The 3D-printed impeller was integrated into the pump casing of the commercially available pump to form a 3D-printed pump model. The surface roughness of the impeller, the hydraulic performance, the axial displacement of the rotating impeller, and the hemolytic properties of the 3D-printed model were measured and compared with those of the commercially available model. Although the surface roughness of the 3D-printed model was significantly larger than that of the commercially available model, the hydraulic performance of the two models almost coincided. The hemolysis level of the 3D-printed model roughly coincided with that of the commercially available model under low-pressure head conditions, but increased greatly under high-pressure head conditions, as a result of the narrow gap between the rotating impeller and the pump casing. The gap became narrow under high-pressure head conditions, because the axial thrust applied to the impeller increased with increasing impeller rotational speed. Moreover, the axial displacement of the rotating impeller was twice that of the commercially available model, confirming that the elastic deformation of the 3D-printed impeller was larger than that of the commercially available impeller. These results suggest that trial models manufactured by 3D printing can reproduce the hydraulic performance of the commercial product. However, both the surface roughness and the deformation of the trial models must be considered to precisely evaluate the hemolytic properties of the model.
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Coração Auxiliar , Impressão Tridimensional , Ponte Cardiopulmonar , Desenho de Equipamento , Hemólise , Hemorreologia , Humanos , PressãoRESUMO
In vitro antithrombogenic testing with mock circulation is a useful type of pre-evaluation in ex vivo testing of mechanical assist devices. For effective in vitro testing, we have been developing a clear quantitative thrombogenesis model based on shear stress and blood coagulability. Bovine blood was used as the test medium. The activating clotting time (ACT) was adjusted with trisodium citrate and calcium chloride from 200 to 1,000 seconds. The blood was then applied to a rheometer and subjected to shear at 50 to 2,880 s-1. Blood coagulation time and degree of thrombogenesis were measured by the torque sensor of the rheometer. Prothrombin time (PT) and activated partial thromboplastin time (APTT) of the test blood were also measured after the application of shear. Blood coagulation time increased, and the degree of thrombogenesis decreased, with increases in shear rate to between 50 and 2,880 s-1. for test bloods with ACTs of 200 to 250 seconds. An ACT of 200 to 250 seconds is thus appropriate for in vitro antithrombogenic testing under a shear rate of 2,880 s-1. APTT was prolonged, whereas PT did not change, with increasing shear rate: that is, increasing the shear rate reduced thrombogenesis related to the intrinsic clotting pathway. An ACT of 200 to 250 seconds was suitable for in vitro antithrombogenic testing, and increasing the shear stress generated in the mechanical assist device reduced thrombogenesis via the intrinsic clotting pathway.
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Coagulação Sanguínea/fisiologia , Coração Auxiliar , Estresse Mecânico , Animais , Testes de Coagulação Sanguínea , Bovinos , Citratos , Tempo de Tromboplastina Parcial , Tempo de ProtrombinaRESUMO
The effect of the flow path geometry of the impeller on the lift-off and tilt of the rotational axis of the impeller against the hydrodynamic force was investigated in a centrifugal blood pump with an impeller supported by a single-contact pivot bearing. Four types of impeller were compared: the FR model with the flow path having both front and rear cutouts on the tip, the F model with the flow path having only a front cutout, the R model with only a rear cutout, and the N model with a straight flow path. First, the axial thrust and the movement about the pivot point, which was loaded on the surface of the impeller, were calculated using computational fluid dynamics (CFD) analysis. Next, the lift-off point and the tilt of the rotational axis of the impeller were measured experimentally. The CFD analysis showed that the axial thrust increased gently in the FR and R models as the flow rate increased, whereas it increased drastically in the F and N models. This difference in axial thrust was likely from the higher pressure caused by the smaller circumferential velocity in the gap between the top surface of the impeller and the casing in the FR and R models than in the F and N models, which was caused by the rear cutout. These results corresponded with the experimental results showing that the impellers lifted off in the F and N models as the flow rate increased, whereas it did not in the FR and R models. Conversely, the movement about the pivot point increased in the direction opposite the side with the pump outlet as the flow rate increased. However, the tilt of the rotational axis of the impeller, which oriented away from the pump outlet, was less than 0.8° in any model under any conditions, and was considered to negligibly affect the rotational attitude of the impeller. These results confirm that a rear cutout prevents lift-off of the impeller caused by a decrease in the axial thrust.