720 results on '"K. Saku"'
Search Results
52. Effects of pindolol on serum lipids, apolipoproteins, and lipoproteins in patients with mild to moderate essential hypertension
- Author
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J, Sasaki, K, Saku, M, Ideishi, K, Arakawa, Y, Kato, E, Kuwano, and T, So
- Subjects
Adult ,Male ,Lipoproteins ,Cholesterol, VLDL ,Blood Pressure ,Cholesterol, LDL ,Middle Aged ,Lipids ,Apolipoproteins ,Pindolol ,Hypertension ,Humans ,Female ,Pulse ,Aged - Abstract
The effects of 12 weeks' administration of the beta-blocker pindolol (5 mg twice daily) on serum lipids, apolipoproteins (apo), and lipoproteins were studied in 20 normolipidemic patients with mild to moderate essential hypertension (WHO I-II). Pindolol significantly increased both high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C), while very-low-density lipoprotein cholesterol (VLDL-C) was significantly decreased. Apo A-II levels were increased significantly and the apo B/apo A-I ratio, which is one of the atherogenic indexes, was decreased significantly after pindolol therapy. Total cholesterol, HDL subfraction cholesterols, the LDL-C/HDL-C ratio, triglycerides, apo A-I, apo B, apo C-II, apo C-III, and apo E did not change significantly.
- Published
- 1989
53. Lack of effect of chlorpromazine and haloperidol on serum lipid levels and on atherogenesis in cholesterol fed rabbits
- Author
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K, Saku, J, Sasaki, and K, Arakawa
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Cholesterol, Dietary ,Male ,Cholesterol ,Arteriosclerosis ,Chlorpromazine ,Body Weight ,Animals ,Haloperidol ,Rabbits ,Lipids ,Triglycerides - Abstract
Effects of chlorpromazine and haloperidol on serum lipid levels and on atheromotous plaques of aortae were studied in 1% cholesterol fed rabbits. To three different groups, subcutaneous injections of saline, chlorpromazine and haloperidol were given daily, following a cholesterol fed diet for twelve weeks. Serum total cholesterol and triglyceride levels were similar at 0, 6, 12 weeks among the three groups. No significant differences in the area with atheromatous plaque of aorta were noted among the three groups. Therefore, chlorpromazine and haloperidol have no preventive action against cholesterol-induced atherosclerosis in rabbits.
- Published
- 1989
54. Serological typing of Pseudomonas aeruginosa--comparison of various antigenic schema
- Author
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J Y, Homma, Y, Hirao, K, Saku, Y, Terada, and J I, Sugiyama
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Antigens, Bacterial ,Epitopes ,Agglutination Tests ,Pseudomonas aeruginosa ,Cross Reactions ,Serotyping - Abstract
Serotyping sera for both the agglutination (using IMSUT sera) and slide agglutination (using TIBS sera) were succesfully prepared using Homma's serotype strains. They were proved to be type specific and distinct. The two typing sera (IMSUT and TIBS) were used to determine the correspondence of major O-antigens among the different kinds of serotype schema which are used at present throughout the world. The serotype sera of Lanyi, Liu and Meitert were also used for the same purpose. The relationships among serotypes of the seven schemata were clarified as shown in tables in the text. Cross-reactions were found among several serotypes in each of several serotype schemata was suggested.
- Published
- 1977
55. [MIC test of Campylobacter jejuni/coli]
- Author
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K, Saku, K, Sugimoto, and Y, Uchiyama
- Subjects
Campylobacter fetus ,Drug Resistance, Microbial ,Microbial Sensitivity Tests ,beta-Lactamases ,Anti-Bacterial Agents ,Culture Media - Abstract
Using 3 kinds of medium, Mueller-Hinton (M-H) agar, M-H agar added with defibrinated horse blood and lysed horse blood, susceptibilities of Campylobacter were tested quantitatively to 12 antibacterial agents. The result showed no remarkable difference between them. MIC was examined with the cell concentration of McFarland unit 0.5 and 100-times dilution, and there was no significant difference between them except for 2 strains, on which erythromycin showed MIC of 6.25 micrograms/ml at McFarland unit 0.5 and 0.39 micrograms/ml at 100-times dilution. Eighty-two clinical isolates of C. jejuni and 6 of C. coli were tested for their susceptibility to 12 antibacterial agents. These strains were most susceptible to gentamicin and amikacin and less susceptible to benzylpenicillin, carbenicillin and cephaloridine with the MIC of 25 micrograms/ml. There were 2 peaks of susceptibility distribution to minocycline (0.2 and 50 micrograms/ml). In tests for beta-lactamase of C. jejuni and C. coli, 3 strains obtained from 1 patient were positive.
- Published
- 1983
56. [Case of bacteremic phlegmon due to Vibrio vulnificus]
- Author
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M, Kaseda, G, Masuda, T, Miyakuni, T, Onodera, Y, Awane, K, Saku, and K, Motegi
- Subjects
Male ,Sepsis ,Vibrio Infections ,Drainage ,Humans ,Cellulitis ,Middle Aged ,Anti-Bacterial Agents ,Vibrio - Published
- 1983
57. [Antibody titer of the serum of patients with Pseudomonas aeruginosa infection. Passive hemagglutination test using original endotoxin protein(OEP)]
- Author
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K, Saku
- Subjects
Endotoxins ,Bacterial Proteins ,Pseudomonas aeruginosa ,Humans ,Pseudomonas Infections ,Hemagglutination Tests ,Antibodies, Bacterial - Published
- 1975
58. Bacteriostatic and bactericidal activities of beta-lactam antibiotics enhanced by the addition of low concentrations of gentamicin
- Author
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G Masuda, K Saku, T Yajima, and K Nakamura
- Subjects
Klebsiella ,medicine.drug_class ,Antibiotics ,medicine.disease_cause ,Microbiology ,Agar plate ,Minimum inhibitory concentration ,Cephalothin ,medicine ,Escherichia coli ,Pharmacology (medical) ,Pharmacology ,biology ,Bacteria ,Chemistry ,Pseudomonas aeruginosa ,Drug Synergism ,Carbenicillin ,biology.organism_classification ,Infectious Diseases ,Gentamicin ,Gentamicins ,medicine.drug ,Research Article - Abstract
The combined effects of low concentrations of gentamicin on certain beta-lactam antibiotics were studied by the agar plate method. the combination of gentamicin with cephalothin produced synergism against 17 of 26 strains of Escherichia coli and 19 of 27 strains of Klebsiella sp. if assessed at the bacteriostatic (minimal inhibitory concentration) level. Synergy against many more strains was apparent when bactericidal concentrations were used. Synergy against most of these strains was observed if bactericidal concentrations with brief exposure times (3 h) to the antibiotics were used for measurement. Additive effects were observed in almost all of the remaining strains. The combination of gentamicin and carbenicillin were synergistic against most strains of Pseudomonas aeruginosa when any bacteriostatic or bactericidal measurement was used as the criterion.
- Published
- 1980
59. Laryngoplasty using suprahyoid muscles--hyoid transposition laryngoplasty
- Author
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T, Morimitsu, T, Nagai, M, Nagai, M, Ide, T, Tono, M, Kurogi, F, Kasano, Y, Adachi, and K, Saku
- Subjects
Male ,Speech, Alaryngeal ,Hypopharyngeal Neoplasms ,Esophageal Neoplasms ,Carcinoma, Squamous Cell ,Humans ,Female ,Laryngectomy ,Middle Aged ,Neoplasm Recurrence, Local ,Surgery, Plastic ,Laryngeal Neoplasms ,Aged - Abstract
A new technique of laryngoplasty using the function of the suprahyoid muscles (hyoid transposition laryngoplasty) was reported. Total laryngectomy is carried out as usual and the tracheal stump is anastomosed directly to the hypopharynx. The hyoid bone is cut medially, then transpositioned and sutured to the posterolateral margins of the tracheal stump. With this procedure, the new glottis is pressed strongly to the tongue base during swallowing and aspiration is avoided. Postoperative swallowing and speech in the cases operated on with this method were satisfactory, and even nasal respiration was possible in some cases.
- Published
- 1985
60. Passive hemagglutination reaction test using formalinized sheep erythrocytes treated with tannic acid and coated with proteast or elastase of Pseudomonas aeruginosa
- Author
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J Y, Homma, T, Tomiyama, H, Sano, Y, Hirao, and K, Saku
- Subjects
Erythrocytes ,Sheep ,Pancreatic Elastase ,Immune Sera ,Hemagglutination Tests ,Antibodies, Bacterial ,Hydrolyzable Tannins ,Endotoxins ,Pseudomonas aeruginosa ,Animals ,Humans ,Cattle ,Pseudomonas Infections ,Mastitis, Bovine ,Respiratory Tract Infections ,Tannins ,Peptide Hydrolases - Abstract
Methods were established for estimating antibodies of protease and elastase of Pseudomonas aeruginosa by passive hemagglutination (HA) tests using fixed sheep erythrocytes coated with each of the two enzymes. High antibody titers of protease and elastase were found in the HA tests on sera in some cases suffered from P. aeruginosa infection. The evaluation of the HA tests was discussed.
- Published
- 1975
61. C-II anapolipoproteinemia and severe hypertriglyceridemia. Report of a rare case with absence of C-II apolipoprotein isoforms and review of the literature
- Author
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K, Saku, C, Cedres, B, McDonald, B A, Hynd, B W, Liu, L S, Srivastava, and M L, Kashyap
- Subjects
Adult ,Male ,Adolescent ,Heparin ,Lipolysis ,Homozygote ,Hyperlipidemias ,Middle Aged ,Kinetics ,Lipoprotein Lipase ,Apolipoproteins ,Cholesterol ,Child, Preschool ,Humans ,Apolipoprotein C-II ,Female ,Apolipoproteins C ,Triglycerides - Abstract
A new case of C-II anapolipoproteinemia (complete apolipoprotein C-II deficiency) as the cause of severe hypertriglyceridemia with chylomicronemia (type I lipoprotein phenotype) is described. The patient was a five-year-old boy living in Connecticut. He had splenomegaly, episodic abdominal pain, and bloody stools. Absence of apolipoprotein C-II (and its isoforms C-II1 and C-II2) was documented by a sensitive and specific radioimmunoassay, analytical isoelectric focusing, and in vitro lipolytic assay. Decreased levels of high- and low-density lipoprotein cholesterol and apolipoproteins A-I and A-II and increased levels of plasma triglycerides and apolipoprotein E were found. Post-heparin extra-hepatic lipoprotein lipase activity was within normal range. Incorporation of exogenous purified human apolipoprotein C-II to an incubation mixture of purified lipoprotein lipase and the patient's triglyceride-rich lipoproteins resulted in a dramatic increase in the catabolic rate of the defective triglyceride-rich lipoproteins. The absence of the isoforms of apolipoprotein C-II in this patient indicates that a common gene exists for the C-II isoproteins, which appear to be necessary for normal triglyceride transport in humans. A literature review of 23 reported cases indicates that xanthomas and hepatosplenomegaly are less common in C-II anapolipoproteinemia than in lipoprotein lipase deficiency, the other major etiologic cause of genetic chylomicronemia.
- Published
- 1984
62. [Bacteriological properties of mucoid type Pseudomonas]
- Author
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K, Saku, H, Tanimoto, and T, Watanabe
- Subjects
Pseudomonas ,Humans ,Respiratory Tract Infections - Published
- 1972
63. Prevalence of canine coronavirus and parvovirus infections in dogs with gastroenteritis in Thailand
- Author
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K. Sakulwira, P. Vanapongtipagorn, A. Theamboonlers, K. Oraveerakul, and Y. Poovorawan
- Subjects
canine coronavirus ,canine parvovirus type 2 ,gastroenteritis ,pcr ,Veterinary medicine ,SF600-1100 - Abstract
Canine coronavirus (CCV) and canine parvovirus type 2 (CPV-2) are the causative agents of gastroenteritis in dogs. Seventy fecal samples from dogs with signs of gastroenteritis (vomiting and diarrhea), twenty-five fecal samples from healthy dogs and one CPV-2 vaccine strain were amplified by semi-nested polymerase chain reaction (PCR) and semi-nested reverse transcriptase polymerase chain reaction (RT-PCR), aimed at specifically studying the gene encoding the most abundant capsid protein VP2 of CPV-2 and spike protein of CCV. The specificity of the CCV RT-PCR product was evaluated by sequencing. Positive specimens comprised 44 samples (62.8%) and 9 samples (12.8%) for CPV-2 and CCV, respectively. In nine CCV positive samples, seven displayed co-infection between CCV and CPV-2. Our CCV sequence (AF482001) showed a 94.9% nucleotide identity to CCV reported in GenBank accession number D13096. High prevalence of CCV and CPV-2 infections was found in 1-2 month- and 3-6 month-old dogs, respectively. Molecular biology of these viruses is important primarily for epidemic control and preventive measures.
- Published
- 2003
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64. Positive resolvents and potentials
- Author
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Yosida, K�saku, primary
- Published
- 1967
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65. ACTIVE VIEW AGENTS FOR PERSONALIZED E-COMMERCE APPLICATIONS
- Author
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K. Sakulwong and T. Sunetnanta
- Subjects
Multi-agent systems ,electronic commerce ,XML ,active rules ,active views ,Information technology ,T58.5-58.64 - Abstract
Giving the right information to the right person at the right time is one of the main factors contributing to the success of e-commerce applications. Existing applications of active views to e-commerce mostly generate application views based on user roles such as customers and vendors, so they cannot completely serve one-to-one marketing. Furthermore, the data controlled by the existing applications is limited to those retrieved from databases, but does not include other web contents such as pictures, descriptive information and hyperlinks. In addition, the integration of active views to existing e-commerce applications still presents some difficulties in tackling heterogenity. This work presents a model of the Active View Agents System (AVAS), based on a co-performance model of multi-agents, to resolve these problems.
- Published
- 2003
66. Fractional esterification rate of cholesterol in high density lipoprotein is correlated with low density lipoprotein particle size in children.
- Author
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T Ohta, Y Kakiuti, K Kurahara, K Saku, N Nagata, and I Matsuda
- Subjects
Biochemistry ,QD415-436 - Abstract
Small low density lipoprotein (LDL) particles are thought to be more atherogenic than larger LDL particles, although this association may depend on plasma triglyceride (TG) and high density lipoprotein (HDL) levels. To help prevent coronary artery disease (CAD), it may be useful to understand risk factors during childhood and adolescence. In the present study, we evaluated low density lipoprotein particle size (LDL-size) by 2-16% gradient gel electrophoresis in 70 healthy children (30 boys and 40 girls) along with conventional lipid and lipoprotein parameters which are thought to affect LDL-size. The fractional and molar esterification rates (FER and MER) of cholesterol in plasma and HDL were also determined. As expected, plasma levels of TG, HDL-cholesterol (HDL-C) and apoA-I were closely associated with LDL-sizes in both sexes (boys: r = -0.694, 0.708 and 0.701, girls: r = -0.579, 0.551 and 0.539, P < 0.001). However, a closer association was found between FER in HDL (FER(HDL)) and LDL-size (boys: r= -0.874, girls: r= -0.642, P < 0.001). In a stepwise multiple regression analysis, FER(HDL) alone accounted for 76% and 41% of the variability in LDL-size in boys and girls, respectively. MER in HDL accounted for additional 4% and 19% in boys and girls, respectively. Other parameters, including plasma TG, HDL-C and apoA-I had no significant additional effects. Thus, the determination of FER(HDL) is useful to predict the particle size of LDL in children.
- Published
- 1997
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67. Closed-Loop Automated Control System of Extracorporeal Membrane Oxygenation and Left Ventricular Assist Device Support in Cardiogenic Shock.
- Author
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Unoki T, Uemura K, Yokota S, Matsushita H, Kakuuchi M, Morita H, Sato K, Yoshida Y, Sasaki K, Kataoka Y, Nishikawa T, Fukumitsu M, Kawada T, Sunagawa K, Alexander J Jr, and Saku K
- Abstract
Venoarterial extracorporeal membrane oxygenation (VA-ECMO) benefits patients with cardiogenic shock (CS) but can increase left ventricular afterload and exacerbate pulmonary edema. Adding a percutaneous left ventricular assist device (LVAD) to VA-ECMO can optimize the hemodynamics. Because managing VA-ECMO and LVAD simultaneously is complex and labor-intensive, we developed a closed-loop automated control system for VA-ECMO and LVAD. Based on the circulatory equilibrium framework, this system automatically adjusts VA-ECMO and LVAD flows and cardiovascular drug and fluid dosages to achieve target arterial pressure (AP, 70 mm Hg), left atrial pressure (PLA, 14 mm Hg), and total systemic flow (Ftotal, 120-140 ml/min/kg). In seven anesthetized dogs with CS, VA-ECMO significantly increased AP and PLA from 24 (23-27) to 71 (63-77) mm Hg and 20.1 (16.3-22.1) to 43.0 (25.7-51.4) mm Hg, respectively. Upon system activation, PLA was promptly reduced. At 60 min postactivation, the system-controlled AP to 69 (65-74) mm Hg, PLA to 12.5 (12.0-13.4) mm Hg, and Ftotal to 117 (114-132) ml/min/kg while adjusting VA-ECMO flow to 59 (12-60) ml/min/kg, LVAD flow to 68 (54-78) ml/min/kg, and cardiovascular drug and fluid dosages. This system automatically optimizes VA-ECMO and LVAD hemodynamics, making it an attractive tool for rescuing patients with CS., Competing Interests: Disclosure: K.S. received research funding from NTT Research, Inc., Abiomed Japan K.K., Asahi Kasei ZOLL Medical Corporation, Neuroceuticals Inc., and Zeon Medical Inc., and honoraria from Abiomed Japan K.K., Mallinckrodt Pharma K.K., and Ono Pharmaceutical Co., Ltd. The other authors have no conflicts of interest to report., (Copyright © ASAIO 2024.)
- Published
- 2024
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68. The need for definition of optimal left ventricular unloading.
- Author
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Nishikawa T, Morita H, Sunagawa K, and Saku K
- Abstract
Competing Interests: Declaration of competing interest None.
- Published
- 2024
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- View/download PDF
69. Potential new treatment for inferior vena cava injury using extracorporeal membrane oxygenation applying flow diversion effect.
- Author
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Maruhashi T, Saku K, Maruki H, Oi M, and Asari Y
- Abstract
Background: Retrohepatic inferior vena cava (IVC) injuries remain among the most lethal and serious liver injuries. Gauze packing is currently the first choice for IVC injuries; however, laparotomy itself poses the risk of circulatory collapse. Thus, less invasive treatment strategies are needed., Methods: In this study, we conducted an animal experiment to replicate and validate successful treatments for an actual case of retrohepatic IVC injury that we had encountered., Results: A woman in her 80s presented to our hospital due to cardiac arrest caused by a pulmonary artery embolism. Venoarterial extracorporeal membrane oxygenation (ECMO) was introduced, and the patient was resuscitated. After resuscitation, contrast-enhanced CT revealed liver and retrohepatic IVC injuries, possibly caused by chest compressions. Liver injury was treated using transarterial embolization of the left hepatic artery. To treat the retrohepatic IVC injury, ECMO flow was increased to enhance the negative drainage pressure. The extravasation of the contrast medium had resolved in IVC angiography, and we opted for nonoperative management. The patient's hemodynamic status gradually stabilized, and ECMO was withdrawn on day 6. We confirmed these findings in a dog model of retrohepatic IVC injury., Conclusions: Our findings from the patient and the animal model suggest that the flow diversion effect of ECMO can effectively manage active bleeding from the IVC by inserting a drainage cannula across the injured lesion. We think this procedure represents a novel treatment option for retrohepatic IVC injuries., Competing Interests: KS received research funding from Abiomed Japan KK, NTT Research, Inc, Asahi Kasei ZOLL Medical Corporation, Neuroceuticals, Inc, and Zeon Medical, Inc. He also received honoraria from Abiomed Japan KK and Mallinckrodt Pharmaceuticals, Inc., (Copyright © Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY. Published by BMJ.)
- Published
- 2024
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70. Effects of bilateral renal denervation on open-loop baroreflex function and urine excretion in spontaneously hypertensive rats.
- Author
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Kawada T, Fukumitsu M, Matsushita H, Yoshida Y, Sato K, Morita H, Nishikawa T, Suehara S, Sawada S, and Saku K
- Subjects
- Animals, Male, Rats, Hypertension physiopathology, Angiotensin II Type 1 Receptor Blockers pharmacology, Blood Pressure physiology, Blood Pressure drug effects, Denervation, Rats, Inbred SHR, Baroreflex physiology, Baroreflex drug effects, Kidney innervation, Telmisartan pharmacology
- Abstract
Bilateral renal denervation (RDN) decreases arterial pressure (AP) or delays the development of hypertension in spontaneously hypertensive rats (SHR), but whether bilateral RDN significantly modifies urine output function during baroreflex-mediated acute AP changes remains unknown. We quantified the relationship between AP and normalized urine flow (nUF) in SHR that underwent bilateral RDN (n = 9) and compared the results with those in sham-operated SHR (n = 9). Moreover, we examined the acute effect of an angiotensin II type 1 receptor blocker telmisartan (2.5 mg/kg) on the AP-nUF relationship. Bilateral RDN significantly decreased AP by narrowing the response range of the total arc of the carotid sinus baroreflex. The slopes of nUF versus the mean AP (in μL·min
-1 ·kg-1 ·mmHg-1 ) in the sham and RDN groups under baseline conditions were 0.076 ± 0.045 and 0.188 ± 0.039, respectively; and those after telmisartan administration were 0.285 ± 0.034 and 0.416 ± 0.078, respectively. The effect of RDN on the nUF slope was marginally significant (P = 0.059), which may have improved the controllability of urine output in the RDN group. The effect of telmisartan on the nUF slope was significant (P < 0.001) in the sham and RDN groups, signifying the contribution of circulating or locally produced angiotensin II to determining urine output function regardless of ongoing renal sympathetic nerve activity., (© 2024. The Author(s), under exclusive licence to The Japanese Society of Hypertension.)- Published
- 2024
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71. Renal denervation and perivascular adipose tissue browning.
- Author
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Kawada T and Saku K
- Subjects
- Humans, Animals, Denervation, Hypertension physiopathology, Hypertension surgery, Adipose Tissue, Brown physiology, Kidney innervation
- Published
- 2024
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72. Acute effects of empagliflozin on open-loop baroreflex function and urine output in streptozotocin-induced type 1 diabetic rats.
- Author
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Kawada T, Yamamoto H, Fukumitsu M, Nishikawa T, Matsushita H, Yoshida Y, Sato K, Morita H, Alexander J Jr, and Saku K
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- Animals, Male, Rats, Blood Pressure drug effects, Diabetes Mellitus, Type 1 physiopathology, Diabetes Mellitus, Type 1 drug therapy, Streptozocin, Rats, Wistar, Urination drug effects, Benzhydryl Compounds pharmacology, Glucosides pharmacology, Baroreflex drug effects, Diabetes Mellitus, Experimental physiopathology, Diabetes Mellitus, Experimental drug therapy, Sodium-Glucose Transporter 2 Inhibitors pharmacology, Sympathetic Nervous System drug effects, Sympathetic Nervous System physiopathology
- Abstract
Although sympathetic suppression is considered one of the mechanisms for cardioprotection afforded by sodium-glucose cotransporter 2 (SGLT2) inhibitors, whether SGLT2 inhibition acutely modifies sympathetic arterial pressure (AP) regulation remains unclear. We examined the acute effect of an SGLT2 inhibitor, empagliflozin (10 mg/kg), on open-loop baroreflex static characteristics in streptozotocin (STZ)-induced type 1 diabetic and control (CNT) rats (n = 9 each). Empagliflozin significantly increased urine flow [CNT: 25.5 (21.7-31.2) vs. 55.9 (51.0-64.5), STZ: 83.4 (53.7-91.7) vs. 121.2 (57.0-136.0) μL·min
-1 ·kg-1 , median (1st-3rd quartiles), P < 0.001 for empagliflozin and STZ]. Empagliflozin decreased the minimum sympathetic nerve activity (SNA) [CNT: 15.7 (6.8-18.4) vs. 10.5 (2.9-19.0), STZ: 36.9 (25.7-54.9) vs. 32.8 (15.1-37.5) %, P = 0.021 for empagliflozin and P = 0.003 for STZ], but did not significantly affect the peripheral arc characteristics assessed by the SNA-AP relationship. Despite the significant increase in urine flow and changes in several baroreflex parameters, empagliflozin preserved the overall sympathetic AP regulation in STZ-induced diabetic rats. The lack of a significant change in the peripheral arc may minimize reflex sympathetic activation, thereby enhancing a cardioprotective benefit of empagliflozin., (© 2024. The Author(s).)- Published
- 2024
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73. Automated control of Impella maintains optimal left ventricular unloading during periods of unstable hemodynamics and prevents myocardial damage in acute myocardial infarction.
- Author
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Nishikawa T, Kamada K, Morita H, Matsushita H, Yokota S, Sato K, Unoki T, Tsutsui H, Sunagawa K, and Saku K
- Subjects
- Dogs, Animals, Male, Disease Models, Animal, Automation, Heart-Assist Devices, Hemodynamics physiology, Myocardial Infarction physiopathology, Myocardial Infarction therapy, Ventricular Function, Left physiology
- Abstract
Background: Left ventricular (LV) unloading by Impella, an intravascular microaxial pump, has been shown to exert dramatic cardioprotective effects in acute clinical settings of cardiovascular diseases. Total Impella support (no native LV ejection) is far more efficient in reducing LV energetic demand than partial Impella support, but the manual control of pump speed to maintain stable LV unloading is difficult and impractical. We aimed to develop an Automatic IMpella Optimal Unloading System (AIMOUS), which controls Impella pump speed to maintain LV unloading degree using closed-feedback control. We validated the AIMOUS performance in an animal model., Methods: In dogs, we identified the transfer function from pump speed to LV systolic pressure (LVSP) under total support conditions (n = 5). Using the transfer function, we designed the feedback controller of AIMOUS to keep LVSP at 40 mmHg and examined its performance by volume perturbations (n = 9). Lastly, AIMOUS was applied in the acute phase of ischemia-reperfusion in dogs. Four weeks after ischemia-reperfusion, we assessed LV function and infarct size (n = 10)., Results: AIMOUS maintained constant LVSP, thereby ensuring a stable LV unloading condition regardless of volume withdrawal or infusion (±8 ml/kg from baseline). AIMOUS in the acute phase of ischemia-reperfusion markedly improved LV function and reduced infarct size (No Impella support: 13.9 ± 1.3 vs. AIMOUS: 5.7 ± 1.9%, P < 0.05)., Conclusions: AIMOUS is capable of maintaining optimal LV unloading during periods of unstable hemodynamics. Automated control of Impella pump speed in the acute phase of ischemia-reperfusion significantly reduced infarct size and prevented subsequent worsening of LV function., (Copyright © 2024 Elsevier B.V. All rights reserved.)
- Published
- 2024
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74. Influence of angiotensin II and telmisartan on in vivo high-resolution renal arterial impedance in rats.
- Author
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Fukuda Y, Kawada T, Kataoka Y, Peterson J, Saku K, Alexander J Jr, and Sunagawa K
- Subjects
- Animals, Male, Benzimidazoles pharmacology, Rats, Benzoates pharmacology, Models, Cardiovascular, Telmisartan pharmacology, Angiotensin II pharmacology, Angiotensin II Type 1 Receptor Blockers pharmacology, Renal Artery drug effects, Renal Circulation drug effects, Rats, Sprague-Dawley, Vascular Resistance drug effects
- Abstract
Angiotensin II (ANG II) is known to play an important role in regulating renal hemodynamics. We sought to quantify this effect in an in vivo rat model with high-resolution renal arterial (RA) impedance. This study examines the effects of ANG II and its type 1 receptor blocker telmisartan (TELM) on RA impedance. In baroreflex-deactivated rats, we measured RA pressure ( P
r ) and blood flow ( Fr ) during random ventricular pacing to induce pressure fluctuation at three different mean Pr (60, 80, and 100 mmHg). We then estimated RA impedance as the transfer function from Fr to Pr . The RA impedance was found to align with a three-element Windkessel model consisting of proximal ( Rp ) and distal ( Rd ) resistance and compliance ( C ). Our study showed Rd reflected the composite characteristics of afferent and efferent arterioles. Rd increased with increasing Pr under the baseline condition with a slope of 1.03 ± 0.21 (× 10-1 ) min·mL-1 . ANG II significantly increased the slope by 0.72 ± 0.29 (× 10-1 ) min·mL-1 ( P < 0.05) without affecting the intercept. TELM significantly reduced the intercept by 34.49 ± 4.86 (× 10-1 ) mmHg·min·mL-1 ( P < 0.001) from the baseline value of 37.93 ± 13.36 (× 10-1 ) mmHg·min·mL-1 , whereas it did not affect the slope. In contrast, Rp was less sensitive than Rd to ANG II or TELM, suggesting Rp may represent the characteristics of elastic large arteries. Our findings provide valuable insights into the influence of ANG II on the dynamics of the renal vasculature. NEW & NOTEWORTHY This present method of quantifying high-resolution renal arterial impedance could contribute to elucidating the characteristics of renal vasculature influenced by physiological mechanisms, renal diseases, or pharmacological effects. The present findings help construct a lumped-parameter renal hemodynamic model that reflects the influence of angiotensin II.- Published
- 2024
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75. Early thrombus formation including hypo-attenuated leaflet thrombosis after surgical bioprosthetic aortic valve replacement.
- Author
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Kono T, Takagi K, Takaseya T, Fukuda T, Saku K, Zaima Y, Shojima T, Arinaga K, and Tayama E
- Subjects
- Humans, Female, Male, Aged, Middle Aged, Retrospective Studies, Anticoagulants therapeutic use, Anticoagulants administration & dosage, Aged, 80 and over, Time Factors, Treatment Outcome, Risk Factors, Echocardiography, Aortic Valve Stenosis surgery, Prosthesis Design, Bioprosthesis adverse effects, Thrombosis etiology, Heart Valve Prosthesis adverse effects, Aortic Valve surgery, Aortic Valve diagnostic imaging, Heart Valve Prosthesis Implantation adverse effects, Heart Valve Prosthesis Implantation instrumentation
- Abstract
Objective: To assess the occurrence, predictors, and outcomes of hypo-attenuated leaflet thickening (HALT) and thrombus outside the prosthetic valve following surgical aortic valve replacement., Methods: A total of 118 patients underwent surgical aortic valve replacement with bioprosthetic valves between July 2020 and June 2022. Sixty-two (52.5%) patients, which is a fairly high number of patients, underwent cardiac computed tomography and transthoracic echocardiography one week after surgery. Patients were divided into two groups, those with HALT (n = 14) and those without HALT (n = 48)., Results: Of the 62 patients who underwent cardiac computed tomography, HALT was observed in 14 (22.5%) patients during the very early postoperative phase. Reduced leaflet motion was observed in two of the 14 patients. The low-attenuation areas were located outside the prosthetic valve in 10 cases (71.4%) in the HALT group and in 14 cases (29.2%) in the non-HALT group. More than 50% of patients (57.1%) with HALT and 79.2% without HALT were administered warfarin. Neither in-hospital deaths nor postoperative thromboembolic events were observed during hospitalization. No patient had a mean pressure gradient > 20 mmHg in either group., Conclusion: HALT was observed in one-fifth of the cases after surgical aortic valve replacement during the very early postoperative phase in an institution wherein administration of continuous heparin infusion after surgery is a standard practice. HALT did not affect the early prognosis or incidence of cerebral infarction., (© 2024. The Author(s), under exclusive licence to The Japanese Association for Thoracic Surgery.)
- Published
- 2024
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76. JCS/JSCVS/JCC/CVIT 2023 guideline focused update on indication and operation of PCPS/ECMO/IMPELLA.
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Nishimura T, Hirata Y, Ise T, Iwano H, Izutani H, Kinugawa K, Kitai T, Ohno T, Ohtani T, Okumura T, Ono M, Satomi K, Shiose A, Toda K, Tsukamoto Y, Yamaguchi O, Fujino T, Hashimoto T, Higashi H, Higashino A, Kondo T, Kurobe H, Miyoshi T, Nakamoto K, Nakamura M, Saito T, Saku K, Shimada S, Sonoda H, Unai S, Ushijima T, Watanabe T, Yahagi K, Fukushima N, Inomata T, Kyo S, Minamino T, Minatoya K, Sakata Y, and Sawa Y
- Subjects
- Humans, Cardiology, Extracorporeal Membrane Oxygenation
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- 2024
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77. Impact of right ventricular and pulmonary vascular characteristics on Impella hemodynamic support in biventricular heart failure: A simulation study.
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Matsushita H, Saku K, Nishikawa T, Unoki T, Yokota S, Sato K, Morita H, Yoshida Y, Fukumitsu M, Uemura K, Kawada T, Kikuchi A, and Yamaura K
- Abstract
Background: Impella (Abiomed, Danvers, MA, USA) is a percutaneous ventricular assist device commonly used in cardiogenic shock, providing robust hemodynamic support, improving the systemic circulation, and relieving pulmonary congestion. Maintaining adequate left ventricular (LV) filling is essential for optimal hemodynamic support by Impella. This study aimed to investigate the impact of pulmonary vascular resistance (PVR) and right ventricular (RV) function on Impella-supported hemodynamics in severe biventricular failure using cardiovascular simulation., Methods: We used Simulink® (Mathworks, Inc., Natick, MA, USA) for the simulation, incorporating pump performance of Impella CP determined using a mock circulatory loop. Both systemic and pulmonary circulation were modeled using a 5-element resistance-capacitance network. The four cardiac chambers were represented by time-varying elastance with unidirectional valves. In the scenario of severe LV dysfunction (LV end-systolic elastance set at a low level of 0.4 mmHg/mL), we compared the changes in right (RAP) and left atrial pressures (LAP), total systemic flow, and pressure-volume loop relationship at varying degrees of RV function, PVR, and Impella flow rate., Results: The simulation results showed that under low PVR conditions, an increase in Impella flow rate slightly reduced RAP and LAP and increased total systemic flow, regardless of RV function. Under moderate RV dysfunction and high PVR conditions, an increase in Impella flow rate elevated RAP and excessively reduced LAP to induce LV suction, which limited the increase in total systemic flow., Conclusions: PVR is the primary determinant of stable and effective Impella hemodynamic support in patients with severe biventricular failure., Competing Interests: Declaration of competing interest Matsushita H, Nishikawa T, Unoki T, Yokota S, Sato K, Morita H, Yoshida Y, Fukumitsu M, Nishiura A, Uemura K, Kawada T, Kikuchi A, and Yamaura K, declare no conflicts of interest. Saku K received research funding from Abiomed Japan K.K., NTT Research, Inc., Asahi Kasei ZOLL Medical Corporation, Neuroceuticals Inc., and Zeon Medical Inc. and honoraria from Abiomed Japan K.K., Mallinckrodt Pharma K.K., and Ono Pharmaceutical Co., Ltd., (Copyright © 2024 Elsevier Ltd. All rights reserved.)
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- 2024
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78. Bailout Procedure Utilizing Balloon Dilatation for a Percutaneous Micro-axial Flow Pump Entrapped Within a Significantly Calcified Subclavian Artery.
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Takagi K, Otsuka H, Saku K, and Tayama E
- Abstract
The IMPELLA 5.5 (Abiomed Inc., Danvers, Massachusetts, United States) is a catheter-based, micro-axial blood pump designed to enhance organ perfusion in patients with cardiogenic shock. Despite its superior hemodynamic support, vascular complications are a significant concern, with many patients needing to discontinue IMPELLA therapy due to these issues. Patients may even require surgical intervention to address device-related vascular injuries. The IMPELLA 5.5 implantation in vessels with severe calcification is particularly associated with complications such as vascular calcification, stenosis, vascular tortuosity, and the use of larger sheaths are risk factors following endovascular therapy and IMPELLA implantation. In this report, we present a case of severe calcification in the right subclavian artery, in which the IMPELLA 5.5 was lodged. The calcifications protruded into the vascular lumen, becoming lodged between the IMPELLA motor and the cannula, complicating extraction despite the vessel having sufficient diameter. We successfully removed the device using a balloon dilation technique, ensuring safe extraction. No vascular complications such as pseudoaneurysm or dissection were observed in the right subclavian artery one month after extraction. This case highlights a potential approach for managing similar complications and vascular access for IMPELLA insertion., Competing Interests: Human subjects: Consent was obtained or waived by all participants in this study. Kurume University issued approval 21001. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Takagi et al.)
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- 2024
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79. Novel closed-loop control system of dual rotary blood pumps in total artificial heart based on the circulatory equilibrium framework: a proof-of-concept in vivo study.
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Yokota S, Uemura K, Unoki T, Matsushita H, Kakuuchi M, Yoshida Y, Sasaki K, Kawada T, Nishikawa T, Kataoka Y, Peterson J, Sunagawa K, Alexander J, and Saku K
- Abstract
Objective: Total artificial heart (TAH) using dual rotary blood pumps (RBPs) is a potential treatment for end-stage heart failure. A well-noted challenge with RBPs is their low sensitivity to preload, which can lead to venous congestion and ventricular suction. To address this issue, we have developed an innovative closed-loop control system of dual RBPs in TAH. This system emulates the Frank-Starling law of the heart in controlling RBPs while monitoring stressed blood volume (V) based on the circulatory equilibrium framework. We validated the system in in-vivo experiments., Methods: In 9 anesthetized dogs, we prepared a TAH circuit using 2 centrifugal-type RBPs. We first investigated whether the flow and inlet atrial pressure in each RBP adhered to a logarithmic Frank-Starling curve. We then examined whether the RBP flows and atrial pressures were maintained stably during aortic occlusion (AO) and pulmonary cannula stenosis (PS), whether averaged flow of dual RBPs and bilateral atrial pressures were controlled to their predefined target values for a specific V, and whether this system could maintain the atrial pressures within predefined control ranges under significant changes in V., Results: This system effectively emulated the logarithmic Frank-Starling curve. It robustly stabilized the flow and atrial pressures during AO and PS without venous congestion or ventricular suction, accurately achieved target values in averaged flow and atrial pressures, and efficaciously maintained these pressures within the control ranges., Conclusion: This system controls dual RBPs in TAH accurately and stably., Significance: This system may accelerate clinical application of TAH with dual RBPs.
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- 2024
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80. Effects of nitric oxide inhalation on pulmonary arterial impedance: differences between normal and pulmonary hypertension male rats.
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Fukumitsu M, Kawada T, Nishikawa T, Yokota S, Matsushita H, Morita H, Sato K, Yoshida Y, Uemura K, and Saku K
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- Animals, Male, Administration, Inhalation, Monocrotaline, Rats, Rats, Sprague-Dawley, Disease Models, Animal, Hypertension, Pulmonary physiopathology, Hypertension, Pulmonary chemically induced, Hypertension, Pulmonary drug therapy, Pulmonary Arterial Hypertension physiopathology, Pulmonary Arterial Hypertension drug therapy, Pulmonary Arterial Hypertension chemically induced, Arterial Pressure drug effects, Nitric Oxide metabolism, Pulmonary Artery physiopathology, Pulmonary Artery drug effects, Vascular Resistance drug effects
- Abstract
Nitric oxide (NO) inhalation improves pulmonary hemodynamics in participants with pulmonary arterial hypertension (PAH). Although it can reduce pulmonary vascular resistance (PVR) in PAH, its impact on the dynamic mechanics of pulmonary arteries and its potential difference between control and participants with PAH remain unclear. PA impedance provides a comprehensive description of PA mechanics. With an arterial model, PA impedance can be parameterized into peripheral pulmonary resistance ( R
p ), arterial compliance ( Cp ), characteristic impedance of the proximal arteries ( Zc ), and transmission time from the main PA to the reflection site. This study investigated the effects of inhaled NO on PA impedance and its associated parameters in control and monocrotaline-induced pulmonary arterial hypertension (MCT-PAH) male rats (6/group). Measurements were obtained at baseline and during NO inhalation at 40 and 80 ppm. In both groups, NO inhalation decreased PVR and increased the left atrial pressure. Notably, its impact on PA impedance was frequency dependent, as revealed by reduced PA impedance modulus in the low-frequency range below 10 Hz, with little effect on the high-frequency range. Furthermore, NO inhalation attenuated Rp , increased Cp , and prolonged transmission time without affecting Zc . It reduced Rp more pronouncedly in MCT-PAH rats, whereas it increased Cp and delayed transmission time more effectively in control rats. In conclusion, the therapeutic effects of inhaled NO on PA impedance were frequency dependent and may differ between the control and MCT-PAH groups, suggesting that the effect on the mechanics differs depending on the pathological state. NEW & NOTEWORTHY Nitric oxide inhalation decreased pulmonary arterial impedance in the low-frequency range (<10 Hz) with little impact on the high-frequency range. It reduced peripheral pulmonary resistance more pronouncedly in pulmonary hypertension rats, whereas it increased arterial compliance and transmission time in control rats. Its effect on the mechanics of the pulmonary arteries may differ depending on the pathological status.- Published
- 2024
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81. Computer-controlled closed-loop norepinephrine infusion system for automated control of mean arterial pressure in dogs under isoflurane-induced hypotension: a feasibility study.
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Sasaki K, Kawada T, Matsushita H, Yokota S, Kakuuchi M, Yokoi A, Yoshida Y, Morita H, Sato K, Nishikawa T, Kutter APN, Kataoka Y, Alexander J Jr, Saku K, Ishikawa T, and Uemura K
- Abstract
Introduction: Intra-operative hypotension is a common complication of surgery under general anesthesia in dogs and humans. Computer-controlled closed-loop infusion systems of norepinephrine (NE) have been developed and clinically applied for automated optimization of arterial pressure (AP) and prevention of intra-operative hypotension in humans. This study aimed to develop a simple computer-controlled closed-loop infusion system of NE for the automated control of the mean arterial pressure (MAP) in dogs with isoflurane-induced hypotension and to validate the control of MAP by the developed system., Methods: NE was administered via the cephalic vein, whereas MAP was measured invasively by placing a catheter in the dorsal pedal artery. The proportional-integral-derivative (PID) controller in the negative feedback loop of the developed system titrated the infusion rate of NE to maintain the MAP at the target value of 60 mmHg. The titration was updated every 2 s. The performance of the developed system was evaluated in six laboratory Beagle dogs under general anesthesia with isoflurane., Results: In the six dogs, when the concentration [median (interquartile range)] of inhaled isoflurane was increased from 1.5 (1.5-1.5)% to 4 (4-4)% without activating the system, the MAP was lowered from 95 (91-99) to 41 (37-42) mmHg. In contrast, when the concentration was increased from 1.5 (1.0-1.5)% to 4 (4-4.8)% for a 30-min period and the system was simultaneously activated, the MAP was temporarily lowered from 92 (89-95) to 47 (43-49) mmHg but recovered to 58 (57-58) mmHg owing to the system-controlled infusion of NE. If the acceptable target range for MAP was defined as target MAP ±5 mmHg (55 ≤ MAP ≤65 mmHg), the percentage of time wherein the MAP was maintained within the acceptable range was 96 (89-100)% in the six dogs during the second half of the 30-min period (from 15 to 30 min after system activation). The median performance error, median absolute performance error, wobble, and divergence were - 2.9 (-4.7 to 1.9)%, 2.9 (2.0-4.7)%, 1.3 (0.8-1.8)%, and - 0.24 (-0.34 to -0.11)%·min
-1 , respectively. No adverse events were observed during the study period, and all dogs were extubated uneventfully., Conclusion: This system was able to titrate the NE infusion rates in an accurate and stable manner to maintain the MAP within the predetermined target range in dogs with isoflurane-induced hypotension. This system can be a potential tool in daily clinical practice for the care of companion dogs., Competing Interests: JA and YK are employees of NTT Res. Inc. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The author(s) declared that they were an editorial board member of Frontiers, at the time of submission. This had no impact on the peer review process and the final decision., (Copyright © 2024 Sasaki, Kawada, Matsushita, Yokota, Kakuuchi, Yokoi, Yoshida, Morita, Sato, Nishikawa, Kutter, Kataoka, Alexander, Saku, Ishikawa and Uemura.)- Published
- 2024
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82. Efficacy and safety of post-closure technique using Perclose ProGlide/ProStyle device for large-bore mechanical circulatory support access sites.
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Unoki T, Konami Y, Nakayama T, Suzuyama H, Horio E, Taguchi E, Saku K, Sawamura T, Nakao K, and Sakamoto T
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- Humans, Retrospective Studies, Male, Female, Treatment Outcome, Middle Aged, Aged, Time Factors, Device Removal adverse effects, Suture Techniques instrumentation, Suture Techniques adverse effects, Femoral Artery, Shock, Cardiogenic therapy, Shock, Cardiogenic mortality, Shock, Cardiogenic physiopathology, Shock, Cardiogenic diagnosis, Risk Factors, Hemorrhage etiology, Hemorrhage prevention & control, Heart-Assist Devices, Extracorporeal Membrane Oxygenation adverse effects, Extracorporeal Membrane Oxygenation instrumentation, Hemostatic Techniques instrumentation, Hemostatic Techniques adverse effects, Punctures, Catheterization, Peripheral adverse effects, Catheterization, Peripheral instrumentation, Vascular Closure Devices
- Abstract
Purpose: Mechanical circulatory support (MCS) using a venoarterial extracorporeal membrane oxygenation (VA-ECMO) device or a catheter-type heart pump (Impella) is critical for the rescue of patients with severe cardiogenic shock. However, these MCS devices require large-bore cannula access (14-Fr and larger) at the femoral artery or vein, which often requires surgical decannulation., Methods: In this retrospective study, we evaluated post-closure method using a percutaneous suture-mediated vascular closure system, Perclose ProGlide/ProStyle (Abbott Vascular, Lake Bluff, IL, Perclose), as an alternative procedure for MCS decannulation. Closure of 83 Impella access sites and 68 VA-ECMO access sites performed using Perclose or surgical method between January 2018 and March 2023 were evaluated., Results: MCS decannulation using Perclose was successfully completed in all access sites without surgical hemostasis. The procedure time of ProGlide was shorter than surgical decannulation for both Impella and VA-ECMO (13 min vs. 50 min; p < 0.001, 21 min vs. 65 min; p < 0.001, respectively). There were no significant differences in the 30-day survival rate and major adverse events by decannulation including arterial dissection requiring endovascular treatment, hemorrhage requiring a large amount of red blood cell transfusion, and access site infection., Conclusion: Our results suggest that the post-closure technique using the percutaneous suture-mediated closure system appears to be a safe and effective method for large-bore MCS decannulation., Competing Interests: Declaration of competing interest Keita Saku received research funding from Omron Healthcare Co., Abiomed Japan K.K., NTT Research, Inc., Asahi Kasei ZOLL Medical Corporation, Neuroceuticals Inc., and Zeon Medical Inc., and honoraria from Abiomed Japan K.K., Ono Pharmaceutical Co., Ltd., and Mallinckrodt Japan Co. Ltd. The other authors declare no conflict of interest., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2024
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83. Donepezil attenuates progression of cardiovascular remodeling and improves prognosis in spontaneously hypertensive rats with chronic myocardial infarction.
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Li M, Zheng C, Kawada T, Uemura K, Yokota S, Matsushita H, and Saku K
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- Animals, Rats, Male, Hypertension drug therapy, Hypertension complications, Prognosis, Disease Progression, Blood Pressure drug effects, Cholinesterase Inhibitors therapeutic use, Cholinesterase Inhibitors pharmacology, Heart Failure drug therapy, Heart Failure physiopathology, Heart Rate drug effects, Donepezil therapeutic use, Donepezil pharmacology, Rats, Inbred SHR, Myocardial Infarction drug therapy, Myocardial Infarction complications, Piperidines pharmacology, Piperidines therapeutic use, Indans pharmacology, Indans therapeutic use, Ventricular Remodeling drug effects
- Abstract
The acetylcholinesterase inhibitor donepezil restores autonomic balance, reduces inflammation, and improves long-term survival in rats with chronic heart failure (CHF) following myocardial infarction (MI). As arterial hypertension is associated with a significant risk of cardiovascular death, we investigated the effectiveness of donepezil in treating CHF in spontaneously hypertensive rats (SHR). CHF was induced in SHR by inducing permanent MI. After 2 weeks, the surviving SHR were randomly assigned to sham-operated (SO), untreated (UT), or oral donepezil-treated (DT, 5 mg/kg/day) groups, and various vitals and parameters were monitored. After 7 weeks of treatment, heart rate and arterial hypertension reduced significantly in DT rats than in UT rats. Donepezil treatment improved 50-day survival (41% to 80%, P = 0.004); suppressed progression of cardiac hypertrophy, cardiac dysfunction (cardiac index: 133 ± 5 vs. 112 ± 5 ml/min/kg, P < 0.05; left ventricular end-diastolic pressure: 12 ± 3 vs. 22 ± 2 mmHg, P < 0.05; left ventricular +dp/dt
max : 5348 ± 338 vs. 4267 ± 114 mmHg/s, P < 0.05), systemic inflammation, and coronary artery remodeling (wall thickness: 26.3 ± 1.4 vs. 34.7 ± 0.7 μm, P < 0.01; media-to-lumen ratio: 3.70 ± 0.73 vs. 8.59 ± 0.84, P < 0.001); increased capillary density; and decreased plasma catecholamine, B-type natriuretic peptide, arginine vasopressin, and angiotensin II levels. Donepezil treatment attenuated cardiac and coronary artery remodeling, mitigated cardiac dysfunction, and significantly improved the prognosis of SHR with CHF., (© 2024. The Author(s), under exclusive licence to The Japanese Society of Hypertension.)- Published
- 2024
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84. Postoperative anticoagulation management using subcutaneous unfractionated heparin for a patient with nonbacterial thrombotic endocarditis: a case report.
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Mine H, Saku K, Takagi K, Nohara S, Hiromatsu S, Fukumoto Y, and Tayama E
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Nonbacterial thrombotic endocarditis (NBTE) presents nonbacterial vegetation on cardiac valves. NBTE requires appropriate anticoagulant therapy to prevent recurrence after surgery. However, there has not yet been established evidence for anticoagulant therapy in NBTE, and low molecular weight heparin is not approved in Japan. We present a case of NBTE that was successfully managed with anticoagulant therapy using subcutaneous unfractionated heparin. A 59-year-old woman was diagnosed with NBTE on the mitral and tricuspid valve associated with breast cancer, underwent valve replacement. Warfarin and continuous intravenous unfractionated heparin were started. However, disseminated intravascular coagulation occurred after heparin was discontinued. Continuous intravenous unfractionated heparin injection was resumed immediately, and subcutaneous unfractionated heparin was administered before discharge. Postoperative echocardiography revealed no vegetation on the prosthetic valves thereafter. Subcutaneous unfractionated heparin therapy is useful to prevent the recurrence of NBTE as the anticoagulation in outpatients., Competing Interests: None declared., (Published by Oxford University Press and JSCR Publishing Ltd. © The Author(s) 2024.)
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- 2024
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85. Reconsidering coronary circulation in the era of LV unloading - the underlying physiology in the non-physiological setting.
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Fukumitsu M and Saku K
- Subjects
- Humans, Ventricular Function, Left physiology, Hemodynamics physiology, Coronary Circulation physiology, Myocardial Infarction
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- 2024
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86. Short-term dynamic characteristics of diuresis during exogenous pressure perturbations with and without arterial baroreflex control.
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Kawada T, Matsushita H, Yokota S, Yoshida Y, Fukumitsu M, Alexander J Jr, and Saku K
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- Animals, Rats, Blood Pressure physiology, Carotid Arteries, Diuresis, Arterial Pressure, Baroreflex physiology
- Abstract
Although body fluid volume control by the kidneys may be classified as a long-term arterial pressure (AP) control system, it does not necessarily follow that the urine flow (UF) response to changes in AP is slow. We quantified the dynamic characteristics of the UF response to short-term AP changes by changing mean AP between 60 mmHg and 100 mmHg every 10 s according to a binary white noise sequence in anesthetized rats ( n = 8 animals). In a baro-on trial (the carotid sinus baroreflex was enabled), the UF response represented the combined synergistic effects of pressure diuresis (PD) and neurally mediated antidiuresis (NMA). In a baro-fix trial (the carotid sinus pressure was fixed at 100 mmHg), the UF response mainly reflected the effect of PD. The UF step response was quantified using the sum of two exponential decay functions. The fast and slow components had time constants of 6.5 ± 3.6 s and 102 ± 85 s (means ± SD), respectively, in the baro-on trial. Although the gain of the fast component did not differ between the two trials (0.49 ± 0.21 vs. 0.66 ± 0.22 µL·min
-1 ·kg-1 ·mmHg-1 ), the gain of the slow component was greater in the baro-on than in the baro-fix trial (0.51 ± 0.14 vs. 0.09 ± 0.39 µL·min-1 ·kg-1 ·mmHg-1 , P = 0.023). The magnitude of NMA relative to PD was calculated to be 32.2 ± 29.8%. In conclusion, NMA contributed to the slow component, and its magnitude was approximately one-third of that of the effect of PD. NEW & NOTEWORTHY We quantified short-term dynamic characteristics of the urine flow (UF) response to arterial pressure (AP) changes using white noise analysis. The UF step response approximated the sum of two exponential decay functions with time constants of ∼6.5 s and 102 s. The neurally mediated antidiuretic (NMA) effect contributed to the slow component of the UF step response, with the magnitude of approximately one-third of that of the pressure diuresis (PD) effect.- Published
- 2024
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87. The impact of ECPELLA on haemodynamics and global oxygen delivery: a comprehensive simulation of biventricular failure.
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Matsushita H, Saku K, Nishikawa T, Yokota S, Sato K, Morita H, Yoshida Y, Fukumitsu M, Uemura K, Kawada T, and Yamaura K
- Abstract
Background: ECPELLA, a combination of veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) and Impella, a percutaneous left ventricular (LV) assist device, has emerged as a novel therapeutic option in patients with severe cardiogenic shock (CS). Since multiple cardiovascular and pump factors influence the haemodynamic effects of ECPELLA, optimising ECPELLA management remains challenging. In this study, we conducted a comprehensive simulation study of ECPELLA haemodynamics. We also simulated global oxygen delivery (DO
2 ) under ECPELLA in severe CS and acute respiratory failure as a first step to incorporate global DO2 into our developed cardiovascular simulation., Methods and Results: Both the systemic and pulmonary circulations were modelled using a 5-element resistance‒capacitance network. The four ventricles were represented by time-varying elastances with unidirectional valves. In the scenarios of severe LV dysfunction, biventricular dysfunction with normal pulmonary vascular resistance (PVR, 0.8 Wood units), and biventricular dysfunction with high PVR (6.0 Wood units), we compared the changes in haemodynamics, pressure-volume relationship (PV loop), and global DO2 under different VA-ECMO flows and Impella support levels., Results: In the simulation, ECPELLA improved total systemic flow with a minimising biventricular pressure-volume loop, indicating biventricular unloading in normal PVR conditions. Meanwhile, increased Impella support level in high PVR conditions rendered the LV-PV loop smaller and induced LV suction in ECPELLA support conditions. The general trend of global DO2 was followed by the changes in total systemic flow. The addition of veno-venous ECMO (VV-ECMO) augmented the global DO2 increment under ECPELLA total support conditions., Conclusions: The optimal ECPELLA support increased total systemic flow and achieved both biventricular unloading. The VV-ECMO effectively improves global DO2 in total ECPELLA support conditions., (© 2024. The Author(s).)- Published
- 2024
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88. Input-size dependence of the baroreflex neural arc transfer characteristics during Gaussian white noise inputs.
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Kawada T, Miyamoto T, Fukumitsu M, and Saku K
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- Rats, Animals, Blood Pressure physiology, Sympathetic Nervous System physiology, Carotid Sinus innervation, Baroreflex physiology, Pressoreceptors physiology
- Abstract
Although Gaussian white noise (GWN) inputs offer a theoretical framework for identifying higher-order nonlinearity, an actual application to the data of the neural arc of the carotid sinus baroreflex did not succeed in fully predicting the well-known sigmoidal nonlinearity. In the present study, we assumed that the neural arc can be approximated by a cascade of a linear dynamic (LD) component and a nonlinear static (NS) component. We analyzed the data obtained using GWN inputs with a mean of 120 mmHg and standard deviations (SDs) of 10, 20, and 30 mmHg for 15 min each in anesthetized rats ( n = 7). We first estimated the linear transfer function from carotid sinus pressure to sympathetic nerve activity (SNA) and then plotted the measured SNA against the linearly predicted SNA. The predicted and measured data pairs exhibited an inverse sigmoidal distribution when grouped into 10 bins based on the size of the linearly predicted SNA. The sigmoidal nonlinearity estimated via the LD-NS model showed a midpoint pressure (104.1 ± 4.4 mmHg for SD of 30 mmHg) lower than that estimated by a conventional stepwise input (135.8 ± 3.9 mmHg, P < 0.001). This suggests that the NS component is more likely to reflect the nonlinearity observed during pulsatile inputs that are physiological to baroreceptors. Furthermore, the LD-NS model yielded higher R
2 values compared with the linear model and the previously suggested second-order Uryson model in the testing dataset. NEW & NOTEWORTHY We examined the input-size dependence of the baroreflex neural arc transfer characteristics during Gaussian white noise inputs. A linear dynamic-static nonlinear model yielded higher R2 values compared with a linear model and captured the well-known sigmoidal nonlinearity of the neural arc, indicating that the nonlinear dynamics contributed to determining sympathetic nerve activity. Ignoring such nonlinear dynamics might reduce our ability to explain underlying physiology and significantly limit the interpretation of experimental data.- Published
- 2024
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89. Mitral valve repair using a semi-rigid posterior band: a 10-year Japanese single-center experience of 244 patients.
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Takagi K, Arinaga K, Takaseya T, Otsuka H, Shojima T, Kono T, Zaima Y, Saku K, Oryoji A, and Tayama E
- Abstract
Background: Mitral valve repair (MVr) is an established procedure for patients who require surgery for primary mitral regurgitation (PMR). The Colvin-Galloway Future Band (CGFB) is a semi-rigid posterior band expected to improve the clinical outcomes of MVr. However, information on the hemodynamic and functional performance and long-term outcomes of CGFB is limited. We evaluated the quality, durability, and clinical performance after MVr using CGFB for PMR as the cohort study., Methods: A total of 244 patients who underwent MVr with CGFB were enrolled. Clinical and echocardiographic assessments were performed (mean follow-up period, 4.0±2.4 years)., Results: Posterior mitral leaflet resection was the most common MVr procedure. CGFBs measuring 28 mm (35.2%) and 30 mm (36.5%) were used. The incidence of systolic anterior motion (SAM) was 1.6%. A total of 93.4% of the patients had no or trace MR at discharge. Over 90% of patients had no or mild MR at the last follow-up. The mean pressure gradient and mitral valve orifice area one year after MVr ranged between 2.6 and 3.6 mmHg and 2.3 and 3.4 cm
2 , respectively. At follow-up, 85.4% of the patients were New York Heart Association class I. Three patients underwent repeat mitral valve surgery., Conclusions: The CGFB demonstrates satisfactory quality and durability in MVr for PMR. Other advantages include a low occurrence of SAM and acceptable hemodynamic outcomes, particularly in patients requiring a smaller annuloplasty device., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://jtd.amegroups.com/article/view/10.21037/jtd-23-1486/coif). The authors have no conflicts of interest to declare., (2024 Journal of Thoracic Disease. All rights reserved.)- Published
- 2024
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90. Preoperative management using Impella support for acute aortic dissection with left coronary malperfusion: a case report.
- Author
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Shojima T, Takagi K, Saku K, Fukuda T, and Tayama E
- Abstract
Background: Acute aortic dissection (AAD) with impaired perfusion of the left coronary artery has a poor prognosis, even after urgent radical aortic surgery, due to extensive myocardial damage. Although Impella, a microaxial-flow catheter pump, is useful in managing acute myocardial infarction, it is generally contraindicated in patients with AAD because it is an intra-aortic device and the aortic structure is compromised in these cases. Here, we introduce a novel intervention that allowed a planned aortic repair after managing circulation using Impella and venoarterial extracorporeal membrane oxygenation in a case of AAD with left main trunk malperfusion., Case Presentation: A 40-year-old man presented with cardiogenic shock. Percutaneous coronary intervention was performed to address left main trunk obstruction using an intra-aortic balloon pump; however, circulatory instability persisted. The patient was transferred to our hospital after venoarterial extracorporeal membrane oxygenation. Impella CP™ was used to improve his circulatory status. However, a subsequent CT scan confirmed an AAD diagnosis. After 5 days of stable circulatory support, the patient underwent aortic root replacement and coronary artery bypass grafting., Conclusions: In patients with AAD and coronary malperfusion, adjunctive circulatory management with Impella may be a valuable therapeutic option., (© 2024. The Author(s).)
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- 2024
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91. CORRIGENDUM: JCS/JSCVS/JCC/CVIT 2023 Guideline Focused Update on Indication and Operation of PCPS/ECMO/IMPELLA.
- Author
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Nishimura T, Hirata Y, Ise T, Iwano H, Izutani H, Kinugawa K, Kitai T, Ohno T, Ohtani T, Okumura T, Ono M, Satomi K, Shiose A, Toda K, Tsukamoto Y, Yamaguchi O, Fujino T, Hashimoto T, Higashi H, Higashino A, Kondo T, Kurobe H, Miyoshi T, Nakamoto K, Nakamura M, Saito T, Saku K, Shimada S, Sonoda H, Unai S, Ushijima T, Watanabe T, Yahagi K, Fukushima N, Inomata T, Kyo S, Minamino T, Minatoya K, and Sakata Y
- Subjects
- Humans, Heart-Assist Devices, Practice Guidelines as Topic standards, Heart Failure therapy, Heart Failure surgery, Extracorporeal Membrane Oxygenation
- Published
- 2024
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92. A Case of Andexanet Alfa Induced Heparin Resistance in Emergent Aortic Surgery: Successful Anticoagulation Management Using Antithrombin Administration.
- Author
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Takagi K, Fukuda T, Saku K, and Tayama E
- Abstract
Andexanet alfa (AnAl) is utilized for the urgent reversal of direct oral anticoagulants (DOACs) in cases of severe bleeding. While the guidelines from the Society of Thoracic Surgeons recommend AnAl for urgent cardiac surgery in patients treated with DOACs, concerns persist regarding the potential of AnAl to induce heparin resistance. This report details the case of an 85-year-old woman diagnosed with acute type A aortic dissection, who received AnAl due to prior edoxaban use. During the emergent aortic surgery, she exhibited heparin resistance following the administration of unfractionated heparin (UFH). The administration of antithrombin III (ATIII) significantly influenced activated clotting times, facilitating successful surgery while maintaining adequate anticoagulation. This case underscores the importance of cautious management of AnAl-induced heparin resistance during critical surgeries, emphasizing the role of ATIII supplementation for effective anticoagulation., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Takagi et al.)
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- 2023
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93. Mechanical circulatory support in cardiogenic shock.
- Author
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Nakata J, Yamamoto T, Saku K, Ikeda Y, Unoki T, and Asai K
- Abstract
Cardiogenic shock is a complex and diverse pathological condition characterized by reduced myocardial contractility. The goal of treatment of cardiogenic shock is to improve abnormal hemodynamics and maintain adequate tissue perfusion in organs. If hypotension and insufficient tissue perfusion persist despite initial therapy, temporary mechanical circulatory support (t-MCS) should be initiated. This decade sees the beginning of a new era of cardiogenic shock management using t-MCS through the accumulated experience with use of intra-aortic balloon pump (IABP) and venoarterial extracorporeal membrane oxygenation (VA-ECMO), as well as new revolutionary devices or systems such as transvalvular axial flow pump (Impella) and a combination of VA-ECMO and Impella (ECPELLA) based on the knowledge of circulatory physiology. In this transitional period, we outline the approach to the management of cardiogenic shock by t-MCS. The management strategy involves carefully selecting one or a combination of the t-MCS devices, taking into account the characteristics of each device and the specific pathological condition. This selection is guided by monitoring of hemodynamics, classification of shock stage, risk stratification, and coordinated management by the multidisciplinary shock team., (© 2023. The Author(s).)
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- 2023
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94. Long thrombus with a removed microaxial blood pump catheter 10 days after ECPELLA support.
- Author
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Takagi K, Saku K, and Tayama E
- Abstract
Competing Interests: Conflict of interest: None declared.
- Published
- 2023
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95. Long-Term Follow-up Study of Hospitalizations for Acute Coronary Syndrome in Kobe-City and Other Districts Under the Hyogo Smoking Ban Legislation - A Nationwide Database Study.
- Author
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Nakai M, Iwanaga Y, Sumita Y, Amano T, Fukuda I, Hirano T, Iida M, Katanoda K, Miyamoto Y, Nakamura M, Saku K, Tabuchi T, Yamato H, Zhang B, and Fujiwara H
- Subjects
- Humans, Follow-Up Studies, Cities, Hospitalization, Acute Coronary Syndrome epidemiology, Acute Coronary Syndrome etiology, Smoke-Free Policy
- Abstract
Background: Hyogo Prefecture has managed smoking ban legislation with partial restrictions in public places (Hyogo-L) since 2013. Previous studies have reported a significant decrease in admissions for acute coronary syndrome (ACS) in Kobe-city, but not in other districts of Hyogo Prefecture in the 2 years after Hyogo-L. The aim of the present study was to define the long-term effect of Hyogo-L., Methods and results: The JROAD-DPC dataset was used to collect information on the number of hospitalizations for ACS in Hyogo Prefecture, and in Osaka-city without smoking ban legislation, from April 2013 to March 2020. Poisson regression analysis was performed to calculate incident rate ratios (IRRs) and 95% confidence intervals (CIs). ACS records of 3,101 in Kobe-city, 11,375 in areas of Hyogo Prefecture other than Kobe-city and 11,079 in Osaka-city were collected for admissions. The incidence of ACS reduced significantly over time in Kobe-city [IRR (95% CI); 0.96 (0.94-0.97)], but did not reduce in the others. The decrease in Kobe-city was observed in ACS patients without smoking, hypertension, and hyperlipidemia, but not in those with such risk factors., Conclusions: The long-term ACS reduction or non-reduction under Hyogo-L was determined at the initial period and the same scenario continued, supporting the importance of legislation and compliance with the smoking ban. The lowering effect was remarkable in ACS patients without risk factors such as non-smoking.
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- 2023
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96. Acute effects of empagliflozin on open-loop baroreflex function and urinary glucose excretion in rats with chronic myocardial infarction.
- Author
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Kawada T, Li M, Nishiura A, Yoshida Y, Yokota S, Matsushita H, Fukumitsu M, Uemura K, Alexander J Jr, and Saku K
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- Animals, Rats, Baroreflex, Glucosides pharmacology, Glucose, Myocardial Infarction drug therapy
- Abstract
Sodium-glucose cotransporter 2 (SGLT2) inhibitors have exerted cardioprotective effects in clinical trials, but underlying mechanisms are not fully understood. As mitigating sympathetic overactivity is of major clinical concern in the mechanisms of heart failure treatments, we examined the effects of modulation of glucose handling on baroreflex-mediated sympathetic nerve activity and arterial pressure regulations in rats with chronic myocardial infarction (n = 9). Repeated 11-min step input sequences were used for an open-loop analysis of the carotid sinus baroreflex. An SGLT2 inhibitor, empagliflozin, was intravenously administered (10 mg/kg) after the second sequence. Neither the baroreflex neural nor peripheral arc significantly changed during the last observation period (seventh and eighth sequences) compared with the baseline period although urinary glucose excretion increased from near 0 (0.0089 ± 0.0011 mg min
-1 kg-1 ) to 1.91 ± 0.25 mg min-1 kg-1 . Hence, empagliflozin does not acutely modulate the baroreflex regulations of sympathetic nerve activity and arterial pressure in this rat model of chronic myocardial infarction., (© 2023. The Physiological Society of Japan.)- Published
- 2023
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97. Large Thrombus Entrapped in a Patent Foramen Ovale during Inferior Vena Cava Filter Protection for Venous Thromboembolism.
- Author
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Nakamura E, Takagi K, Saku K, Negoto S, Anegawa T, Imai S, Otsuka H, Hiromatsu S, and Tayama E
- Abstract
Background . A large thrombus entrapped in the patent foramen ovale (PFO) is an extremely rare condition. Moreover, it is considered even rarer after temporary inferior vena cava filter (TIVCF) placement for the prevention of fatal pulmonary embolism due to venous thromboembolism (VTE). Case Report . A 58-year-old man presented with syncope following chest pain and dyspnea due to PE exacerbation during TIVCF protection, which then led to cardiogenic shock. Echocardiography revealed a large thrombus entrapped in the PFO, and computed tomography (CT) showed a bilateral pulmonary artery embolism. The patient was treated with open surgical embolectomy for a pulmonary artery thrombus and PFO thrombus with simultaneous closure of the PFO. The patient's postoperative course was uneventful. Results and Conclusion . Surgical embolectomy was useful with respect to the feasibility of resection of both intracardiac thrombus and pulmonary artery thrombus performed simultaneously, contributing to the prevention of systemic embolisms, and echocardiography plays an important role for early diagnosis., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have influenced the work reported in this paper., (Copyright © 2023 Eiji Nakamura et al.)
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- 2023
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98. Impact of vericiguat on baroreflex-mediated sympathetic circulatory regulation: An open-loop analysis.
- Author
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Yokoi A, Kawada T, Yokota S, Kakuuchi M, Matsushita H, Nishiura A, Li M, Uemura K, Alexander J Jr, Tanaka R, and Saku K
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- Rats, Animals, Rats, Inbred WKY, Nitroprusside pharmacology, Sympathetic Nervous System physiology, Blood Pressure physiology, Baroreflex physiology, Arterial Pressure physiology
- Abstract
Aims: To quantify in vivo the effects of the soluble guanylate cyclase (sGC) stimulator, vericiguat, on autonomic cardiovascular regulation in comparison with the nitric oxide (NO) donor, sodium nitroprusside., Methods: In anesthetized Wistar-Kyoto rats, baroreflex-mediated changes in sympathetic nerve activity (SNA), arterial pressure (AP), central venous pressure (CVP), and aortic flow (AoF) were examined before and during the intravenous continuous administration (10 μg·kg-1·min-1) of vericiguat or sodium nitroprusside (n = 8 each). Systemic vascular resistance (SVR) was calculated as SVR = (AP-CVP) / AoF., Results: Neither vericiguat nor sodium nitroprusside affected fitted parameters of the baroreflex-mediated SNA response. Both vericiguat and sodium nitroprusside decreased the AP mainly through their peripheral effects. Vericiguat halved the slope of the SNA-SVR relationship from 0.012 ± 0.002 to 0.006 ± 0.002 mmHg·min·mL-1·%-1 (P = 0.008), whereas sodium nitroprusside caused a near parallel downward shift in the SNA-SVR relationship with a reduction of the SVR intercept from 1.235 ± 0.187 to 0.851 ± 0.123 mmHg·min/mL (P = 0.008)., Conclusion: Neither vericiguat nor sodium nitroprusside significantly affected the baroreflex-mediated SNA response. The vasodilative effect of vericiguat became greater toward high levels of SNA and AP, possibly reflecting the increased sGC sensitivity to endogenous NO. By contrast, the effect of sodium nitroprusside was more uniform over the range of SNA. These results help better understand cardiovascular effects of vericiguat., Competing Interests: The authors declare no conflict of interest regarding this study., (Copyright: © 2023 Yokoi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
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- 2023
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99. Inflammatory response of Teflon felt strip 41 years after surgical repair for Ebstein's anomaly.
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Kono T, Tahara N, Bekki M, Saku K, Sugiyama Y, Honda A, Takaseya T, Shojima T, Takagi K, Abe T, Fukumoto Y, and Tayama E
- Subjects
- Humans, Polytetrafluoroethylene, Retrospective Studies, Ebstein Anomaly diagnostic imaging, Ebstein Anomaly surgery
- Published
- 2023
- Full Text
- View/download PDF
100. How to incorporate tricuspid regurgitation in right ventricular-pulmonary arterial coupling.
- Author
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Yoshida K, Axelsen JB, Saku K, Andersen A, de Man FS, Sunagawa K, Vonk Noordegraaf A, and Bogaard HJ
- Subjects
- Animals, Rats, Pulmonary Arterial Hypertension physiopathology, Male, Rats, Sprague-Dawley, Vena Cava, Inferior surgery, Balloon Occlusion, Tricuspid Valve Insufficiency physiopathology, Heart Ventricles physiopathology, Pulmonary Artery physiopathology, Stroke Volume
- Abstract
Adaptation of the right ventricle (RV) to a progressively increasing afterload is one of the hallmarks of pulmonary arterial hypertension (PAH). Pressure-volume loop analysis provides measures of load-independent RV contractility, i.e., end-systolic elastance, and pulmonary vascular properties, i.e., effective arterial elastance (E
a ). However, PAH-induced RV overload potentially results in tricuspid regurgitation (TR). TR makes RV eject to both PA and right atrium; thereby, a ratio of RV end-systolic pressure (Pes ) to RV stroke volume (SV) could not correctly define Ea . To overcome this limitation, we introduced a two-parallel compliance model, i.e., Ea = 1/(1/Epa + 1/ETR ), while effective pulmonary arterial elastance (Epa = Pes /PASV) represents pulmonary vascular properties and effective tricuspid regurgitant elastance (ETR ) represents TR. We conducted animal experiments to validate this framework. First, we performed SV analysis with a pressure-volume catheter in the RV and a flow probe at the aorta in rats with and without pressure-overloaded RV to determine the effect of inferior vena cava (IVC) occlusion on TR. A discordance between the two techniques was found in rats with pressure-overloaded RV, not in sham. This discordance diminished after IVC occlusion, suggesting that TR in pressure-overloaded RV was diminished by IVC occlusion. Next, we performed pressure-volume loop analysis in rats with pressure-overloaded RVs, calibrating RV volume by cardiac magnetic resonance. We found that IVC occlusion increased Ea , suggesting that a reduction of TR increased Ea . Using the proposed framework, Epa was indistinguishable to Ea post-IVC occlusion. We conclude that the proposed framework helps better understanding of the pathophysiology of PAH and associated right heart failure. NEW & NOTEWORTHY This study reveals the impact of tricuspid regurgitation on pressure-volume loop analysis in right ventricle pressure overload. By introducing a novel concept of parallel compliances in the pressure-volume loop analysis, a better description is provided for the right ventricular forward afterload in the presence of tricuspid regurgitation.- Published
- 2023
- Full Text
- View/download PDF
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