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High-speed grounding switches (HSGS) for 1000kV (UHV) transmission lines are required to interrupt a delayed zero current with a long arcing time. This requirement was met by allowing pressure rise in the opening operation to last efficiently for a long time through optimizing the exhaust volume and the residual volume of a puffer-type interrupting chamber and utilizing the effect of pressure rises due to arcing.

Discusses the development of an interrupting chamber for 1000kV (UHV) transmission lines using high-speed grounding switches (HSGS). Information on electric power in Japan; Information on HSGS and how they work; Details on the required interruption performance.

Treating a thoracic aortic aneurysm (TAA) after coronary artery bypass (CABG) surgery requires an appropriate surgical procedure to preserve the bypass grafts. We present a case of open stent grafting. The patient was a 71-year-old man with a history of CABG. Chest computed tomography (CT) revealed a saccular-shaped aortic aneurysm in the aortic arch with diameter of 56 mm. Coronary angiography revealed the LIMA and SVG grafts were patent. The chest was opened via re-midsternotomy. After a circulatory arrest was induced at 30 ℃ with cerebral perfusion, the anterior surface of the arch was incised in a hemi-circumferencial mannar between the left common carotid and left subclavian arteries. The stent graft was inserted into the aortic arch and was deployed. The proximal side of the graft was then trimmed, and the posterior aortic wall and the graft were continuously anastomosed, the aortic incision was continuously closed involving anterior side of the graft. Finally, the left axillary artery was reconstructed. The patient's postoperative course was uneventful and he was discharged on postoperative day 10. A open stent grafting via an aortotomy was useful in the surgery for TAA after CABG.

An 83-year-old woman was admitted because of dyspnea. Transthoracic echocardiography revealed severe aortic valve stenosis with a systolic gradient of 105 mmHg. Coronary angiography showed 75% stenosis at segment 1. Computed tomography( CT) of the chest revealed a mass, of 15 mm in diameter, in the right segment 1 of the lung. She was diagnosed with severe aortic valve stenosis, right coronary artery stenosis, and a lung tumor suspected to be lung cancer. We performed right lobe partial resection, aortic valve replacement and coronary artery bypass grafting through a median sternotomy. The tumor was diagnosed as adenocarcinoma by pathological examination. The postoperative course was uneventful, and she was discharged three weeks after the operation.

Background: Patients with chronic heart failure (CHF) are often treated using many diuretics for symptom relief; however, diuretic use may have to continue despite hypotension development in these patients. Here, we present a case of heart failure with preserved ejection fraction (HFpEF), which is defined as ejection fraction ≥50% in CHF, and refractory hypotension, which was treated with midodrine and droxidopa to normalize blood pressure., Case Presentation: The patient was a 62-year-old man with a history of HFpEF due to mitral regurgitation and complaints of dyspnea on exertion. He had been prescribed multiple medications at an outpatient clinic for CHF management, including azosemide 60 mg/day, bisoprolol 2.5 mg/day, enalapril 2.5 mg/day, spironolactone 50 mg/day, and tolvaptan 15 mg/day. The systolic blood pressure (SBP) of the patient remained at 70-80 mmHg because the use of the diuretic could not be reduced or discontinued owing to edema and weight gain. He was hospitalized for the exacerbation of CHF. Although midodrine 8 mg/day was administered to improve hypotension, the SBP of the patient increased only up to 90 mmHg. On the 35th day after hospitalization, the urine volume decreased significantly (< 100 mL/day) due to hypotension. When droxidopa 200 mg/day replaced intravenous noradrenaline on the 47th day, the SBP remained at 100-120 mmHg and the urine volume increased., Conclusions: Oral combination treatment with midodrine and droxidopa might contribute to the maintenance of blood pressure and diuretic activity in HFpEF patients with refractory hypotension. However, further long-term studies evaluating the safety and efficacy of this combination therapy for patients with HFpEF are needed.

A 65-year-old woman was admitted to our hospital with fever and left hemiplegia. She was diagnosed with infective endocarditis with multiple brain abscess. At first, heart failure was not present, and she was given medical treatment with antibiotics. But on day 12 after admission, she progressively developed heart failure. Transthoracic echocardiogram demonstrated pseudoaneurysm of the sinus of Valsalva, ruptured into the left atrium. At operation, another fistula to the right ventricular outflow tract was revealed. They were repaired with autologous pericardial patches, and the aortic valve was replaced with a bioprosthetic valve. The postoperative course was uneventful.

We report a successful case of 50-year-old woman with aortoesophageal fistula due to tuberculous pseudoaneurysm of the thoracoabdominal aorta. We underwent endovascular repair with stent graft. Her clinical course improved without additional surgical repair or postoperative complications. The patient remains well at 3-year follow-up.

A 67-year-old woman was diagnosed with infective endocarditis. She had no history of any cardiac event or dental treatment. Echocardiography showed a large vegetation attached to the anterior leaflet of the tricuspid valve with severe tricuspid regurgitation. Surgery consisted of removal of the vegetation and tricuspid valve plasty with a glutaraldehyde-treated autologous pericardial patch and artificial chordae of the anterior leaflet. Her postoperative course was uneventful. Five years after surgery, neither recurrence of infection nor worsening of tricuspid regurgitation was noted.

We report a case of hemothorax complicated with celiac artery compression syndrome (CACS). A 43-year-old man presented with a sudden onset left back pain. Computed tomography (CT) showed its hemothorax, esophageal artery aneurysm and severe stenosis of the celiac truncus with its anterior compression by median accurate ligament, and a diagnosis of CACS associated with rupture of the aneurysm was made. Emergent transcatheter arterial embolization of the aneurysm resulted in a technical failure, although the patient's condition was stable and performed esophageal artery ligation through video-assisted thoracoscopic surgery on day 5 after onset. After surgery, the patient recovered without significant incidents. A cause of this aneurysmal development was supposed to be a significantly increased esophageal arterial blood flow with its luminal dilation to compensate a decreased celiac blood flow. Segmental arterial mediolysis could not be excluded as another cause.

On weaning from cardiopulmonary bypass, a 59-year-old Japanese woman with mitral valve plasty suddenly showed a greatly increased heart rate, and an electrocardiogram revealed elevated ST-segments. There was also abnormal wall motion in the inferior region and apical ballooning of the left ventricle. We diagnosed the condition as takotsubo cardiomyopathy (acute left ventricle apical ballooning syndrome), possibly caused by catecholamine release and regional stress-induced ischemia. We believe this to be the first case report of takotsubo cardiomyopathy observed during heart surgery. We hypothesize that the condition was mediated by regional myocardial stunning and that it could be prevented by administration of angiotensin converting enzyme inhibitors before surgery and by the use of superior biocompatible cardiopulmonary bypass components. Once takotsubo cardiomyopathy occurs, we recommend mechanical circulatory assistance during weaning from the bypass.

A 49-year-old man with a successful bypass grafting for coarctation of the aorta is presented. He has been suffering from hypertension since his 30s. Angiography and magnetic resonance imaging (MRI) revealed the stenosis of distal aortic arch and developed collateral circulation. After left thoracotomy, bypass grafting using a 16 mm woven Dacron graft was placed between the left subclavian artery and the descending aorta. He had a satisfactory postoperative course with no residual pressure gradient. We recommend this procedure to be a safe and minimally invasive technique that can avoid injury to the collateral.

Endoventricular circular patch plasty (Dor ventriculoplasty) is an effective strategy for severely impaired left ventricular function due to ischemic cardiomyopathy. Cardiac resynchronization therapy improves cardiac function in patients with severe congestive heart failure and an intraventricular conduction delay. The present case demonstrates the efficacy of adding cardiac resynchronization to Dor ventriculoplasty and mitral annuloplasty in a patient with severely impaired left ventricular function and an intraventricular conduction delay.

We studied the changes in arterial baroreceptor reflex (ABR) afferent activity and efferent activity induced by nonpulsatile systemic circulation (NC) during total left heart bypass (TLHB) in rabbits. To evaluate the influence of the circuit priming fluid and exposure to NC, we directly measured aortic depressor nerve activity (ADNA) (n = 5) and renal sympathetic nerve activity (RSNA) (n = 5) before the start of partial left heart bypass (PLHB) (Before), after PHLB (After), and 5 min after the start of TLHB (During THLB) while maintaining the mean aortic pressure. The circuit priming fluid did not affect the ABR. ADNA exhibited periodic discharge at Before and After, but at During THLB, this periodic discharge transformed into a continuous discharge, and ADNA increased significantly. However, there were no significant differences in RSNA. Our results suggested that in the acute phase under NC, the ABR differed from that under natural circulation.

We directly measured aortic depressor nerve activity (ADNA) in rabbits to investigate changes in arterial baroreceptor afferent activity (ABAA) in response to nonpulsatile systemic circulation (NC) during total left heart bypass (TLHB). ADNA was measured before and 5, 20, 30, 40, 50, and 60 min after the start of TLHB while maintaining the mean aortic pressure (MAP) at preestablished values (n=10). At 5 min, the ADNA was significantly increased compared to its baseline value. At 30 min, it was significantly decreased compared to its value at 5 min and thereafter remained the same. The ADNA was then measured before and 5 and 30 min after the start of TLHB under increased MAP (n=10). The results showed that the percentage changes in ADNA during TLHB were significantly less than that observed when the MAP was increased before TLHB. We conclude that ABAA acutely adapts to NC 30 min after its initiation, but changes in ABAA are depressed under NC combined with increased MAP.

Contact between blood and artificial materials has various effects on blood. Impairment of platelet function is an especially important and well known effect, but its precise mechanism is not clearly understood. The authors constructed a circulation model to investigate the effect of extracorporeal circulation on platelet membrane glycoproteins (GPs), especially GP Ib, and to compare the changes in GP Ib in heparin coated (group C) and nonheparin coated (group N) circuits. As determined by flow cytometry, GP Ib in both groups decreased on initiating circulation, but the decrease in group N was significantly larger than that in group C. There was no observed change in GP IIb/IIIa levels in either group. The extent of shear stress induced platelet aggregation significantly decreased during circulation in both groups. Decreases in the extent of shear stress induced platelet aggregation were significantly less with the use of heparin coated circuits. In addition, the amount of GP Ib in the high speed pellet decreased progressively during circulation in both groups. In contrast, the amount of GP Ib in the Triton insoluble (low speed) pellet increased dramatically during circulation. However, expression of GP Ib in the Triton soluble platelet fraction was low in both groups. From the results, it was concluded that the cause of the decrease in platelet function during extracorporeal circulation is attributable to the internalization of GP Ib from the platelet surface inside the platelet. It also can be said that a heparin coated circuit is one effective means of controlling this change.

In this article, the clinical experience with a cardiopulmonary bypass (CPB) using a newly developed hollow fiber oxygenator with an ultra-thin layer of silicone is reported. A comparative study of biocompatibility between the new oxygenator and a heparin coated oxygenator is also described. The CPB was performed with a silicone coated oxygenator, Mera Excelung Binding Prim HPO 15 H-C (Group I, n = 6) or Binding Prim HPO 25 H-C (Group II, n = 10) (Senko Medical Instrument Mfg., Tokyo, Japan). Air could be vented through the silicone coated hollow fibers, and it was easy to prime the circuits. The CPB duration was 101 +/- 37 min and 170 +/- 64 min for Groups I and II, respectively. There were no deaths and no complications from CPB. Partial arterial pressure of O2 levels 60 minutes after the start of CPB were 529 +/- 28 mm Hg and 529 +/- 28 mmHg for Group I and II, respectively. Partial arterial pressure of CO2 levels 60 min after the start of CPB were 36.4 +/- 4.6 mmHg and 39.4 +/- 4.4 mmHg, respectively. Plasma free hemoglobin at 60 min was 33.5 +/- 17.2 mg/ dL and 46.7 +/- 26.1 mg/dL for Groups I and II, respectively. As an evaluation of biocompatibility, the effects of the new oxygenator on platelet activation (GP Ib, IIb/IIIa), coagulation (TAT), fibrinolysis (PIC), and inflammatory response (C3a, granulocyte elastase) were investigated during CPB and comparing to those of the heparin coated oxygenator. There were no significant differences in GP Ib, GP IIb/IIa, TAT, PIC, and granulocyte elastase between the two oxygenators. However, 60 min after the start of CPB, the C3a was significantly lower for the new oxygenator group than for the heparin coated oxygenator group (p < 0.03). The new oxygenator showed good gas transfer, low hemolysis, and good biocompatibility. Because of its durability and good biocompatibility, the new oxygenator was determined to be suitable for prolonged extra corporeal circulation.

Background: A membrane oxygenator consisting of a microporous polypropylene hollow fiber with a 0.2-microm ultrathin silicone layer (cyclosiloxane) was developed. Animal experimental and preliminary clinical studies evaluated its reliability in bypass procedures., Methods: Five 24-hour venoarterial bypass periods were conducted on dogs using the oxygenator (group A). In 5 controls, bypass periods were conducted using the same oxygenator without silicone coating (group B). As a preliminary clinical study, 14 patients underwent cardiopulmonary bypass with the silicone-coated oxygenator., Results: Eight to 16 hours (mean, 12.2 hours) after initiation of bypass, plasma leakage occurred in all group B animals, but none in group A. The O2 and CO2 transfer rates after 24 hours in group A were significantly higher than at termination of bypass in group B (p < 0.005 and p < 0.03, respectively). Scanning electron microscopy of silicone-coated fibers after 24 hours of bypass revealed no damage to the silicone coating of the polypropylene hollow fibers. In the clinical study, the oxygenator showed good gas transfer, acceptable pressure loss, low hemolysis, and good durability., Conclusions: This oxygenator is more durable and offers greater gas transfer capabilities than the previous generation of oxygenators.

The authors developed a new membrane oxygenator that consists of microporous polypropylene hollow fibers coated with a 0.2 micron ultrathin silicone layer. Five venoarterial bypasses were conducted on mongrel dogs for 24 hr using these new oxygenators. The blood flow rate was maintained at 750 ml/min, and the V/Q ratio was maintained at 1:1. As a control, three venoarterial bypasses were conducted under the same conditions using an oxygenator with the same design but without the silicone coating. Eight to 16 hr after the initiation of bypass, severe plasma leakage occurred in all control experiments, so the bypasses were terminated. However, plasma leakage did not occur throughout the 24 hr of any of the experiments using the new oxygenator. The O2 transfer rate of the new oxygenators after 24 hr of perfusion was 59.7 +/- 6.6 ml/min/m2, and the plasma free hemoglobin level 8 hr after the initiation of bypass was 41.4 +/- 40.2 mg/dl, compared with 145.3 +/- 189.6 mg/dl in the control group. Scanning electron microscopic examination of the silicone coated fibers after 24 hr of bypass revealed a few scattered platelet adherents and no damage to the silicone coated surface. These results suggest that this new oxygenator has satisfactory gas transfer and good durability.

The Nikkiso HPM-15 is a minimally sized centrifugal pump. Preliminary results regarding clinical use of this pump for cardiopulmonary bypass (CPB) procedures have been reported previously. Recently, we have managed some additional cases using a newly developed controller. This article reports our clinical experiences with the use of this pump. We have managed 23 cases with a Nikkiso centrifugal pump. Twenty-two patients underwent CPB and 1 patient with fulminant viral myocarditis underwent percutaneous cardiopulmonary support (PCPS). With this pump, the circuit was extremely easy to prepare and deaeration was achieved readily. Hemodynamics during CPB and PCPS were stable in all cases. The increase in serum-free hemoglobin levels during CPB with this pump was as low as that seen in preliminary tests. A decrease in the platelet count was observed after the initiation of CPB with this pump; however, platelet counts returned to preoperative values 7 days after surgery. Moreover, urine output during CPB with this pump was as high as that seen in preliminary tests. No abnormalities in renal or liver function occurred during CPB. It appears that this new centrifugal pump is safe and easy to operate, and we conclude that it is useful for CPB and PCPS.