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Biomedical subjects

T Jikuya

Publications and source records attributed to T Jikuya.

At least 73 records · Page 4Linked to original sources
PubMed1992

A compact centrifugal pump for cardiopulmonary bypass.

A majority of the cardiopulmonary bypass (CPB) systems still utilize bulky roller pumps. A direct-drive small centrifugal pump intended for second-generation CPB pump has been developed. The pump has a 50 mm diameter impeller and provides a 6 L/min flow at 3,000 rpm against 300 mm Hg. A flexible drive shaft allows us to separate the pump head from the console resulting in easier manipulation. An in vitro study showed that the pump generated less hemolysis (index of hemolysis = 0.0011, comparable to the value for Bio-medicus BP-80). To improve blood flow around the shaft-seal region and to reduce thrombus formation around the shaft, six holes were drilled through the impeller. In biventricular bypass experiments using calves, our pump demonstrated excellent antithrombogenicity and durability for 48 h. And the compact and atraumatic centrifugal pump system showed excellent performance and easy manipulation under actual CPB conditions in animal.

Animals↗
PubMed1992

Development of an atraumatic small centrifugal pump for second-generation cardiopulmonary bypass.

A small and light direct-drive centrifugal pump has been developed for cardiopulmonary bypass. In the development process, blood compatibility studies including a hemolysis study, an in vitro fluid dynamic performance study, and in vivo durability and feasibility studies were performed. The centrifugal pump with a 50 mm diameter impeller resulted in almost the same index of hemolysis value as did a Bio-Medicus centrifugal pump. Heat dissipation from the motor was prevented by using a flexible drive cable. Forty-eight-hour sealing durability around the driving axis was accomplished by using a fluoro-rubber V-ring that connected to the hard chrome-plated stainless steel. In vitro and in vivo performances of the pump were satisfactory. Thrombus formation behind the impeller was prevented by using a holed impeller that generated blood flow from the back to the surface of the impeller. Elimination of air during priming procedures was also easier with this modification. This centrifugal pump has one-quarter of the priming volume, size, and weight of magnetically coupled centrifugal pump systems.

Animals↗
PubMed1992

[Biventricular heart assist using centrifugal pump and roller pump in profound ventricular failure after open heart surgery: a case report].

A forty-seven-year-old female with profound biventricular heart failure probably caused by coronary artery spasm after open mitral commissurotomy was successfully survived by mechanical circulatory support. Centrifugal and roller pumps were applied to left and right side circulatory assist respectively. Recovery of cardiac function was evaluated by transesophageal echocardiography and hemodynamic parameters during intentional low flow assist. Finally, she was weaned from assist after 136 hours. No systemic thromboembolism was recognized after pump removal. Combination of centrifugal and roller pumps could be applicable to biventricular heart assist without crucial complication.

Cardiac Output, Low↗
PubMed1992

[Long-term clinical results after aortic valve replacement with mechanical heart valves and mitral valve replacement with porcine valves].

Long-term clinical results of aortic valve replacement (AVR) with mechanical heart valves and mitral valve replacement (MVR) with porcine valves were analysed. Sixty-three patients received isolated AVR and 48 received isolated MVR. Sixty-eight patients with MVR including double or triple valve replacement were also added in order to evaluate the primary tissue failure (PTF). The patients with operative deaths were excluded. Survival rate at 11 years in AVR was 68 +/- 10% and 67 +/- 15% in MVR without statistical difference. At 11 years, 76 +/- 8% of the patients in AVR were free from valve-related complications in contrast with the poor result of 34 +/- 31% in MVR (p less than 0.01). Main cause of this poor result in MVR was PTF as indicated in following event free rates; 83 +/- 9% at 7 years, 61 +/- 25% at 10 years and 49 +/- 31% at 13 years. There was no statistical difference between patients of above 50 years and below 49 years in PTF. Valve-related death event free was 93 +/- 5% in AVR and 86 +/- 11% in MVR at 11 years (not significant), however, there was statistical difference in re-operation event free rate as 94 +/- 5% in AVR and 76 +/- 11% in MVR at 11 years (p less than 0.001). These results suggest that the use of porcine valves in mitral position is confined to the selected patients.

Adult↗
PubMed1990

[Preoperative therapeutic embolization for massive hemoptysis from bronchial collaterals in tetralogy of Fallot--a case report successfully treated by total correction].

Hemoptysis from bronchial collateral arteries in cyanotic heart diseases is a troublesome complication. We report a case of Tetralogy of Fallot presented with massive hemoptysis which was successfully treated with transcatheter therapeutic embolization prior to the radical operation. A 28-years old man was admitted to our hospital because of hemoptysis and dyspnea. On the day of admission, he had a massive hemoptysis and became asphyxic. Diagnostic cardiac catheterization performed next day revealed Tetralogy of Fallot. Bronchial arteriogram demonstrated large bronchial collateral arteries with heavy staining around the right lower lobe bronchus. Therapeutic embolization with Gelfoam was performed and the hemostasis was obtained. The radical operation was performed 4 months later. Before cardiopulmonary bypass, the right bronchial artery was ligated. He was weaned from the extracorporeal circulation under the stable circulatory condition, and respirator on the first post operative day without any complications, and he was discharged on the 57th day after the operation. We emphasize the efficacy of therapeutic embolization of the well developed bronchial collateral arteries as a pretreatment of hemoptysis in the cyanotic heart disease.

Adult↗
PubMed1989

Popliteal artery entrapment syndrome of the monozygotic twin--a case report and pathogenetic hypothesis.

A 22 year old Japanese man with popliteal artery entrapment syndrome in which both popliteal arteries were segmentally occluded and deviated medially, underwent surgical treatment by grafting and patching with autologous veins. His identical co-twin was also found to have a less severe form of popliteal artery entrapment syndrome. This is the first report of popliteal artery entrapment syndrome presenting in a pair of monozygotic twins and the concordance of the syndrome suggests that genetic factors may play a part in the development of this rare syndrome.

Adult↗
PubMed1989

[Surgical treatment of right subclavian aneurysm--a case report].

A case of arteriosclerotic aneurysm of right subclavian artery is reported. The patient was 74 years old male. A huge arteriosclerotic aneurysm was found at the origin of right subclavian artery. Calcification of thoracic aorta and arch vessels was prominent. Under the temporary bypass between brachiocephalic artery and right common carotid artery, replacement of the aneurysm with 8 mm Dacron graft was successfully performed. To avoid the systemic embolism, partial clamp was applied to intact arteries. As the perfusion of the brain was maintained through the temporary bypass during the reconstruction of right common carotid and subclavian arteries, intracranial complication was prevented.

Aged↗
PubMed1989

[Coexistence of abdominal aortic aneurysm and intraabdominal malignancy; two case reports].

We experienced two cases of abdominal aortic aneurysm which had intra-abdominal malignancy (early gastric cancer). Case 1 was a 72 year-old man who was treated by two-stage operation of them. Gastrectomy was performed about 7 months prior to the aneurysmectomy. Case 2 was a 70 year-old man who was diagnosed both lethal diseases, renal dysfunction, chronic respiratory failure and multiple ventricular arrhythmia. He was treated by one-stage operation and was discharged with no complications. Coexistence of abdominal aortic aneurysm and intra-abdominal malignancy is rare and it is difficult to decide whether to operate the malignancy first, the aneurysm first or both simultaneously. In Japan, 28 cases were reported and 18 cases could be analyzed in detail. In these cases, most frequent coincidental malignancy was the gastric cancer (13/18, 72.2%) and one-stage operation was performed in 8 (44.4%) cases. In general, the risk of infection during upper gastrointestinal surgery is less than that during lower abdominal surgery. We concluded therefore that concomitant resection of the upper gastrointestinal malignancy, especially early gastric cancer, should be considered.

Aged↗
PubMed1988

[A staged surgical treatment of an abdominal and iliac aneurysm associated with hydronephrosis and urinoma: report of a case].

Hydronephrosis and urinoma are extremely rare complication of the abdominal aneurysm. A case of the aorto-iliac aneurysm associated with right hydronephrosis and urinoma is reported. The patient is 71 year-old female. She was admitted because of right lower abdominal pain. A diagnosis of the infrarenal abdominal aneurysm with involvement of the common iliac artery and right hydronephrosis due to ureter obstruction was made. A leakage of urine from right renal pelvis (urinoma) was also confirmed. A staged treatment for hydronephrosis was selected. At first, percutaneous nephrostomy was made under ultrasonographic guidance. Urinoma was completely disappeared thereafter. Two weeks later, the aneurysm was replaced with a Y-shaped Dacron graft and the right ureter was mobilized from the perianeurysmal fibrous tissue. On the 35th postoperative day, balloon ureteroplasty was performed through the nephrostomy catheter. Three months after operation, nephrostomy catheter was successfully withdrawn because of improved urinary passage through the right ureter. We emphasize the efficacy of staged surgical treatment combined with percutaneous nephrostomy for the abdominal aneurysm associated with hydronephrosis.

Aged↗
PubMed1985

Acute but intermittent sticking of a Björk-Shiley mitral valve in closed position.

An acute, intermittent sticking of a Björk-Shiley valve placed in the mitral position is described. It occurred shortly after the valve replacement, but 9 hours later, this 10-year-old female patient recovered from the accident without reoperation. Fluid infusion, left atrial compression, a sharp precordial blow or atrioventricular sequential pacing were effective for unlocking or prevention of the stuck valve. The mechanism was suspected to be impingement of remnant chordae tendinea.

Blood Pressure↗
PubMedDate not supplied

Intraoperative determination of mediastinal constraints for a total artificial heart.

The anatomic constraints to mediastinal fit of a total artificial heart (TAH) were largely neglected during the early developmental stages, precipitating failure due to compression or torsion of intrathoracic conduits and vascular structures. Cadaveric studies quantifying anatomic constraints are limited by postmortem factors causing distortion of critical structures. This study defines the anatomic constraints and parameters necessary for designing an implantable TAH. Importantly, these parameters were measured in 12 consecutive patients undergoing orthotopic cardiac transplant (mean body surface area, 2.0 +/- 0.1 m2) after native heart amputation. A full sized contour model of the cylindrical TAH (diameter, 97 mm; width, 78 mm) was inserted into the pericardial cavity to verify fit, which was found adequate in each case, with no identifiable compression of adjacent vascular structures. Intraoperative measurements obtained define intrathoracic and pericardial constraints for a cardiac prosthesis (mean pericardial dimensions: length, 133.0 mm; width, 154.0 mm; depth, 129.0 mm). The parameters measured will provide useful reference for other prosthetic devices, since they were obtained intraoperatively rather than postmortem. The current dimensions of our TAH were found to be acceptable for orthotopic implantation.

Adult↗