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Biomedical subjects

Eiki Tayama

Publications and source records attributed to Eiki Tayama.

At least 19 recordsLinked to original sources
PubMed2006

Infection management in a patient with a left ventricular assist device: a case report of long-term cefazolin sodium hydrate administration.

A 55-year-old woman suffered from a bloodstream infection (Staphylococcus aureus), which originated from pump inflow and outflow skin exits, from 4 months after a parocorporeal left ventricular assist device (LVAD) had been implanted. In addition to local irrigation, repeated administration of a weekly unit of cefazolin hydrate was temporarily effective, but fever frequently recurred. Because short-term antibiotic administration had limited effectiveness, a much longer-term course of cefazolin was begun at 14 months post-LVAD implantation and was planned to continue until future transplantation. Unfortunately, the patient died from a cerebral embolism at 19 months after LVAD implantation; long-term consecutive cefazolin administration had suppressed the infection for over 5 months without side effects. To treat intractable LVAD-associated bloodstream infection, long-term administration of a narrow-spectrum beta-lactam drug is an effective option.

Anti-Bacterial Agents↗
PubMed2006

Leaflet movement of the ATS valve in the aortic position: unique behavior observed in 19-mm valves.

BACKGROUND: Leaflet opening angles of ATS valves in vivo tend to be less than those reported by the manufacturer, and there is a wide variation in opening angles even among valves of the same size. METHODS: Leaflet movement of aortic ATS valves was evaluated by cineradiography in 77 patients. The mean period from valve replacement to cineradiography was 40.2 months, and during that period, the ATS valve was replaced due to prosthetic valve obstruction in 1 of the 77 patients. RESULTS: In 76 patients with a normally functioning ATS valve, the mean opening angle of 19-mm valves (66.3 degrees +/- 2.3 degrees) was significantly less (p < 0.0001) than that of ATS valves 21 mm or larger (72.2 degrees +/- 3.8 degrees in 21-mm, 72.4 degrees +/- 2.8 degrees in 23-mm, and 72.8 degrees +/- 2.9 degrees in 25-mm valves). No significant differences were found in the opening angles of ATS valves 21 mm or larger, and the opening angles exceeded 65 degrees in all 69 patients with valves in this category. In one case of obstruction in a 21-mm valve, the opening angle was 57.5 degrees. The closing angle was 24.9 degrees +/- 1.3 degrees, which corresponded well with the manufacturer's in vitro data. CONCLUSIONS: The opening angle in the 19-mm ATS aortic valve is significantly less than that in valves 21 mm or larger, and an opening angle of less than 65 degrees probably indicates prosthetic valve obstruction in aortic ATS valves sized 21 mm or larger.

Adolescent↗
PubMed2006

Long-term survivors after valve replacement with a Starr-Edwards mitral disk valve prosthesis.

We report four long-term survivors after valve replacement with a Starr-Edwards (S-E) mitral caged-disk valve. A model 6520 disk valve, size 3M, had been used in all of the four patients. Of the four patients, three underwent replacement of the disk valves 23, 24, and 26 years after mitral valve replacement (MVR), respectively. A pacemaker was implanted in the remaining patient 33 years after MVR. The S-E disk valves were considered hemodynamically slightly stenotic compared with modern bileaflet valves. No disk wear was detected in any of the three explanted valves, and in the remaining patient, a noninvasive evaluation of the disk showed that it was functioning normally. These results suggest the favorable long-term durability of the S-E disk valve.

Aged↗
PubMed2004

Mechanical unloading improves intracellular Ca2+ regulation in rats with doxorubicin-induced cardiomyopathy.

OBJECTIVES: We sought to assess whether mechanical unloading has beneficial effects on cardiomyocytes from doxorubicin-induced cardiomyopathy in rats. BACKGROUND: Mechanical unloading by a left ventricular assist device (LVAD) improves the cardiac function of terminal heart failure in humans. However, previous animal studies have failed to demonstrate beneficial effects of mechanical unloading in the myocardium. METHODS: The effects of mechanical unloading by heterotopic abdominal heart transplantation were evaluated in the myocardium from doxorubicin-treated rats by analyzing the intracellular free calcium level ([Ca(2+)](i)) and the levels of intracellular Ca(2+)-regulatory proteins. RESULTS: In doxorubicin-treated rats, the duration of cell shortening and [Ca(2+)](i) transients in cardiomyocytes was prolonged (432 +/- 28.2% of control in 50% relaxation time; 184 +/- 10.5% of control in [Ca(2+)](i) 50% decay time). Such prolonged time courses significantly recovered after mechanical unloading (114 +/- 10.4% of control in 50% relaxation time; 114 +/- 5.8% of control in 50% decay time). These effects were accompanied by an increase in sarcoplasmic reticulum Ca(2+) ATPase (SERCA2a) protein levels (0.97 +/- 0.05 in unloaded hearts vs. 0.41+/- 0.09 in non-unloaded hearts). The levels of other intracellular Ca(2+)-regulatory proteins (phospholamban and ryanodine receptor) were not altered after mechanical unloading in doxorubicin-treated hearts. These parameters in unloaded hearts without doxorubicin treatment were similar to normal hearts. CONCLUSIONS: Mechanical unloading increases functional sarcoplasmic reticulum Ca(2+) ATPase and improves [Ca(2+)](i) handling and contractility in rats with doxorubicin-induced cardiomyopathy. These beneficial effects of mechanical unloading were not observed in normal hearts.

Animals↗
PubMed2004

High-intensity transient signals due to prosthetic valve obstruction: diagnostic and therapeutic implications.

BACKGROUND: High-intensity transient signals (HITS) can be detected by transcranial Doppler ultrasonography (TCD) in patients carrying a mechanical prosthetic valve. The HITS counts and a frequency analysis were evaluated in patients with prosthetic valve obstruction in the aortic position. METHODS: Simultaneous echocardiographic, cineradiographic, and TCD evaluations for a St. Jude Medical valve were performed in 108 patients. All patients were asymptomatic and had no significant stenosis of the carotid artery. The HITS were identified according to criteria established by consensus of the International Cerebral Hemodynamics Symposium. RESULTS: The HITS counts in 69 patients with normal prosthetic valve function were 2.2 +/- 4.4, and the counts in 39 patients with prosthetic valve obstruction (group D) were 8.3 +/- 10.8. This difference was significant (p = 0.0002). In 2 patients of group D who had a greater rate of less than 400 Hz HITS, which were produced by solid microemboli, thrombolysis resulted in a mitigation of restricted leaflet movement equal to or greater than 10(o). The total number of HITS decreased and the rate of less than 400 Hz HITS also markedly decreased after thrombolysis in these 2 patients. On the other hand, 4 patients who obtained no improvement of leaflet movement by thrombolysis had lower rates of less than 400 Hz HITS than did the 2 patients. CONCLUSIONS: These results suggest that measurement of HITS counts is useful for detection of prosthetic valve obstruction, and that a frequency analysis of HITS may be valuable to clarify the cause of the obstructed prosthetic valves.

Adult↗
PubMed2004

Usefulness of a multidetector-row computed tomography scanner for detecting pannus formation.

BACKGROUND: Prosthetic valve dysfunction (PVD) as a result of pannus or thrombus formation is an infrequent but serious complication. Currently available diagnostic tools, however, are insufficient to detect a minute pannus and thrombi. The use of a more advanced diagnostic image, multidetector-row computed tomography scanner, may enable us to determine the anatomic and functional causes of PVD. METHODS: Patients who underwent aortic valve replacement with a St. Jude Medical valve were examined by transthoracic echocardiography and cineradiography to diagnose PVD. Sixteen patients with PVD (PVD group) and 12 patients with normal prosthetic valve function (control group) were studied using the multidetector-row computed tomography scanner. The multidetector-row computed tomography findings in 2 patients with PVD were validated by the observations during reoperation. RESULTS: In 13 of 16 patients (81%) in the PVD group and 3 of 12 patients (25%) in the control group, multidetector-row computed tomography demonstrated that an abnormal small tissue, regarded as pannus, was found to extend from the left ventricular septum into the pivot guard. These findings were confirmed by the observations during reoperation in 2 patients in the PVD group. CONCLUSIONS: Multidetector-row computed tomography can be a useful diagnostic technique for anatomic and functional evaluation of PVD as a result of pannus formation.

Adult↗
PubMed2004

Replacement of an aortic Starr-Edwards ball valve prosthesis 28 years after implantation.

A 53-year-old woman who had undergone aortic valve replacement with a Starr-Edwards (S-E) valve (Model 1260) and open mitral commissurotomy 28 years previously was hospitalized with cardiac failure. Echocardiography showed mitral stenosis, mitral regurgitation, and a normally functioning S-E prosthesis. At reoperation, the mitral and aortic valves were replaced with St Jude bileaflet mechanical prostheses. Examination of the explanted S-E prosthesis revealed no structural abnormality other than lipid infiltration of the silastic ball.

Aortic Valve↗
PubMed2004

Right atrial myxoma in a patient presenting with syncope.

We describe a case of right atrial myxoma in a 62-year-old woman presenting with syncope. The patient had a 4-month history of syncope and felt faint on lying flat in bed before the admission. Transthoracic and transesophageal echocardiography showed a large right atrial mass that was prolapsing through the tricuspid valve into the right ventricle during diastole. Coronary angiography revealed a tumor stain through the right coronary artery and no significant stenosis of the coronary arteries. During operation, cardiopulmonary bypass was initiated with cannulation into the aorta and retrograde femoral vein and superior vena caval cannulation. The large tumor was attached by a short stalk to the interatrial septum at the border of the fossa ovalis. The tumor and the interatrial septum including the stalk with a 1.5-2.0 cm cuff extending the full thickness of the septum were completely excised. A histologic examination of the tumor confirmed the diagnosis of cardiac myxoma. We emphasize a characteristic feature of syncopal attacks, and discuss the importance of prevention of intraoperative systemic and pulmonary tumor embolization resulting from venous cannulation for cardiopulmonary bypass in patients with right atrial myxomas.

Female↗
PubMed2004

Non-occlusive condition with the Better-Header roller pump: impacts of flow dynamics and hemolysis.

PURPOSE: Impacts on hemolysis and backflow using a non-occlusive setting with the Better-Header (BH) roller pump were investigated. METHODS AND RESULTS: Pump flow of a non-occlusion setting was measured with a pump speed of 3 L/min and 5 L/min against various after-loads. With the non-occlusive setting (BH-NO350), backflow was less than 10% if the pump pressure head was <300 mmHg. When the outlet line is occluded, 80% of the set flow was shunted through the pressure relief valve and outlet pressure did not develop hazardous overpressure. During surgery with the BH-NO350, flow loss was <5% while the pump pressure was maintained at approximately 200 mmHg. An in vitro hemolysis test was conducted at 5 L/min against 350 mmHg, using the standard occlusion (BH-SO), the non-occlusion (BH-NO350), and the centrifugal pump (CP). The CP demonstrated less hemolysis than the other two groups; the BH-SO and the BH-NO350 had similar hemolytic characteristics. During cardiopulmonary bypass, no significant differences in hemolysis were seen among the BH-SO, the BH-NO350, and the CP. CONCLUSION: Possible flow loss of the non-occlusion setting with the BH should be almost negligible in most clinical situations. The BH-NO350 demonstrated hemolytic characteristics similar to those of the BH-SO, but not as good as those of the CP.

Blood Pressure↗
PubMed2003

Obstruction of St Jude Medical valves in the aortic position: histology and immunohistochemistry of pannus.

OBJECTIVE: This study aims to reveal the morphological, histological, and immunohistochemical mechanism of pannus formation using resected pannus tissue from patients with prosthetic valve dysfunction. METHOD: Eleven patients with prosthetic valve (St Jude Medical valve) dysfunction in the aortic position who underwent reoperation were studied. We used specimens of resected pannus for histological staining (hematoxylin and eosin, Grocott's, azan, elastica van Gieson) and immunohistochemical staining (transforming growth factor-beta, transforming growth factor-beta receptor 1, alpha-smooth muscle actin, desmin, epithelial membrane antigen, CD34, factor VIII, CD68KP1, matrix metalloproteinase-1, matrix metalloproteinase-3, and matrix metalloproteinase-9). RESULTS: Pannus without thrombus was observed at the periannulus of the left ventricular septal side; it extended into the pivot guard, interfering with the movement of the straight edge of the leaflet. The histological staining demonstrated that the specimens were mainly constituted with collagen and elastic fibrous tissue accompanied by endothelial cells, chronic inflammatory cells infiltration, and myofibroblasts. The immunohistochemical findings showed significant expression of transforming growth factor-beta, transforming growth factor-beta receptor 1, CD34, and factor VIII in the endothelial cells of the lumen layer; strong transforming growth factor-beta receptor 1, alpha-smooth muscle actin, desmin, and epithelial membrane antigen in the myofibroblasts of the media layer; and transforming growth factor-beta, transforming growth factor-beta receptor 1, and CD68KP1 in macrophages of the stump lesion. CONCLUSIONS: Pannus appeared to originate in the neointima in the periannulus of the left ventricular septum. The structure of the pannus consisted of myofibroblasts and an extracellular matrix such as collagen fiber. The pannus formation after prosthetic valve replacement may be associated with a process of periannular tissue healing via the expression of transforming growth factor-beta.

Actins↗
PubMed2003

Transcatheter coil embolization of a high-flow coronary artery fistula using 0.052-inch gianturco coils: a case report.

A giant, high-flow coronary fistula is usually difficult to treat by transcatheter coil embolization, but the 0.052-inch Gianturco coil, which is larger and has a stronger shape memory than conventional coils, is now available. Using this device and additional conventional coils, a high-flow coronary artery fistula in a healthy 31-year-old man was successfully embolized. The new Gianturco coil widens the indication for the transcatheter embolization of coronary artery fistulas.

Adult↗
PubMed2003

Rupture of an aneurysm resulting from a coronary artery fistula: a case report.

A rare case of coronary-to-pulmonary artery fistulas associated with formation of a saccular aneurysm that ruptured into the pericardium occurred in a 69 year-old-female who had experienced an episode of unconsciousness 3 months earlier and who suffered a second episode. She was diagnosed as having a cardiac tamponade caused by rupture of a coronary artery aneurysm formed by a left coronary artery - pulmonary artery fistula. The hemorrhage stopped after pericardial drainage. She was referred for surgical treatment of the aneurysm and suture closure of the afferent coronary artery into the aneurysm, transpulmonary closure of the fistulas, and aneurysmorrhaphy. There was adhesion between the aneurysm and pericardium. Her postoperative course was uneventful and she has remained well for 4 months after the operation.

Aged↗
PubMed2003

Anomalous origin of the left coronary artery from the pulmonary artery: successful direct reimplantation in a 50-year-old man.

Anomalous origin of the left coronary artery from the pulmonary artery is a rare congenital coronary artery anomaly that is often referred to as Bland White Garland syndrome. Most patients with this anomaly require surgical intervention early in life, and it is extremely rare that patients reach middle age without any symptoms. We present a 50-year-old man with this anomaly, who underwent direct reimplantation of the left main coronary trunk to the ascending aorta. His postoperative course was uneventful, and three and a half years after the operation, he is well and does not require medication. Several surgical procedures can be used to treat this anomaly, but we prefer to use direct reimplantation, whenever technically possible. To our knowledge, this patient is the oldest patient to have undergone a direct reimplantation without any angioplasty.

Age Factors↗
PubMed2003

Left atrial thrombosis following mitral valve repair and maze procedure: case report.

The case is described of a 71-year-old woman with left atrial thrombosis after successful mitral valve repair and a Kosakai-maze procedure. At three months after surgery, electrocardiography showed a normal sinus rhythm, but echocardiography revealed a mural thrombus on the posterior wall of the left atrium. During those three months, the anticoagulation level (thrombotest index range: 29-41%) was lower than target level. Anticoagulant therapy with heparin plus warfarin failed to reduce the thrombus size. Anticardiolipin antibodies were positive, and lupus anticoagulants negative. A Doppler study of the mitral valve indicated peak velocity 1.48 m/s, mean pressure gradient 4.5 mmHg, and valve area 2.1 cm2. During reoperation, an old spherical thrombus (weight 38 g) which was firmly adhered to the posterior wall and included an incision line of the Kosakai-maze procedure, was identified and totally removed. After reoperation, the patient received warfarin and an antiplatelet agent to maintain the INR at 2.5-3.5. Echocardiography performed at 11 months postoperatively revealed no thrombus formation on the left atrium.

Aged↗
PubMed2002

Histological and immunohistological study of cryopreserved aortic valve grafts: the possibility of a clinical application for cryopreserved aortic valve xenograft.

The influence of preservation techniques on xenogeneic immune responses was examined to investigate the possibility of their clinical use. Mongrel dogs and pigs were used as allogeneic and discordant xenogeneic donors of aortic valve grafts, respectively. The allografts and xenografts were implanted in the abdominal aorta of mongrel dogs after cryopreservation or after fresh preservation. Allografts and xenografts were explanted at Days 7 and 42 for histological and immunohistochemical examination. In the fresh preserved allografts and the fresh preserved xenografts, the media of aortic wall grafts were significantly acellular at 7 days. Significant aortic medial destruction and neointimal proliferation with significant destruction of the valve leaflets was observed at 42 days. However, no differences were found among the preservation techniques in the xenogeneic grafts. To alleviate the lack of homografts, approaches such as the tissue-engineered graft may become an alternative in patients who are acceptable candidates.

Animals↗