Biomedical subjects

Yoichi Miwa

Publications and source records attributed to Yoichi Miwa.

8 recordsLinked to original sources

PubMed2006

Recurrent severe mitral regurgitation due to left ventricular apical wall motion abnormality caused by coronary vasospastic angina: a case report.

A 76-year-old man developed congestive heart failure due to severe mitral regurgitation after episodes of vasospastic angina. Echocardiography demonstrated left ventricular apical akinesis with ballooning and deformity of the anterior mitral leaflet becoming concave toward the left atrium. The acetylcholine provocation test induced diffuse coronary vasospasm in the distal segments of both right and left coronary arteries and reproduced severe mitral regurgitation. Follow-up echocardiography demonstrated decreased mitral regurgitation with ameliorated apical wall motion. Coronary vasospasm remained refractory to antivasospastic medications and severe mitral regurgitation relapsed 1 month after discharge. Mitral valve annuloplasty with a Carpentier-Edwards physio ring was performed, and no recurrence of mitral regurgitation was observed despite some episodes of vasospastic angina. We speculate that vasospastic angina and the resultant apical wall motion abnormality caused tethering of the mitral subvalvular apparatus, leading to inappropriate mitral coaptation and severe regurgitation.

Aged↗

PubMed2006

[Recurrent episodes of takotsubo-like transient left ventricular ballooning occurring in different regions: a case report].

A 62-year-old male with emphysema developed recurrent episodes of transient left ventricular ballooning occurring in different regions. Left ventriculography revealed symmetric mid-ventricular ballooning when he was 60 years old, and he also developed mid-ventricular ballooning of larger extent at the age of 62 years. Furthermore, as he was treated for severe asthma attack 3 months later, left ventricular apical ballooning occurred. Echocardiography also demonstrated akinetic wall motion in the right ventricular apex. These episodes showed myocardial infarction-like onset, ST elevations on electrocardiography, no significant increases in cardiac enzymes, wall motion abnormalities incompatible with coronary artery disease, and complete recovery within a few weeks. From these findings, we speculate that the recurrent left ventricular wall motion abnormalities including the mid-ventricular ballooning were so-called takotsubo-like left ventricular dysfunction.

Echocardiography↗

PubMed2005

Retrievable Günther Tulip filter complicated by sepsis and retroperitoneal hemorrhage: successful management by filter retrieval.

We encountered complications of septic shock and retroperitoneal hemorrhage which occurred after implantation of a retrievable Günther Tulip filter. A 79-year-old woman was diagnosed as right femoral vein thrombosis, and a retrievable Günther Tulip filter was deployed prior to a total knee replacement surgery. However, the patient developed septicemia due to Citrobacter freundii, followed by thrombocytopenia and retroperitoneal hemorrhage. A large hematoma was formed along the lateral side of the filter struts. We considered that the filter should be removed to control retroperitoneal hemorrhage and prevent secondary infection of the hematoma. Removal of the retrievable filter was effective in managing these complications.

Aged↗

PubMed2004

[Usefulness of dobutamine stress echocardiography in a patient with aortic valve stenosis and left ventricular dysfunction: a case report].

A 76-year-old man with previous antero-septal myocardial infarction and aorto-coronary bypass surgery developed exertional dyspnea. Echocardiography revealed diffuse left ventricular hypokinesis and aortic stenosis with a mean pressure gradient of 29 mmHg. Coronary angiography showed no significant lesions in the bypass grafts and total occlusions of the proximal left anterior descending artery and mid circumflex artery. Dobutamine stress echocardiography was performed to evaluate the severity of aortic stenosis and left ventricular functional reversibility. Administration of dobutamine increased the mean pressure gradients to 48 mmHg and increased the stroke volume by 28% without change in aortic valve area of about 0.5 cm2. We considered that our patient had severe aortic stenosis with contractile reserve. After aortic valve replacement, he improved with better left ventricular function.

Aged↗

PubMed2004

[Isolated left ventricular noncompaction in the elderly: a case report].

A 83-year-old man with an implanted pacemaker was admitted to our hospital for dyspnea. Echocardiography revealed left ventricular dilation and diffuse hypokinesis mimicking dilated cardiomyopathy. Multiple trabeculations and deep intertrabecular recesses were prominent in the apical and posterior walls. Computed tomography with contrast medium also showed prominent trabeculations. Thallium-201 and iodine-123-beta-methyl-p-iodophenyl-pentadecanoic acid scintigraphy demonstrated fixed defects in the inferior wall. These findings were consistent with isolated noncompaction of the ventricular myocardium. The patient's symptoms of heart failure improved in response to treatment, including carvedilol. Isolated noncompaction of the ventricular myocardium is recognized as a rare congenital disorder of infancy with fatal outcomes, with some reports of cases in adults. The present patient is the most elderly described to date.

Aged↗

PubMed2003

HMG-CoA reductase inhibitor has protective effects against stroke events in stroke-prone spontaneously hypertensive rats.

BACKGROUND AND PURPOSE: Recent clinical studies suggest that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors (statins) exert protective effects against nonhemorrhagic stroke. In a murine cerebral ischemia model produced by occlusion of the middle cerebral artery, statins were shown to reduce infarct size. However, the effect of statins on hypertension-based stroke is unknown. The purpose of this study is to clarify the effect of a statin on stroke in stroke-prone spontaneously hypertensive rats (SHR-SP), in which both cerebral hemorrhage and infarction occur. METHODS: We treated SHR-SP chronically from 4 weeks of age with cerivastatin (2 mg/kg per day by gavage) or vehicle. The physiological parameters, the incidence of stroke-associated symptoms, and mortality were assessed. RESULTS: At 14 weeks of age, the incidence (13+/-3% versus 37+/-8%; P<0.01) and the size of stroke (1.6+/-0.2 versus 2.2+/-0.1 arbitrary units; P<0.01) were significantly decreased by cerivastatin, although blood pressure and plasma cholesterol levels were not different. Moreover, stroke-associated symptoms and early mortality of SHR-SP were markedly reduced in the statin-treated group (mortality at the age of 15 weeks: 15% versus 50%; P<0.05). Statin treatment significantly reduced superoxide production from nonstroke parenchyma of brain and infiltration of inflammatory cells to the stroke lesions. CONCLUSIONS: Our data show that a high dose of statin exerts protection against hypertension-based stroke and ameliorates the disease severity via inhibition of superoxide production and modulation of inflammation in brain.

Animals↗

PubMed2003

[Reversible left ventricular dysfunction manifesting as hyperkinesis of the basal and the apical areas with akinesis of the mid portion: a case report].

A 60-year-old man underwent emergent cardiac catheterization because of anterior chest oppression. He had been treated with calcium antagonist and nitrate. Coronary angiography showed no organic stenosis. However, left ventriculography revealed that the basal and the apical areas were hyperkinetic and the mid portion was akinetic. Echocardiography showed that the bizarre-shaped left ventricular dysfunction had completely recovered after a week. Serial electrocardiography demonstrated initial ST-segment elevation in the precordial leads followed by T-wave inversion in II, III, a VF and V4-V6. Coronary artery spasm provocation tests were negative. Endomyocardial biopsy revealed focal myocardial depletion and mild fibrosis. The present case may be an atypical form of tako-tsubo-like left ventricular dysfunction in which the left ventricular contraction is symmetric with both hyperkinetic and akinetic areas.

3-Iodobenzylguanidine↗

PubMed2002

A 3-hydroxy-3-methylglutaryl co-enzyme A reductase inhibitor reduces hypertensive nephrosclerosis in stroke-prone spontaneously hypertensive rats.

BACKGROUND: Recent studies suggest that 3-hydroxy-3-methylglutaryl co-enzyme A reductase inhibitors (statins) exert their protective effects against cardiovascular diseases independently of their cholesterol-decreasing effects. OBJECTIVE: To clarify the effect of a statin on hypertensive nephrosclerosis. METHODS: We treated stroke-prone spontaneously hypertensive rats (spSHRs) chronically, starting at the age of 4 weeks, with cerivastatin (2 mg/kg per day by gavage) or vehicle. Physiological parameters, plasma chemistry and urine protein excretion were analysed. At 14 weeks of age, the rats had their kidneys removed for use in assays. RESULTS: Compared with vehicle treatment, statin treatment reduced proteinuria and renal injury independently of blood pressure and cholesterol concentrations in spSHRs. Although expression of adhesion molecules and infiltration of inflammatory cells were not different whether or not cerivastatin treatment was used, renal fibrosis was significantly reduced in statin-treated spSHRs. We also found that expression of transforming growth factor-beta1 in kidneys was significantly inhibited in statin-treated spSHRs. CONCLUSION: Cerivastatin prevents or retards hypertension-induced renal injury via inhibition of renal fibrosis and proteinuria. These results show the potential of statins as protective tools against proteinuric renal diseases, independent of their cholesterol-decreasing effects.

Animals↗