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Biomedical subjects

K Imanaka

Publications and source records attributed to K Imanaka.

At least 37 records · Page 2Linked to original sources
PubMed2000

Global myocardial ischemia as a complication of an acute type A aortic dissection--rapid diagnosis of a case by transesophageal echocardiography.

A 36-year-old female was admitted for severe chest pain followed by profound shock. Electrocardiography showed severe ST segment depression (0.5-0.7 mV) in all leads except aVR and aVL. Echocardiography revealed an intimal flap in the ascending aorta and coexisting grade 3 aortic regurgitation. She was immediately intubated and transferred to the intensive care unit. Transesophageal echocardiography (TEE) demonstrated an intimal tear at 2 cm above the sinotubular junction, and the ostium of the left main trunk was oppressed by the intimal flap during diastole. Emergency graft replacement of the ascending aorta and aortic hemiarch concomitant with aortic valve resuspension was performed successfully. The ECG changes reversed to normal immediately after the operation. The patient was extubated 2 days postoperatively and discharged from the hospital 14 days postoperatively. TEE is useful for the rapid evaluation of coronary malperfusion as a complication of acute aortic dissection, especially in patients with hemodynamic instability.

Acute Disease↗
PubMed1999

Hemodynamic effects of carbon dioxide insufflation under single-lung ventilation during thoracoscopy.

BACKGROUND: The hemodynamic effects of carbon dioxide insufflation under single-lung ventilation were studied in 22 consecutive thoracoscopic harvests of the left internal mammary artery, which was used for minimally invasive coronary artery bypass grafting. METHODS: An electrocardiograph, arterial catheter, Swan-Ganz catheter, and transesophageal echocardiograph were used to monitor seven hemodynamic variables. Baseline data were obtained during ventilation of both lungs and the measurements were repeated after the left lung was collapsed and at 5 and 30 minutes after hemithorax insufflation with low-flow (2 to 3 L/minute) carbon dioxide gas was begun. The intrapleural pressure was maintained at 8 to 10 mm Hg. RESULTS: Thoracoscopic harvest of the internal mammary artery was completed in all cases with a mean insufflation time of 44+/-12 minutes. There were no significant changes in the mean arterial pressure, heart rate, cardiac index, and left ventricular ejection fraction throughout the procedure, whereas the central venous pressure, mean pulmonary arterial pressure, and pulmonary capillary wedge pressure (p < 0.05 for each variable) during insufflation. CONCLUSIONS: Low-flow carbon dioxide insufflation into the left hemithorax with an intrapleural pressure of 8 to 10 mm Hg under selective right-lung ventilation does not compromise the human heart with normal to moderately depressed function and can be an efficacious adjunct in specific thoracoscopic procedures.

Aged↗
PubMed1999

Right ventricular thrombosis early after bidirectional Glenn shunt.

Thrombosis in the right ventricle occurred early after bidirectional superior cavopulmonary shunt in 2 patients with pulmonary atresia with intact ventricular septum and major right ventricular coronary artery communication, and perioperative brain infarction occurred in 1 patient. Clinicians should be aware of the hazards of this potentially lethal complication, and transfusion of platelets and fresh plasma should be minimized. Although the hemodynamic state is good, echocardiography should be performed frequently and strict anticoagulation should be started as early as possible.

Coronary Vessel Anomalies↗
PubMed1999

Extracardiac conduit replacement with autologous tissue only, via a left anterior small thoracotomy.

A 13-year-old boy, who had undergone a Rastelli procedure 8 years before, developed severe extracardiac conduit stenosis and infectious endocarditis. Sternal re-entry appeared to be dangerous and to require extensive adhesiolysis. Through a left anterior small thoracotomy, however, good exposure was obtained and the operation was performed safely and much less invasively. The main pulmonary artery was reconstructed with autologous tissues only, i.e. fibrous tissue bed and broadly based pericardial pedicle. There was no residual stenosis. The patient convalesced rapidly.

Adolescent↗
PubMed1999

Coronary artery bypass grafting in a patient with human immunodeficiency virus: role of perioperative active anti-retroviral therapy.

In a patient with severe ischemic heart disease and advanced human immunodeficiency virus (HIV) infection, vigorous perioperative treatment with anti-retroviral agents was given and coronary artery bypass surgery using cardiopulmonary bypass was successfully performed. This strategy could become the standard for patients with cardiovascular disease and advanced HIV infection. The following aspects of this case require further investigation: (1) lack of a reactive increase in the neutrophil count, (2) transient extreme reduction of lymphocytes, and (3) a relative decrease in the CD8+ cell ratio.

Acquired Immunodeficiency Syndrome↗
PubMed1998

Unilateral absence of pulmonary artery and ventricular septal defect in an infant.

A 2-month-old boy was diagnosed as having a rare combination of absence of left pulmonary artery and ventricular septal defect. He underwent intracardiac repair at the age of 8 months. Reconstruction of the left pulmonary artery was impossible because it could not be visualized through a median sternotomy. Although his early postoperative course was uneventful, he needed ipsilateral pneumonectomy 3 months later because of unremitting hemoptysis. Hilar left pulmonary artery, which used to exist, was not found even by histologic examination.

Aorta, Thoracic↗
PubMed1998

Lateral difference in the reproduction of arm positioning movement: an examination of the hypothesis on the levels of psychological processes.

The purpose of this study was to determine whether the hypothesis on the levels of psychological processes (Hatta, 1977, 1978) accounts for lateral differences in arm positioning movement (a spatial localization task). Fifteen right-handed male subjects were asked to perform a constrained criterion movement, 12 cm in length, with the left or right arm. Then, after a 10-sec retention interval, they were asked to perform the movement with the same arm, estimating lengths of 6, 12 or 24 cm. Different levels of psychological processes were assumed to be involved in estimating these various movement lengths--half, the same, or double that of the original. All possible combinations of the arm (left/right) and three movement length were tested. The CE scores were lower (more accurate) for the left arm (half; 1.5 +/- 8.1 mm, same; 4.3 +/- 6.2mm, double; 5.9 +/- 20.3 mm) than those for the right arm (half; 5.9 +/- 7.6 mm, same; 10.6 +/- 10.6 mm, double; 11.8 +/- 23.6 mm) in all conditions, indicating a lateral difference (the right hemisphere dominance) in arm positioning tasks. This typical lateral difference, which displayed no significant difference among conditions, is supposed to be mediated by complex or high-level psychological processes. These psychological processes are required by the subjects in the estimation of the various movement lengths. This study suggests that the level of psychological processes is a crucial factor in the manifestation of lateral differences in the performance of arm positioning movements.

Adult↗
PubMed1998

[Atrial septal defect and severe pulmonary hypertension in an adult who needed nitric oxide inhalation after repair].

A 51-year-old male was diagnosed as having an ostium secundum atrial septal defect with severe pulmonary hypertension. Although pulmonary artery pressure was as high as 96/32 and pulmonary vascular resistance was 14.2 U.m2, he underwent corrective surgery, because pulmonary to systemic blood flow ratio was 2.0. After he regained consciousness in ICU, pulmonary hypertensive crises recurrently occurred and the hemodynamics became quite unstable. Administration of conventional drugs proved to be ineffective. Since inhalation of low dose (3-4 ppm) nitric oxide was started, however, his condition was markedly improved and he recovered uneventfully thereafter. Two years later, pulmonary artery pressure was reduced to 52/28 and pulmonary vascular resistance was 9.9 U.m2. Although good outcome can not be expected in all surgically treated cases, we should refrain from deciding easily that surgery is contraindicated, because no criteria of surgical indication for atrial septal defect with pulmonary hypertension appears to be perfect.

Administration, Inhalation↗
PubMed1997

Mitral valve repair with extensive resection of the anterior leaflet for regurgitation due to Barlow's disease. Report of a case.

We recently performed mitral valve repair for a case of mitral regurgitation due to Barlow's disease, which is relatively rare in Japan. Both the anterior and posterior leaflets were affected by advanced myxomatous change, and appeared markedly thickened and redundant. Although extensive resection of the anterior leaflet is not a generally accepted method, nearly one fourth of the anterior leaflet was resected in this case. Now, at 36 months after the operation, there is only trivial regurgitation and the patient is doing well and without symptoms. We believe that extensive resection of the anterior leaflet can be a useful treatment for repair of a redundant anterior leaflet with excess tissue.

Cardiac Surgical Procedures↗
PubMed1997

Selective modification of somatosensory evoked potential during voluntary finger movement in humans.

We examined changes in somatosensory evoked potentials (SEPs) during voluntary movement of fingers innervated by the stimulated nerve and those not innervated by the stimulated nerve and the relationship to the kind of movement modality. Analysis showed that the amplitude of most components at F3, C3', and P3, except for P45 at C3, N35 and P45 at P3, decreased during voluntary finger movement tasks. Further, we found that the components of P40 at F3, P45 at C3', and N35 at P3 were increased during the voluntary pulling movement of the second and the third digits compared to those during the voluntary pushing movement of the fourth and the fifth digits, whereas all other components were decreased at F3, C3', and P3. We also found that not all components of SEPs were decreased while some SEPs in middle latency were increased. In conclusion, we confirmed the selectivity in attenuation of the SEPs. Moreover, we noted an interesting finding that the selectivity of attenuation of the SEPs was most frequently observed in the N20, P30 (P25 at F3), N35 (N30 at F3), and P45 (P40 at F3) components at F3, C3', and P3.

Adult↗
PubMed1997

Changes in central motor-sensory system following voluntary movement of stimulated finger.

OBJECTIVE: We examined which components of somatosensory evoked potentials (SEP) were modulated during the voluntary movement of stimulated fingers and discuss our findings with respect to the decrease in SEPs in terms of both centrifugal and centripetal mechanisms. METHODS: The study was performed in the Laboratory of Physiology, Institute of Health and Sport Sciences, University of Tsukuba. Experiments were performed on 10 healthy young male subjects, aged 19-21 years. All subjects were right-handed and were free of neurological disease. RESULTS: We found that N20-P25 (P22 at frontal area) -N35-(N30 at frontal) P45 (P40 at frontal area) components at the F3, the C3' and the P3 were consistently evoked, but N35 was increased at P3 and N30 attenuation at F3 during a sustained voluntary movement. Furthermore, the present experiments showed that frontal N30 was markedly decreased during a sustained voluntary movement. We also found that all SEPs components, except for parictal N35, were significantly decreased during sustained voluntary movement tasks. CONCLUSIONS: We concluded that the suppression of SEPs appeared to be due to the interaction of both centrifugal and centripatal mechanisms. Namely, in a particular type of movement task, more prenounced afferent mechanisms may contribute to the decrease in SEPs, while in the other types of tasks, more pronounced afferent activities may contribute to the decrease in SEPs.

Adult↗
PubMed1997

[Improvement of cardiac function by aortic valve replacement for chronic aortic regurgitation with carbomedics heart valve].

Cardiac function after aortic valve replacement for chronic aortic regurgitation with CarboMedics heart valve was evaluated repeatedly by echocardiography and some examinations in 27 cases. There was no late death and all patients belonged to NYHA I functional class postoperatively. Systolic and diastolic dimensions of left ventricle, left ventricular mass index, cardiothoracic ratio and SV1+RV5 on electrocardiography improved significantly within half a year and those improved results remained thereafter. Fractional shortening of left ventricle also improved gradually and the difference reached statistical significance one year later. This investigation revealed reduced systolic function or eccentric myocardial hypertrophy were often reversible. Average values of systolic diameter and fractional shortening late after operation were within normal range even in cases whose preoperative systolic function were severely depressed. Left ventricular mass index decreased markedly although postoperative values were still out of normal range in most cases. These results suggest that aortic valve replacement can be indicated even in cases of aortic regurgitation with severely impaired preoperative cardiac function.

Adolescent↗
PubMed1997

[Reoperation for relief of valvular and supravalvular stenosis late after aortic valve replacement with Manouguian's anulus enlargement: report of a case].

Thirteen year-old boy who received aortic valve replacement with Manouguian's anulus enlargement for congenital aortic stenosis 7 years ago developed valvular and supravalvular stenosis. Pressure gradient between left ventricle and aorta was 55 mmHg. The etiology of supravalvular stenosis was extensive patch plasty of ascending aorta and severe degeneration of expanded polytetrafluoroethylene patch. Moreover, white hard mass existed just outside the patch and was one of the components of the stenosis. This mass was acellular calcification without foreign body reaction. Degenerated prosthetic patch was thoroughly resected, and redo Manouguian's procedure with autogeneous pericardium was performed. We tried to use two sizes larger 21 mm valve, but, after all, 19 mm valve was sewn into place. His postoperative course was uneventful.

Adolescent↗
PubMed1997

[Reoperation for mitral regurgitation 13 years after aortic valve replacement and manouguian's anulus enlargement: report of a case].

The patient was 22-year-old female. She had undergone aortic valve replacement and Manouguian's anulus enlargement with low porosity woven Dacron patch for congenital aortic stenosis 13 years ago, and developed mitral regurgitation 9 years after that operation. Two regurgitant flow were observed. One was originated from the orifice due to mitral prolapse. The other was from a tear in the anterior leaflet. It was around the tip of the prosthetic patch, approximately 7 mm in size, and was repaired easily. But the mitral valve itself was found to be malformed and prolapsed, requiring mitral valve replacement. Her postoperative course was uneventful.

Adult↗
PubMed1997

[A case of multifocal Langerhans cell granulomatosis: a BAL follow up study].

Langerhans cell granulomatosis, once called histiocytosis X, is a rare disease. A case of multifocal Langerhans cell granulomatosis in the bone, lymph nodes, skin and lungs of an 18-year-old man is described. Head CT and MRI showed a soft tissue mass of the left temporal bone. Lymph node and skin biopsies substantiated a diagnosis of Langerhans cell granulomatosis. A High resolution CT scan of the lung revealed a small cystic lesion, and bronchoalveolar lavage (BAL) showed an increased number of S-100 positive cells. Steroid therapy resulted in complete resolution, and no S-100 positive cells were obtained in the follow-up BAL study.

Adolescent↗