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Biomedical subjects

F Iwaya

Publications and source records attributed to F Iwaya.

At least 19 recordsLinked to original sources
PubMed1999

Cerebral blood flow and oxygen metabolism during cardiopulmonary bypass with moderate hypothermic selective cerebral perfusion.

Cerebral blood flow was measured using transcranial doppler during cardiopulmonary bypass in nine patients with selective cerebral perfusion for surgery of arch aorta (group S). For comparison, 11 adult open heart patients (group C) were also measured. The authors' selective cerebral perfusion at 28 degrees C resulted in moderate hypothermia and antegrade perfusion using independent pumps for three branches. Total flow in the three branches was 500 ml/min. A Labodop DP-100 doppler ultrasound velocimeter was used to measure middle cerebral arterial blood flow velocity. Hemoglobin concentration and oxygen saturation were also measured in arterial and jugular venous blood. The arteriovenous oxygen content difference (Ca-vO2) was calculated and multiplied by the middle cerebral arterial blood flow velocity value, which resulted in the cerebral metabolic rate for oxygen (CMRO2). The cerebral perfusion pressure of group S was lower than in group C, and the arterial carbon-dioxide tension (PaCO2) of group S was higher than in group C during cardiopulmonary bypass. Middle cerebral arterial blood flow velocity values of both groups remained constant before, during and after cardiopulmonary bypass. The CMRO2 decreased during cardiopulmonary bypass and showed no difference between the two groups. The changes in PaCO2 might be significant factors in the increase in cerebral blood flow during selective cerebral perfusion. This study supports the conclusion that, compared with our routine open heart surgery procedures, our selective cerebral perfusion procedures had the same cerebral blood flow and oxygen metabolism during cardiopulmonary bypass.

Adult↗
PubMed1998

[Partial median sternotomy for pediatric cardiac surgery].

In order to minimize scarring and thereby improve the postoperative cosmetic appearance of pediatric cardiac surgery patients, we perform partial median sternotomy incisions. A short midline skin incision, from 1 to 2 cm below the articular notch of the second rib to the xiphoid process, is made. The sternum was divided from the xiphoid process to the articular notch of the second rib. The thymus is mobilized and the pericardium incised longitudinally. The aorta and superior and inferior vena cava are mobilized to facilitate direct cannulation. Cardiopulmonary bypass is instituted in the usual fashion. Twenty-four pediatric patients underwent repair of cardiac anomalies through a partial median sternotomy incision at our institution between June 1997 and September 1998. The average age of the patients was 4 years and 4 months (range, 4 days to 12 years) and the average weight was 16.0 kg (range, 3.2 to 40.5 kg). Cases included 13 VSD (ventricular septal defect) [including one DCRV (double chambered right ventricle) and one PS (pulmonary stenosis)], 9 ASD (atrial septal defect), one ECD (endocardial cushion defect), and one DORV (double outlet right ventricle) with mitral atresia. All patients were extubated within 3 hours after surgery and the average length of the ICU stay was within 24 hours (except for one 4-day-old baby who died of LOS (low cardiac output syndrome) on the 16th postoperative day). There were no wound infections or hospital mortalities. In our experience, this approach is safe, provides good exposure, and provides excellent cosmetic results.

Cardiac Surgical Procedures↗
PubMed1998

[Partial median sternotomy for pediatric cardiac surgery].

In order to minimize scar appearance and thereby improve postoperative cosmetic appearance for pediatric cardiac surgery patients, we performed partial median sternotomy incisions. A short midline incision, from 1 to 2 cm below the articular notch of the 2nd rib to the xiphoid process, was made. The sternum was divided from the xiphoid process to the articular notch of the 2nd rib. The thymus was mobilized and the pericardium incised longitudinally. The aorta and superior and inferior vena cava were mobilized to facilitate direct cannulations. Cardiopulmonary bypass was instituted in the usual fashion. From June to December 1997, 14 patients between the ages of 4 days and 12 years have undergone cardiac repair using this technique. Cases included 7 VSD (including 4 pulmonary hypertension and 1 DCRV), 5 ASD, 1 ECD and and 1 DORV with mitral atresia. All patients were extubated within 3 hours after surgery, and there were no wound infections or hospital mortalities (except one 4 day old baby who died by LOS on the 16th postoperative day). In our experience, this approach is safe and provides good exposure with excellent cosmetic results.

Cardiac Surgical Procedures↗
PubMed1997

Evaluation of hemolysis in a pulsatile assist device for centrifugal pump.

To evaluate the blood trauma caused by a new device for producing a pulsatile flow of the centrifugal pump, the pulsatile assist device for the centrifugal pump (PAD-CP) that we have developed, a hemolysis study was performed in vitro and in animal experimentation. For the in vitro testing, 2 identical sets of hemolysis test circuits were prepared with 2,400 ml of bovine blood. The 2 circuits were pumped simultaneously. Plasma total hemoglobin levels were less than 40 mg/dl after 3 h, under a pump flow of 2 L/min. Hemolysis increased to a severe level after 4 h of 4 L/min pump flow. The cause of this hemolysis was thought to be a vibration of the circuit because of incomplete compression of the polyurethane tube in the PAD-CP. Five adult sheep (average body weight, 47 kg) were used for in vivo evaluation of hemolysis. Hemolysis was less than 30 mg/dl of plasma hemoglobin after 4 h of open chest extracorporeal circulation with 3.0-3.6 L/min of flow rate using the PAD-CP. Other hematologic changes after PAD-CP driving were within normal limits. We conclude that the PAD-CP has proven to have possible clinical applications.

Animals↗
PubMed1996

[A case of left ventricular myxoma].

Left ventricular myxoma is very rare, and only 37 cases have been reported at present time. We here report a case of surgical extirpation of a left ventricular myxoma arising from the septal wall of the left ventricule. A 74-year-old woman was examined by transesophageal echocardiography because of palpitation. It revealed a small mass in the left ventricular cavity. This mass was then diagnosed and confirmed as a myxoma by echocardiogram, CT and MRI. MRI imaging showed the intensity of the myxoma to be higher than that of the myocardium. The myxoma was removed by transaortic approach using extracorponeal circulation. The grayly gelatinous mass was 11 x 12 x 12 mm and weighed 0.6 g. It was diagnosed as a myxoma pathohistologically. The patient recovered uneventfully and was discharged four weeks after the operation.

Aged↗
PubMed1996

[A case of malignant lung fibrous histiocytoma].

Malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma in adults. However primary MFH of the lung is very rare and only a few cases have been reported in the literature. A 79-year-old man complained of coughing and was treated at our hospital. The chest X-ray and CT scan showed a mass shadow in left lung. He underwent partial resection of the left upper lobe (S 5). No other abnormal lesions were detected in the abdomen or extremities, and the tumor was diagnosed as malignant fibrous histiocytoma (MFH) of the lung. He has been well for 18 months since the operation.

Aged↗
PubMed1996

[Total cavopulmonary connection using a knitted dacron prosthesis impregnated with gelatin (GELSEAL) as an intracardiac conduit].

It is important to find a suitable vascular prosthesis as an intracardiac conduit for a total cavopulmonary connection because of the need for long-term patency. A 7-year-old girl with a double outlet of right ventricle, hypoplastic left ventricle, pulmonary atresia and single atrium with azygos connection underwent a total cavopulmonary connection using a knitted dacron prosthesis impregnated with gelatin (GELSEAL) as an intracardiac conduit. Her postoperative course was uneventful. GELSEAL is soft, easy to hand and effective at preventing blood loss. The conduit is also expected to have long-term patency because of good healing with thin and uniform pseudointimal formation. However, long-term patency especially in the right side of the heart is still unknown. She should be followed with close anticoagulant therapy and careful observation.

Anastomosis, Surgical↗
PubMed1996

[A case of congenital tricuspid regurgitation associated with atrial septal defect and peripheral pulmonary stenosis].

This report describes a 5-year-old girl with congenital tricuspid regurgitation associated with an atrial septal defect and peripheral pulmonary stenosis. The girl was diagnosed with the heart murmur at birth and recently developed the cardiomegaly. Cardiac echocardiography and catheterization showed severe tricuspid regurgitation, an atrial septal defect of the secundum type and peripheral pulmonary stenosis. In the operative findings, the tricuspid annulus was dilated to 33 mm in diameter, and leaflets were attached normally to the antomic annulus. There was a large cleft of the anterior leaflet of the tricuspid valve. Suture of the cleft and annuloplasty of the tricuspid valve, suture closure of the atrial septal defect and patch dilatation of peripheral pulmonary stenosis were successfully performed. Including this case, 19 other cases with congenital tricuspid regurgitation undergoing surgery were reported to date.

Child, Preschool↗
PubMed1995

Postoperative alteration in the size of Dacron vascular prostheses implanted in the infrarenal abdominal aorta.

The degree and significance of postoperative alteration in the size of Dacron grafts in the infrarenal abdominal aorta was assessed by computed tomography. We studied a total of 41 knitted Dacron fabric grafts, comprising 28 Gelseal triaxial grafts and 13 Hemashield Microvel grafts, and 29 woven Dacron fabric (Veri-Soft Woven) grafts which were used to replace the infrarenal abdominal aneurysms. These three types of Dacron fabric dilated immediately after replacement to 1.4-1.5 times the manufactured size, but did not dilate further after the surgery.

Aortic Aneurysm, Abdominal↗
PubMed1995

In vitro evaluation of a pulsatile assist device for a centrifugal pump using a new principle.

To induce a pulsatile flow in a centrifugal pump, we developed a new device (pulsatile assist device for centrifugal pump: PADCP) using a new concept. This device consists of a flexible polyurethane tube with an air chamber which is connected to the arterial side of the centrifugal pump circuit directly. A mock circulation system was used for evaluation of this PADCP. Thirty to 40 mm Hg of pulse pressure was obtained under 3-6 L/min of flow rate. By increasing the driving pressure of the PADCP from 200 to 600 mm Hg in a mock system, 4-48 mm Hg of pulse pressure was gained accompanied by a decrease in pump flow and increased left atrial pressure. The decreased pump flow and increased left atrial pressure were recovered easily by increasing the flow rate of the centrifugal pump. Pressures at the proximal site of the PADCP were less than 500 mm Hg. The PADCP was useful to induce a pulsatile flow in a centrifugal pump.

Blood Flow Velocity↗
PubMed1995

[A case of adult Wilms' tumor with vena caval involvement].

The patient was a 35-year-old female with the chief complaint of macrohematuria. Computerized tomographic (CT) scan, ultrasonography and magnetic resonance imaging (MRI) revealed the presence of a large and inhomogeneous mass in the left kidney, and a tumor thrombus growing in the inferior vena cava. Angiography also showed a hypervascular tumor in the left kidney. The chest X-ray and CT scan demonstrated multiple metastatic lesions in the bilateral lungs. Radical nephrectomy and thrombectomy was performed under the diagnosis of left renal tumor with its invasion of inferior vena cava. Pathological findings revealed that this tumor was nephroblastoma, and its type was clear cell sarcoma of the kidney (CCSK). The patient received chemotherapy according to National Wilms' Tumor Study (NWTS) IV chemotherapeutic drug regimen. In general, CCSK is known to have poor prognosis. However, doxorubicin has been reported to have a relatively good antitumor effect for CCSK. However, in this case, the evaluation after the first course of chemotherapy was progressive disease, because some new lesions appeared, although most old pulmonary metastatic lesions were reduced.

Adult↗
PubMed1995

[A case of ruptured thoracoabdominal aortic aneurysm complicated with high aortic occlusion].

We report a rare case of 76-year-old man who developed ruptured thoracoabdominal aortic aneurysm complicated with abdominal high aortic occlusion. His left limb was amputated due to Buerger's disease. CT showed that the aneurysm extended from the descending thoracic aorta to the upper part of the abdominal aorta and its had a maximum width of 68 x 83 mm. Angiogram revealed the aortic occlusion at the level of the left renal pelvis. We performed emergency operation, which was aneurysmectomy and replacement with artificial vascular graft, under femoro-femoral and subrenal aortic extracorporeal bypass. Because of the severe calcification at the subrenal aorta and the weak pulsation of the left renal artery, the bypass was placed from the aortic graft to the right lower limb and the left renal artery was reconstructed. Abdominal aortic occlusion might increase his hypertension and might cause aneurysmal change on the proximal aortic wall.

Aged↗
PubMed1994

[A case of left ventricular outflow tract obstruction after repair of ostium primum defect].

We report a 3-year-old girl with left ventricular outflow tract obstruction after repair of ostium primum defect. The girl had closure of an ostium primum defect performed at the age of 1 year. Two years later, she developed left ventricular hypertrophy with systolic ejection murmur. Echocardiography showed discrete stenosis of the left ventricular outflow tract. Cardiac catheterization showed a peak systolic gradient of 63 mmHg across the left ventricular outflow tract. At the reoperation, the fibrous tissue was excised and myectomy was done. After the operation the peak systolic gradient across the left ventricular outflow tract disappeared. Since there is a possibility of occurrence of the left ventricular outflow tract obstruction after repair of atrioventricular septal defect, long term follow up is mandatory.

Child, Preschool↗
PubMed1993

[A case of left atrial myxoma with ventricular septal defect and patent foramen ovale].

A 51-year-old female was referred to our institute because of chest oppressive feeling. Echocardiography and magnetic resonance imaging revealed a left atrial tumor with ventricular septal defect. At operation patent foramen ovale was recognized. After excision of the tumor including intraatrial septum, which defect was repaired using a Teflon patch, and the ventricular septal defect was closed directly.

Female↗
PubMed1993

[Left main coronary artery stenosis following aortic valve replacement using a solid coronary perfusion catheter: report of two cases].

We experienced two cases of iatrogenic left main coronary artery stenosis (IOCS) following double (aortic and mitral) valve replacement (DVR). The solid coronary perfusion catheter may attribute IOCS, with grave consequence. There have been no IOCS since the time we exchanged a solid catheter for a soft one. One case, she was successfully treated percutaneous transluminal coronary angioplasty (PTCA), because she developed angina pectoris about 5 years after PTCA. But she developed angina pectoris again and angiographically left main coronary was severe stenotic. So she was undergone aorto coronary bypass grafting (CABG) to the left anterior descending. The other case, he developed angina pectoris about 3 months after DVR. He was treated with PTCA. Angiographically left mine coronary artery stenosis reduced 50% from 90%. Generally the treatment of IOCS is CABG, but we performed PTCA for 2 patients. Because we thought it was very hazardous for us to perform them open heart surgery. When it is very hazardous to perform patients open heart surgery, they need to be performed PTCA.

Angioplasty, Balloon, Coronary↗