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Biomedical subjects

Y Shiokawa

Publications and source records attributed to Y Shiokawa.

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

Mitral valve replacement using bileaflet mechanical prosthetic valve in the first year of life.

OBJECTIVE: The operative management and long term outcome of mitral valve replacement in infancy remain a therapeutic challenge. The selection of a prosthetic valve for this particular age group might affect the clinical outcome. Here we present our experience of mitral valve replacement in 6 infants using small bileaflet mechanical prosthetic valves. METHODS: Between January 1994 and August 1997, 6 infants (their age ranged from 3 months to 11 months, and their body weight from 2978 g to 7403 g) underwent mitral valve replacement using a mechanical valve prosthesis (16 mm CarboMedics prosthetic valve in 5, and 17 mm St. Jude Medical prosthetic valve Hemodynamic Plus in 1). The preoperative morphological features of the mitral valve were stenosis in 1, regurgitation in 3, and a combination of these in 2. The prosthesis was fixed at the annulus in 3, and at the supra-annular position in 3. Anticoagulation was performed using warfarin. RESULTS: There was no operative mortality. Postoperative catheterization revealed an acceptable wedge pressure in the pulmonary arteries, ranging from 10 to 12 mmHg. During the mean follow-up period of 36 months, late death due to residual pulmonary hypertension occurred in 1 patient at 10 months after surgery. Excluding this patient, all remaining patients are doing well with no need for repeated operation with no thromboembolic complication. The actuarial survival rate and the reoperation free rate at 70 months are 83 +/- 15% and 100%, respectively. CONCLUSION: Mitral valve replacement using a small size bileaflet mechanical prosthetic valves in infancy can be performed with low operative mortality and with satisfactory mid-term results.

Follow-Up Studies↗
PubMed2000

Clinicopathological study of intracranial fusiform and dolichoectatic aneurysms : insight on the mechanism of growth.

BACKGROUND AND PURPOSE: Intracranial fusiform aneurysms can be divided into 2 clinically different subtypes: acute dissecting aneurysms and chronic fusiform or dolichoectatic aneurysms. Of these 2, the natural history and growth mechanism of chronic fusiform aneurysms remains unknown. METHODS: A consecutive series of 16 patients with chronic fusiform aneurysms was studied retrospectively to clarify patient clinical and neuroradiological features. Aneurysm tissues were obtained from 8 cases and were examined to identify histological features that could correspond to the radiological findings. RESULTS: Four histological features were found: (1) fragmentation of internal elastic lamina (IEL), (2) neoangiogenesis within the thickened intima, (3) intramural hemorrhage (IMH) and thrombus formation, and (4) repetitive intramural hemorrhages from the newly formed vessels within thrombus. IEL fragmentation was found in all cases, which suggests that this change may be one of the earliest processes of aneurysm formation. MRI or CT detected IMH, and marked contrast enhancement of the inside of the aneurysm wall (CEI) on MRI corresponded well with intimal thickening. Eight of 9 symptomatic cases but none of 7 asymptomatic cases presented with both radiological features. CONCLUSIONS: Data suggest that chronic fusiform aneurysms are progressive lesions that start with IEL fragmentation. Formation of IMH seems to be a critical event necessary for lesions to become symptomatic and progress, and this can be monitored on MRI. Knowledge of this possible mechanism of progression and corresponding MRI characteristics could help determine timing of surgical intervention.

Adult↗
PubMed2000

Asymmetric synthesis and determination of the absolute configuration of FK584, an agent for the treatment of overactive detrusor.

FK584[(-)-N-tert-butyl-4,4-diphenyl-2-cyclopentenylamine hydrochloride, (-)-4-HCl], a potential candidate for the treatment of overactive detrusor, was synthesized in a 4-step approach starting with Sharpless oxidation of cyclopentenol 6 (kinetic resolution). This epoxidation is a rare case in that the empirical rule does not work. Regio- and stereoselective introduction of tert-butylamine to the obtained epoxycyclopentanol 5 and subsequent conversion of the resulting diol to an olefin completed the synthesis. The absolute configuration of FK584 was determined to be S by X-ray crystallographic analysis of the salt of S-(+)-mandelic acid.

Amines↗
PubMed2000

[Patching of the raw surface of the posterior right ventricular wall in Ross procedure to prevent bleeding and to confirm anastomosis of the conduit].

An 8-year-old boy underwent Ross procedure to repair aortic regurgitation and subaortic stenosis. In reconstruction of the right ventricular outflow tract, the raw surface of the right ventricular posterior wall was covered with autologous pericardial patch to prevent bleeding and to confirm the anastomosis of the pulmonary tract conduit made of expanded polytetrafluoroethylene. Bleeding from the posterior wall was absent and he led uneventful postoperative course. Same technique was used in 4 other patients, and satisfactory results were obtained. This technique, first reported from India, seems very useful in Ross procedure.

Anastomosis, Surgical↗
PubMed1999

Norwood procedure without circulatory arrest.

In the Norwood procedure for hypoplastic left heart yndrome, the distal descending thoracic aorta was cannulated just superior to the diaphragm through median sternotomy. In combination with cerebral perfusion through the graft anastomosed to the innominate artery, which was used as a systemic-to-pulmonary shunt later, this technique enabled us to completely avoid circulatory arrest and deep hypothermia throughout the operation.

Anastomosis, Surgical↗
PubMed1999

Clinical results of mitral valve repair by reconstructing artificial chordae tendineae in children.

OBJECTIVE: There are an increasing number of reports concerning mitral valve repair by reconstructing the chordae tendineae with the use of expanded polytetrafluoroethylene sutures in adults. However, little information is available about application or results of this technique in children. METHODS: Between January 1995 and December 1997, 16 children who had from moderate to severe mitral regurgitation mainly as the result of a prolapse of the anterior leaflet (age range, 5 months-12.8 years) underwent mitral valve repair by reconstruction of artificial chordae. Either unilateral or bilateral Kay-Reed annuloplasty was also performed to correct annular dilatation in all patients. RESULTS: No operative death or morbidity was observed. Before discharge, immediate postoperative echocardiography showed less than trivial mitral regurgitation in all patients. The follow-up was complete in all cases by a clinical examination and serial echocardiograms, and the median follow-up period was 14.8 months (range, 1.3-26.4 months). There were no valve-related events during the entire follow-up period. The degree of mitral regurgitation, estimated by echocardiography performed at recent follow-up period, was none in 5 patients, trivial in 10 patients, and mild in 1 patient. The diastolic and systolic dimensions of the left ventricle decreased and were 95.0% and 96.2% of the normal values, respectively. CONCLUSIONS: Although further investigations and long-term results are still called for, mitral valve repair by reconstruction of the artificial chordae was found to be safe and effective even in infants and children.

Adult↗
PubMed1999

Clinical results of arterial switch operation for double-outlet right ventricle with subpulmonary VSD.

OBJECTIVE: An arterial switch operation is considered a good alternative for the repair of double-outlet right ventricle (DORV) with atrioventricular concordance connection and subpulmonary ventricular septal defect (VSD) when intraventricular rerouting is not feasible. The clinical results of an arterial switch operation with ventricular septal defect closure for this anomaly were studied. METHODS: Between 1986 and 1997, 27 patients ranging from 10 days to 5 years of age (mean 0.4 years) underwent an arterial switch operation with ventricular septal defect closure for the correction of double outlet right ventricle with subpulmonary VSD. The 50% rule was used to define double-outlet right ventricle. Arch anomalies were associated in nine cases, and were corrected either previously or simultaneously. A subarterial muscle resection was performed in 14 without any subsequent stenosis of the ventricular outflow tract. The relationship of the great arteries was mostly anteroposterior in 15 and mostly side by side in 12. The left coronary artery (main trunk or circumflex artery) courses behind the pulmonary artery in 15/27 (six/15 in the anteroposterior relation and ten/12 in the side by side relation). The Lecompte maneuver was used to reconstruct the pulmonary artery in all but five cases with a side by side relationship of the great arteries. RESULTS: There was one operative death (3.7%) and three late deaths. The actuarial survival rate was 83 +/- 8% at 9 years. Right ventricular outflow tract obstruction including peripheral pulmonary stenosis developed in seven cases operated on in the early era. The reoperation free rate was 46 +/- 20% at 9 years. CONCLUSION: Although double-outlet right ventricle with subpulmonary VSD has complex features, including an aortic arch obstruction and coronary artery anomalies, an optimal definitive surgical repair using an arterial switch operation can be performed safely with a thorough understanding of this variable anomaly. The prevention of right ventricular outflow tract obstruction at the time of an arterial switch operation may thus help improve the rate of late morbidity.

Child, Preschool↗
PubMed1999

[Spinal anesthesia for a patient with long-term SMON].

SMON (subacute myelo-optico-neuropathy) may result from clioquinol neurotoxicity. An 81-year-old woman underwent internal fixation for left intertrochanteric fracture. She had been diagnosed as having SMON twenty years previously. Sensory examination revealed paresthesia and decreased deep sensation in the lower extremity. A recent neuropathological report shows that in long-term SMON of about fifteen years, degeneration is located from the medulla oblongata to T5-6. We performed spinal anesthesia of which the level of analgesia was below T5-6 in the present case. The level of anesthesia was determined by the pinprick test, and was recognized as below T10. Postoperatively, both the sensory level of analgesia and vital signs remained stable. There was no worsening of neurological findings after spinal anesthesia, including the postoperative period. In conclusion, spinal anesthesia which was limited to below the level of degeneration could be applied in a case of long-term SMON.

Aged↗
PubMed1999

A new technique of surface anatomy MR scanning of the brain: its application to scalp incision planning.

BACKGROUND AND PURPOSE: Surface anatomy scanning (SAS) is an established technique for demonstrating the brain's surface. We describe our experience in applying SAS with superposition of MR venograms to preoperative scalp incision planning. METHODS: In 16 patients, scalp incision planning was done by placing a water-filled plastic tube at the intended incision site when we performed SAS using half-Fourier single-shot fast spin-echo sequences. Two-dimensional phase-contrast MR angiograms were obtained to demonstrate the cortical veins and then superimposed upon the SAS images. The added images were compared with surgical findings using a four-point grading scale (0 to 3, poor to excellent). RESULTS: In each case, neurosurgeons could easily reach the lesion. Surgical findings correlated well with MR angiogram-added SAS images, with an average score of 2.56. CONCLUSION: Our simple technique is a useful means of preoperatively determining brain surface anatomy and can be used to plan a scalp incision site.

Adult↗
PubMed1999

[Clinical results of mitral valve surgery in children].

The clinical results of mitral valve surgery in children were evaluated. Fifty children (age ranged between 1 month and 12 years) with mitral valve regurgitation have undergone valve surgery with low operative mortality (2%). Valve plasty using several techniques including annuloplasty have been performed with quite high success rate (92%), while valve replacement was required in four patients who had the prolapse of the anterior mitral leaflet (8%). Reoperation was required in 5 patients (10%), and there were 4 late deaths. Introduction of the reconstructive technique of the chordae tendinae using artificial chordae resulted 100% success rate of mitral repair for the prolapse of the anterior mitral leaflet without death and reoperation. The reoperation free rate and the actuarial survival rate at 15 years of the patients with mitral regurgitation were 70 +/- 12% and 85 +/- 7%, respectively. In ten patients with mitral valve stenosis (age ranged between 1 month and 5 years), 5 patients required valve replacement (50%), and 2 patients died (20%). The clinical results of the surgery for the mitral stenosis were still unsatisfactory, and the reoperation free rate at 2 years was 42 +/- 30% and the actuarial survival rate at 13 years were 32 +/- 18%.

Blood Vessel Prosthesis↗
PubMed1999

[Descending aorta perfusion through median sternotomy in primary repair of aortic interruption complex].

Circulatory arrest is frequently used in aortic arch reconstruction in pediatric cardiac surgery. However, risks of postoperative acute renal failure and neurological deficit can not be ignored. We performed primary repair of aortic interruption in one-month old girl. After commencing extracorporeal circulation with bicaval venous cannulae and with arterial cannulae into the pulmonary trunk and the innominate artery, the descending aorta was cannulated just superior to the diaphragm. The cannula in the pulmonary trunk was then removed. Arch reconstruction and closure of the ventricular septal defect were performed with continuous perfusion to the brain and the lower body. The extracorporeal circulation time and the aortic cross-clamp time were 117 min and 21 min, respectively. Postoperative renal function was excellent, and there was no finding of neurological deficit. Cannulation of the descending aorta is a simple and useful technique with safety, in arch reconstruction in infants.

Aorta, Thoracic↗
PubMed1999

[Efficacy of intravenous administration of atrial natriuretic peptide after cardiac surgery in neonates and infants].

Intravenous infusion of alpha-human atrial natriuretic polypeptide (hANP) and furosemide was performed in 12 patients (4: TGA, 3: univentricular heart, 3: HLHS, 2: VSD) after cardiopulmonary bypass. Their mean age at the operation was 68 days (6 patients in neonate), the mean body weight was 3.3 kg. All patients were treated with nitroglycerin in dose of 2 micrograms/kg/min and chlorpromazine in dose of 2.8 micrograms/kg/min and catecholamine in mean dose of 6.5 micrograms/kg/min. The criteria of indication for hANP was poor effect of furosemide alone. The hANP was given for 6-144 hours in dose of 0.1-0.2 microgram/kg/min. With the hANP and furosemide infusion, urine volume increased from 85.0 +/- 14.2 ml/kg/day to 107.9 +/- 25.3 ml/kg/day (p < 0.05), whereas the systemic arterial pressure, the central venous pressure and the renal function were unchanged. We conclude that the combination of the hANP and the furosemide is very effective in neonates and infants.

Atrial Natriuretic Factor↗
PubMed1998

The surgical anatomy of the left ventricular outflow tract in hearts with ventricular septal defect and aortic arch obstruction.

BACKGROUND: Profound understanding of the left ventricular outflow tract (LVOT) anatomy is crucial to improve surgical results in patients with aortic arch obstruction, ventricular septal defect, and subaortic stenosis. METHODS: We studied the morphology of the LVOT in 32 postmortem hearts with aortic arch obstruction and a ventricular septal defect. In case of subaortic obstruction, the length of the subaortic muscular component was measured anteriorly and posteriorly within the left ventricle. RESULTS: Seven of the 32 hearts had no subaortic stenosis. Nine had aortic override, which caused LVOT narrowing. Sixteen hearts contained a subaortic shelf, downstream to the ventricular septal defect, which deviated into the left ventricle in 15. In 10 of these the shelf was muscular; in 6 it was a fibrous ridge. In cases with a muscular shelf, the posterior part was significantly shorter than the anterior part (p < 0.004). In 9 hearts the LVOT was further narrowed because of the abnormal relationship between the mitral valve and the subaortic shelf. CONCLUSIONS: The present study confirms the complexity of LVOT stenosis in aortic arch obstruction and ventricular septal defect and provides a better understanding of the options to achieve surgical relief.

Aorta, Thoracic↗
PubMed1998

Clinical results of the staged Fontan procedure in high-risk patients.

BACKGROUND: For high-risk Fontan candidates, the introduction of a bidirectional Glenn shunt before total cavopulmonary connection (a two-staged strategy) may extend the indications for the Fontan procedure. The clinical results of the two-staged and one-staged Fontan procedure were thus reviewed and compared. METHODS: Between November 1991 and July 1996, the two-staged strategy was performed in 40 high-risk Fontan candidates with a mean interval of 17.2 months after introducing the bidirectional Glenn shunt (staged group). We considered a young age (<2 years), high mean pulmonary arterial pressure (> or =20 mm Hg), high pulmonary vascular resistance (> or =3 Wood units), small pulmonary artery (Nakata index <200 mm2/m2), atrioventricular valve incompetence (> or = moderate), distortion of pulmonary artery, anomalous pulmonary venous return, and poor ventricular function as risk factors for the successful completion of Fontan circulation. During the same period, 68 patients underwent the modified Fontan procedure in a one-step fashion (primary group). RESULTS: In the staged group after the bidirectional Glenn shunt, the mean pulmonary arterial pressure and ventricular end-diastolic pressure were both found to have decreased significantly to the same level as those in the primary group, whereas the pulmonary artery demonstrated a significantly smaller size than that in the primary group. Operative morbidity was similar in both groups. Operative mortality was also similar and low in both groups (1.5% in the primary group and 0% in the staged group). CONCLUSIONS: A bidirectional Glenn shunt was found to be a useful interim palliation in high-risk Fontan candidates. This two-staged strategy may extend the operative indications for the Fontan procedure.

Adolescent↗
PubMed1998

Mixed type of total anomalous pulmonary venous connection.

BACKGROUND: The mixed type of total anomalous pulmonary venous connection is a rare condition in which some diagnostic and surgical problems still remain to be solved. METHODS: In 9 patients a single pulmonary vein was connected to the systemic vein at a site different from the drainage site of the confluence of three other pulmonary veins. In 2 other patients, four pulmonary veins made a confluence which had two drainage sites. Correct diagnosis was made in all 7 patients who received cardiac catheterization but only in 5 of the 9 patients by color Doppler echocardiography. Total correction was performed in 3 patients and the single anomalous pulmonary vein was left uncorrected in 8 other patients. RESULTS: There were two in-hospital deaths. Seven patients with a single residual anomalous pulmonary vein have been in good condition without clinical symptoms of congestive heart failure or pulmonary hypertension. CONCLUSIONS: Diagnosis of mixed type of total anomalous pulmonary venous correction by echocardiography is sometimes difficult. When a mixed type is suspected, cardiac catheterization is recommended if the condition of the patient permits it. A single anomalous pulmonary vein may be left uncorrected without serious complications, but close observation is needed to prevent congestive heart failure and pulmonary vascular obstructive disease.

Cardiac Catheterization↗
PubMed1998

A combined surgical and endovascular treatment for a case with five vertebro-basilar aneurysms and bilateral internal carotid artery occlusions.

BACKGROUND: Whereas multiple aneurysms may be found in 20% of patients in whom one aneurysm is discovered, the identification of five vertebrobasilar aneurysms is distinctly rare. We described such a case treated by surgical and endovascular method. CASE DESCRIPTION: A case of multiple aneurysms treated with combined surgical clipping and intravascular surgery is described. Five separate posterior circulation aneurysms and bilateral internal carotid artery occlusion were identified in one patient. Three of the aneurysms were treated surgically. Access to the fourth aneurysm was deemed difficult because of its location and because of the previously placed surgical clips; this aneurysm was treated by endovascular approaches that provided optimum therapy in this unusual multiple aneurysms case. CONCLUSIONS: We have described an unusual case of multiple posterior circulation aneurysms in the setting of bilateral internal carotid occlusions, treated by a combination of surgical and endovascular therapies. We will be able to provide safer treatment for such difficult cases in the future.

Adult↗