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Biomedical subjects

K Fukae

Publications and source records attributed to K Fukae.

At least 19 recordsLinked to original sources
PubMed2001

[Reoperation for obstructed extracardiac valved conduit after Rastelli operation].

Between July 1988 and November 2000, 61 patients who were 11.3 +/- 3.8 years old underwent reoperation for obstructed extracardiac valved conduit at 7.0 +/- 2.1 years after Rastelli operation. The right ventricular outflow tract was reconstructed with nonvalved (n = 36) or valved (n = 9) conduit and Danielson's procedure (n = 16). One patient who underwent Danielson's procedure and concomitant aortic valve replacement died in 7 days after reoperation. Mean systolic pressure gradient across the right ventricular-pulmonary artery decreased from 58.6 mmHg to 14.6 mmHg. Re-reoperation was performed in 6 patients after Danielson's procedure for restenosis caused by contracture of xenograft outflow patches. There is no re-reoperation in patients with nonvalved conduit replacement. Postoperative pulmonary regurgitation by UCG was moderate in 12 patients with nonvalved conduit replacement and two with Danielson's procedure. In our experience, reoperation for obstructed extracardiac valved conduit after Rastelli operation is safe and nonvalved conduit replacement provides good midterm results.

Adolescent↗
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

Effects of intra-aortic ballon pumping on renal sympathetic nerve activity and renal circulation in dogs.

BACKGROUND: Little is known on how intra-aortic balloon pumping (IABP) affects neural circulatory regulation, even though many studies have been done to clarify the effects of IABP on hemodynamics. Although IABP is used clinically in patients with severe heart failure, whose sympathetic nerve activity is increased, there are no previous reports that demonstrate the effects of IABP on neural regulation in heart failure. The aim of this study is to determine the effects of IABP on neural regulation of renal circulation with both normal and failing heart condition in dogs. METHODS: We directly measured renal sympathetic nerve activity and hemodynamic parameters (heart rate, central venous pressure, distal aortic pressure, proximal aortic pressure, left ventricular pressure, renal sympathetic nerve activity, ascending aortic flow, and renal arterial flow) before and during IABP driving in both normal and failing heart condition in dogs (n=7). Acute heart failure models were made by coronary ligation. RESULTS: IABP driving inhibits renal sympathetic nerve activity and improves renal circulation in failing heart condition, while these phenomena do not occur in normal heart condition. CONCLUSIONS: These findings suggest that IABP may show its full effect on renal circulation via neural regulation especially in failing heart condition.

Animals↗
PubMed1999

Comparative study of retrograde and selective cerebral perfusion with transcranial Doppler.

BACKGROUND: Retrograde cerebral perfusion (RCP) is a simple technique and is expected to provide cerebral protection. However, its optimum management and limitations remain unclear. Transcranial Doppler has been used to monitor cerebral perfusion. Using this Doppler technique, we compared cerebral blood flow for RCP with that for selective cerebral perfusion. METHODS: Thirty-two consecutive patients underwent elective surgical repair of an aortic aneurysm involving the aortic arch at Kyushu University Hospital. Retrograde cerebral perfusion was used in 15 patients and selective cerebral perfusion, in 17 patients. Continuous measurement of middle cerebral artery blood flow velocities was performed by transcranial Doppler technique. RESULTS: Retrograde middle cerebral artery blood flow velocities during RCP could be measured in only 3 patients, whereas middle cerebral artery blood flow velocities during selective cerebral perfusion could be measured in all but 1 woman. The increase in middle cerebral artery blood flow velocities after RCP was significantly greater than that after selective cerebral perfusion. CONCLUSIONS: The measurement of middle cerebral artery blood flow velocities with transcranial Doppler technique is practicable during selective cerebral perfusion but difficult during RCP. The increase in middle cerebral artery blood flow velocities after RCP indicates reactive hyperemia and reflects the critical decrease in cerebral blood flow during this type of perfusion.

Adult↗
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

[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

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↗
PubMed1997

Mechanism of abrupt hypotension with stretch of right atrium during cardiac surgery.

During cardiac surgery abrupt hypotension sometimes occurs by the atrium being pulled, though the hypotensive mechanism is not known. The effects of mechanical stretching of the right atrium on haemodynamics and renal sympathetic nerve activity in the anesthetized rabbit was investigated. During stretching of the right atrial appendage with a metal weight (right atrial stretch), both mean arterial pressure (mAP) and renal sympathetic nerve activity significantly decreased. Bilateral vagotomy significantly reduced the change in mean arterial pressure with right atrial stretch (P < 0.01), and significantly increased renal sympathetic nerve activity (P < 0.01). The duration of the decreases of mean arterial pressure with right atrial stretch was significantly shortened after vagotomy. Decreases of blood flow of the descending aorta with right atrial stretch were observed and not affected by vagotomy. These results suggest that hypotension with mechanical stimulation of the right atrium is not only due to the decrease in cardiac output but also to sympathetic inhibition through the vagus via cardiac baroreflex.

Animals↗
PubMed1996

Effects of hypothermia during cardiopulmonary bypass and circulatory arrest on sympathetic nerve activity in rabbits.

OBJECTIVES: Little is known about the effect of hypothermia on neural regulation. We investigated the effects of hypothermia during cardiopulmonary bypass (CPB) on control of renal (RSNA) and lumbar sympathetic nerve activity (LSNA), and plasma catecholamine levels. METHODS: We directly measured RSNA (n = 14) and LSNA (n = 6) during CPB in anesthetized rabbits. CPB was performed via cannulae in the aortic root for arterial perfusion and the right atrium for venous drainage. Systemic hypothermia was induced by core cooling. RSNA and LSNA were recorded at the nasopharyngeal temperature of 37, 30, 24, and 18 degrees C and after rewarming up to 37 degrees C while keeping mean arterial pressure at 70 mmHg by altering perfusion flow. Other variables such as blood gases or electrolytes were kept constant. RESULTS: RSNA at the temperature of 30, 24, and 18 degrees C significantly decreased by 91, 97, and 95% from control (37 degrees C), respectively. LSNA decreased by 18, 57, and 89% from control as well. The decreases in RSNA at 30 and 24 degrees C were greater than those in LSNA (P < 0.05). At 18 degrees C both RSNA and LSNA nearly disappeared. Circulatory arrest for 20 min during hypothermia at 18 degrees C caused no increase in RSNA while it increased LSNA. Plasma catecholamine levels at 18 degrees C were not different from those at 37 degrees C. Rewarming to 37 degrees C increased RSNA and LSNA by 321 and 92% from control (37 degrees C before cooling), respectively (P < 0.01). CONCLUSIONS: Hypothermia progressively decreased and rewarming markedly increased sympathetic nerve activity, but the effects of hypothermia on RSNA and LSNA were not uniform.

Animals↗
PubMed1996

The effects of pulsatile and nonpulsatile systemic perfusion on renal sympathetic nerve activity in anesthetized dogs.

It is still controversial whether to pulse or not to pulse for the establishment of ideal extracorporeal circulation. We directly measured the renal sympathetic nerve activity in mongrel dogs (n = 10, weighing from 13 to 21 kg) to determine the effects of pulsatile and nonpulsatile systemic perfusion on the control of the sympathetic nerve activity during left ventricular assistance. Pulsatile perfusion was generated with an air-driven, diaphragm-type blood pump, and nonpulsatile perfusion was generated with a centrifugal pump. Renal sympathetic nerve activity and the blood flow of the descending aorta were then recorded during pulsatile and nonpulsatile systemic perfusion. Other variables, such as mean arterial pressure, central venous pressure, left atrial pressure, and blood gas levels, were kept constant. At the same mean arterial pressure, renal sympathetic nerve activity during pulsatile perfusion decreased significantly to 80% of renal sympathetic nerve activity during nonpulsatile perfusion (26.8 +/- 2.4 vs 33.4 +/- 2.9 spikes/sec, p < 0.01). Total systemic vascular resistance during pulsatile perfusion decreased significantly to 85% of that during nonpulsatile perfusion (5700 +/- 580 vs 6667 +/- 709 dynes.sec.cm-5, p < 0.05). These results suggest that pulsatile systemic perfusion, compared with nonpulsatile systemic perfusion, reduces sympathetic nerve activity and peripheral vascular resistance and thus may improve both microcirculation and organ function.

Animals↗
PubMed1996

Successful management of junctional tachycardia by hypothermia after a Fontan operation.

We report herein the findings of a 2-year-old boy in whom junctional tachycardia developed 2 days after he underwent a modified Fontan operation and thereafter was successfully treated by hypothermia without paralyzing and artificially ventilating the patient. Chlorpromazine was useful in achieving moderate hypothermia by surface cooling without producing any unfavorable effects associated with topical cooling.

Child, Preschool↗
PubMed1995

Maldistribution of the cerebral blood flow in retrograde cerebral perfusion.

Retrograde cerebral perfusion (RCP) through a superior vena caval (SVC) cannula has now become a useful alternative for brain protection during aortic arch operations. However, little is still known about its physiological effects, especially regarding the flow distribution in the brain. We studied the cerebral blood flow distribution under hypothermic conditions using mongrel dogs (n = 6, weighing 9.5 to 14 kg). We measured the cerebral tissue blood flow of the cortex with a laser Doppler flowmeter and cerebral tissue blood flow of the medulla using the hydrogen clearance method. The cerebral blood distribution at 28 degrees C with a whole body bypass flow of 100 ml/kg per min and aortic pressure of 88.3 +/- 20.4 mmHg was used as a control. Then the body temperature was decreased to 20 degrees C and the descending aorta was cross-clamped just distal to the origin of the left subclavian artery to establish antegrade cerebral perfusion (ACP). The perfusion flow was decreased to 54.8 +/- 12.4 ml/kg per min so as to make the aortic pressure similar to the control conditions. After measuring the cerebral blood flow distribution in ACP, the perfusion was then switched to RCP through the bilateral internal maxillary vein and the SVC pressure was kept at 40 mmHg. In RCP, the cerebral blood flow of the medulla was quite similar to that in ACP (12.4 ml/min per 100 g versus 15.2 ml/min per 100 g, NS). In contrast, the cerebral blood flow of the cortex significantly decreased to 16% of the flow in ACP (7.8 perfusion units versus 50 perfusion units, P < 0.01). Because of the maldistribution of the cerebral blood flow in RCP, careful attention should be paid to the clinical application of this method.

Animals↗