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Biomedical subjects

N Atsumi

Publications and source records attributed to N Atsumi.

At least 19 recordsLinked to original sources
PubMed2003

[Management of mediastinitis after pediatric cardiac surgery with continuous closed irrigation method].

Two cases are presented as a successful management for mediastinitis with the continuous closed irrigation method after pediatric cardiac surgery. The continuous closed irrigation method has significant advantages over conventional open irrigation method or muscle flap in pediatric cases, because the system is simple to handle and easy to wash out any infectious tissue debris without additional invasive intervention. However, adequate duration of the irrigation and subsequent antibiotic regimen is still unclear. We conclude that the continuous closed irrigation method is an effective management which is applicable to most of mediastinitis cases after pediatric cardiac surgery.

Blood Vessel Prosthesis Implantation↗
PubMed2001

Persistent fifth aortic arch associated with type A aortic arch interruption. Histological study and morphogenesis.

A male infant, having a persistent fifth aortic arch and interruption of the aorta distal to the left subclavian artery, underwent successful surgical treatment. A histological study of the excised segment of the aorta showed that the ductal tissue extended to the junction between the fifth arch and the descending aorta with consequent narrowing in the corresponding region. The ductal tissue, however, did not contribute to occlusion in the fourth aortic arch. The morphogenesis of this combination of aortic arch anomalies was also discussed.

Aorta, Thoracic↗
PubMed2000

Extended septoplasty for subaortic stenosis developed 19 years after double-outlet right ventricle repair.

A 27-year-old woman developed subaortic stenosis 19 years after double-outlet right ventricle repair. Subaortic stenosis was caused by a narrow ring of fibromuscular ridge associated with a bulge of the underlying septal muscle. The aortic valve was bicuspid and stenotic. We conducted extended septoplasty, replacing the aortic valve. Postoperative cineangiogram showed an adequate left ventricular outflow pathway. Double-outlet right ventricle repair may thus be followed by subaortic stenosis as long as 19 years after initial surgery. This lesion was assumed due to acquired disease secondary to flow disturbances in the left ventricular outflow, so reconstructing an adequate outflow pathway is effective and appears to help avoid recurring stenosis.

Adult↗
PubMed1999

Atrial fibrillation after coronary artery bypass grafting. An increase in high-frequency atrial activity in patients with right coronary artery revascularization.

The increase in atrial high-frequency activity has been reported as a marker of the risk of paroxysmal atrial fibrillation. The presence of proximal right coronary artery disease is a predictor of atrial fibrillation after bypass surgery, however, the potential mechanism remains controversial. In this study, high-frequency atrial activity to clarify the electrophysiologic background for the predisposition to have proximal right coronary artery disease leading to atrial fibrillation after coronary revascularization was investigated. Before and soon after coronary revascularization, frequency analyses were performed on the 100 ms segment at the end of signal-averaged P waves in 22 patients with right coronary artery disease as opposed to the 23 patients without disease. Under the spectrum curve, area ratio (AR50) and magnitude ratios (MR) were calculated as follows; AR50 = (area 20-50 Hz/0-20 Hz) x 100, and MR = (magnitude at 20, 30, 40 and 50 Hz, respectively/maximal magnitude) x 100. In patients with proximal right coronary artery disease, high-frequency atrial components increased significantly in the 20 to 50 Hz range after coronary revascularization, and the incidence of postoperative atrial fibrillation was higher than in those without disease. In patients without right coronary artery disease, the frequency distribution of P waves was unchanged. Postoperatively, the two groups showed the same atrial frequency distribution. This data suggests that the increase in high-frequency atrial activity after right coronary artery revascularization might be associated with the pathogenesis of postoperative atrial fibrillation.

Adult↗
PubMed1999

Aortic dissection in an elderly patient with atrial septal defect.

We report a case of acute aortic dissection that occurred in the late course of surgically untreated atrial septal defect. A 60-year-old man with acute aortic dissection and atrial septal defect was operated on successfully, and we discuss the causal relationship between these two unusual conditions.

Aortic Dissection↗
PubMed1999

Low-dose protamine based on heparin-protamine titration method reduces platelet dysfunction after cardiopulmonary bypass.

OBJECTIVE: The heparin-protamine titration method that uses the Hepcon hemostasis management system (Medtronic HemoTec Inc, Englewood, Colo) reduced blood loss in cardiac surgery in previous reports, but the mechanism is not fully understood. This study tests the hypothesis that reduced protamine administration preserves platelet function in human cardiac surgery. METHODS: Platelet count, alpha-granule secretion, and aggregation to thrombin before and after cardiopulmonary bypass in human beings were evaluated. In the control group (n = 14), a fixed dose of protamine (3 mg/kg) was administered. In the titration group (n = 20), protamine doses were based on the heparin concentration measured by the Hepcon system. RESULTS: Heparin concentrations before protamine administration were higher in the titration group (P =.0012), but protamine doses of patients in the titration group were markedly lower than those of the control group (P <.0001). During protamine infusion at a rate of 0.3 mg. kg(-1). min(-1), the percentage of granule membrane protein-140-positive platelets significantly increased in the control group compared with the titration group (18.8% +/- 8.6% vs 13.0% +/- 5.3%, P =.0188). After protamine administration, aggregation of washed platelets to thrombin recovered almost to the preoperative level in the titration group; however, it remained lower in the control group (20% +/- 20% vs 55% +/- 18%, P =.0009). CONCLUSION: Low-dose administration of protamine, based on a heparin-protamine titration method, restores not only the blood coagulation but also the platelet responses to thrombin and attenuates platelet alpha-granule secretion during heparin neutralization. Overdose of protamine activates platelets and may predispose patients to excessive bleeding after cardiac surgery.

Blood Loss, Surgical↗
PubMed1999

Lower extremity hematoma as a complication of warfarinization in patients with artificial heart valves.

Four cases of lower extremity hematoma in patients undergoing anticoagulant therapy after heart valve replacement are herein reported, with special emphasis on the comparative diagnostic value of ultrasonography and computerized tomography. Although conservative management is sufficient for patients with no neurological impairment, needle aspiration after autolysis of the hematoma, which can be confirmed by CT study, is also recommended.

Acute Disease↗
PubMed1999

[A case of lateral femoral circumflex artery as a free graft for coronary artery bypass surgery].

A 46-year-old man had a three-vessel coronary disease. We performed quadruple coronary artery bypass grafting (CABG) with the left internal thoracic artery (LITA), right gastroepiploic artery (RGEA), saphenous vein and lateral femoral circumflex artery (LFCA). Postoperative coronary angiogram showed that the LFCA bypass graft was patent and supplied sufficient blood to the anastomosed vessel. There was no stenosis at the anastomotic site. However, the LFCA graft showed a string sign. Long-term follow-up and angiographic studies is necessary to establish the use of LFCA as an arterial free graft for coronary revascularization.

Cardiac Surgical Procedures↗
PubMed1998

Right thoracotomy as an alternative for redo mitral valve replacement and concomitant repair of the tricuspid valve.

BACKGROUND: We report the results of a right thoracotomy for reoperation on the mitral plus concomitant procedures. Access to aorta or repair of other lesions by this approach is controversial. EXPERIMENTAL DESIGN AND SETTING: Retrospective study. Institutional practice (University of Tsukuba Hospital, Tsukuba Japan). METHODS: Until 1995, 9 patients underwent right thoracotomy for mitral reoperation. The indication for this approach was no retrosternal space with the pericardium left open. Seven patients had deteriorated bioprosthesis, 1 periprosthetic valve leakage, and 1 re-stenosis. Four were associated with moderate tricuspid regurgitation. Operations were performed under fibrillation. Cardioplegia was used in 1. RESULTS: Through thoracotomy, 4 underwent mitral valve re-replacement, and 4 mitral valve re-replacement plus tricuspid annuloplasty. One was abandoned because of severe pleural adhesion. No neurological injury, or perioperative myocardial infarction occurred. CONCLUSIONS: The right thoracotomy was an effective alternative to repeat sternotomy for redo mitral valve operation. Also, concomitant repair of the tricuspid valve could be safely done by this approach.

Aged↗
PubMed1997

Aprotinin inhibits plasmin-induced platelet activation during cardiopulmonary bypass.

BACKGROUND: In the past few years, aprotinin has been used in cardiac surgery with impressive results of reducing blood loss, but several adverse effects of aprotinin also have been reported. One of the most likely mechanisms is the inhibition of plasmin by aprotinin, although this indirect effect has not been reproduced in all experimental studies. METHODS AND RESULTS: We evaluated the platelet function and fibrinolytic activity during human cardiac surgery, with or without aprotinin. During cardiopulmonary bypass (CPB) in humans without aprotinin (n=16), decrease of platelet aggregation induced by thrombin, increase of alpha-granule secretion of platelet and microparticle formation, and increase of plasmin/alpha2-antiplasmin complex (PIC) were observed. In contrast, low-dose aprotinin (1.0 x 10(6) KIU), which was administered only into the priming fluid of extracorporeal circuits (n=10), maintained platelet aggregation induced by thrombin and reduced alpha-granule secretion and microparticle formation of platelets during CPB. In vitro, plasmin (0.8 CU/mL) released alpha-granules of washed platelets, and this activation was completely inhibited by aprotinin (10 KIU/mL). CONCLUSIONS: Aprotinin has indirect effects to inhibit platelet activation, and this may partly explain the reduction of blood loss during cardiac surgery. To prevent the adverse effects, a single and minimal use of aprotinin is important. The results of in vivo and in vitro studies suggest that platelet preservation was demonstrated by the lower concentration of aprotinin (1.0 x 10(6) KIU per patient or 10 KIU/mL) compared with the concentration that inhibits plasma fibrinolysis.

Aged↗
PubMed1997

[Aortic valve regurgitation due to quadricuspid valve: a report of complicated case].

A 66-year-old male with the congestive heart failure was diagnosed grade 4 aortic valve regurgitation due to quadricuspid valve associated with bacterial endocarditis, widely patent left coronary artery ostium, chronic renal failure, and secondary hyperparathyroidism. Coronary arteriography showed that the size of left coronary ostium was widely patent 10 mm in diameter, and trans-esophageal echo cardiogram revealed perforation and vegetations on the coronary cusps of the aortic valve.

Aged↗
PubMed1997

[NO inhalation therapy for post-operative pulmonary hypertensive crisis of the case of truncus arteriosus].

Two-months-old baby underwent complete correction by Barbero-Marcial's procedure for type I truncus arteriosus. Postoperative hemo-dynamics was fairly stable immediately after the operation. However, the acute rise in pulmonary pressure occurred on the 2nd postoperative day. The pulmonary vasodilation therapy with prostaglandin E1 and amrinone had failed. Thirty ppm of inhaled nitric oxide (NO) was started and it resulted in an immediate decrease in pulmonary arterial pressure. Complete weaning from NO was achieved 9 days after surgery by simultaneous administration of PGE1 and amrinone. Although inhalation of NO reduced pulmonary arterial pressure, combination of PGE1 and amrinone with NO inhalation exerted a pulmonary vasodilation and brought the patient to full recovery in this case with pulmonary hypertensive crisis.

Administration, Inhalation↗
PubMed1996

[Inhaled nitric oxide for postoperative pulmonary hypertensive crisis in a patient with complete atrioventricular canal associated with Down's syndrome: a case report].

Two-year-old boy with Down's syndrome was treated with inhaled nitric oxide for pulmonary hypertensive crisis after correction of complete atrioventricular canal and persistent ductus arteriosus. The acute rise in pulmonary pressure and hemodynamic instability occurred on 3rd, 4th and 6th post operative days and pulmonary vasodilation with prostaglandin E1 and amrinone had failed. Twenty ppm of inhaled nitric oxide effectively reduced the pulmonary pressure and the patient was subsequently weaned from ventilation. Inhaled nitric oxide exerted a pulmonary vasodilation without decreasing systemic pressure in this patient with postoperative pulmonary hypertensive crisis.

Acute Disease↗
PubMed1996

[Management of postoperative pulmonary hypertensive crisis in children--indication and usefulness of inhaled nitric oxide therapy as a pulmonary vasodilator].

Among 176 pediatric patients who underwent open heart surgery from 1990 to 1996, 7 developed severe pulmonary hypertensive crisis (PHC) postoperatively. All patients were treated with conventional medical therapy consisting of hyperventilation and deep sedation. Prostaglandin E1 and/or amrinone were administered initially as a pulmonary vasodilator, and in 3 of the 7 patients this resulted in immediate improvement in hemodynamics. These patients subsequently weaned off ventilatory support and they were discharged from the hospital. In 4 other patients, pulmonary vasodilator therapy with prostaglandin E1 and amrinone had failed and they were treated with inhaled nitric oxide (NO). In all patients, inhalation of NO resulted in immediate decrease in pulmonary pressure without significant change in systemic arterial pressure. Two patients successfully weaned from the ventilator, whereas in 2 patients decrease in pulmonary pressure was transient. They developed airway bleeding and died as a result of respiratory insufficiency. Although inhaled NO effectively reduced pulmonary pressure in patients with PHC, this effect was not maintained over 12 hours in patients associated with bronchopulmonary dysplasia. In patients at risk for severe PHC, rapid treatment with NO inhalation after initial event as well as the prevention of lung injury caused by mechanical ventilation were found to be important in the postoperative management.

Administration, Inhalation↗
PubMed1996

[Anatomic correction of double-outlet right ventricle associated with hereditary spherocytosis--a case report].

A 3-year-old boy with hereditary spherocytosis (HS) underwent anatomical correction for double-outlet right ventricle. In addition to acute injury to the red blood cells during cardiopulmonary bypass, chronic mechanical trauma related to the presence of internal conduit and transannular patch must be considered in this patient with HS. We therefore performed splencetomy prior to cardiac surgery to prevent perioperative serious hemolysis. Preoperative examination showed the anatomy was considered suitable for REV procedure. The position of the aorta was anterior, VSD was classified as subpulmonic and associated with subvalvular stenosis. Under cardiopulmonary bypass, infundibular septum was resected and intraventricular tunnel was constructed. The pulmonary artery was transected at the level of the valve commissures and translocated onto the right ventricle without transection of aorta. Right ventricular outflow tract was reconstructed with a patch bearing monocusp. No serious complication due to hemolysis occurred perioperatively. Postoperative angiocardiography revealed no stenosis in both left and right ventricular outflow tract. The patient was discharged on the 57th postoperative day and is doing well.

Child, Preschool↗
PubMed1995

Distal circulatory support for thoracic aortic operations: effects on intracranial pressure.

Spinal cord ischemia can result from aortic clamping during thoracic aortic operations. The perfusion gradient for spinal cord perfusion is positively influenced by distal aortic pressure and negatively influenced by intracranial pressure (ICP). Hemodynamic and ICP changes were examined in a swine model of descending thoracic aortic surgery where distal aortic perfusion was achieved under one of three conditions: (1) clamping without support, (2) a passive aortofemoral shunt, or (3) a left atrium-femoral artery bypass system. With aortic clamping alone, ICP increased from 9.8 +/- 2.2 mm Hg to 15.2 +/- 2.8 mm Hg (p < 0.05). With passive shunting, ICP was decreased to 13.8 +/- 3.0 mm Hg, which was still significantly elevated above baseline. However, with active bypass, ICP remained at control level (9.8 +/- 2.2 mm Hg). Mean distal aortic pressure, which was 82 +/- 10 mm Hg in the control state, decreased to 20 +/- 0.5 mm Hg with clamping alone and to 39 +/- 9 mm Hg with passive shunting, whereas with active support, a distal pressure of 64 +/- 8 mm Hg was achieved. In contrast to passive shunting, active distal bypass results in maintenance of ICP at baseline levels and results in distal aortic pressure significantly greater than that achieved with either aortic clamping alone or passive shunting. Thus, active distal circulatory support produces the greatest salutary effect on the two determinants of the spinal cord perfusion pressure gradient: ICP and distal aortic pressure. This support modality may be the best adjunctive technique to maintain the spinal cord perfusion gradient and hence minimize the risk of ischemic injury.

Animals↗