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Biomedical subjects

N Mitsui

Publications and source records attributed to N Mitsui.

At least 37 records · Page 2Linked to original sources
PubMed1998

[An emergency aortic valve replacement for cardiogenic shock patient with severe aortic stenosis and regurgitation using percutaneous cardiopulmonary support].

The percutaneous cardiopulmonary support system (PCPS) was used in a 64-year-old woman with cardiogenic shock due to sustained ventricular fibrillation (Vf) caused by severe aortic stenosis and regurgitation. The Vf attack was resistant to cardioversion and adrenaline for lack of left ventricular support by PCPS. She was transported to the operation theater with PCPS in situ and emergency aortic valve replacement was performed. Although preoperative cardiac resuscitation time was long (35 minutes), she was discharged from the hospital on foot without any neurological complications on 84th postoperative day. Because PCPS does not decrease left ventricular systolic stress in poorly contracting dilated heart, early surgical treatment is needed in patients with severely damaged heart.

Aortic Valve↗
PubMed1998

[Early hemodynamic effects of olprinone hydrochloride after coronary artery bypass grafting].

Our purpose was to evaluate the hemodynamic effects of olprinone hydrochloride early after coronary artery bypass grafting (CABG). Fifteen patients undergoing CABG were administered a constant infusion of 0.1 microgram/kg/min of olprinone and continued for 4 hours. No bolus infusion of olprinone was administered before continuous infusion. Systolic systemic arterial pressure, systolic pulmonary arterial pressure, systemic vascular resistance and pulmonary vascular resistance were significantly decreased. There were no significant changes in heart rate, mean central venous pressure, mean left atrial pressure and left ventricular stroke work index. Cardiac index was significantly increased, but a correlation between cardiac index and mixed venous blood oxygen saturation was not found. Double product was significantly decreased, which described above suggest that olprinone achieved improvement of left cardiac function without more myocardial oxygen consumption. Severe transient hypotension (systolic arterial pressure < 80 mmHg) after infusion of olprinone was observed in three patients. Olprinone administered soon after CABG surgery had beneficial effects in terms of improvement of hemodynamic status without more oxygen consumption and reduction of pulmonary vascular resistance. However transient hypotension was a serious clinical problem in patients after open heart surgery, especially in CABG patients who need suitable systolic arterial pressure to keep enough blood perfusion of arterial bypass grafts.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1998

[Successful emergency coronary artery bypass grafting after use of a percutaneous cardiopulmonary support system in a patient with cardiopulmonary arrest secondary to acute myocardial infarction].

A 37-year-old woman was taken to a hospital because of sudden chest pain. She lapsed into shock, and the ECG indicated acute myocardial infarction. The ECG later showed ventricular fibrillation, and the patient was given cardiac massage while being transported to our hospital, where she was resuscitated with a percutaneous cardiopulmonary support system. Emergency coronary angiography revealed 99% stenosis of the left main coronary artery. PTCA was performed, and the stenotic lesion was released, but dissection and rapid formation of a thrombus were detected in the LAD. Re-PTCA was performed, but the hemodynamics did not improve, and emergency CABG of the LAD, D1, and LCx was performed. Postoperative max CPK was 18,957 IU/L. Although postoperative MRSA pneumonia developed as a complication, weaning from the respirator was performed 17 days after the operation. The patient was discharged, ambulatory, 74 days after the operation.

Adult↗
PubMed1998

[Preoperative magnetic resonance angiography findings and postoperative neurological complications in 93 cases of CABG with cardiopulmonary bypass].

Between February 1994 and January 1997, 102 of the 146 patients treated by coronary artery bypass grafting (CABG) had undergone magnetic resonance angiography (MRA) of the brain and neck before the operation, and arterial stenosis or occlusion had been detected in 38 (36.9%) of them. Two of these patients had complicating severe calcification of the ascending aorta, and CABG was performed without cardiopulmonary bypass (CPB). Seven patients without stenotic lesions on MRA were also treated by CABG without CPB for other complications. In addition to the 102 patients one patient had been found to have occlusion of the left common carotid artery and poor enhancement of the distal portion, and as a result we switched from CABG to percutaneous transluminal angioplasty (PTCA). We enrolled 93 patients in this study excluding these 10 patients. The patients were distributed into the three groups according to the MRA findings. Group C = no stenotic lesions (58 patients). Group S = stenosis of < 70% (26 patients), Group SS = stenosis of > or = 70% (9 patients). Enhancement distal to the stenotic or occlusive lesions was good in all patients in group S and SS. We then examined them for the incidence of postoperative neurological complications. There were no significant differences among the three groups in regard to age, male/female ratio, or incidence of hypertension and hyperlipidemia. In Group S, the incidence of diabetes was significantly higher than in the other Groups. The incidence of prior stroke was significantly higher and the number of coronary arteries affected was significantly larger in group SS than the other groups. There were no significant differences among the three groups with regard to intraoperative variables. The lowest mean arterial pressure on CPB was 44.3 +/- 7.4 mmHg, 48.0 +/- 8.8 mmHg, 46.3 +/- 7.8 mmHg in Group C, S, and SS, respectively, In all groups the lowest mean arterial pressure on CPB was below 50 mmHg. There were no significant differences among the three groups with regard to time to awaken and time to extubation. Two patients experienced transient conciousness disturbance after CABG, one in Group C, the other in Group SS, but no new lesions were detected by brain CT. Only one patient, in Group C. suffered a stroke and had a new lesion on brain CT a month after the operation. No strokes occurred in the perioperative period. In nine patients with good enhancement distal to the severe stenotic or occlusive lesion on MRA of the brain and neck the lowest mean arterial pressure on CPB was below 50 mmHg, but there was no postoperative neurological complications due to the low perfusion pressure on CPB. The results of this study suggested that CABG with CPB can be performed safely in patients with good enhancement distal to the stenotic or occlusive lesions on MRA of the brain and neck.

Aged↗
PubMed1998

Isolated tricuspid regurgitation caused by a dilated tricuspid annulus.

In most of the previously reported cases of isolated tricuspid regurgitation, both tricuspid leaflets and subvalvar tissue have been absent, hypoplastic, or fused. For this reason, tricuspid valvoplasty was difficult and valve replacement was adopted in many cases. In the present case of a 52-year-old man, however, the tricuspid valve showed no abnormalities other than a severely dilated tricuspid annulus. Ring annuloplasty was performed, and this resulted in a subsequent satisfactory course without anticoagulant therapy.

Dilatation, Pathologic↗
PubMed1998

Study of left ventricular bypass using Wankel type semipulsatile blood pump.

The influence of the Wankel type semipulsatile left ventricular assistance on hemodynamics was investigated with a computer simulation and an animal experiment. A simulation circuit was constructed to express the circulatory system. A current source was added to create a semipulsatile blood pump. The left and right ventricles were replaced by variable compliances. Left heart failure was simulated by decreasing the amount of compliance change of the left ventricle. Under the condition of heart failure when semipulsatile assist flow increased, the mean aortic pressure (AoP), tension time index (TTI), and diastolic pressure time index (DPTI) increased, and the cardiac output, pulse pressure (PP), and pulsatility indicator (PI) decreased. In an animal experiment, a Wankel type blood pump was used in a calf. With the increase of the assist flow, AoP curves became less pulsatile, and PP and PI decreased in accordance, which was predicted by the numerical simulation.

Animals↗
PubMed1998

Accidental entry of an implantable cardioverter defibrillator lead into the left hepatic vein detected by transesophageal echocardiography.

We report a case of accidental entry of an implantable cardioverter defibrillator lead into the hepatic vein, which was not noted on fluoroscopy but was apparent when transesophageal echocardiography (TEE) was used incidentally. The lead was depicted in the hepatic vein as strongly echogenic, accompanied by an acoustic shadow. Additional bending of the stylet was helpful for successful advancement of the lead. TEE provides additional information in such cases, although indications for its use should be explored because of its possible complications.

Adolescent↗
PubMed1997

Trial manufacture of eccentric roller type total artificial heart.

Working toward a completely implantable total artificial heart, we have designed an eccentric roller type total artificial heart. The actuator of this artificial heart is a drum type eccentric roller that squeezes the blood chambers. The blood chambers are made of silicone rubber and are torus in shape. The shape of the artificial heart is an almost circular cylinder, and its length and diameter are 10 cm and 8 cm, respectively. The 2 main characteristics of this artificial heart are that it discharges blood in a pulsatile mode and that it requires no reversing of the motor. Because we have not completed the artificial heart yet, we have tested the eccentric roller mechanism on the prototype with an overflow type mock circulation with a 100 mm Hg afterload. The prototype worked at the roller speeds of 50, 100, and 150 rpm with flow rates of 1.7, 3.7, and 5.4 L/min, respectively. Next the prototype was connected to a Donovan type mock circulatory system and worked at roller speeds of 88-214 rpm with flow rates of 3.0-8.4 L/min against mean afterloads of 82-120 mm Hg.

Biocompatible Materials↗
PubMed1997

[Successful surgical treatment of double-outlet right ventricle with intramural coronary artery, using the modified Aubert procedure--a case report].

The modified Aubert procedure and left ventricular outflow tract reconstruction were performed successfully for double-outleft right ventricle with subpulmonary ventricular septal defect, which showed an unusual Shaher type 5a coronary artery pattern. This pattern was characterized by two coronary ostia arising from the right septal sinus and intramural segment in a left trunk of the coronary artery. In this case, the neo-pulmonary artery was reconstructed without prosthetic materials. However, postoperative echocardiography showed no evident supravalvar pulmonary stenosis. The modified Aubert procedure without prosthetic marerids can be used for double-outlet right ventricle and transposition of the great arteries which show dilated prelimonary artery.

Double Outlet Right Ventricle↗
PubMed1997

[Monitoring for spinal cord ischemia by the use of the motor evoked potentials, the evoked spinal cord potential and the segmental evoked spinal cord potential during thoracoabdominal aortic surgery--a case report].

A 55-year-old woman, who was detected an enlargement of the aorta with body CT, was admitted to our hospital. Preoperative examination revealed that the aneurysm was expanded from ascending aorta to the abdominal aorta above the celiac artery. She underwent total arch replacement using elephant trunk technique. Forty-four days after operation, she underwent thoracoabdominal aortic replacement with monitoring for spinal cord ischemia by the use of the motor evoked potentials (MEP), the evoked spinal cord potential (ESCP) and the segmental evoked spinal cord potential (S-ESCP). Under the partial cardiopulmonary bypass with femoral venous drainage and femoral arterial cannulation on normothermia, the aneurysmal part of the aorta was segmentally cross-clamped and the three lumbar arteries and the celiac artery were reconstructed one by one. During the operation, the monitor showed no remarkable change, even while the aorta was cross clamped. Her postoperative course was uneventful without any spinal cord damage. Combined use of MEP, ESCP, and S-ESCP was useful for monitoring spinal cord injury during thoracoabdominal aneurysmal repair.

Aorta, Thoracic↗
PubMed1997

[Anomalous origin of the right pulmonary artery from the ascending aorta--a report of three operative cases].

Three patients with anomalous origin of the right pulmonary artery from the ascending aorta were reported. Case 1: A 33-day-old premature infant (body weight 984 g) with the right pulmonary artery arising from the ascending aorta (RAPAA) and the patent ductus arteriosus (PDA). Banding of the right pulmonary artery (RPAB) and ligation of PDA were performed as a palliative operation. AT 3-month-old (BW 2,200 g), division and direct anastomosis of the anomalous vessel to the main pulmonary trunk was done as a radical operation under hypothermic cardiopulmonary bypass (CPB). Case 2: A 16-day-old infant with RAPAA and PDA. Division and direct anastomosis of the anomalous vessel to the main pulmonary trunk and ligation of PDA were performed as a radical operation under hypothermic CPB. Case 3: A 74-day-old infant with RAPAA and Ebstein's anomaly. RPAB was performed as a first palliative operation and left Blalock-Taussig shunt as a second operation. Glenn operation is scheduled as third operation prior to Fontan type operation.

Aorta↗
PubMed1996

A modified maze procedure performed only on the left atrium for chronic atrial fibrillation associated with mitral valve disease: report of a case.

We describe herein the successful treatment of a patient with chronic atrial fibrillation (AF) associated with mitral valve stenosis and regurgitation, achieved by performing a modified maze procedure on the left atrium alone. The patient was a 51-year-old man who had suffered from intractable AF for 17 years, causing multiple cerebral emboli and palpitations. He had undergone open mitral commissurotomy and balloon commissurotomy 15 and 7 years ago, respectively. On admission, an echocardiogram revealed mitral valve restenosis and thrombosis in the left atrial appendage. Prosthetic valvular replacement was performed following isolation of all pulmonary veins with cryoablation to the posterior wall of the left atrium and excision of the left atrial appendage. Postoperatively, the AF disappeared and echocardiogram demonstrated a left atrial kick in the mitral valvular inflow without any evidence of thrombosis in the left atrium. Thus, we believe that our modified "left side only" maze procedure is a simple and efficient method for the treatment of chronic AF with mitral valve disease.

Atrial Fibrillation↗
PubMed1996

Pooled air in open heart operations examined by transesophageal echocardiography.

BACKGROUND: The clinical significance of pooled air detected by transesophageal echocardiography during open heart operations is not clear. METHODS: Thirty-eight consecutive patients undergoing an open heart operation or an operation on the ascending aorta were divided into two groups on the basis of the absence (group 1, n = 14) or presence (group 2, n = 24) of pooled air. They were examined for intramyocardial echo contrast, ST segment elevation, conduction disturbances, and regional wall motion abnormalities. RESULTS: Echo contrast was found in no patient in group 1 and 66.7% of group 2 patients (p < 0.001). New regional wall motion abnormalities were detected in no patient in group 1 versus 33.3% of group 2 patients (p < 0.05), and ST segment elevation was seen in 33.3% of group 2 patients versus no group 1 patients (p < 0.05). Intramyocardial cardial echo contrast was newly detected after the appearance of pooled air more frequently in patients with ST segment elevation (p < 0.001). Atrioventricular block and sinus arrest appeared in 3 patients and 2 patients, respectively. Postoperative regional wall motion abnormalities were found in 25.0% of patients and were not closely related to intraoperative echo contrast findings. CONCLUSIONS: Pooled air, which is often detected in open heart operation by means of transesophageal echocardiography, is related to several cardiac events, including ST segment elevation, conduction disturbances, and regional wall motion abnormalities, although most of these are transient.

Adolescent↗
PubMed1996

Coronary artery fistula to bronchial artery on contralateral side of coronary atherosclerosis and myocardial insufficiency. A case report.

Among coronary vessels anomalies is the rare coronary artery fistula. Myocardial insufficiency resulting from fistula steal phenomenon can not be clinically distinguished from that of coronary atherosclerosis, if these conditions coexists in the same patient. The authors present a case of extracardiac left coronary artery fistula connecting the circumflex branch and left bronchial artery, with inferior wall myocardial insufficiency attributable to the right coronary artery atherosclerosis.

Aged↗
PubMed1996

[Efficacy of left atrial only procedure for the treatment of chronic atrial fibrillation associated with mitral valve disease].

We supposed that chronic atrial fibrillation originated as a result of discontinuity of the refractory period of the dilated left atrium in the mitral valvular disease. We then performed left atrial only procedures to treat the chronic atrial fibrillation (AF) associated with mitral valve disease. These procedures were the left atrial isolation and the modified left sided maze procedure, consisting of isolation of all pulmonary veins and cryoablation to the posterior wall of the left atrium, in addition to excision of the left atrial appendage. Twenty-eight patients underwent these procedures over the past thirty months. Patient ages and the duration of AF ranged from 37 to 71 years and from 0.5 to 26 years, with an average of 8.3 years, respectively. Chronic AF disappeared in twenty-four patients (86%) at discharge. Three patients with severe tricuspid insufficiency had sustained AF and one patient had atrial flutter postoperatively. Three patients showed sick sinus syndrome postoperatively and two of these required a DDD pacemaker. Severe tricuspid regurgitation (p < 0.020) was the factor in recurrence of AF. Left atrial only procedures were effective in the treatment of chronic AF associated with mitral valvular disease.

Adult↗
PubMed1996

Numerical simulation of nonpulsatile left ventricular bypass.

A computer simulation was carried out to investigate the influence of nonpulsatile left ventricular assistance on hemodynamics. A simulation circuit was constructed to represent the circulatory system. A source of current was added to denote the nonpulsatile blood pump. The left and right ventricles were replaced by variable compliances. Left heart failure was simulated by decreasing the amount of compliance change of the left ventricle. We introduced a pulsatility indicator (PI) to clarify the pulsatility characteristics in the hemodynamics; this PI was defined as the ratio of the pulse pressure (PP) to the mean aortic pressure (AoP). When nonpulsatile bypass flow increased, the mean AoP, tension time index (TTI), and diastolic pressure time index (DPTI) increased, and cardiac output, PP, and PI decreased. When assisted flow increased with the constant total flow rate, the mean AoP and DPTI changed little; the PP, TTI, and PI decreased, and the endocardial viability rate increased. The PI would be helpful in evaluating the effect of pulsatility.

Blood Pressure↗
PubMed1996

[Role of noninvasive graphic diagnosis in acute type A aortic dissection and selection of the adjunct for cerebral protection].

We have evaluated the usefulness of graphic diagnostic modalities (transthoracic echocardiography [TTE], high speed CT, transesophageal echocardiography [TEE], surface echocardiography [SE]) in acute type A aortic dissection and selected the adjunct to protect cerebral damage during operation followed by pre and intraoperative diagnosis. 1) Angiopraphy was undergone in only 5 cases of 22 cases of acute type A dissection. Intimal flap of the ascending aorta was completely diagnosed by TTE and CT. It was sometimes difficult to show the location of the intimal tear by TTE and CT (diagnostic sensitivity 64%, specificity 88%). However, TEE and SE showed the location of intimal tear in all cases (sensitivity 100%, specificity 100%) and also clarified the dissection of the coronary arterial orifice. CT and SE were useful to detect dissection of the cervical branches. 2) The adjunct for cerebral protection was selected by the diagnosis of the distension of the dissection. Retrograde cerebral perfusion was used in the cases with intimal tear in the ascending aorta (10 cases) and selective cerebral perfusion was selected in cases of the distended dissection, in which dissection involved the arch aorta and replacement of aortic arch was required (12 cases). Cerebral perfusion time and operative mortality was 48 min and 10% in the former and 72 min and 17% in the latter, respectively. Operative mortality was not different in both groups.

Adult↗