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Biomedical subjects

T Maseki

Publications and source records attributed to T Maseki.

At least 37 records · Page 2Linked to original sources
PubMed1994

Resection of aortic aneurysms without aortic clamp technique with the aid of hypothermic total body retrograde perfusion.

Aneurysms involving either the aortic arch or the proximal descending thoracic aorta in five patients were resected with the aid of profound hypothermic total body retrograde perfusion. Traditional surgical management of the aortic arch and the descending thoracic aorta necessitates clamping of the aorta. However, this technique may be associated with rupture or atheroembolism. Rupture occurring at the clamping site may be difficult to repair. Atheroembolism to the brain compromises the neurologic system, and multiple organ embolism is associated with disseminated intravascular coagulopathy. Atheroembolism in cardiovascular surgery has become increasingly prevalent. It is necessary to prevent clamp injuries and to preserve the function of the vital organs, such as the brain, heart, and liver, during aortic reconstruction. We applied a total body retrograde perfusion technique to operations for aortic aneurysms. Total body retrograde perfusion consists of cerebral protection by continuous perfusion through the superior vena cava, intermittent retrograde coronary perfusion through the coronary sinus, and continuous abdominal visceral perfusion through the inferior vena cava. It can yield a relatively bloodless operating field without the need for aortic clamping. We believe this new adjunct offers excellent results in the surgical treatment of aneurysms of the aortic arch or adjacent structures.

Adult↗
PubMed1993

Effects of magnesium on isolated canine coronary arterial tension.

The effects of magnesium on the tension of isolated canine coronary arterial strips were studied. In the solution containing K+ of 20 mEq.l(-1), Ca2+ of 4 mEq.l(-1), and Na+ of 127 mEq.l(-1), the tension was 811 +/- 111 mg with Mg2+ of 1 mEq.l(-1), 494 +/- 135 mg with Mg2+ of 10 mEq.l(-1), 272 +/- 126 mg with Mg2+ of 20 mEq.l(-1), -52 +/- 63 mg with Mg2+ of 30 mEq.l(-1), -69 +/- 80 mg with Mg2+ of 40 mEq.l(-1). In the solution containing K+ of 20 mEq.l(-1), Na+ of 12 mEq.l(-1) and Ca2+ of 0 mEq.l(-1), the tension was 102 +/- 22 mg with Mg2+ of 1 mEq.l(-1), 3 +/- 35 mg with Mg2+ of 10 mEq.l(-1), -49 +/- 33 mg with Mg2+ of 20 mEq.l(-1), -59 +/- 49 mg with Mg2+ of 30 mEq.l(-1), -65 +/- 54 mg with Mg2+ of 40 mEq.l(-1). The data demonstrated that Mg2+ above 30 mEq.l(-1) inhibited the increase in tension caused by Ca2+ and Mg2+ above 20 mEq.l(-1) inhibited the increase in tension caused by low Na+ concentration.

Journal Article↗
PubMed1993

[Operative management of aortic arch aneurysm using selective cerebral perfusion].

Hypothermic circulatory arrest for aortic arch surgery can be tolerated for a limited period of time. To avoid this disadvantage, we used hypothermic cardiopulmonary bypass (CPB) with selective cerebral perfusion (SCP), in which the femoral artery, right axillary artery (RAA) and left common carotid artery (LCCA) were separately cannulated and perfused by individual pump heads. The pressures of bilateral superficial temporal arteries were monitored to maintain the cerebral perfusion pressure at 50 mmHg. The flow of RAA and LCCA was maintained at 5 ml/min/body weight kg, the pressure of each superficial temporal artery at 50 mmHg and the nasopharyngeal temperature at 20 degrees C. To perform the "open distal repair", the CPB was stopped while cerebral perfusion was maintained. Between 1986 and 1991, 20 patients were operated on with this method. Mean duration of SCP was 169 minutes (73 to 210), and mean duration of CPB was 290 minutes (136 to 472). There was no intraoperative death. Operative mortality rate within 30 days after surgery was 10% (2/20). Neurological sequelae occurred in one patient with emergency operation for acute aortic dissection, into LCC of whom we had trouble in inserting a cannula. It was considered that SCP could be performed for at least 2 hours with the results of good cerebral protection.

Aged↗
PubMed1993

[Safe and accurate coronary artery bypass grafting: combined use with single aortic clamp and retrograde coronary perfusion].

Neurological injury following myocardial revascularization may result from embolization of atheromatous debris from clamping the diseased aorta. The hazards of manipulating and clamping the aorta has been reported in some literatures. The proximal anastomoses with partial occluding clamp is conventional technique, but it may cause neurological injury, aortic tear or traumatic laceration. We developed a technique for coronary bypass grafting with single aortic cross clamp and combined antegrade/retrograde infusion of cardioplegia. Our method allows accurate performance of the proximal anastomosis without partial clamping and adequate protection of myocardium.

Aorta↗
PubMed1993

[Surgical results in diabetics undergoing coronary artery bypass grafting].

Diabetes mellitus is a well-known risk factor in the patients undergoing coronary artery bypass grafting (CABG) and with increasing frequency diabetic patients are referred for CABG. From the fact that the arteriosclerosis is more diffuse and advanced in patients with diabetes, the presence of the diabetic state might be expected to be at risk for CABG. We retrospectively evaluated the surgical results in 91 patients with diabetes mellitus operated on from January, 1985, to June, 1991, compared with a control group of 339 patients during the same period. Compared with nondiabetic patients, diabetic patients had more extensive coronary artery disease and, therefore, received the more number of grafts per patient. However, no difference was noted in the incidence of operative mortality, morbidity and postoperative complication. The incidence of postoperative sternotomy infection was slightly higher, if not statistically significant, in the diabetic patients. Our study demonstrates that patients with diabetes mellitus can be operated on relatively safely.

Aged↗
PubMed1992

Clinical application of total body retrograde perfusion to operation for aortic dissection.

The use of profound hypothermia and total circulatory arrest in the surgical treatment of aortic dissection has previously been reported. However, the safe period of prolonged circulatory arrest with hypothermia remains controversial. We have developed a technique of hypothermic total body retrograde perfusion to achieve systemic organ protection: cerebral protection by continuous retrograde perfusion through the superior vena cava, myocardial protection by coronary sinus infusion, and abdominal visceral organ perfusion by continuous retrograde perfusion through the inferior vena cava. Our technique yields a relatively bloodless operating field and avoids hypoperfusion of vital organs through a false lumen.

Adolescent↗
PubMed1992

[Analysis of preoperative predictors influencing early patency of coronary artery grafts].

Under the recent trend of popular use of arterial grafts, we investigated the predictors of coronary artery bypass graft patency using modified scoring system of Greenlane hospital. A total of 127 grafts including 58 arterial grafts (53 in situ ITA, 3 free ITA, and 3 GEA) and 69 saphenous vein grafts were placed in 43 patients for average of 2.95 grafts per patient during the period from April 1990 to December 1991. Early patency of arterial grafts (98.3%) were significantly better than that of saphenous vein grafts (91.3%) (p less than 0.01). With regard to recipient vessels, both coronary flow-demand score (= score of the size of perfused myocardium x viability index x index of proximal stenotic lesion/3) and distal run-off score influenced early graft patency significantly. It seems that better patency of arterial grafts were reflected on the bias that these grafts were preferentially placed on larger coronary arteries such as the left anterior descending artery, not on the advantage of arterial grafts.

Adult↗
PubMed1992

[Problems and prevention in using arterial grafts for coronary artery bypass grafting].

The arterial graft has proved to be superior to the saphenous vein graft for coronary bypass grafting (CABG), because of its excellent long-term patency. However, there mains controversial on the choice of the arterial grafts. Six hundreds and twenty seven patients who had CABG using both arterial grafts and saphenous vein grafts, operated upon over 11-years period between 1980 and 1991, have been analysed. Some disadvantages and complications associated with the use of arterial grafts were demonstrated in our series. We discussed, the flow capacity, myocardial protection and postoperative complications in using arterial grafts for CABG.

Aged↗
PubMed1992

[Surgical treatment of aortic root abscesses using a hand-made valved xenopericardial conduit].

A case is described in which a new treatment was taken to eradicate an aortic root abscess in a 56-year-old man with aortic prosthetic valve endocarditis. Debridement of all apparently infected tissue created left ventricular-aortic discontinuity, involving the orifice of the right coronary artery. A conduit of a diameter of 23 mm was made by hand with a glutaraldehyde preserved xenopericardial graft. A 21 mm St. Jude Medical prosthetic valve was sewn in it at 2 cm to its edge. The hand-made valved conduit was used to reconstruct the left ventricular outflow tract and aortic root. A saphenous vein graft was anastomosed end-to-side to the right coronary arterial system and to the conduit distal to the prosthetic valve. The aortography revealed no aortic regurgitation nor abnormalities of the conduit, such as aneurysm formation, and the coronary arteriography showed a functioning graft 5 months after surgery.

Abscess↗
PubMed1992

[Spontaneous coronary artery dissection: a case report and a review of literature].

Operative cases of spontaneous coronary artery dissection have rarely been reported. We report an operative case of spontaneous right coronary artery dissection. The patient was a 60-year-old man with a history of angina pectoris. A selective coronary angiography demonstrated the dissection of right coronary artery #2-#3 and the stenosis in both 4 postero-lateral branch and left anterior descending artery. He was successfully managed with aorta-coronary bypass. Postoperative coronary angiography revealed the existence of dissecting lesion, however the native RCA flow was improved.

Aortic Dissection↗
PubMed1992

[Surgical treatment of acquired tricuspid stenosis].

There is no definitive surgical procedure for acquired lesions of the tricuspid valve (TV). From Feb, 1978, through March, 1990, the surgical treatment for the organic lesions of TV was performed in 10 patients, repair in 6 and TV replacement in 4. TV was repaired by commissurotomy, annuloplasty or valvuloplasty, or combination of them. When residual significant tricuspid regurgitation (TR) and/or stenosis (TS) was detected by intraoperative pulsed Doppler echocardiography after reparative procedures, TV was replaced. Follow-up periods ranged from 1 to 12 years (mean, 45.3 months). There was no early death, and late death was noted in one patient 32 months after operation. Preoperatively, 7 patients were in NYHA class IV and 3 in class III. Out of survivors, 7 are in class I and 2 in class II because of progression of mitral stenosis or coronary artery disease. Following surgery, the patients exhibited significant decrease in the cardiothoracic ratio (69.3 +/- 7.2 to 56.9 +/- 6.4%; p less than 0.01) and in the mean right atrial pressure (11.4 +/- 3.6 to 8.6 +/- 3.1 mmHg; p less than 0.05). The postoperative right ventriculography showed mild to moderate TR in 3 of 6 patients who underwent TV repair. In conclusion, TV repair could be a reasonable procedure for the organic TV lesions, although careful follow-up is recommended for residual TR.

Adult↗
PubMed1992

[Operative management of Stanford type A aortic dissection using selective cerebral perfusion].

Ten patients underwent surgical treatment for type A aortic dissection from October 1986 to April 1989 using hypothermic cardiopulmonary bypass (CPB) with selective cerebral perfusion (SCP). CPB was begun with femoral artery cannulation. The right axillary artery (RAA) and the left common carotid artery (LCCA) were separately cannulated and perfused with CPB blood by individual pump heads. The average flow to the RAA was 5.4 +/- 1.2 ml/min/kg body weight (mean +/- SD) and 5.6 +/- 2.6 ml/min/kg body weight to the LCCA. The average blood pressure of the superficial temporal artery was 53.1 +/- 15.1 mmHg in the right side and 52.5 +/- 24.7 mmHg in the left. The nasopharyngeal temperature during SCP was maintained at 19.3-24.7 degrees C (mean, 21.1 degrees C). The SCP time ranged from 112 to 197 minutes (mean, 168 +/- 20.8 minutes). There was one operative death. She died of myocardial infarction 3 days after operation. There were two late deaths. One patient died of infection 3 months after operation and another died of cholecystitis 4 months after operation. Cerebral infarction developed in the last patient. Among the 10 patients it was only one neurological sequela, which was surmised to be caused by technical problem in carotid artery cannulation. The good cerebral protection was obtained in our experience by SCP as mentioned above.

Aged↗
PubMed1992

[Management of infected transvenous permanent pacemakers].

Between November, 1980, and January 1991, a total of 115 transvenous pacemakers were implanted in 102 patients at our hospital. Infection at the site of implantation developed in three cases or 2.6%. The median time of the onset of infection postoperatively was eleven and a half months, the range being two and a half to twenty-four months. Coagulase positive Staphylococcus aureus was cultured from the infected site of one patient and coagulase negative Staphylococcus epidermidis and saprophyticus in two patients. Staphylococcus aureus septicemia developed in one patient. Conservative medical treatment consisting of the application of two or more antibiotics was unsuccessful in all three cases. In two patients, removal of the infected pacemaker generator and implantation of a completely new pacemaker system at a new, clean site were conducted. In one of these two patients, the septic pacemaker electrode was withdrawn 3 months after removal of the infected pacemaker generator. In the other patient, limited thoracotomy with incision of the left brachiocephalic vein was performed for removal of the electrode three weeks after removal of the infected pacemaker generator.

Adult↗
PubMed1991

Effects of sodium and temperature on tension in isolated canine coronary artery.

The effects of sodium and temperature on tension of isolated canine coronary arterial strips were studied. In 20 mEq. l(-1) K solution, the strength of tension was inversely related to the Na concentration. At 37 degrees C, the tension was significantly increased at 70 mEq. l(-1) Na and below. The tension was gradually suppressed by lowering of the temperature from 37 degrees C to 10 degrees C. At 10 degrees C, tension did not developed significantly at Na concentrations between 127 mEq. l(-1) and 12 mEq. l(-1). It was concluded that the decrease in Na concentrations increased the tension of the canine coronary artery and the lowering of temperature supressed the tension inducted by the decrease in Na concentrations.

Journal Article↗
PubMed1991

Effects of calcium and temperature on tension in isolated canine coronary artery.

The effects of calcium and temperature on the tension of isolated canine coronary arterial strips were studied. In 20 mEq. l(-1) K solution, the tension was significantly increased from 0 mg with 0 mEq. l(-1) Ca to 33 +/- 18 mg with 0.2 mEq. l(-1) Ca at 37 degrees C, from -40 +/- 18 mg with 0 mEq. l(-1) Ca to -17 +/- 11 mg with 0.2 mEq. l(-1) Ca at 30 degrees C, from -77 +/- 19 mg with 0 mEq. l(-1) Ca to -52 +/- 17 mEq. l(-1) with 1 mEq. l(-1) Ca at 25 degrees C, from -88 +/- 13 mg with 0 mEq. l(-1) Ca to -41 +/- 18 mg with 2 mEq. l(-1) Ca at 20 degrees C, from -125 +/- 16 mg with 0 mEq. l(-1) Ca to -116 +/- 13 mg with 2 mEq. l(-1) Ca at 15 degrees C. Ca higher than 0.2 mEq. l(-1) produced a dose-dependent increase in tension between 37 degrees C and 15 degrees C. In spite of the presence of 4 mEq. l(-1) Ca, the development of tension was strongly supressed by lowering the temperature below 20 degrees C, and completely inhibited at 10 degrees C. The rate of a decrease in tension caused by cooling was about 5.5 mg. degrees C(-1). This study demonstrated that Ca(2+) produced a dose-dependent increase in tension in high-K solution, which was suppressed as the temperature was lowered.

Journal Article↗
PubMed1991

Lack of correlation between the amount of eugenol released from zinc oxide-eugenol sealer and cytotoxicity of the sealer.

The purpose of this study was to examine a possible correlation between the eugenol released from a zinc oxide-eugenol sealer (Canals) and the degree of cytotoxicity. The cytotoxicity and eugenol release from root canal filling material containing eugenol was examined for test solutions at several experimental periods. No positive correlation was found between eugenol release and cytotoxicity of the root canal filling material.

Animals↗
PubMed1991

[Evaluation of maintenance of cardiac output during DDD and VVI pacing by exercise Doppler echocardiography].

To evaluate the efficacy of DDD pacing for cardiac reserve, we assessed increases in the stroke volume and cardiac output during randomized treadmill exercise in 16 patients by DDD and fixed-rate ventricular (VVI) pacing. The stroke volume index and cardiac index were determined using suprasternal Doppler measurements. Ten patients who showed sinus rhythm during exercise were excluded from this study. Compared with the findings during VVI pacing, those during DDD pacing showed: 1) a greater exercise-induced positive chronotropic response (mean maximum heart rate 122 +/- 22 beats/min vs 70 beats/min, p < 0.01), 2) a lesser increase in the stroke volume index (34 +/- 7 to 39 +/- 9 ml/m2 vs 31 +/- 7 to 49 +/- 11 ml/m2, p < 0.05), 3) a greater increase in the cardiac index (2.43 +/- 0.45 to 4.48 +/- 1.36 L/min/m2 vs 2.22 +/- 0.47 to 3.43 +/- 0.45 L/min/m2, p < 0.05), and 4) prolongation of exercise duration (6.35 +/- 2.00 min vs 5.97 +/- 1.81 min, NS). These findings indicated that VVI pacing promoted a greater stroke volume than DDD pacing, which provides a compensatory increase in contractility and the preload in cases without an increase in heart rate during exercise, however, the increase in cardiac output was insufficient due to the absence of a chronotropic response. In conclusion, a DDD pacemaker could effectively increase heart rate, causing a significant increase in cardiac output and extending exercise duration.

Adult↗