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Biomedical subjects

Y Kosakai

Publications and source records attributed to Y Kosakai.

At least 91 records · Page 5Linked to original sources
PubMed1992

Clinical experience of mitral valve reconstruction with artificial chordae implantation.

To expand the application of mitral valve reconstruction for pure mitral regurgitation due to diffuse leaflet prolapse, we have employed artificial chordae implantation using GPEP strips in 9 patients and 4-0 PTFE sutures in 20 patients since November 1986. The total number of GPEP strips implanted was 20 with a range from 1 to 4 (average 2.2 per patient) and 45 pairs of PTFE sutures with a range from 1 to 6 (average 2.3 per patient). There was one hospital death (3.4%). All other patients survived operation without valve-related complications except 1 patient who required reoperation for failure of mitral valve reconstruction. In 27 survivors free from reoperation, the amount of mitral regurgitation assessed postoperatively was none or trivial in 19 patients, mild in 7 and moderate in 1. All 27 patients improved to NYHA functional class I or II. So far, our results were no less acceptable than those with conventional procedures for mitral valve prolapse.

Adolescent↗
PubMed1992

[Surgical decisions for active infective endocarditis in patients with acute neurological complications].

The surgical management of 7 patients with active infective endocarditis and recent (within 16 days) neurological injury was presented. All patients had preoperative computed tomographic scans which revealed no evidence of intracranial hemorrhage and underwent successful corrective cardiac surgery. In the early postoperative period, 4 patients died of cerebral hemorrhage, subarachnoid hemorrhage, or progression of cerebral edema. Two of the 3 surviving patients showed no aggravation of cerebral infarcts postoperatively. In the remaining surviving patient, intracerebral mycotic aneurysms were resolved spontaneously after postoperative antibiotic therapy, although new cerebral hemorrhage, a complication of emboli, occurred after open heart surgery. The results of this study indicated that 1) cerebrovascular complications were the causes of the 4 deaths in this series, and 2) although heparinization during open heart surgery may result in intracerebral hemorrhage from mycotic aneurysm or infarction, early surgical intervention after recent cardiogenic embolic strokes may save patients with minor cerebral infarcts.

Adolescent↗
PubMed1992

[A case report of spinal epidural hematoma complicated after open heart surgery].

The authors reported the first case of acute spinal epidural hematoma (SEH) developed after open heart surgery. The patient was noticed that her legs felt weak and numb on the first postoperative day evening. On the next day morning, neurological examination revealed that flaccid paralysis of both legs and also loss of all sensory perception below the level of Th-6 spine bilaterally. The prolonged effect of anesthesia and painless onset made delayed recognition of the lesion. SEH (Th5-7) was diagnosed with MRI and decompressive surgery was immediately done, sixty hours after the beginning of cardiac operation. But in this case neurological deficits were not changed. We concluded that a routine diagnostic approach was very important procedure to find out this serious complication for all patients underwent open heart surgery in early period of its onset.

Cardiac Surgical Procedures↗
PubMed1992

[Mitral valve surgery for patients after undergoing percutaneous transvenous mitral commissurotomy (PTMC)--investigation on indication of PTMC based on the intraoperative findings].

Ten patients underwent open heart surgery for mitral valve after PTMC because of post PTMC MS (n = 4) and MR (n = 6) out of 150 patients undergoing PTMC in our hospital between June 1987 and October 1991. Intraoperative findings of 4 patients with residual mitral stenosis included severe thickening, stiffening and calcification on anterior and posterior leaflets, commissures and subvalvular apparatus. Mitral valve repair was possible in 2 and mitral valve replacement (MVR) was necessary in the other 2. In all 6 cases who massive mitral regurgitation after PTMC, in repairable tears in the mitral leaflets necessitated MVR. Since in these cases changes in the leaflets were less severe than those of the commissures or subvalvular apparatus, surgical repair could have been possible if open mitral commissurotomy (OMC) was done primarily. Patients selection for PTMC versus OMC based on precise morphological evaluation of mitral valve would reduce occurrence of massive MR resulting in surgical replacement.

Adult↗
PubMed1992

[One-staged repair for coarctation of the aorta and annuloaortic ectasia with severe aortic regurgitation in a patient with Turner syndrome].

A 27-year-old woman with Turner syndrome was admitted to NCVC for congestive heart failure. 2-D echocardiography and magnetic resonance imaging (MRI) disclosed annuloaortic ectasia with severe aortic regurgitation and coarctation of the aorta. One staged operation by a modified Bentall procedure and extra-anatomical bypass grafting from the ascending aorta to the infrarenal abdominal aorta was successfully performed. The postoperative course was uneventful. The pressure gradient between upper and lower extremities decreased as to be 30 mmHg compared with preoperative 60 mmHg.

Adult↗
PubMed1992

[Long-term follow-up of exercise tolerance after coronary bypass grafting].

Six hundred forty-eight serial graded exercise tests were performed on 400 patients up to 10 years after coronary bypass graftings (CABG). The maximal attained exercise tolerance, over 10 METS, were observed in 60% of patients and the negative response to exercise test in 43% of patients. The positive response in various parameters were observed at the following rates: graft occlusion-30% vs graft patent-46% (p less than 0.01); incomplete revascularization-39% vs complete revascularization-22% (p less than 0.01); and less than or equal to 8 METS 4-45% vs greater than or equal to 10 METS-28% (p less than 0.01), respectively. However, no significant difference was observed among number of vessels diseased, number of graftings, and presence of old myocardial infarction. The maximal attained stage of exercise, over 10 METS, in various parameters were at the following rates: less than or equal to 59 years old-70% vs greater than or equal to 60 years old-44% (p less than 0.01); male-63% vs female-32% (p less than 0.01); and graft patent-63% vs graft occlusion-50% (p less than 0.05), respectively. The serial analysis of exercise test demonstrated that improved exercise tolerance appears to persist for at least 5 years after CABG. However, the patients in complete revascularization had a tendency to increase the rate of positive response. In conclusion, the completeness of revascularization as well as graft patency was the main factor limiting exercise tolerance, and correlates with the extent and the duration of improvement after CABG.

Coronary Artery Bypass↗
PubMed1991

The effects of several pharmacologic agents upon postischemic recovery.

Using an isolated working rat heart model, the effects of DL-verapamil, ryanodine, gabexate mesilate (FOY), recombinant human superoxide dismutase (RH-SOD), and coenzyme Q10 upon myocardial protection were evaluated. Under conditions of normothermic ischemia, all these compounds, except RH-SOD, when added to the St. Thomas' cardioplegic solution at an optimal concentration, showed beneficial effects upon functional recovery and enzyme leakage. In contrast, the above compounds, except ryanodine and FOY, failed to improve the protective properties of the St. Thomas' cardioplegic solution under conditions of hypothermic ischemia. Our results indicate that calcium overload via the calcium channel and calcium-induced calcium release from sarcoplasmic reticulum (SR) may contribute to the onset of ischemic-reperfusion injury. However, under conditions of hypothermic ischemia, calcium-induced calcium release from SR plays a dominant role in calcium overload. Furthermore, intracellular calcium overload may activate proteases and result in the acceleration of myocardial injury.

Animals↗
PubMed1991

Recurrent epicardial fibrosarcoma which arose 12 years after the first resection.

Primary malignant tumours of the heart are very rare, with an incidence of only 0.0017%-0.03% in consecutive autopsy series. Fibrosarcoma of the heart is also rare, representing only about 0.3% of all cardiac tumours. We observed a case of epicardial fibrosarcoma which developed 12 years after the first resection of an epicardial tumour. A 31-year-old woman was referred to our hospital because of fatigue, nausea and right back pain. She had had surgery to resect an epicardial tumour when she was 19 years old. On admission, there was a huge, heterogeneous tumour on the right inferior side of the heart. At surgery, the tumour was totally resected and a pathological diagnosis of fibrosarcoma was made. The patient was free of symptoms for 6 months, but died of a recurrence 11 months after the operation. It is postulated that the epicardial tumour had only been partially resected and had been latent for a rather long period but began to grow rapidly 12 years after the initial resection.

Adult↗
PubMed1991

Protective effect of vitamin A against the methotrexate-induced damage to small intestine: a study on the crypt cells.

Vitamin A (VA) protects the small intestine from the methotrexate (MTX)-induced damage. The in vivo effects of MTX and/or VA on crypt cells of small intestine were investigated using rats orally administered MTX (15 mg/kg body weight) and/or VA (5,000 IU/kg body weight). The thymidine kinase activity of crypt cells separated from villus cells of small intestine of MTX plus VA-treated rats was lower than that from control rats but higher than that from MTX-treated rats. VA-treated rats showed almost the same activity of thymidine kinase as control rats. The amounts of the end products, adenosine monophosphate (AMP) and guanosine monophosphate (GMP), contained in crypt cells of treated rats were determined to investigate the in vivo effects of MTX and/or VA on de novo purine synthesis. MTX treatment significantly decreased the amounts of both AMP and GMP but both amounts were not affected by MTX plus VA treatment. Treatment with VA alone appeared to increase their amounts slightly. Thus, although the oral administration of MTX to rats inhibited DNA synthesis in crypt cells, VA coadministration protected the salvage pathway of pyrimidine synthesis and the de novo purine synthesis in crypt cells.

Animals↗
PubMed1991

Percutaneous transluminal coronary angioplasty and coronary artery bypass surgery--early and follow-up clinical results.

To evaluate the efficacies of percutaneous transluminal angioplasty (PTCA) and coronary artery bypass grafting (CABG) for angina pectoris, early and follow-up data were reviewed in 495 patients who had undergone these procedures from 1986 to 1988. In 173 patients with single vessel disease, there were no significant differences in initial success rate and early and late incidences of major complications or cardiac death between 152 patients with elective PTCA and 21 with urgent. When compared in 161 patients with multivessel disease, however, significant differences in success rate were found between 130 patients in the elective PTCA group and 31 in whom PTCA was urgent (81.6% vs. 64.5%, p less than 0.05). Significant differences were also found in early incidence of major complications (3.1% vs. 12.9%, p less than 0.01), early mortality (1.5% vs. 9.7%, p less than 0.01), and the late incidence of cardiac events (6.2% vs. 25.0%, p less than 0.01). These results show that freedom from cardiac death and overall cardiac events in the elective PTCA group as significantly better than that in the urgent group at 42 months of follow-up. Comparing early and follow-up results, on the other hand, there was no statistically significant difference between the elective and urgent CABG groups. Thus, there appear to be limitations on the urgent use of PTCA for refractory unstable angina caused by multivessel disease, and urgent CABG was recommended to high-risk patients of urgent PTCA.

Adult↗
PubMed1991

[Long-term follow-up results on Bentall's and our modified procedure].

Replacement of the ascending aorta and the aortic valve with composite graft, including reimplantation of coronary ostia, were performed in 84 patients from October, 1978 to December, 1989. Annuloaortic ectasia was the most common indication for surgery (76 patients). Thirty patients (36%) had the Marfan syndrome. Thirty-five patients were performed with original Bentall's procedure. Thirty patients were carried out with our modified technique like Inberg's, the coronary arteries were excised with attachment of the selected piece of the aortic wall, and implanted to the tube prosthesis with continuous suture. Nineteen patients were operated with modified technique by Cabrol or other interposition graft method. The actuarial free of death related to the operation of 4 years was 83%, 88%, and 74% (p = NS) in each methods respectively. The complications of anastomosis, for example, leakage and dilatation of coronary ostia were not seen in our modified Bentall's procedure. In conclusion, our modified method is proved to be reliable and competent.

Adult↗
PubMed1991

[Effects of nitroglycerin upon myocardial metabolism after open heart surgery].

The effects of intravenous administration of nitroglycerin (TNG) on hemodynamics and myocardial metabolism after open heart surgery were evaluated in 22 patients without ischemic heart disease. On 12 hours after starting the continuous infusion of TNG at a rate of 0.2 micrograms/kg/min on 10 patients (TNG group), coronary blood flow (CBF) increased (p less than 0.01) and myocardial oxygen metabolism improved remarkably. However, anaerobic metabolism still existed in TNG group and no significant difference between TNG group and Control group even after 12 hour continuous drug infusion. From these studies, it was concluded that the intravenous administration of TNG at a rate of 0.2 microgram/kg/min increased CBF, however did not improve myocardial metabolism after open heart surgery possively probably because of changes in coronary collateral function.

Adult↗
PubMed1991

[Invasive treatment in patients with prior coronary artery bypass grafting].

In eight hundred eighty three patients with prior coronary bypass grafting (CABG), cardiac symptoms were recurred in 179 patients in late follow-up period (mean 5 +/- 2.8 years). Of 179 patients, 43 patients had PTCA eventually. In these, 57 times of angioplasties were attempted. Twenty-one lesions in venous bypass grafts and 50 in native coronary arteries were performed, respectively. The initial success rate per bypass graft and per stenosis of native coronary artery were 68% and 74%, respectively. Five patients had elective CABG following failed PTCA. There were no emergency CABG procedures required after unsuccessful PTCA. Intracoronary thrombolysis (ICT) were performed in 13 patients. In these, 15 ICT attempts were made. Nine lesions in venous bypass grafts, 9 for native coronary arteries, and 3 for both were attempted. The primary success rate per occlusion was 67%. Twenty reoperation were done. There was one hospital death and one late death due to congestive heart failure 4 years after the reoperation. In conclusion, invasive treatments in patients with prior CABG can be performed with satisfactory safety and good results. Therefore, invasive treatment should be considered in the patients with CABG if cardiac symptoms are disabling and angiographically suitable lesions are present in the native coronary arteries or vein grafts.

Aged↗
PubMed1991

[Influences of intra-aortic balloon pumping on peripheral hemodynamics].

The influences of intra-aortic balloon pumping (IABP) on peripheral dynamics were assessed by Doppler echocardiography. The subjects were 20 patients requiring IABP support, postoperatively, to control low cardiac output state. The flow velocity integral in systole (Int S) and that in diastole (Int D) were measured from left common carotid, superior mesenteric, and terminal aortic flow pattern, and the sum of Int S and Int D (Int S + Int D) was calculated with and without balloon pumping. 1) IABP increased cardiac output significantly (p less than 0.01). 2) Common carotid flow: IABP increased Int S significantly (p less than 0.01), but neither Int S nor Int S + Int D changed significantly with IABP. 3) Superior mesenteric flow: IABP increased Int D significantly (p less than 0.01), but both Int S and Int S + Int D remained unchanged with IABP. 4) Terminal aortic flow: None of Int S, Int D and Int S + Int D changed significantly with IABP. These results suggest that the carotid area can receive much of the increase in cardiac output in systole with IABP, and that the superior mesenteric area can receive much of the volume of blood displaced in the aorta by balloon inflation in diastole.

Aged↗
PubMed1990

[Effects of intra-aortic balloon pumping on mitral flow dynamics after aortocoronary bypass surgery].

Improvement in left ventricular function following intra-aortic balloon pumping (IABP) in 15 patients (aged 51 to 86 years) after coronary artery bypass grafting was evaluated. Using transesophageal atrial echocardiography, the mitral flow velocity integrals in the rapid filling phase (IntR) and in the contraction phase (IntA) were measured from transmitral flow patterns, and the sum of IntR and IntA (IntR + IntA), and the ratios of IntA to IntR (IntA/IntR) were calculated for ON and OFF states of balloon pumping (IABP OFF test). The same parameters were determined during 1:2 assist balloon pumping (IABP 1:2 test); the cardiac cycle with balloon assist was defined as "ON", and that without balloon assist as "OFF". 1. IABP OFF test: IABP increased IntR from 6.4 +/- 1.6 cm to 7.6 +/- 1.9 cm (p less than 0.01), suggesting that a decreased afterload improves left ventricular relaxation. IntA did not change with balloon assist (ON 3.5 +/- 1.2 cm, OFF 3.7 +/- 1.2 cm). IntR + IntA increased from 10.0 +/- 2.0 cm to 11.1 +/- 2.4 cm during IABP (p less than 0.01). IABP reduced the IntA/IntR from 0.62 +/- 0.25 to 0.50 +/- 0.20 (p less than 0.01). The increment in the IntA/IntR without IABP suggests that impaired diastolic filling of the left ventricle due to an increased afterload may be compensated for by enhanced left atrial contraction.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗