Biomedical subjects

R Kuribayashi

Publications and source records attributed to R Kuribayashi.

At least 37 records · Page 2Linked to original sources

PubMed1997

Is the dog a useful model for accelerated calcification study of cardiovascular bioprostheses?

Chitosan posttreatment has been shown to be effective in prevention of calcification of the glutaraldehyde treated bovine pericardium when implanted subdermally in rats for 12 weeks. The efficacy of chitosan posttreatment in complete calcium mitigation of the glutaraldehyde treated porcine aortic valves implanted in the right side of the heart in dogs was well-documented in our previous study. In this study, an attempt has been made to evaluate the merit of the chitosan posttreatment in prevention of calcification of the glutaraldehyde (GA) treated porcine aortic valved conduits in the systemic circulation in dogs for a period of 5 months. Eleven mongrel dogs underwent left thoracotomy. Porcine aortic valved conduits treated with 0.625% GA (n = 5) and GA-chitosan (n = 6) were implanted in the descending thoracic aortas of the dogs for 5 months. Gross histological observations showed no calcification in either the 0.625% GA treated or in the GA-chitosan treated valved conduits at 5 months. This was confirmed by results of quantitative analyses for calcium in each explant. There was no significant difference in calcium content between the GA only (Ca, 0.43 +/- 0.26 mg/g) and GA-chitosan treated (Ca, 0.51 +/- 0.19 mg/g; p = 0.5959) valved conduits. This study suggests that the dog is not a suitable model for evaluating the efficacy of a calcium mitigating agent in bioprostheses implanted in systemic circulation.

Animals↗

PubMed1997

Mitral regurgitation caused by mitral paraannular cyst.

A case of mitral regurgitation (MR) caused by mitral paraannular cyst is reported. A 37-year-old woman on maintenance hemodialysis was admitted to Akita University Hospital because of congestive heart failure. Echocardiography revealed mitral paraannular cyst, which caused coaptation failure of the mitral leaflets and significant MR. She underwent decapsulation of the cyst followed by mitral valve replacement. Postoperative echocardiography showed no recurrence of the cyst three years after surgery. Although mitral annular calcification has been described as a cause of MR in patients with uremia, a report of a solitary intracardiac cyst which causes significant MR is quite rare.

Adult↗

PubMed1997

Apico-aortic shunt: a support technique during surgery on the descending thoracic aorta.

To find out whether apico-aortic shunt may become an alternative support technique during surgery on the descending thoracic aorta, performance between apico-aortic shunt and aorto-aortic shunt was compared. In 5 sheep weighing 20-25 kg, apico-aortic shunt and aorto-aortic shunt were instituted with covalently bonded heparin coated polyvinyl tube (internal diameter 5 mm). After clamping the descending thoracic aorta, apico-aortic shunt and aorto-aortic shunt were opened for 30 minutes each. Proximal pressure was elevated to 200 mmHg and distal pressure was fallen to 55 mmHg after clamping the descending thoracic aorta. Opening of apico-aortic shunt and aorto-aortic shunt decreased proximal pressure to 178 +/- 14.8 and 173 +/- 12.0 mmHg, respectively (p = 0.57), and raised distal pressure to 82.4 +/- 7.8 and 90.0 +/- 3.5 mmHg, respectively (p = 0.83). The baseline blood flow of the descending thoracic aorta was 1.4-1.5 l/min. Apico-aortic shunt and aorto-aortic shunt were 0.76 +/- 0.16 and 0.80 +/- 0.22 l/min, respectively (p = 0.67). Blood gas tension, pH and BE measurement showed no significant change and difference between apico-aortic shunt and aorto-aortic shunt, and before and after clamping the descending thoracic aorta. Using apico-aortic shunt, interposition of bioprosthetic valved conduit in the descending thoracic aorta in 10 sheep was successfully performed without paraplegia and any other complications. We concluded that apico-aortic shunt may become an alternative support technique during surgery on the descending thoracic aorta in some specific situations.

Animals↗

PubMed1996

Surgical treatment of isolated secundum atrial septal defect in patients more than 50 years old.

BACKGROUND: Arrhythmia-related thromboembolic accidents continue to occur in patients even after closure of secundum atrial septal defect. Older age is usually not a contraindication to the repair of an atrial septal defect. To assess the importance of the type of management in elderly patients with atrial septal defect our clinical experience is reviewed. METHODS: Between 1974 and 1994, 49 patients 50 years of age or older (average, 57.4 years) underwent surgical closure of secundum atrial septal defect. All patients have been followed up for 2 to 21 years (mean, 9.7 years). RESULTS: There were no operative deaths. Functional classes in most of the patients were improved after operation. There were two cerebrovascular thromboembolic accidents with one permanent neurologic dysfunction, hemiparesis, and one septal dehiscence in the early postoperative period. One patient (2%) died of renal failure 6 years after operation, late arrhythmias developed in 3 patients (6%), 3 patients had a late stroke (6%), and 1 patient was not available for follow-up. CONCLUSIONS: Long-term operative results are satisfactory and beneficial to the quality of life in elderly patients. Because there is no safe and effective nonsurgical alternative to surgical closure, atrial septal defect repair in elderly patients without severe pulmonary vascular disease should not be delayed once the diagnosis had been made.

Age Factors↗

PubMed1996

Use of the glutaraldehyde-chitosan-treated porcine pericardium as a pericardial substitute.

The efficacy of chitosan post-treatment of glutaraldehyde-treated porcine pericardial substitute for the prevention of postoperative epicardial reaction and adhesion formation in mongrel dogs has been assessed. Glutaraldehyde (0.625%)-treated porcine pericardium showed moderate to dense adhesions to the heart and other underlying organs with moderate to severe epicardial reaction. None to minimal epicardial reaction without adhesion was observed in glutaraldehyde-treated porcine pericardium post-treated with chitosan at 5 months. Presumably, chitosan post-treatment prevents the slow release of residual glutaraldehyde and reduces the toxicity of the glutaraldehyde-treated implants, minimizing the chance of adhesion formation and epicardial reaction.

Animals↗

PubMed1996

Composite graft replacement of the aortic root in patients with Marfan's syndrome.

Between October, 1979 and September 1994, 18 consecutive patients with Marfan's syndrome underwent replacement of the ascending aorta and aortic valve with a composite graft. There were 11 men and seven women; the mean age was 38.7 years. All patients had annuloaortic ectasia with significant aortic regurgitation. Ten of the 18 patients had aortic dissection. Concomitant procedures were performed in three patients. The hospital mortality rate was 17%, and two patients with concomitant procedures died early after surgery. There were three late deaths, two of which were related to late aortic complications. The actuarial 8-year survival rates in patients with and without aortic dissection were 58.3% and 77.8%, respectively. Since aortic dilatation and its complications are progressive in patients with Marfan's syndrome, improved surgical results can be obtained early in the course of the disease before cardiac disturbances and aortic dissections emerge.

Actuarial Analysis↗

PubMed1996

Carotid artery resection for head and neck cancer.

BACKGROUND: Carotid artery resection has been shown to yield a chance of cure in patients with advanced head and neck carcinoma involving the carotid artery. However, the criteria for the identification of those who are vulnerable to neurologic injury after resection have not been established. Interposition grafting may minimize the risk of neurologic morbidity, although it is technically difficult when there is involvement of the internal carotid artery close to the skull base. METHODS: We studied 24 patients with head and neck tumor involvement of the carotid artery. We performed carotid artery resection in 16 of them, including 10 in whom the carotid artery was reconstructed with interposition grafts covered with muscle flaps. When it was thought that the reconstruction would be difficult, positron emission tomography was performed during balloon test occlusion of the internal carotid artery to assess the adequacy of hemispheric collateral blood flow before carotid resection. In one patient with interposition graft, carotid rupture occurred as a result of wound infection, but none of the other patients experienced perioperative death, persistent hemiplegia, or delayed stroke. RESULTS: Twelve patients have survived longer than 8 months, and seven (43.8%) were alive without disease at 12 months after resection, whereas all four patients who could not be treated operatively died within 8 months as a result of local primary tumors. CONCLUSIONS: Carotid artery resection is the only therapy offering any potential for cure or palliation. Positron emission tomography is a rapid quantitative means of determining the cerebral blood flow, particularly when resection is planned without reconstruction.

Aged↗

PubMed1996

Efficacy of the chitosan posttreatment in calcification prevention of the glutaraldehyde-treated porcine aortic noncoronary cusp implanted in the right ventricular outflow tract in dogs.

Calcific tissue failure results in poor performance of the bioprosthetic heart valve. Chitosan post-treatment has been shown to be effective in calcification prevention of the glutaraldehyde-treated bovine pericardium when implanted subdermally in rats for 12 weeks. The present study investigated the effectiveness of the chitosan posttreatment in prevention of calcification of the glutaraldehyde-treated porcine aortic noncoronary cusp 5 months after implantation in the right ventricular outflow tract (RVOT) in mongrel dogs. Either 0.625% glutaraldehyde-treated (Group 1, n = 6) or glutaraldehyde-chitosan-treated (Group 2, n = 6) porcine aortic noncoronary cusp with the aortic wall was sewn to the RVOT. Gross histological observations showed moderate calcification of the glutaraldehyde-treated cusps, but no calcification was noticed in the glutaraldehyde-chitosan-treated grafts at 5 months. This was confirmed by results of quantitative analyses for calcium in half of each explanted cusp with aortic wall. The calcium content of the 0.625% glutaraldehyde-treated cusps (Ca, 40.6 +/- 24.9 mg/g dry wt) was significantly (p < 0.01) higher than that of glutaraldehyde-chitosan-treated cusps (Ca, 1.3 +/- 0.29 mg/g dry wt). These findings suggest that chitosan post-treatment is effective in complete calcium mitigation of the glutaraldehyde-treated porcine aortic noncoronary cusps implanted in the RVOT in dogs.

Animals↗

PubMed1996

[Coronary artery bypass grafting in a patient with severe coronary disease due to Kawasaki disease: a case report].

A 14-year-old girl with severe coronary artery disease due to mucocutaneous lymph node syndrome, "Kawasaki disease", admitted to our hospital. Though she had no angina on any effort in her daily life, coronary angiography (CAG) demonstrated 90% stenosis and a large aneurysm of left main trunk. Based on the CAG findings, we determined to do the coronary artery bypass grafting (CABG) to left anterior descending artery (LAD) and 1st diagonal branch (D1) to prevent the occurrance of fatal acute myocardial infarction. We attempted to use bilateral internal thoracic arteries (ITAs) at the beginning of this surgery. While LAD was grafted with left one, D1 was done with saphenous vein (SV) because of difficulty of harvesting right one. The weaning from cardiopulmonary bypass was easy and the postoperative course was of no event. A month later, CAG showed the good patency of both left ITA and SV graft.

Adolescent↗

PubMed1996

[Aortic root replacement employing Cabrol and Piehler techniques].

Between February, 1982, and September, 1994, 24 patients underwent aortic root replacement using a valve-bearing composite graft and coronary perfusion grafts. The indications for surgery were annulo-aortic ectasia in 21 patients, and aortic dissection associated with significant aortic regurgitation in 3 patients. Aortic root was reconstructed employing the techniques described by Cabrol and colleagues (Cabrol operation) in 16, and by Piehler and Pluth (Piehler operation) in 8. Two of 16 patients who underwent Cabrol operation required concomitant procedures. Four patients (25.0%) who underwent Cabrol operation had technical troubles relating to coronary reattachements (kinking and torsion of coronary grafts in 2, obstruction of left limb of coronary graft in 1, and coronary graft compression by aortic wall wrapping in 1), while one patient (12.5%) having Piehler operation had coronary graft compression by partial wrapping of aortic root. The hospital deaths occurred in 4 patients undergone Cabrol operation, with the hospital mortality rate being 16.7%. Three patients including 2 with concomitant procedures died of low cardiac output and one died of rupture of residual dissecting aneurysm of the aortic arch. No pseudoaneurysm nor anastomotic stenosis was observed in any hospital survivors. Late deaths occurred in 5 patients, in whom there was no late complication relating to coronary reconstruction. However, late obstruction of left ostial stenosis developed in one patient who underwent Piehler operation, which required coronary artery bypass. We conclude that aortic root replacement using coronary perfusion grafts provides sound coronary anastomoses without late pseudoanurysm. Coronary reattachments is facilitated by use of Piehler technique, preventing coronary graft kinking or torsion. Late coronary ostial stenosis should be considered as a possible cause of fatal myocardial infarction and sudden death, and careful follow-up is required for patients having these kinds of operation for the prevention of late cardiac events.

Adult↗

PubMed1995

[Evaluation on the perioperative left ventricular function of aortic valve replacement in patients with chronic aortic regurgitation].

To evaluate the perioperative left ventricular function in 36 patients undergoing aortic valve replacement (AVR) in patients with isolated chronic aortic regurgitation (AR), hemodynamic variables before and within the first 24 hours and one month after operation were measured with Swan-Ganz catheter and echocardiography. The patients were divided into two groups based on preoperative left ventricular end-systolic volume index (LVESVI): 5 patients had a LVESVI of 90 ml/m2 and greater (group I), 31 had a LVESVI smaller than 90 ml/m2 (group II). Left ventricular dimension at end-diastole and end-systole, left ventricular end-diastolic volume index at one month after operation significantly decreased in comparison with that of preoperation. However, left ventricular ejection fraction in the two groups were not improved, and left ventricular mass index in group I did not decreased. On the other hand, changes of cardiac index, stroke volume index and left ventricular stroke work index within the first 24 hours after operation were not significantly different between the two groups. The incidence of postoperative premature ventricular contraction in group I was significantly higher than that of group II. However, there was no difficult problems in postoperative management of the two groups. It is suggested that AVR in AR with left ventricular dysfunction can safely be operated and its postoperative management is similar to AVR in AR with no left ventricular dysfunction.

Adult↗

PubMed1994

Long-term results of primary closure for ventricular septal defects in the first year of life.

The long-term results of primary closure for large ventricular septal defects (VSDs) in infants under 1 year of age with severe symptoms were studied over a period of more than 10 years. Between January, 1971 and March, 1982, 49 infants underwent primary closure of a VSD through a right ventriculotomy using complete cardiopulmonary bypass with mild hypothermia. There were four hospital deaths but no late deaths. Two of four infants with residual shunts had a left ventricular-right atrial shunt which necessitated reoperation. Surgical heart block occurred in two infants who recovered sinus rhythm in the late period. The cardiothoracic ratio decreased from 60.5% preoperatively to 50.6% in the late postoperative period. Examination by cardiac catheterization revealed that the pulmonary-to-systemic pressure ratio (Pp/Ps) of 23 patients with a Pp/Ps of over 0.75 fell from 0.89 +/- 0.09 preoperatively to 0.42 +/- 0.12 by 1 month postoperatively, then to 0.27 +/- 0.05 in the late postoperative period. The latest values for the cardiac index and left ventricular ejection fraction were 3.4 l/min per m2 and 64.4%, respectively. More than 10 years after their operation, all the survivors were growing normally and maintaining a good quality of life, which supports our recommendation that primary repair should be performed in the first year of life for infants with large VSDs.

Bundle-Branch Block↗

PubMed1994

[Aortic dissection with giant pseudoaneurysm as a rare late complication of aortic valve replacement--a case report].

A 60-year-old man who had received aortic valve replacement for aortic regurgitation at 47 years of age developed sudden syncope and shock on Mar. 28, 1991. Close examination including CT scan and aortography revealed DeBakey type I aortic dissection with giant pseudoaneurysm which compressed superior vena cava and right pulmonary artery and caused superior vena cava syndrome. He underwent elective ascending aortic replacement under profound hypothermic cardiopulmonary bypass and circulatory arrest on Jun. 17, 1991. The giant pseudoaneurysm was present posterolaterally to the ascending aorta. It communicated with the false lumen and contained massive thrombi. The intimal tear of the ascending aorta existed along the suture line of previous aortotomy.

Aortic Dissection↗

PubMed1994

[Adjunctive methods for surgery of descending thoracic aortic aneurysm].

During the last 6 years, we employed partial extracorporeal circulation (PEC) in 7 cases and left heart bypass (LHB) in 9 cases as adjunctive methods for surgery of descending thoracic aortic aneurysm. During the aortic clamping, systemic heparinization was performed to keep an ACT more than 400 seconds in a PEC group, while it was kept from 200 to 250 seconds in LHB group. The bypass flow was controlled to maintain the distal arterial pressure over 50 mmHg in both groups. Hemodynamics during the aortic clamping were stable in both groups and significant differences were not found between them. However, ventricular fibrillation occurred in one case of LHB group, who suffered from coronary artery disease, and required subsequent PEC to maintain systemic circulation. Both PEC and LHB provided adequate intraoperative hemodynamics and postoperative serum biochemistries. But we preferred to adopt PEC to maintain the diatal perfusion in cases with heart disease, who are likely to develop circulatory deterioration under the aortic clamping.

Adult↗

PubMed1994

[Total aortic replacement in a patient with extensive thoracoabdominal aortic aneurysm--a case report].

A 35-year-old woman with a form fruste of Marfan's syndrome, presented the extensive thoracoabdominal aortic aneurysm. CT scan, MRI and aortogram revealed that she had a true aneurysm of ascending aorta and aortic arch and chronic DeBakey IIIb dissecting aneurysm extending throughout the descending thoracic and abdominal aorta. The surgical treatment was consisting of two staged operations. At the first operation, ascending aorta and aortic arch were reconstructed under cardiopulmonary bypass and selective cerebral perfusion. Elephant trunk method was employed for the second operation. The second operation was performed by graft replacement of the entire descending thoracic and abdominal aorta with reattachment of intercostal and visceral arteries. She discharged the hospital without any complication including paraplegia.

Adult↗

PubMed1994

[Conduction disturbances after coronary artery bypass grafting with retrograde cardioplegia].

We studied forty-six cases, who had undergone coronary artery bypass grafting with retrograde cold blood cardioplegia for myocardial protection, to manifest the frequency and causative factors of postoperative conduction disturbances. We obtained the following conclusions. 1) Postoperative conduction disturbances developed in nineteen cases (41.3%), all of which were right bundle branch blocks, but these were usually transient and were not associated with further complications in the follow-up period. 2) There were no significant differences in many factors, including number of grafts, aortic cross-clamp times, or peak CK-MB between cases with and without postoperative conduction disturbances.

Adult↗

PubMed1993

Surgical treatment of acute aortic dissection: efficacy of retrograde cardioplegia for myocardial protection.

The operative morbidity and mortality of patients with Stanford type A acute aortic dissection undergoing urgent operation using retrograde cardioplegia for myocardial protection were evaluated to assess the efficacy of such surgery. A total of 18 patients (12 men and six women, 19-71 years of age) were operated on 9-137 h after onset of dissection using cardiopulmonary bypass with deep hypothermia and retrograde cardioplegia. Graft replacement was performed in ten patients, primary anastomosis in three, and Cabrol and Bentall operations in five. All patients were weaned from cardiopulmonary bypass, but four died in hospital (mortality rate 22%). Thirteen patients were in good health at follow-up ranging from 3 to 98 months, and the remaining patient died from rectal cancer 5 months after surgery. It is concluded that urgent operation of patients with Stanford type A acute aortic dissection can be performed with reasonable operative and excellent follow-up results. Retrograde cardioplegia is an easy and reliable method of myocardial protection to repair the fragile aortic wall.

Acute Disease↗

PubMed1993

[Surgical treatment of cardiac myxomas].

Between April 1975 to March 1991, 17 patients (5 man and 12 women, mean age 49.8 years old) underwent surgical treatment for cardiac myxomas. Fifteen patients had left atrial myxomas, and the other 2 had the ventricular myxomas (left ventricular myxoma 1 and right ventricular myxoma 1). In cases with left atrial myxomas, the tumor was resected through the transatrial approach alone in 12 patients, and the left atriotomy was added in other 3. Left ventriculotomy was required to resect the left ventricular myxoma in addition to the atrial approach. Right ventricular myxoma, which attached the outflow tract, could be removed through the small right vertical ventriculotomy. All patients recovered well, and there was no recurrence in any patient during the follow-up period.

Adult↗