Biomedical subjects

N Mukohara

Publications and source records attributed to N Mukohara.

At least 55 records · Page 3Linked to original sources

PubMed1992

[Coronary artery bypass grafting in patients with poor left ventricular function using retrograde continuous cold blood cardioplegia].

Patients with poor left ventricular function or those requiring urgent surgery may have more extensive ischemic myocardial injury if myocardial preservation is incomplete. We have performed coronary artery bypass grafting (CABG) aimed at complete revascularization in such cases using RC-CBCP, which is considered more effective on myocardial preservation during aortic cross-clamping in particular to protect ischemic area distal to severe coronary artery stenosis or obstruction. In the present study, in 25 patients with poor left ventricular function (left ventricular ejection fraction; LVEF less than or equal to 0.3) including 10 patients who required urgent surgery, the operative results were evaluated. All the distal and proximal anastomoses of grafts (average 2.5 grafts) were completed during one aortic cross-clamping using RC-CBCP, therefore graft flow was obtained immediately after release of the aortic clamping. Though this method required 142 minutes of a mean aortic cross-clamping time, myocardial protection was considered to be preferable judging from postoperative isoenzymatic evaluation and improved ventricular function. Fifteen patients with elective CABG were all alive and restored to NYHA class I to II. Among 10 patients requiring urgent CABG, 4 patients with acute myocardial infarction died but others were restored to NYHA class I to II. We conclude that it is important to aim at complete coronary revascularization in patients with poor left ventricular function and RC-CBCP achieves more effective myocardial protection during CABG in the patients.

Adult↗

PubMed1992

[Coronary artery bypass grafting using retrograde continuous cold blood cardioplegia].

Coronary artery bypass grafting was performed in 166 patients with severe coronary artery disease using retrograde continuous cold blood cardioplegia (RC-CBCP) during the last 3 years and 8 months. In this study, myocardial protection was assessed from the aspect of enzymatic analyses and clinical results of these patients. Six hospital deaths were not related to the myocardial protection. Even in the groups of patients with medically refractory unstable angina, multiple occlusion of the coronary artery, low cardiac function and left main trunk lesion, RC-CBCP provided excellent protection of the myocardium and satisfactory results of operation as well as in each control group. Consequently we conclude that RC-CBCP affords safer and more effective myocardial protection in patients with severe coronary artery disease.

Adult↗

PubMed1992

[Retrograde continuous cold blood cardioplegia via coronary sinus].

Though the retrograde continuous cold blood cardioplegia (RC-CBCP) is a useful method of myocardial protection for more complicated cardiac surgery, the most important problem is whether the right ventricle is satisfactorily protected or not. In the present study 60 patients with valvular heart disease given RC-CBCP were compared with 30 patients given antegrade continuous cold blood cardioplegia. Judging from myocardial temperature measured in the right ventricular wall, the ventricular septum and the left ventricular wall at the end of initial cardioplegic infusion, myocardial distribution of cardioplegic solution in the RC-CBCP group was as favorable as in the antegrade group. Injury to mitochondria in the right ventricular myocardium observed in the biopsy specimen taken just prior to aortic unclamping was usually trifling in the RC-CBCP group, and was not different significantly from that in the antegrade group. Cold blood cardioplegia dose perfused per left ventricular mass weight (LVMW) had significant correlation with injury to mitochondria, and the dose of more than 5ml/100gLVMW/min seemed to be preferable. There was no hospital death in all patients. Peak CK-MB after unclamping was less in the RC-CBCP group than the antegrade group. In conclusion, RC-CBCP is a safe and effective means of myocardial protection for both right and left ventricles.

Blood↗

PubMed1992

[Clinical appraisal of myocardial protection for coronary artery bypass grafting--efficacy of retrograde continuous cold blood cardioplegia].

Myocardial protection is one of the most important problems during coronary artery bypass grafting in patients with severe coronary artery disease. In this communication we have demonstrated retrograde continuous cold blood cardioplegia (RC-CBCP) in such cases with preferable results. In this study myocardial protection for CABG surgery was evaluated from the points of the myocardial distribution of cardioplegic solution, the changes of the value of myocardial enzyme, the recovery of cardiac function after unclamping of the aorta, and the results of operation [mortality and incidence of perioperative infarction (PMI)]. The effects of myocardial protections were compared among the following 4 groups: group-A (n = 38) where antegrade cardioplegia with 10 ml/min of CBCP was used; group-R (n = 52), retrograde cardioplegia with 10 ml/min of CBCP; group-Rm (n = 59), retrograde cardioplegia with 7-8 ml/100 g LVMW (left ventricular mass weight)/min of CBCP; group-Rmt (n = 65), RC-CBCP with terminal warm blood cardioplegia (TWB). Judging from myocardial temperature measured at the end of initial cardioplegic infusion, the myocardial distribution of cardioplegic solution in group-R was significantly favorable even in the distal area of severe coronary artery stenotic lesions exceeding 90% compared with group-A. The recovery of cardiac function assessed from the incidence of occurrence of spontaneous beating and the dose of cathecholamine at the weaning of cardiopulmonary bypass were most excellent in group-Rmt among the 4 groups. There was no significant difference in postoperative peak CK-MB and LDH-1 isoenzyme levels among the 4 groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

[Two cases of hypertrophic obstructive cardiomyopathy (HOCM) treated with mitral valve replacement].

The first patient was a 60-year-old female who had suffered from several episodes of cardiac failure due to severe mitral regurgitation and HOCM. The patient underwent urgent MVR because she had cardiac tamponade due to left ventricular perforation during cardiac catheterization. The second patient was a 64-year-old female with a history of several cardiac failures. The patient had an operation because she had been symptomatic under medical treatments. She underwent MVR instead of myectomy due to relatively thin ventricular septum. Both of them are doing well after the operations in NYHA class I. Although myotomy and myectomy are preferable procedure for HOCM as a first choice, MVR should be considered for the patients who have severe mitral valve regurgitation or the thin interventricular septum.

Cardiomyopathy, Hypertrophic↗

PubMed1992

[Retro-TH catheter for retrograde coronary sinus perfusion].

Retrograde coronary perfusion via the coronary sinus for myocardial protection can be performed more safely and exactly with Retro-TH catheter (3 way balloon catheter) which was originally designed. In addition, this catheter can be useful for selective cerebral perfusion in patients with aortic aneurysm involving aortic arch and for selective visceral and renal perfusion in patients with thoracoabdominal aneurysm. From January 1987 to March 1992, we performed 735 open-heart surgery, 12 surgery for aortic arch aneurysm and 6 surgery for thoracoabdominal aneurysm with the aid of this catheter and obtained satisfactory results.

Catheterization↗

PubMed1992

[A case of subglottic tracheal stenosis following tracheostomy successfully treated with laryngo-tracheal anastomosis].

A 77-year-old male patient underwent laryngo-tracheal anastomosis for subglottic tracheal stenosis. He developed exertional dyspnea 10 month after tracheostomy. Anterior and lateral wall of the cricoid cartilage and the first two tracheal cartilages were resected, preserving the recurrent laryngeal nerves. The distal trachea was anastomosed to the thyroid cartilage primarily and tracheostomy was made at 6th tracheal ring. Postoperatively, anterior flexion of the neck was maintained for a week. Oral intake was started on the 2nd postoperative day. The patient showed smooth recovery. The important points of this operation are: 1) preoperative evaluation of the residual subglottic space, 2) intraoperative care for preservation of the recurrent nerves, especially at the lateral sides of the crycoid cartilage, and 3) postoperative maintenance of the cervical anterior flexion.

Aged↗

PubMed1992

[Surgical treatment of active infective endocarditis and prosthetic valve endocarditis].

Fifteen patients with active native valve endocarditis (NVE) and 5 with prosthetic valve endocarditis (PVE) were subjected to this study. Among the patients with NVE, one of 10 with simple destruction of leaflets and 2 of 5 with annular infection died postoperatively of cerebral bleeding and persistent infection. Five patients with annular infection, whose microorganisms were Streptococcus faecalis, Staphylococcus epidermidis and gram-negative coccus, had a shorter duration from onset to operation (mean 38 days) compared with the others (mean 85 days). A patient with NVE requires an urgent operation, especially when these microorganisms are identified. Among those with PVE, 3 underwent operation at the active phase and one at the chronic phase. Two patients with mechanical valve endocarditis by Staphylococcus and Candida died, but the other 2 with bioprosthetic valve endocarditis by alpha-Streptococcus survived, because infection was localized in the leaflets. Another patient with mechanical valve endocarditis by alpha-Streptococcus survived with conservative management. While a patient with bioprosthetic valve endocarditis requires an early operation as well as NVE, a patient with mechanical valve endocarditis requires selected management considering the microorganism and general condition.

Adult↗

PubMed1991

Combined glyceraldehyde-3-phosphate dehydrogenase/phosphoglycerate kinase in catecholamine-stimulated guinea-pig cardiac muscle. Comparison with mass-action ratio of creatine kinase.

The steady-state reactant levels of triose-phosphate isomerase and the glyceraldehyde-3-phosphate dehydrogenase/phosphoglycerate kinase system were examined in guinea-pig cardiac muscle. Key glycolytic intermediates, including glyceraldehyde 3-phosphate were directly measured and compared with those of creatine kinase. Non-working Langendorff hearts as well as isolated working hearts were perfused with 5 mM glucose (plus insulin) under normoxia conditions to maintain lactate dehydrogenase near-equilibrium. The cytosolic phosphorylation potential ([ATP]/([ADP].[Pi])) was derived from creatine kinase and the free [NAD+]/([NADH].[H+]) ratio from lactate dehydrogenase. In Langendorff hearts glycolysis was varied from near-zero flux (hyperkalemic cardiac arrest) to higher than normal flux (normal and maximum catecholamine stimulation). The triose-phosphate isomerase was near-equilibrium only in control or potassium-arrested Langendorff hearts as well as in postischemic 'stunned' hearts. However, when glycolytic flux increased due to norepinephrine or due to physiological pressure-volume work the enzyme was displaced from equilibrium. The alternative phosphorylation ratio [ATP]'/([ADP]).[Pi]) was derived from the magnesium-dependent glyceraldehyde-3-phosphate dehydrogenase/phosphoglycerate kinase system assigning free magnesium different values in the physiological range (0.1-2.0 mM). As predicted, [ATP]/([ADP].[Pi]) and [ATP]'/([ADP]'.[Pi]') were in excellent agreement when glycolysis was virtually halted by hyperkalemic arrest (flux approximately 0.2 mumol C3.min-1.g dry mass-1). However, the equality between the two phosphorylation ratios was not abolished upon resumption of spontaneous beating and also not during adrenergic stimulation (flux approximately 5-14 mumol C3.min-1.g dry mass-1). In contrast, when flux increased due to transition from no-work to physiological pressure-volume work (rate increase from approximately 3 to 11 mumol C3.min-1.g dry mass-1), the two ratios were markedly different indicating disequilibrium of the glyceraldehyde-3-phosphate dehydrogenase/phosphoglycerate kinase. Only during adrenergic stimulation or postischemic myocardial 'stunning', not due to hydraulic work load per se, glyceraldehyde-3-phosphate levels increased from about 4 microM to greater than or equal to 16 microM. Thus the guinea-pig cardiac glyceraldehyde-3-phosphate dehydrogenase/phosphoglycerate kinase system can realize the potential for near-equilibrium catalysis at significant flux provided glyceraldehyde-3-phosphate levels rise, e.g., due to 'stunning' or adrenergic hormones.

Animals↗

PubMed1991

Interaction between adenosine and beta-adrenoceptors.

Interaction between adenosine and isoproterenol (ISP) on myocardial inotropic action was studied in open-chest dog hearts. The local myocardial force and the left ventricular (LV) dP/dt were measured as indices of myocardial contractility. Isoproterenol [ISP, 9.47 microM (2 micrograms/ml)] was infused into the left circumflex coronary artery at rates of 0.05 ml/min (low dose ISP) or 0.2 ml/min (high dose ISP). Two mM adenosine or 0.5 mM N6-phenylisopropyl-adenosine (PIA) were infused into the coronary artery at rates of 0.2 (4 x 10(-7) mol/min), 0.5 (1 x 10(-6) mol/min) and 10 ml/min (2 x 10(-5) mol/min) in the presence of either a low or a high dose of ISP. Adenosine infusion at a rate of 0.2 ml/min did not modify myocardial contractility in the presence of the both doses of ISP. The larger doses of adenosine, 0.5 ml/min and 10 ml/min, decreased myocardial-developed tension and LVmax dP/dt dose-dependently. However, the dose of adenosine which affected myocardial contractility was inphysiologically high in comparison with the concentration in the ischemic myocardium. PIA, a potent agonist of adenosine A1-receptor, attenuated an increase in myocardial contractility in a dose-dependent manner which was caused by intracoronary ISP infusion. This indicates that A1-adenosine receptors exist, but a functional adenosine-catecholamine antagonism does not play a significant role in the canine left ventricle.

Adenosine↗

PubMed1991

[Pressure monitoring of the coronary sinus during retrograde cardioplegia].

Though the retrograde perfusion via the coronary sinus is a useful way of myocardial protection for more complicated cardiac surgery, coronary venous injury and inadequate preservation of the right ventricle were considered to be disadvantageous. In order to deal effectively with these problems we made a 3-way balloon catheter (Retro-Higami type 12 Fr) and evaluated the importance of monitoring the perfusion pressure in the coronary sinus in 214 patients. The mean perfusion pressure during retrograde cardioplegia infused by a pump was 29.4 +/- 9.1 mmHg, and had significant relation to the left ventricular mass weight (LVMW) which was calculated by UCG method. High perfusion pressure above 40 mmHg, which could have induced coronary venous injury, was noticed in 24 patients, but proper countermeasures could avoid venous injury completely. In 16 of those the high perfusion pressure was due to inadequate position of a tip of the catheter, and in other 8 it was due to relatively high flow rate of cardioplegic solution to LVMW. Twenty-eight patients showed low perfusion pressures below 20 mmHg, due mainly to the leakage from the orifice of the coronary sinus. The coronary sinus pressure during continuous gravity retroperfusion which was 9.2 +/- 2.6 mmHg seemed to bring optimal delivery of cardioplegic solution to the myocardium. On the basis of the results obtained from this clinical study we conclude that the monitoring of coronary sinus pressure during retroperfusion is useful not only to avoid coronary venous injury but to maintain adequate perfusion.

Adult↗

PubMed1991

[Emergent coronary artery bypass grafting (CABG) for over-80-year-old patients].

We experienced 2 emergent CABG for over-80-year-old patients. First patient, an 81-year-old male, showed total occlusion of left main truncus (LMT) and 90% stenosis of right coronary artery (RCA), and fell in shock. He underwent PTCA for LMT under intraaortic balloon pumping (IABP) and recovered from shock. But 3 days later, pulmonary congestion and heart failure developed along with mitral regurgitation. Emergent CABG to left anterior descending branch (LAD) and RCA was performed using saphenous vein grafts in combination with mitral annuloplasty by Kay's method. Second patient, an 82-year-old male, showed 50% stenosis of LMT, 99% stenosis of LAD and total occlusion of RCA, and fell in shock. Emergent CABG to LAD and RCA was performed using saphenous vein grafts under IABP. In spite of some perioperative serious complications, both patients survived and have been doing well. Some problems of CABG for elderly patients were discussed.

Aged↗

PubMed1991

[Analysis of problems in patients over 70 years of age undergoing open-heart surgery for ischemic heart disease].

The operative results of ischemic heart disease in 102 patients over 70 years of age were compared with the results in 296 patients under 70 years, operated on between January 1985 and February 1991. The incidence of emergent or urgent operations increased significantly with the increase of age (under 64 yrs; 29% of 217 patients, 65 to 69 yrs; 46% of 79, 70 to 74 yrs; 49% of 70, over 75 yrs; 75% of 32) and the mortality rates increased accordingly (5.9%, 11.3%, 15.7%, 37.5% respectively). The mortality rate of isolated coronary artery bypass grafting over 70 years was significantly higher than under 70 years. The mortality rate of mechanical complication after myocardial infarction increased in the patients over 70 years. The incidence of postoperative complication in the patients over 70 years was higher and infectious (11%), pulmonary (10%) and embolic (9%) complications were prominent among others. The tendency of increase in the in-hospital expenses was seen with the increase of age. Although elderly patients have increased morbidity and mortality, particularly when operated on emergency or urgently, survivors quality of life are excellent and justify continued performance of open-heart surgery in the patient over 70 year of age.

Age Factors↗

PubMed1991

[A case of bilateral multiple pulmonary arteriovenous fistula treated by the right fistula plication and resection of the left lingual lobe with use of microwave tissue coagulator (MTC)].

A 53-year-old man with the history of brain abscess and multiple cerebral arterio-venous malformations underwent the staged operation for bilateral multiple pulmonary arterio-venous fistulas (PAVF). Right fistula plication and the resection of the left lingular lobe using MTC were performed through posterolateral thoracotomy. Postoperatively, the patient showed the right residual fistula, but, he has been doing well without PAVF complications such as polycythemia and hypoxemia. In conclusion, 1) PAVF with central nervous system complications should be treated aggressively either by surgery or by embolization. 2) MTC was useful for the resection of the lung because of no air leak and bleeding coming from the resected section.

Arteriovenous Fistula↗

PubMed1991

[Aorto-caval fistula due to rupture of abdominal aorto-iliac aneurysm--a case report of successful repair].

A 62-year-old man who had complained of swelling of bilateral lower extremities, exertional dyspnea and jaundice for 3 months was referred to our hospital with a diagnosis of large abdominal aneurysm and congestive heart failure. His aortography and Doppler echocardiography revealed that he had the aorto-caval fistula due to rupture of abdominal aorto-iliac aneurysm. He underwent a reconstruction of abdominal aorta with woven Dacron bifurcation graft together with a closure of fistula with 3 mattress sutures. The postoperative course was uneventful and he is free from any symptoms. Problems of diagnosis, operative management and results are discussed, reviewing the previously reported cases in Japan.

Aorta, Abdominal↗

PubMed1991

[Aortitis syndrome with aortic regurgitation and bilateral coronary ostial stenosis].

A 17-old-male was admitted to our hospital with the chief complaints of anterior chest oppression and syncope. His aortography showed severe aortic regurgitation with annular dilatation, and his coronary angiography revealed 90% stenosis of the left coronary ostium and total occlusion of the right coronary ostium. Because his symptoms increased in spite of steroid therapy during 2 weeks, aortic valve replacement with 25 mm SJM prosthetic valve and coronary artery bypass grafting using internal thoracic artery (IHA) and gastroepiploic artery (GEA) were performed at acute stage. Postoperative course was almost uneventful. Postoperative angiography showed graft patency and no evidence of perivalvular leakage. This is, to the best of our knowledge, the first report of coronary reconstruction using IHA and GEA for coronary disease associated with aortitis syndrome.

Adolescent↗

PubMed1991

[A case report of pulmonary sequestration (Pryce I) associated with infective endocarditis].

We experienced a case of pulmonary sequestration of Pryce type I associated with infective endocarditis (IE). A 19-old-man had prolonged high fever of 39 degrees C against antibiotic therapy. He was referred to our hospital because of the positive blood culture and abnormal echocardiographic findings, which were severe aortic regurgitation with vegetations clinging the aortic cusps. In addition, his chest X-ray film showed mass lesion behind the cardiac shadow, and continuous murmur was auscultated on this portion. The left pulmonary arteriography revealed no arterial distribution to the left lower lobe, while aortography showed an aberrant artery arising from the descending aorta entering into this lobe. One month after aortic valve replacement for IE, left lower lobectomy and amputation of the aberrant artery were performed successfully. Pathologically, inflammatory changes of the aortic valve and proliferations of intimal and medial wall of the aberrant artery were shown. However, alveo-bronchial structure of the resected lobe was normal. Diagnosis, complications and surgical management of pulmonary sequestration were discussed.

Adult↗

PubMed1990

Diamond-shaped anastomosis for duodenal atresia: an experience with 44 patients over 15 years.

During the period between 1974 and 1988 44 patients were treated for congenital intrinsic duodenal obstruction using a diamond-shaped anastomosis (35 atresias, including two multiple atresias and nine stenoses). Neither gastrostomy nor transanastomotic tube was used. Postoperatively, oral feeding was started on days 2 to 6 (3.66 +/- 1.41 day). Intravenous fluid administration was discontinued on days 3 to 20 (7.54 +/- 3.58 day). Fourteen patients died, none related to the operative procedure. Of 30 survivors, 21 patients have been followed from 6 months to 15 years. Body weight was within the normal range at the latest visit. Current barium study performed in 19 patients showed no blind loop, megaduodenum, or anastomotic malfunction. The diamond-shaped anastomosis provides the following advantages: (1) early recovery of anastomotic function, and (2) avoidance of later complications, such as formation of a blind loop or anastomotic stenosis.

Anastomosis, Surgical↗