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Biomedical subjects

T Kunihara

Publications and source records attributed to T Kunihara.

At least 37 records · Page 2Linked to original sources
PubMed2001

Isolation technique for stroke prevention in patients with a mobile atheroma.

Mobile atheroma in the proximal aorta is a risk factor for brain complication after cardiovascular operation. We report a new technique of replacing the ascending and transverse aorta by establishing selective hypothermic antegrade cerebral perfusion. After cooling, cerebral vessels are clamped and systemic perfusion is started. This technique was applied in 5 patients. All patients woke up normally and recovered without neurologic complication.

Aged↗
PubMed2001

Is preservation of the aortic valve different between acute and chronic type A aortic dissections?

OBJECTIVES: In repair of acute type A aortic dissection, the type of proximal repair of the ascending aorta has been of great interest; however, very few reports are available regarding this issue in chronic aortic dissection. The surgical strategies for proximal repair in chronic dissection may not the same as those for acute dissection. We reviewed our 10-year experience of both acute and chronic type A aortic dissections in order to elucidate the validity of valve preservation and the long-term results of aortic regurgitation (AR). METHODS: From 1990 to 1999, 93 patients (55 acute and 38 chronic dissections) underwent operation for type A aortic dissection. Five Marfan patients were included in each group. The degree of AR was evaluated by echocardiography before and after (at hospital discharge and late follow-up) operation. RESULTS: In acute type A aortic dissection (n=55), 16 patients had AR grade II or greater (29%), of whom seven had AR grade III (13%). In 29 patients, dissection was found below the sinotubular junction (STJ) and 14 patients had AR grade II or greater (48%). The aortic valve was replaced in four patients (7%), of whom three had Marfan's syndrome. Only one non-Marfan patient required aortic valve replacement because of valve stenosis. In those whose aortic valve was preserved (n=51), three patients still had AR grade II at hospital discharge, while at late follow-up, AR had deteriorated to grade III in two of them, although no reoperation has been required so far. In chronic type A aortic dissection (n=38), 14 patients had AR grade II or greater (37%), of whom 11 had AR grade III or greater (29% vs. 13% in acute dissection; P=0.051). In 15 patients, dissection was found below the STJ and 12 patients had AR grade II or greater (80% vs. 48% in acute dissection; P=0.043). The aortic valve was replaced in eight patients (21% vs. 7% in acute dissection; P=0.051), including three Marfan patients. Of those whose aortic valve was preserved (n=30), two patients required reoperation for severe AR. The freedom from postoperative AR grade III or greater was 89% at 5 years for operative survivors with acute dissection and 92% for those with chronic dissection, respectively. CONCLUSIONS: This retrospective study suggests that preservation of the aortic valve in acute type A aortic dissection is feasible in non-Marfan patients regardless of the degree of AR. In chronic dissection, aortic root replacement needs to be considered when the degree of AR is greater than moderate because of a dilated STJ and/or annulus. In both acute and chronic dissections, satisfactory mid- to long-term results with a low incidence of reoperation were obtained in those whose aortic valve was preserved.

Acute Disease↗
PubMed2001

The adenosine triphosphate-sensitive potassium channel opener nicorandil protects the ischemic rabbit spinal cord.

OBJECTIVE: We investigated the protective effects of an adenosine triphosphate-sensitive potassium channel opener nicorandil in the rabbit model of spinal cord ischemia. METHODS: Rabbits were randomized into 4 groups (each n = 6): the nicorandil group (100 microg/kg intravenous nicorandil 10 minutes before ischemia); the glibenclamide plus nicorandil group (3 mg/kg intravenous glibenclamide, an antagonist of adenosine triphosphate-sensitive potassium channels, 10 minutes before nicorandil administration); the vehicle group (vehicle alone); and the sham operation group (without spinal cord ischemia). Spinal cord ischemia was induced by balloon occlusion of the infrarenal abdominal aorta for 15 minutes at 39 degrees C. Neurologic function was graded into Johnson's score at 8 hours, 1 day, and 2 days. Histopathologic examination was performed at 2 days, and the number of intact motor neuron cells was compared. RESULTS: Johnson scores of the glibenclamide plus nicorandil and vehicle groups were significantly lower than those of the sham operation and nicorandil groups at each time point, and no statistically significant difference was observed between the glibenclamide plus nicorandil and vehicle groups. Histopathologic examination revealed that motor neurons were almost normal in the nicorandil group, whereas about 55% of motor neurons were lost in the vehicle and glibenclamide plus nicorandil groups. CONCLUSIONS: Nicorandil has a protective effect on the ischemic rabbit spinal cord, and the beneficial effect seems mediated through the activation of adenosine triphosphate-sensitive potassium channels.

Animals↗
PubMed2001

Preoperative disseminated intravascular coagulation associated with aortic aneurysms.

BACKGROUND: To report clinical experiences with disseminated intravascular coagulation (DIC) associated with aortic aneurysms (AA) and discuss therapeutic strategy. METHODS DESIGN AND SETTINGS: uncontrolled, observational study in a university hospital. PATIENTS: among 547 patients with AA treated between 1991 and 1999, 10 patients (7 males, 3 females, mean age 68.5+/-2.5) presenting a preoperative DIC score (defined by the Ministry of Health and Welfare in Japan) of 6 or higher were analyzed. The etiology was dissection for 5 and non-dissection for 5 patients. Six of 10 patients had a bleeding tendency. Eight patients received preoperative anticoagulant therapy. Prosthetic replacement was undertaken for 8 patients except for 2 patients in poor condition. RESULTS: There were no operative deaths in 8 surgical cases. One non-surgical case died of deteriorated bleeding tendency. The mean DIC score was 8.0+/-0.6 at admission, which was reduced to 4.4+/-0.5 at discharge (p<0.05). Prothrombin time, platelet counts, and fibrinogen levels tended to be normalized by the 7th postoperative day. Serum FDP levels decreased with surgery, but tended to increase at the time of discharge and the later follow-up period. Hematologic disturbances and bleeding tendency recurred in 2 patients in the follow-up period. CONCLUSIONS: In the majority of patients presenting DIC with aortic aneurysm, surgical treatment can be performed safely if adequately managed by anticoagulant therapy. Consumptive coagulopathy usually resolved after surgical intervention, but some patients developed DIC in the later period. If DIC recurs, it is essential to search for contributory causes.

Aged↗
PubMed2001

A case of an ascending aortic aneurysm due to mesoaortitis complicated with idiopathic thrombocytopenic purpura.

An 80-year-old man was referred to our hospital for the surgical treatment of an ascending aortic aneurysm. The diagnosis of idiopathic thombocytonenic purpura was also made by hematological studies which included the examination of the aspirated bone marrow. Preoperative chest computed tomography showed an ascending aortic aneurysm with a maximum diameter of 80 mm. Echocardiography demonstrated mild aortic regurgitation. The platelet count increased by intravenous administration of immunoglobulin. A prosthetic graft replacement of the ascending aorta and aortic valve repair were carried out with the aid of cardiopulmonary bypass, selective cerebral perfusion and hypothermic circulatory arrest. No difficulty was encountered in hemostasis and the postoperative course was uneventful. Histological examination of the aneurysmal wall showed chronic mesoaortitis with patchy destruction of musculo-elastic medial tissue and adventitial focal lymphocytic infiltrates that were similar to syphilitic mesoaortitis, although serological treponemal tests were all negative. Perioperative administration of gamma-globulin is useful to minimize the hemorrhagic complication in a patient undergoing cardiovascular surgery with idiopathic thrombocytopenic purpura.

Aged↗
PubMed2000

Surgical experience of the thoracic aortic aneurysm due to Takayasu's arteritis.

We have treated 10 patients with thoracic aortic aneurysms due to Takayasu's arteritis during the last 15 years and presented surgical results. In the surgical treatment of thoracic aortic aneurysm due to Takayasu's arteritis, therapeutic strategy is different from that for atherosclerotic aneurysm and should be determined by the location and the extent of aneurysmal lesions and the degree of inflammation. Palliative procedure, which was taken to reduce surgical risk, has failed to prevent the recurrence of aneurysmal formation or to minimize surgical risk in the later period. Radical surgical treatment for thoracic aortic aneurysms is highly recommended if technically possible. Penoperative steroid therapy to control the degree of inflammation, appropriate strategy for multiple or extensive lesions and progress in the organ protection method that enabled radical treatment, all these will contribute to the improvement of surgical results.

Adult↗
PubMed2000

Distribution of arterial involvement in thromboangiitis obliterans (Buerger's disease): results of a study conducted by the Intractable Vasculitis Syndromes Research Group in Japan.

The clinical profile of thromboangiitis obliterans (TAO) has been changing. The purpose of this study was to clarify the distribution of arterial involvement in this disease, based on a nationwide survey carried out in 1993. A total of 825 TAO patients with complete records were analyzed. There were 749 men and 76 women, with a mean age of 50.8 +/- 0.4 years. The survey assessed clinical manifestations categorized by Fontaine's classification, distribution of the lesions, associated diseases, responses to treatment, and outcome. This study focused on the distribution of arterial involvement. There were 42 patients (5.1%) with upper-extremity arterial involvement only, 616 (74.7%) with lower-extremity involvement only, and 167 (20.2%) with both. The most frequently affected arteries were the anterior (41.4%) or posterior (40.4%) tibial arteries in the lower extremities, and the ulnar artery (11.5%) in the upper extremities. There were no significant differences in the distribution of arterial involvement between men and women or between the right and left sides. In conclusion, approximately 25% of the patients had upper-extremity involvement. The anterior or posterior tibial arteries were most commonly affected. There was no significant difference in the distribution of arterial involvement between male and female patients.

Adolescent↗
PubMed2000

Midline exposure of the thoracoabdominal aorta.

Extended aortic replacement from the aortic arch to the descending thoracic or thoracoabdominal aorta has been performed through a left thoracotomy or a thoracoabdominal incision combined with or without a median sternotomy. However, a left thoracotomy incision may be unfavorable when dense adhesion of the lung is anticipated. We report a redo patient who underwent simultaneous replacements of the aortic arch and the thoracoabdominal aorta through a midline incision without entering the left pleural cavity.

Aged↗
PubMed2000

Lazaroid reduces production of IL-8 and IL-1 receptor antagonist in ischemic spinal cord injury.

BACKGROUND: 21-aminosteroids (lazaroids) have demonstrated the protective effect against cerebral ischemic injury through the inhibition of lipid peroxidation. We examined whether lazaroids affected the production of proinflammatory and antiinflammatory cytokines in ischemic spinal cord injury model. MATERIALS: Anesthetized New Zealand white rabbits underwent a 20-minute infrarenal aortic cross-clamping (AXC) with pretreatment of either an intravenous 3 mg/kg lazaroid U74389G (group L; n = 10) or the same volume saline (group P; n = 10). Sham operation group (group S; n = 6) underwent only exposure of the aorta. Plasma concentrations of interleukin (IL)-8, -1beta, -1 receptor antagonist (IL-1ra) and tumor necrosis factor (TNF)-alpha were measured at four time points. Functional assessment with Tarlov score at 24 and 48 hours after pretreatment, pathologic assessment of the spinal cord, and measurements of cytokine levels in the spinal cord were performed. RESULTS: The maximum elevation of plasma IL-8 and -1ra levels occurred at 1 hour after declamping in four measurement points. Plasma IL-8 and -1ra levels in group L were significantly lower than those in group P (*p < 0.05). Plasma TNFalpha peaked at 5 minutes after declamping, but decreased afterwards. Plasma TNFalpha levels were not different among three groups. Spinal IL-8 levels in group L (0.98 +/- 0.34 ng/g tissue) were lower than those in group P (7.26 +/- 2.26 ng/g tissue)(*p < 0.05). Spinal IL-1ra and TNFalpha were not significantly different. Tarlov score and pathologic assessment were better in group L. CONCLUSIONS: Lazaroid U-74389G reduced the production of systemic IL-8 and -1ra and spinal IL-8 when AXC caused spinal cord injury. These results indicate that lazaroids may attenuate ischemic endothelial cell injury or activation of leukocytes.

Animals↗
PubMed2000

Surgical management of atherosclerotic aortic arch aneurysms using selective cerebral perfusion: 7-year experience in 52 patients.

OBJECTIVE: Patients with atherosclerotic aortic arch aneurysms are at greater risk for brain complication. We report our techniques and results of operation using selective cerebral perfusion. METHODS: We retrospectively analyzed 52 consecutive patients with atherosclerotic aortic arch aneurysms (mean age, 70 years, range, 53-86 years), who underwent operation between April 1992 and March 1999. The operation was non-elective in 11 patients (21.1%). Concomitant operations included eight coronary artery bypass grafting and one aortic valve replacement. Simultaneous distal aortic reconstruction was performed in three patients. The operation was performed through median sternotomy. To avoid brain embolism, total arch replacement with a branched prosthesis was performed in 48 patients, in an attempt to exclude affected segments of aorta. In addition, retrograde femoral artery perfusion was avoided and cerebral circulation was isolated before aortic manipulation. To achieve even blood flow distribution, we employed perfusion and continuous pressure monitoring of all the three arch vessels. The perfusion rate was 12+/-2 ml/kg per min and the pressure was kept around 50 mmHg. Deep hypothermic arrest of the lower torso (bladder temperature, 22 degrees C) was used during open distal aortic anastomosis. RESULTS: The hospital mortality rate was 11.5% (six of 52), and 7.3% (three of 41) for elective cases. Only one patient (1. 9%) developed permanent focal neurological deficit. Six other patients showed temporary brain complications, which was global (delirium) in three and focal in three others. CONCLUSIONS: Selective cerebral perfusion is a safe brain protection method, and our strategy seems effective for embolic stroke prevention.

Aged↗
PubMed2000

[Clinical evaluation of hepatic blood flow and oxygen metabolism during thoracoabdominal aortic surgery using pulse dye-densitometry combined with hepatic venous oxygen saturation].

OBJECTIVE: There has been no report that pulse dye-densitometry (PDD), a novel non-invasive modality for monitoring hepatic blood flow (HBF), was applied during cardio-pulmonary bypass (CPB). We investigated weather PDD was useful to measure HBF during thoracoabdominal aortic surgery using partial CPB. Furthermore, HBF and hepatic metabolism were assessed during selective visceral perfusion or shunt using PDD, hepatic venous oxygen saturation (ShO2), and analysis of hepatic metabolic products. METHODS: A prospective study was carried out in eight patients who underwent thoracoabdominal aortic surgery from April 1998 to October 1999. Operative adjuncts were partial CPB with mild hypothermia in six (femoral veno-arterial bypass: FF group) and deep hypothermic circulatory arrest in two (DHCA group). Measurements were performed at following five time points; just before initiating CPB, just after establishing CPB, during selective visceral perfusion, during selective visceral shunt, and just after weaning CPB. RESULTS: Plasma clearance rate of indocyanine green measured by PDD well correlated with that obtained by in vitro spectrophotometry (p < 0.0001, R2 = 0.644). PDD demonstrated that decreased IIBF during selective visceral perfusion or shunt was well compensated by increased hepatic oxygen extraction rate in FF group and reduced oxygen consumption in DHCA group. Lactic acid extraction ratio and arterial ketone body ratio also decreased during this period. ShO2 during selective visceral shunt correlated with systemic systolic arterial pressure (SAP), and it showed a marked decrease under 20% when SAP was below 80 mmHg. Postoperative time course of serum total bilirubin and alanine aminotransferase of almost patients were within acceptable limits except the patient who required large amount of homologous blood transfusion. CONCLUSIONS: PDD proved to be a useful modality that enabled non-invasive monitoring of HBF even during partial CPB. Decreased HBF during selective visceral perfusion or shunt in thoracoabdominal aortic surgery was within physiological compensation, which led us conclude that it might be effective adjuncts, for visceral organ protection.

Adult↗
PubMed2000

Surgical results of Stanford type B aortic dissection. Comparisons between partial and subtotal replacement of the dissected aorta.

BACKGROUND: Surgical results for Stanford type B aortic dissection were retrospectively compared between the subtotal prosthetic replacement of the thoracoabdominal dissected aorta (STR) and partial replacement of the descending aorta at the intimal tear (PR). METHODS: Twenty-two patients (11 males and 11 females with mean age of 56.9+/-2.6 years) undergoing repair of aneurysms were analyzed. All operations were performed with the aid of femorofemoral partial cardiopulmonary bypass. Reconstruction of the critical artery for spinal cord blood supply was determined by evoked spinal cord potential (ESP) monitoring in non-urgent cases. Operative mortality and incidence of complications were compared between the PR group (Group I; n=15) and the STR group (Group II; n=7). RESULTS: There were one operative death and one late death in Group I. No early or late deaths occurred in Group II. Postoperative paraplegia occurred in 1 patient in Group I and 2 patients in Group II. Among patients undergoing selective reconstruction of the critical intercostal arteries, paraplegia occurred in only one patient. Incidence of postoperative complications was not significantly different between Group I and Group II. Presence of rupture (p<0.001) and development of acute renal failure (p<0.05) revealed significant determinants of postoperative mortality by multivariate analysis. Operative procedure did not influence postoperative mortality or occurrence of paraplegia. CONCLUSIONS: Operative results of STR with selective reconstruction of the critical arteries and PR for aortic dissection were comparable. Subtotal replacement of the thoracoabdominal dissected aorta is encouraged to apply for patients with diffuse, large postdissection aneurysms or those with a high risk of future enlargement of remaining false channels such as Marfan syndrome, under adequate reconstruction of the critical segmental arteries.

Acute Kidney Injury↗
PubMed2000

Arterial thoracic outlet syndrome with embolic cerebral infarction. Report of a case.

Cerebral embolism is a very rare but recognized manifestation of arterial complications of thoracic outlet syndrome, and is associated with retrograde embolization in the cerebral arteries. We herein report a case of embolic brain infarction due to arterial thoracic outlet syndrome while discussing the etiology, diagnosis, and surgery.

Cerebral Infarction↗
PubMed1999

Current trends in thromboangiitis obliterans (Buerger's disease) in women.

BACKGROUND AND PURPOSE: Thromboangiitis obliterans (TAO) affects mainly young male smokers and rarely women. Clinical manifestations between men and women with TAO were compared based on the Japanese Nationwide Survey database. PATIENTS AND METHODS: From the database registered in 1993, 850 patients with complete records were analyzed. There were 771 males and 79 females, with the mean age of 50.8 +/- 0.4 years. The following factors were compared: Fontaine's classification, distribution of lesions, associated disease, response to treatment, and outcome. RESULTS: Fontaine's classification at the first consultation (P = 0.372) and at the survey (P = 0.740), the incidence of migratory superficial phlebitis (P = 0.76), ulcer formation (P = 0.306), requirement for amputation (P = 0.809) were not different between men and women. Nonsmokers at the first consultation were more common among women (25.3%) than among men (4.9%; P <0.0001). CONCLUSIONS: Clinical presentations in women with TAO were almost equal to those in men. The only difference was the higher incidence of nonsmokers in women at the first consultation, but it did not influence the response to treatment or outcome.

Adolescent↗
PubMed1999

Abdominal aortic aneurysms in aged patients: analysis of risk factors in non-ruptured cases.

BACKGROUND AND METHODS: A retrospective analysis of 304 patients (274 males and 30 females) surgically treated for non-ruptured, infrarenal abdominal aortic aneurysm (AAA) to determine the relative contribution of preoperative, operative, and postoperative factors to mortality and to the development of postoperative complications. 1) Risk factors, hospital mortality and long-term survival rate were compared between patients aged 75 or older (- group I; n=79) and those under 75 years of age (group II; n=225). 2) These risk factors were subjected to univariate and multivariate analysis to determine their relative contribution to patient hospital mortality and to the development of major postoperative complications in aged patients. RESULTS: Maximum diameter of AAA, the prevalence of respiratory dysfunction, diabetes mellitus and the total volumes of intraoperative blood loss were significantly different between the two groups. A higher hospital mortality was noted in the aged patients (10.1% versus 3.1%, p<0.05). The majority of deaths in group I resulted from organ dysfunctions, especially involved with respiratory failure. The long term survival rate at 3 and 5 years was not different between operative survivors in the two groups. Incremental risk factors for hospital death in aged patients included the presence of symptomatic AAA, the maximum diameter of AAA, the postoperative development of myocardial infarction, respiratory complications and gastrointestinal bleeding. Operation time and the volumes of intraoperative blood loss significantly correlated with the postoperative development of respiratory failure, renal failure and multiple organ failure. CONCLUSIONS: 1) A higher operative mortality and higher prevalence of postoperative complications were noted in aged patients with AAA. 2) To reduce operation time and the volumes of intraoperative blood loss would be essential to improve surgical results of AAA in aged patients.

Adult↗
PubMed1999

Ruptured abdominal aortic aneurysms: analysis of factors influencing surgical results in 184 patients.

BACKGROUND: Rupture is often the first manifestation in patients with abdominal aortic aneurysms. Although elective surgery for non-ruptured abdominal aortic aneurysms has provided satisfactory surgical results, operative mortality of ruptured abdominal aortic aneurysms (rAAA) has not improved. The purpose of this study was to identify predictors for early hospital death in patients with rAAA. METHODS DESIGN: A retrospective study. SETTING: A university hospital and 20 affiliated hospitals. PATIENTS: PATIENTS undergoing surgical treatment for rAAA (n=183) between 1968 and 1997. INTERVENTIONS: All patients were surgically treated and divided into operative survivors (n=119) and non-survivors (n=64). MEASURES: The patient-related, procedure-related, and postoperative factors were compared between the two groups. A multivariate analysis was also conducted to determine predictors for hospital deaths. RESULTS: In univariate analysis, age at operation (p=0.004), preoperative hemodynamic conditions (p<0.0001), extent of hematoma (p<0.0001), preexistent renal dysfunction (p=0.001), and volumes of blood loss at operation (p=0.001) were significantly different between the two groups. The morbidity of postoperative renal failure (p<0.0001), gut ischemia (p=0.003), heart failure or ischemic heart disease (p<0.0001), and multiple organ dysfunction syndrome (p<0.0001) was higher in the non-survivors' group. Multivariate analysis also identified preoperative hemodynamic conditions, blood loss volume at operation, pre-existent renal dysfunction, postoperative renal failure, heart failure, and multiple organ dysfunction syndrome as incremental risk factors for hospital deaths. CONCLUSIONS: Every effort to maintain preoperative hemodynamic conditions, to reduce volumes of blood loss at operation, and to minimize deterioration of organ functions postoperatively is all essential to improve patient survival.

Adult↗
PubMed1999

Takayasu's aortitis treated surgically by extensive aortic replacement. A case report.

A case report of Takayasu's arteritis with aneurysmal involvement of the ascending aorta, aortic arch and descending thoracic aorta is presented. The patient underwent successful two-stage operation by use of Elephant trunk technique. During the first operation, replacement of ascending aorta and aortic arch was done under selective cerebral perfusion. During the second-stage operation, replacement of the descending thoracic aorta was performed under partial cardiopulmonary bypass. The postoperative course was uneventful and one year after surgery the patient is doing well. Specific conditions and operative strategy required in case of extensive aortic involvement in Takayasu's arteritis are discussed.

Aortography↗