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Biomedical subjects

S Kawada

Publications and source records attributed to S Kawada.

At least 73 records · Page 4Linked to original sources
PubMed1999

Surgical treatment of patent ductus arteriosus (PDA) through mini subaxillary extrapleural approach.

In this study, a new surgical technique for the surgical treatment of patent ductus arteriosus (PDA) is evaluated. The subaxillary extrapleural approach was performed on 836 patients with patent ductus arteriosus. And 20 of these patients were evaluated for postoperative outcomes compared with the routine technique. The results indicated that the new method is safe, less traumatic and has better cosmetic effects. It is concluded in this article that the subaxillary extrapleural approach for PDA is a good modification to the routine surgical technique, that is surgery through the posterolateral approach.

Cardiac Surgical Procedures↗
PubMed1999

[Optimum anticoagulation control after bileaflet mechanical valve replacement: a prospective multi-institutional study].

This study was undertaken to assess optimum anticoagulation control after bileaflet mechanical valve replacement by using the international normalized ratio of prothrombin time (PT-INR). From January to December 1995, 261 patients (pts) underwent mechanical valve replacement in the aortic (n = 95), mitral (n = 126), aortomitral (n = 39) or isolated tricuspid (n = 1) valve position in 8 medical centers in Tokyo, Japan. The St. Jude Medical valves were implanted in 184 pts and the Carbomedics valves in 77. There were 17 valve-related events as follows: 11 thromboembolic events (3.62%/pt-yr) including 10 transient ischemic attacks. 5 non-fatal bleeding events (1.65%/pt-yr), 2 reoperations (0.66%/pt-yr). At 18 postoperative months, free rates from all deaths (actuarial survival) thromboembolism, reoperation and all valve-related events were 95.3%, 95.7%, 98.7% and 88.9%, respectively. Under anticoagulant therapy, thrombin-antithrombin III complex and D-dimmer remained in high levels at 1 month after operation, and both values decreased to the control level at 6 months. In patients with thromboembolic events, PT-INR tended to be less than 2.0. The patients with bleeding events showed some increase of PT-INP or received anti-platelet agents. The 5 to 95 percentile of PT-INR at 6 months was 1.2 to 3.0 in the patients without valve-related events. These results suggested that optimum range of PT-INR might be between 1.2 and 3.0 after bileaflet mechanical valve replacement in patients without high risk of thromboembolism and between 2.0 and 3.0 in patients with the high risk.

Adolescent↗
PubMed1999

Angioplasty/bypass combination therapy in an 89-year-old man with left main trunk disease.

We report a case of an 89-year-old man presenting with unstable angina and left main trunk disease. Minimally invasive direct coronary artery bypass grafting supplemented by catheter intervention was successfully performed. In view of the increasing elderly population, angioplasty/bypass combination therapy may be an important alternative for elderly coronary artery disease patients.

Aged↗
PubMed1998

[Near-infrared spectroscopy during hypothermic selective cerebral perfusion--a clinical study of its value].

The purpose of this study is to assess the value of near-infrared spectroscopic oxymetry (NIRO) in monitoring cerebral oxygenation and metabolism during selective cerebral perfusion (SCP) for surgery of the aortic arch. The measurement protocol during SCP comprised oxyhemoglobin (HbO2), deoxyhemoglobin (Hb), and total hemoglobin levels in the brain. From March 1994 through March 1997, 14 patients underwent surgical treatment of the aortic arch anomalies with intraoperative monitoring with NIRO. The temporary circulatory arrest was accomplished at a rectal temperature of 22 degrees C and the hypothermic SCP was employed for the cerebral protection. SCP was initiated at a flow rate of 10 ml/kg/min so as to maintain HbO2 at the same level as immediately before the circulatory arrest (baseline). The longitudinal changes of HbO2 level during the process revealed four different patterns and were grouped accordingly. Three of the patients maintained HbO2 level above the baseline during SCP (Group A). HbO2 level reached to the baseline at initial flow rate but decreased gradually thereafter in 4 patients (Group B). Gradual increment of the perfusion flow rate failed to elevate HbO2 level to the baseline in the 5 patients (Group C1). In this group, HbO2 level started to elevate about 60 minutes after the initiation of SCP. HbO2 level of the remaining 2 patients was absolutely resistant to the increment of SCP flow rate and kept low values throughout SCP (Group C2). All the patients recovered uneventfully without any neurological abnormality. Our analyses for the longitudinal behavior of the HbO2 level confirmed the previously reported evidences that the values were affected not only by perfusion flow rate but also by hemodilution, blood transfusion, and perfusion pressure. Furthermore, our present study disclosed another evidence that HbO2 level was strongly affected by subclavian steal phenomenon. Although there were no differences in the clinical outcome among the groups, referring to the theories that HbO2 level is better not to be departed from baseline level, it could be concluded that HbO2 level monitoring in the setting of the determined hematocrit and hypothermia was effective for securing the adequate demand and supply balance of the cerebral oxygenation. Our conclusion may extend further that NIRO is a useful means in determining the optimal perfusion flow rate of SCP during surgery of the aortic arch.

Aged↗
PubMed1998

[The role of bidirectional cavopulmonary shunt on selection of Fontan patients].

There are no objection against that pulmonary vascular resistance index (PVRI) is one of the most important factors for completion of successful application of Fontan-type operation. However, calculated PVRI in single ventricle physiology in often unreliable because of difficulty in accurate measurement of pulmonary blood flow, especially in patients with decreased pulmonary blood flow. Although the role of bidirectional cavopulmonary shunt (BCPS) in such patients has been increasingly recognized, the impact of BCPS on PVRI has not been fully understood. Between November 1993 and November 1996, 24 patients, aged between 0.54 and 22.2 years, with a wide variety of cardiac malformations underwent BCPS, and were followed up for the mean of 15.1 months. There were four hospital deaths (16.7%) and three deaths in follow-up (12.5%). Serial catheterization revealed that significant increase in mean arterial oxygen saturation from 75.8% to 83.9% (p = 0.005), and decrease in mean Nakata's index from 433 to 311 (p < 0.0001). PVRI calculated by using formulas derived from Ohm's law before BCPS (Pulmonary flow was derived from Fick formula) was highly (greater than 10 u.m2) or moderately (between 4 and 10 u.m2) elevated in 6 and 7 patients, respectively. However, PVRI in these patients was normal after BCPS. Fourteen out of 24 patients underwent total cavopulmonary connection (TCPC) with 8 to 15 months of interval from BCPS, and have been currently surviving, and in NYHA functional class I or II, except 2 patients who underwent take-down. In conclusion, early and midterm outcome after staged operation appears to be excellent. BCPS is a good interim procedure, in part because one can more properly select patients undergoing Fontan operations from the PVRI point of view.

Adolescent↗
PubMed1998

[Surgical repair of isolated congenital tricuspid regurgitation with artificial chordae--a case of two year-follow up].

Isolated congenital tricuspid regurgitation derived from primary dysplasia of the valvular apparatus is a rare cardiac abnormality. A 23-year-old woman was first diagnosed to have an isolated tricuspid regurgitation during infancy and was followed up at our hospital. She developed progressive cardiomegaly at the age of 22 years. The chest roentgenogram at the time of admission revealed marked cardiomegaly with a cardiothoracic ratio of 64%. Despite the severe regurgitation of the tricuspid valve, the catheter examination disclosed v and mean pressures of the right atrium of 9 mmHg and 5 mmHg, respectively. The operative findings revealed a markedly dilated tricuspid annulus of 45 mm in diameter (157% of normal) and fragile and redundant valve leaflets, anterior leaflet in particular. Anterior papillary muscle was absent without any vestige thereof. Chordae tendinae of the anterior and posterior leaflets were absent and those of the septal leaflet were attached to the ventricular septum. Each commissure was tethered to the ventricular wall by thick and short chordal tissue. The chordal abnormalities were repaired by four artificial chordae of 4-0 ePTFE suture and an annuloplasty with Carpentier-Edwards ring (36 mm) was added. She recovered uneventfully and was discharged on postoperative day 30. A follow-up echocardiography at 2 years after surgery showed excellent function and trivial regurgitation of the valve. No evidences of thrombus or calcification of the artificial chordae were detected. This experience draws us to conclude that the artificial chordal replacement is one of the useful surgical options for the repair of isolated congenital tricuspid regurgitation.

Adult↗
PubMed1998

Complications following reparative surgery for aortic coarctation or interrupted aortic arch.

Repair of aortic coarctation or interrupted aortic arch continues to be associated with major long-term morbidity. Thus, we conducted a review of 87 consecutive patients who underwent aortic arch repairs, focusing particular attention on the complications that developed. A two-stage strategy was employed if cardiac lesions were associated. The median age at surgery was 1.5 months with a range of 12 h to 56 years. The aortic arch was repaired using end-to-end anastomosis, subclavian flap aortoplasty, subclavian arterial turning-down aortoplasty, patch aortoplasty, tube graft interposition, or other methods. There were 10 patients who died soon after repair, and all of whom had complex cardiac anomalies. Of the remaining 77 patients, 8 developed recurrent stenosis. These 8 patients were all similar in age, being under 3 months old, and weighing 4 kg or less. A multivariable analysis of the infants identified interrupted aortic arch as an independent risk factor for the development of this complication with an odds ratio of 6.45. Complications following prosthesis-free techniques were similar in prevalence and timing. All reinterventions were mortality-free, but catheter dilation and patch aortoplasty were not always successful. Three extraanatomic bypasses were successfully performed, and one adult who had undergone a previous graft and pseudoaneurysm operation was successfully treated with an extraanatomic bypass. These findings led us to conclude that the initial repair should be performed without a prosthesis, and that reintervention for stenosis should combine catheter dilation and extraanatomic bypass.

Adolescent↗
PubMed1998

Surgical management of isolated congenital tricuspid regurgitation.

BACKGROUND: Isolated congenital tricuspid regurgitation without downward displacement of the leaflet is a rare clinical entity. Degenerative cusps and lack of chordae may preclude valvuloplasty and require valve replacement. METHODS: Three consecutive patients with isolated congenital tricuspid regurgitation underwent surgical repair between May 1995 and April 1997. Their ages were 23, 15, and 8 years old. Tricuspid valvuloplasty was feasible in all of them, with use of a gathering suture of the anterior leaflet, artificial chordae implantation, and ring annuloplasty. RESULTS: All 3 patients survived and recovered well after the operation. The cardiothoracic ratios on their chest roentgenograms decreased from 0.64 to 0.52 in patient 1, from 0.58 to 0.48 in patient 2, and from 0.60 to 0.44 in patient 3. Postoperative echocardiograms showed competent tricuspid valves and the disappearance of regurgitation in all cases. CONCLUSIONS: Although malformation of the valve is extensive in isolated congenital tricuspid regurgitation, application of artificial chordae with conventional valvuloplasty technique can avoid the use of prosthetic valves by establishing the competence of the tricuspid valve.

Adolescent↗
PubMed1998

Correction of total anomalous pulmonary venous connection of the cardiac type.

Surgical treatment of the cardiac type of total anomalous pulmonary venous connection requires special techniques. The treatment and outcome in 17 consecutive patients who had undergone primary repairs of the cardiac type between 1965 and 1996 were reviewed. The median age was 3 months and median weight 4.2 kg. The connection was the coronary sinus in ten patients, and the right atrium in six. Interatrial communication was routinely augmented. The right atrial cavity was partitioned using a patch to direct the anomalous pulmonary veins into the left atrium through the atrial septal defect in the first 13 patients. In the last four patients, the free wall flap of the right atrium was developed as a neoseptum. There were three early postoperative deaths during the early period of conventional repair. Two patients developed residual or recurrent diffuse obstruction in the individual lobar veins; reoperation to relieve the obstruction was attempted but unsuccessful. One sudden death occurred in a patient with occasional heart block. Ten survivors have been asymptomatic during follow-up, but two incomplete heart blocks and one atrial flutter were noted among patients who underwent conventional repair. The right atrial wall flap technique was not associated with any mortality or morbidity, such as arrhythmia and recurrent pulmonary vein stenosis during 12 to 63 months of postoperative obstruction. In conclusions, a flap technique using the right atrial wall appears to be a promising method to decrease the incidence of supraventricular arrhythmias and pulmonary vein drainage obstruction following repair of the cardiac type.

Cardiac Surgical Procedures↗
PubMed1998

[Basic approaches in minimally invasive cardiac surgery (MICS) and its selection].

Recently, minimally invasive cardiac surgery (MICS) has been developed and popularized as a less stressful and less invasive technique in the field of cardiac surgery. There are eight currently available MICS approaches for open heart surgery. The optimum approach should be selected for each patient based on the results of preoperative examination including chest X-ray, computed tomography, and angiography. Between December 1996, when we first introduced MICS for mitral repair, and the end of November 1998, we performed MICS in 67 patients [excluding cases of MIDCAB]. These included 11 patients who received the Port-Access (Heartport, Inc.) system. Although no patients died in hospital stay, one died of cerebrovascular bleeding eight months later. All patients were evaluated in the outpatient department as being NYHA class I. In view of future technological progress, we expect that MICS will gradually become more widespread in cardiac surgery.

Cardiac Surgical Procedures↗
PubMed1998

A case report of Candida parapsilosis endocarditis.

A 57-year-old male was treated for fungal endocarditis caused by Candida parapsilosis which precipitated severe cardiac valve vegetation and insufficiency. His condition resulted from a three-month installation of a central venous catheter for hyperalimentation and chemotherapy following total gastrectomy for gastric cancer. Aortic valve replacement combined with fluconazole administration resulted in satisfactory recovery with no adverse events during an 18-month follow up period.

Antifungal Agents↗
PubMed1997

Detrimental effects of exogenous glutamate on spinal cord neurons during brief ischemia in vivo.

BACKGROUND: Paraplegia remains a serious complication of thoracoabdominal aortic operations. However, despite growing in vitro evidence, it has been difficult to demonstrate glutamate neurotoxicity in vivo because of the reuptake activity that occurs. We hypothesized that glutamate can be toxic to the spinal cord under metabolic stress. METHODS: Infrarenal aortic isolation was performed in New Zealand white rabbits. Group A animals (n = 7) then received a segmental infusion of glutamate (50 mmol/L) for 5 minutes. Group B animals (n = 7) received saline as a negative control. Group C animals (n = 6) were pretreated with a segmental infusion of 2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(f)-quinoxaline (4 mg/kg), a competitive alpha-amino-3-hydroxy-5-methylisoazole-4-propionic acid/kainate antagonist, followed by the segmental infusion of glutamate (30 mmol/L) for 4 minutes. Group D animals (n = 6) received the vehicle agents only, followed by the same glutamate infusion (30 mmol/L) as in group C as a control for group C. Neurologic status was assessed at 12, 24, and 48 hours after operation and scored using the Tarlov system. RESULTS: Group A animals exhibited paraplegia or paraparesis with marked neuronal necrosis. Group B animals recovered fully. Group C animals had better neurologic function than group D animals (p = 0.0039). CONCLUSIONS: Exogenous glutamate can have detrimental effects on spinal cord neurons during a brief period of ischemia. This model may be useful for the purpose of assaying a glutamate receptor antagonist in vivo.

Animals↗
PubMed1997

Long-term follow-up study of patients with unilateral moyamoya disease.

Although a number of cases of unilateral Moyamoya disease have been reported, the natural history of this disease remains unclear. The clinical features of 17 patients initially diagnosed with unilateral Moyamoya disease at our hospital are reported. Age at onset was 3-45 years (mean, 13.5). Of these 12 cases had onset of symptoms in childhood and five had onset in adulthood. Seven were male and 10 were female. An ischemic attack was the initial episode in ten of the 12 pediatric cases, two of the five adult cases presented with intraventricular hemorrhage. Of the 12 pediatric patients six developed contralateral lesions between 4 and 34 months (mean, 20) after the diagnosis of a unilateral lesion. The remaining six pediatric patients and all adult patients did not develop lesions on the normal side. The mean age at onset for patients later developing contralateral lesions was 6.2 years. The pediatric cases remaining unilateral was 7.7 years. The normal hemisphere of three of the pediatric patients has remained unchanged on repeated follow-up angiograms for over 10 years. Young children tended to develop the vascular pathology bilaterally. However, there were some pediatric cases whose normal or atypical sides remained unchanged without development of bilateral lesions.

Adolescent↗
PubMed1997

Long-term results of surgically treated moyamoya disease.

Various surgical procedures have been tried for patients with Moyamoya disease. The most effective treatment, however, is still controversial. We retrospectively evaluated the long-term results of 71 patients (26 men and 45 women) with Moyamoya disease surgically treated in our institute. They consisted of 56 pediatric patients (younger than 15 years) and 15 adult patients. Symptoms in all patients were due to cerebral ischemia. We did 123 operations on 119 hemispheres: 18 superficial temporal artery--middle cerebral artery (STA-MCA) anastomoses, six STA-MCA anastomoses with indirect bypass (IB), 41 encephalo-duro-arterio-synangiosis (EDAS), 29 encephalo-duro-arterio-myo-synangiosis (EDAMS) and 29 ribbon EDAMS. Average follow-up periods for each procedure were: 7 years for STA-MCA anastomosis, 6.2 years for STA-MCA anastomosis with indirect bypass, 11 years for EDAS, 5.6 years for EDAMS and 2.6 years for ribbon EDAMS, respectively. The results of each procedure were satisfactory because the preoperative transient ischemic attacks disappeared. Analysis of follow-up angiograms shows excellent filling of the ACA and MCA territory in the patients undergoing ribbon EDAMS. However, long-term follow-up study shows that about 10% of the patients had severe difficulty in social or school life because of intellectual impairment.

Anastomosis, Surgical↗
PubMed1997

Long-term follow-up of surgical patients with single-ventricle physiology: prognostic anatomical determinants.

Although univentricular or biventricular repair is not always possible for hearts with single-ventricle physiology, it has been proven to produce a satisfactory outcome. It is hypothesized that patient prognosis can be predicted by anatomical diagnosis at presentation. Between 1961 and 1995, 158 patients with single-ventricle physiology, including tricuspid atresia and hypoplastic left heart syndrome, were referred to the authors' institute, and underwent 260 surgical interventions. Follow-up was 99% complete. Patient survival and anatomical risk factors were examined by the Kaplan-Meier method, and multivariate analysis including the Cox proportional hazard model. Mean (s.e.m.) actuarial survival rates at 1, 5, 10 and 20 years following birth were 70.3(3.6)%, 56.3(4.0)%, 48.8(4.2)%, and 40.9(4.7)%, respectively. Definitive palliation was attempted in 38 patients (univentricular in 35 and biventricular in three). Multivariate analysis identified systemic ventricular outflow tract obstruction, mitral atresia, situs ambiguus, and pulmonary vein drainage tract obstruction as independent prognostic factors for overall survival. Visceral heterotaxy was the only independent risk factor for lack of application or failure (death or take-down within 30 days of operation) of univentricular or biventricular repair. In conclusions, these anatomical factors in hearts with single-ventricle physiology affect long-term mortality, despite multiple and heterogeneous surgical efforts.

Female↗
PubMed1997

Video-assisted cardioscopic staple closure for atrial septal defect.

Our goal was to determine the feasibility of video-assisted cardioscopic closure of atrial septal defect (ASD) without cardiopulmonary bypass using a staple catheter device and guiding catheter in an experimental setting. An artificial linear atrial septal defect (AASD) was created in 7 swine under video-assisted cardioscopic view, and staple closure was attempted at the AASD with a stapler inserted through a trocar guiding catheter via the right atrium under median sternotomy. The staple device was successfully and safely anchored in 4 animals. The whole process of stapling could be monitored by cardioscope and by post mortem macroscopic examination. In conclusion, although the size and flexibility of the stapler and the guiding catheter must be improved, our results demonstrate that there is a strong potential for video-assisted staple closure of ASD using this novel technique, which could contribute to the reduction of the number of open heart operations and thereby iatrogenic morbidity.

Animals↗