Biomedical subjects

Y Koh

Publications and source records attributed to Y Koh.

At least 73 records · Page 4Linked to original sources

PubMed1993

[Mechanical dilation of the internal thoracic artery graft by using balloon catheter].

We evaluated the free flow of the internal thoracic artery grafts (ITA) which were dilated with a balloon catheter. Further, we examined the postoperative angiographic findings and histology of the ITAs by scanning electron microscopy. In 25 patients with internal thoracic artery grafting, the artery was dilated with a balloon catheter (Fogarty IMAG kit) that was withdrawn at tensions of less than 30 gm. The mean free flow rate of the left ITAs (LITAs) increased from 64.2 ml/min to 101.9 ml/min by injection of papaverine to ITAs (p < 0.05). The mean free flow rate of the balloon dilated LITAs were 160.8 ml/min which was significantly higher when compared with that of control and papaverine (p < 0.01, p < 0.01). The mean free flow rate of the balloon dilated right ITAs (RITAs) showed 183.2 ml/min, it was significantly higher (p < 0.01, p < 0.05) compared with that of control (78.4 ml/min) and papaverine (129.2 ml/min). Irregularity was documented in 16% of the ITAs in spite of the great patency rate (100%) from the postoperative angiogram. Using scanning electron microscopy, endothelial cell borders were well demarcated in the proximal portion of the dilated ITA. However, the distal portion of the endothelium displayed gradual destruction. Although mechanical dilation of the ITA graft by balloon calibration is very effective in increasing the free flow rate of ITA, we should be prepared for the intimal damage of the ITA graft.

Adult↗

PubMed1993

[Biventricular repair with a modified Glenn shunt for the hypoplastic right ventricle].

Between 1982 and 1990, 14 patients with small right ventricle underwent biventricular repair with a modified Glenn shunt. The patients consisted of 8 cases of pulmonary atresia and intact ventricular septum, 2 with pulmonary stenosis and intact ventricular septum, 3 with tetralogy of Fallot, 1 with pulmonary atresia and straddling tricuspid valve. Nine patients had one or more prior preliminary palliative procedures. Repairs consisted of a modified Glenn shunt and closure of the intracardiac and extracardiac shunt, with right ventricular outflow reconstruction in 13, and pulmonary valvotomy in 1. In nine patients superior vena cava was not ligated. There was one operative death (7%). Preoperative RVEDV ranged from 19 to 70% of normal with a mean of 36.1% of normal. Preoperative pulmonary resistance ranged from 1.6 to 5.3 unit with a mean of 2.8 unit. Preoperative PA index ranged from 102 to 444 mm2/m2 with a mean of 234.3 mm2/m2. No patients died later. Follow-up 2 to 9 year after operation showed that 9 patients were in the New York Heart Association class I and 4 were in class II. Our experience shows that this procedure can be safely done for patients, who have hypoplastic right ventricle smaller than 40% of normal and are not candidate for Fontan procedure because of high pulmonary vascular resistance and inadequate size of pulmonary artery. In this procedure a modified Glenn shunt without ligation of SVC may effectively reduce the volume overload on the right ventricle.

Adolescent↗

PubMed1993

[Surgical repair in hearts with univentricular atrioventricular connection and subaortic stenosis].

Between 1986 and 1990, fourteen patients with univentricular atrioventricular connection and subaortic stenosis underwent surgical treatment. The patients consisted of 7 cases of double inlet left ventricle, 4 with double inlet right ventricle, 3 with tricuspid atresia. The palliative operation was performed in 6 infants ranging in age from 17 days to 6 months. Four patients with mild subaortic stenosis underwent pulmonary artery banding, in two patients this was combined with repair of coarctation of the aorta. Two patients with severe subaortic stenosis underwent the Norwood operation. There were no operative deaths. One of two patients who underwent the Fontan operation 2 years after the Norwood operation died later. The definitive operation was performed in 8 children ranging in age from 4 to 11 years. Five of these 8 patients had previous pulmonary artery banding. Five children with double inlet left ventricle underwent septation combined with enlargement of bulboventricular foramen. Postoperatively all remained in sinus rhythm and had no pressure gradient between Aorta and left ventricle. A Fontan operation combined with a Damus operation was performed in 2 children, 1 of double inlet right ventricle and 1 of tricuspid atresia. In both cases, postoperative angiogram showed no pulmonary incompetence. One patient underwent enlargement of bulboventricular foramen after a Fontan operation. All survived later. Young infants and neonates with severe subaortic stenosis can survive by the Norwood operation. Infants with mild subaortic stenosis, although can survive by pulmonary artery banding, should be closely followed for the development of subaortic stenosis. For relief of subaortic stenosis, enlargement of bulboventricular foramen may be effective in septation.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Coarctation↗

PubMed1993

Anatomic correction of atrioventricular discordance.

Between June 1989 and September 1991, 11 patients underwent anatomic correction of atrioventricular discordance. Their ages at operation ranged from 1 to 11 years (mean 6.7 years) and their weights ranged from 7.1 to 31.8 kg (mean 19.1 kg). Atrial situs was solitus in nine and inversus in two patients. Ventriculoarterial connection was discordant in five and was double-outlet right ventricle in six patients. Associated congenital heart defects were seen in all patients, including 10 with ventricular septal defect, eight with atrial septal defect, nine with pulmonary stenosis or pulmonary atresia, seven with tricuspid regurgitation, and four with mitral regurgitation. Five patients had prior Blalock-Taussig shunts. One patient with an intact ventricular septum had repeated pulmonary banding. Anatomic correction consisted of the Senning and Rastelli procedures in three, the Mustard and Rastelli procedures in five, the Senning and arterial switch operations in two, and the Mustard and arterial switch operations in one patient. In addition, mitral valvuloplasty or valvular annuloplasty was performed in three patients. We did not encounter kinking or torsion of the translocated coronary arteries in our three patients with the arterial switch operation. There was one surgical death. The other patients pursued satisfactory postoperative courses (mean follow-up period of 12.6 months). We recommend that anatomic correction for atrioventricular discordance should be indicated, especially in patients with any sign of systemic right ventricular dysfunction.

Cardiac Surgical Procedures↗

PubMed1993

[Definitive repair for double inlet ventricle and common atrio-ventricular valve].

From 1982 through 1990, 13 patients with double inlet ventricle and common atrio-ventricular valve underwent definitive cardiac surgery. Nine patients simultaneously had anomalous systemic venous connection and 4 had anomalous pulmonary venous connection. One patient with double inlet left ventricle underwent a successful partition of ventricle and atrio-ventricular valve. All other 12 patients underwent a Fontan operation, which utilized different techniques to deal with various forms of anomalous systemic and pulmonary venous connection. Four patients with common atrioventricular valve regurgitation underwent a Fontan operation combined with a concomitant circular annuloplasty of atrio-ventricular valve. In all 4 patients, the degree of regurgitation decreased postoperatively. There was one operative death (mortality 7.7%). Most of patients with double inlet ventricle and common atrio-ventricular valve now are considered to be suitable not for partition but for the Fontan operation. Because of the complexity of anatomic variables, however, the repair of anomalous systemic or pulmonary venous connections in conjunction with the Fontan operation requires an individualised plan in each patient to provide unobstructed systemic and pulmonary venous pathways. We think that a circular annuloplasty could effectively decrease the degree of atrio-ventricular valve regurgitation in most cases.

Adolescent↗

PubMed1992

[Surgical correction of atrioventricular discordance--results and follow-up].

Between January 1977 and October 1991, 47 consecutive patients with atrioventricular discordance, ventriculoarterial discordance, and two ventricles underwent intracardiac repair at the Heart Institute of Japan. Their ages at operation ranged from 2 months to 21 years (average 9.2 years) and period of follow-up ranged from 1 month to 168 months (average 65.1 months). There were five basic anatomic types according to the associated anomalies, grouped into (1) situs solitus, ventriculoarterial (V-A) discordance or double-outlet right ventricle (DORV), ventricular septal defect (VSD) and pulmonary outflow tract obstruction (POTO) (31 patients); (2) situs solitus, V-A discordance and VSD (6 patients); (3) situs solitus, V-A discordance and tricuspid regurgitation (TR) (2 patients); (4) situs inversus, V-A discordance or DORV, VSA and POTO (7 patients); (5) situs inversus, V-A discordance and VSD (1 patient). TR was evident preoperatively in 13 patients (28% of 47 patients), one of whom had Ebstein's anomaly. The conventional operation, which consisted of closure of VSD (34 patients), posterolateral pulmonary outflow enlargement (2 patients), tricuspid valvuloplasty (2 patients), and tricuspid replacement (1 patient) using the anatomical right ventricle as the systemic ventricle, was performed in 35 patients (RV group). The anatomic correction (so-called "double switch operation"), the new alternative operation using the anatomical left ventricle as the systemic ventricle, was achieved in 12 patients (LV group). Anatomic correction consisted of Senning and RV-PA ECR in 3, Mustard and RV-PA ECR in 4, Senning and arterial switch in 2, and Mustard and arterial switch in 1 patient.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

[Assessment of long-term systemic ventricular function after the surgical repair in patients with atrioventricular discordance].

Long-term systemic ventricular function at rest and during supine bicycle exercise was studied in 12 patients with atrioventricular discordance (AVD group) using multigated radionuclide blood pool imaging. For comparison, similar measurements were made in eight children (control group). The mean age at the exercise test was 12.3 years in AVD group and was 14.8 years in the control group. In AVD group, ages at the operation ranged from three to 21 years (mean 12.3 years), and the exercise test was performed from one to 9.8 years after the operation (mean 5.3 years). The operative procedures in AVD group consisted of closure of the ventricular septal defect in 11 patients, extracardiac conduit between the left ventricle and the pulmonary artery in nine patients, postero-lateral left ventricular outflow reconstruction in two patients, tricuspid annuloplasty in one patient, and tricuspid valve replacement in one patient. Exercise tolerance of AVD group was less than that of the control group. Heart rate and blood pressure were significantly increased during exercise in both groups. In the control group, end-diastolic count index (EDCI) (= end-diastolic volume) remained unchanged and end-systolic count index (ESCI) (= end-systolic volume) decreased during exercise. In contrast, both EDCI and ESCI were decreased in AVD group. As a consequence, systemic right ventricular ejection fraction (RVEF) increased during exercise in the control group, but remained unchanged in AVD group. Although stroke count index (SCI) (= stroke volume index) did not increased during exercise in AVD group, output count index (OCI) (= cardiac index) increased with the increase of heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1992

[A successful transatrial repair of post-infarction ventricular septal defect].

A 63-year-male underwent successful operation for the ventricular septal perforation (VSP) caused by the inferior myocardial infarction. As the condition was stable, an operation was performed at the 43rd day after onset of myocardial infarction. Exposure was obtained by the opening the right atrium and retracting the tricuspid valve. The defect was in the posterior portion of the ventricular septum and closed using a Dacron patch. His postoperative course was uneventful. Postoperative examinations show no residual shunt. We believe that this approach may offer reduced mortality and morbidity in a selected group of patients with acquired posterior VSP, by avoiding such complications as further trauma to the ventricle, hemorrhage, and arrhythmias.

Cardiac Surgical Procedures↗

PubMed1992

[A case report--combined Jatene procedure and extended aortic arch reconstruction for the original Taussig-Bing malformation associated with hypoplastic aortic arch, subaortic stenosis and coarctation of the aorta].

A successful repair with combined Jatene procedure (Lecompte modification) and extended aortic arch reconstruction in a two-month-old boy with the original Taussig-Bing malformation, associated with hypoplastic aortic arch, subaortic stenosis and coarctation of the aorta was described. The ascending aorta was measuring 8 mm and the distal aortic arch was 4 mm in outer diameter. The interventricular rerouting was not feasible, because the infundibular septum was almost aligned to the interventricular septum. So that arterial switch operation was preferred. The primary interventricular foramen was enlarged by wedge resection and the secondary interventricular foramen was closed with a patch of preserved equire pericardium. An extensive patch angioplasty of entire aortic arch down to descending aorta was performed with a composite patch of Xenomedica (preserved equire pericardium) and Dacron velour. Hypertrophied muscle bundles were resected for relief of subaortic stenosis. Jatene procedure was then performed. During neo-pulmonary reconstruction, distal pulmonary orifice was shifted towards right to avoid kinking and compression on the coronary arteries. One stage correction consisting of Jatene procedure and extended aortic arch reconstruction was considered to be a procedure of choice in this type of complex anomalies.

Aorta, Thoracic↗

PubMed1992

[Successful Norwood operation for single left ventricle associated with severe subaortic stenosis, coarctation of aorta and hypoplastic aorta].

A 4 month-old boy who had double-inlet left ventricle, severe subaortic stenosis, hypoplastic ascending aorta and coarctation of the aorta revealed severe respiratory failure. An urgent Norwood operation was done. The procedure consisted of enlargement of the ascending aorta and main pulmonary artery and a systemic-pulmonary shunt using 5 mm PTFE tube. Postoperative course was uneventful.

Aorta↗

PubMed1992

[Combination therapy with 5-FU, etoposide and CDDP (FEP regimen) in advanced primary and recurrent gastric cancer].

Surgery is still the treatment of choice in gastric cancer. However, despite the availability of extended surgical procedures, the majority of patients with stage IV gastric cancer have a poor prognosis. Therefore, other treatment modalities, especially systemic chemotherapy, have been investigated intensively. The recent successes achieved with combination chemotherapy regimens, such as EAP, strongly indicated that gastric cancer is chemosensitive. We also treated previously untreated patients with advanced and recurrent gastric cancer. Chemotherapy of CDDP 30 mg/m2 was given intravenously (i.v.) on day 1; etoposide 70 mg/m2 (i.v.) on days 2 to 4; and 5-FU 500 mg/m2 (i.v.) on days 2 to 5. The courses were repeated every 3 weeks. FEP induced an overall response rate of 25%, including 25% PR (primary tumor) and 25% PR (liver-metastasis). The median survival rate for all patients was 7.3 months and partial responses were seen in three patients with a median response duration of 13.1 months. In 2 patients with PR of primary tumor, one patient underwent a second-look operation and one patient refused an operation. Therefore, ten of 12 patients entered have died, and 2 patients remain alive. We concluded that FEP regimen can be useful in the treatment of advanced and recurrent gastric cancer. Moreover, the preoperative use of effective regimens seems to improve prognosis.

Adult↗

PubMed1992

[Method to make the tricuspid extracardiac conduit by heterogeneous pericardium].

We described here, how to make tricuspid extracardiac conduit by heterogeneous pericardium for Rastelli procedure. We have developed some ingenious devices which allow to obtain good hemodynamics. One of the devices is large valvular leaflets as long as 130% of the circumference of the conduit. Another device is the commissural suture as figure of eight. We used 121 tricuspid extracardiac conduits between January 1985 and March 1991. There were two reoperations: One from stenosis at the suture with ventricle and the other from infective endocarditis. This hand-made conduit has the advantages of flexibility, fitness with the pulmonary artery, wide range of size and very little regurgitation. These advantages indicate that the tricuspid extracardiac conduit made by heterogeneous pericardium is a valved conduit substitute of choice for Rastelli procedure. The durability of the conduit is to be further evaluated.

Animals↗

PubMed1991

[A design of the electrophysiological model on the action of antiarrhythmic agent in hypoxic condition and the electrophysiological study of flecainide].

Pharmacologic action of antiarrhythmic agents in hypoxia was studied with the microelectrode using the guinea pig papillary muscle. Tyrode solution saturated with 95% O2 and 5% CO2 provided normoxic condition and that with 95% N2 and 5% O2 hypoxic condition. The parameters measured were as follows: 1) Vmax: the maximum rate of rise of the action potential, 2) ERP: effective refractory period, 3) ERP/APD90%: the ratio of effective refractory period to action potential duration at 90% repolarization. [1] When the papillary muscle was perfused more than 15 minutes with the hypoxic solution, irreversible changes ensued inevitably. Accordingly, a perfusion with the hypoxic solution for 15 minutes was succeeded by that with the normoxic solution for 30 minutes. This was then followed by another perfusion with the hypoxic solution. [2] Flecainide was examined in 7 cases. The rate of the depression of Vmax by flecainide was significantly (p less than 0.01) increased in hypoxia (16.3 +/- 4.2%) than in normoxia (7.4 +/- 2.0%). There were no significantly differences in the rate of the change of ERP between both conditions. The rate of ERP/APD90% was significantly (p less than 0.01) increased by flecainide during hypoxia (2.2 +/- 0.8%) than during normoxia (0.1 +/- 2.1%). [3] The depression of Vmax and the increase of ERP/APD90% by flecainide occurred in a dose-dependent manner in normoxia. it was concluded that the depression of Vmax by flecainide over the concentration of 2 micrograms/dl were ascribed to its inhibitory effect on the fast Na channel and that its depressive effects were enhanced during hypoxic condition. This inhibitory action was regarded as the main antiarrhythmic action of flecainide. From the above results, it is expected that flecainide could be effective in the treatment of ventricular arrhythmias in the ischemic heart disease.

Action Potentials↗

PubMed1991

[Conotruncal repair of tetralogy of Fallot under 2 years old].

From October 1985 to September 1990, a repair within the conotruncal portion of the right ventricle-Conotruncal repair-was used for the primary repair of consecutive 34 patients with tetralogy of Fallot under the age of 2 years. There were three summarized points of this maneuver: the first was non-use of the tricuspid septal leaflet for closure of the ventricular septal defect, the second was short patch infundibuloplasty with a large monocusp, and the last was total resection of the infundibular septum. Length of the patch infundibuloplasty was just 30% of the right ventricle length according to our formula: 30% of RV (cm) = 1.28 X BSA (m2) + 1.10. The VSD patch was placed between the pulmonary annulus and the ventricular septal crest, consisting of the membranous flap and the posterior extension of the trabecula septomarginalis. The right ventricular (RV) to systemic arterial pressure ratio was 0.49 +/- 0.15 (N = 33) and central venous pressure was 10.2 +/- 1.9 cmH2O (N = 33) six hours after ICU admission and 8.4 +/- 1.5 cmH2O (N = 7) 18 days after operation. RV end-diastolic volume showed no increase after operation: 105 +/- 31 before repair to 104 +/- 23% of Normal after repair in the same patients. Post-operative intubation period was 14 +/- 8 hours and hospital admission period was 17 +/- 6 days after operation. All patients were in sinus rhythm. The 28% of patients showed incomplete right bundle branch block (RBBB) and other 28% of patients showed complete RBBB.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Surgical Procedures↗

PubMed1991

[Evaluation of pre-operative 5-fluorouracil treatment of the patients with gastric cancer--alteration of the inhibition rate of thymidilate synthetase by dose difference].

5-fluorouracil (5-FU) was orally administered before surgical operation to two groups of patients, one treated at 300 mg for 7 days and the other treated at 400 mg for 5 days, to examine the change of TSIR in gastric patients. Tumor tissue, lymph node and normal lesions were collected from removed specimens immediately frozen. As a result, there were no differences in FdUMP volumes of various tissues between 300 mg and 400 mg groups. TSIR tended to be higher in the order of normal tissue, lymph node and tumor lesions. TSIR was significantly higher in 400 mg group than 300 mg group. We believe that further studies on TSIR will provide a useful information as to various studies, including efficacy reinforcement by combination therapy, problems in resistance, histological efficacy and sensitivity tests.

Fluorouracil↗

PubMed1991

[Hemodynamic changes and ventricular function before and after Fontan procedure for univentricular heart].

Ventricular function and hemodynamic parameters before and after Fontan operation were studied in patients with univentricular heart (UVH) of left ventricular (LV) type (9 cases, ages: 6-66, mean 13 years) and right ventricular (RV) type (13 cases, ages: 6-17, mean 9 years) without atrioventricular valve regurgitation. The preoperative ejection fraction (EF) was poor and only 44% of LV type and 23% of RV type met the Choussat's criterion (EF greater than or equal to 60%). There were 2 hospital deaths each in LV type and in RV type, but their causes could not be attributed to preoperative parameters of ventricular function. In survivors, the EF reduced from 62.9 +/- 7.0% before Fontan procedure to 43.4 +/- 12.6% after the procedure in LV type (p less than .05) and from 54.5 +/- 7.0% to 47.0 +/- 9.0% in RV type (p less than .01), although the ventricular end-diastolic pressure (EDP) also reduced from 12.7 +/- 2.7 mmHg before to 6.6 +/- 1.9 mmHg after the operation in LV type (p less than .05) and 10.4 +/- 2.6 mmHg to 5.5 +/- 2.4 mmHg in RV type (p less than .05). the ventricular end-diastolic volume (EDV) also reduced from 185 +/- 35% to 126 +/- 58% of expected normal volume in LV type (p less than .05) and 173 +/- 28% to 99 +/- 18% of expected normal volume in RV type (p less than .01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

[Pulmonary artery banding for double inlet left ventricle].

Thirteen patients with double-inlet left ventricle who had undergone pulmonary artery banding (PAB) were reviewed. At the time of PAB, the age ranged from 2 months to 3 years. Pulmonary-systemic arterial pressure ratio and pulmonary arterial mean pressure were reduced from 0.95 +/- 0.12 to 0.4 +/- 0.18, and from 57.3 +/- 11.6 mmHg to 29.9 +/- 12.7 mmHg after PAB. Pulmonary resistance showed no statistically significant change after PAB. (from 7.6 +/- 5.2 unit to 4.8 +/- 3.9 unit) Ventricular end-diastolic volume decreased from 379.9% +/- 140.0% to 275.7% +/- 118.0% after PAB. The smallest one was 170% who successfully underwent septation procedure. Ejection fraction significantly decreased from 64.5 +/- 6.1% to 56.3 +/- 7.9%. (p less than 0.005) Ventricular end-diastolic pressure showed no significant change after PAB. (from 9.2 +/- 2.8 mmHg to 9.9 +/- 2.0 mmHg) After PAB subaortic stenosis occurred in three cases and pressure gradient were 10, 20, and 85 mmHg, respectively. Seven cases, including three cases with subaortic stenosis, underwent septation procedure and all survived. Before septation, ventricular end-diastolic volume calculated as % of normal left ventricular volume ranged from 173% to 570% and pulmonary resistance ranged from 1.6 unit to 11 unit. These data suggested that the patients with double-inlet left ventricle had efficient ventricular volume and cardiac function for septation even after PAB.

Child, Preschool↗

PubMed1990

[An evaluation of 3-dimensional position of mandibular condyle to glenoid fossa using tomogram: an analytical technique and its clinical application].

In recent years, temporomandibular disorder (TMD) is occasionally found among orthodontic patients and has become a great concern in orthodontics. From this point of view, a certain technique has been hopefully anticipated for diagnosis and treatment planning. The purpose of this study was to develop a new method for evaluating three-dimensional position of the mandibular condyle relative to the glenoid fossa and also to investigate its clinical application. Seven-layered tomograms were taken and contours of the condyle and glenoid fossa were traced on an acetate paper. These contours were entered into a personal computer by use of a digitizer and were equally divided into 9 parts for the condyle and 15 parts for the glenoid fossa, consisting of 10 and 16 points on the contours of condyle and glenoid fossa. Three-dimensional configuration of the TMJ was thus constructed by 108 triangles for the condyle and 180 triangles for the glenoid fossa. The shortest distance between the condyle and the glenoid fossa (CGFD) was then calculated along a perpendicular line to center of gravity of a triangle on the condyle. For evaluating the position of the condyle to the glenoid fossa easily in a three dimensional space, surface of the condyle was divided into five areas, i.e. anterior, posterior, middle, lateral and medial areas. In order to investigate whether or not the CGFD is accurate enough to identify the distance between surface of the condyle and glenoid fossa, a model of hemi-spherical solid shell was made, of which the thickness is 3.0 mm. Tomograms of the model were taken to analyze the thickness. Direct measurement of the same area was also made by calipers. Two means were approximately 3.0 mm, which is the thickness itself and no significant differences were indicated at 5% level of confidence. The present technique was applied to diagnosis of an orthodontic patient with painful clicking as TMD. The analyzed CGFDs were coincident with clinical symptom. It is shown that the present approach provides an availability and a possibility to evaluate positional relationship between the mandibular condyle and the glenoid fossa of patients with TMDs.

Humans↗