Non-surgical closure of atrial septal defect.

BACKGROUND: Recently many devices for the transcatheter closure of atrial septal defect (ASD) were developed in the world. Several ASD closing devices, such as Clamshell device, buttoned device, ASD occluder system (ASDOS), Angel Wings, are not fully acceptable from a practical point of view. We reported the clinical trials of transcatheter closure of ASD for Clamshell double umbrella device and Amplatzer septal occluder (ASO) in Japan. METHODS: Clamshell devices were implanted in 11 patients. Clinical trials for ASO device were carried out in 34 patients in Japan. We reported the results of 17 patients in National Children's Hospital. RESULTS: Clamshell devices were implanted in all of the patients successfully. Minimal residual shunt was present in four patients (36%), 1 year after the procedure by Doppler color flow imaging. Nine of 11 umbrellas demonstrated fracture of the stainless steel arm. Arm fracture occurred between 1 week and 12 months after implantation. The implantations of ASO device were successful in all of the 17 patients. Sixteen out of 17 (94.1%) had complete closure in the average observation period of 5.5 months. Complications were minimal and transient. CONCLUSIONS: With respect to complete closure rate, easy manipulation, and complication rate, ASO is the best transcatheter ASD closure device among all the devices at the present time.

Heart transplantation in children in foreign countries with reference to medical, transportation, and financial issues.

Heart transplantation is increasingly becoming accepted worldwide as therapy for end-stage heart failure not only in adult patients but also in pediatric practice. The new law in Japan for organ transplantation from brain-dead patients was established on 16 October 1998, but there is no definite law or protocol for brain death in children under the age of 6 years and children less than 15 years of age cannot become donors. These facts make organ transplantation from the cadavers of neonates, infants and young children almost impossible in Japan, even though there are children who need heart or heart-lung transplantation. The present authors have to date transferred 8 patients to the USA or Germany for heart transplantation: 4 successfully underwent heart transplantation, but 4 died during the waiting period overseas. There are many things to consider; not only the medical problems involved in transportation, but also the financial issues when transferring patients to other countries. This report details the experience with the 8 cases that were transferred overseas for heart transplantation, and highlights the problems that need to be considered.

Transcatheter occlusion of patent ductus arteriosus with a new detachable coil system (DuctOcclud): a multicenter clinical trial.

A multicenter clinical trial of DuctOcclud, a new detachable coil for transcatheter occlusion of patent ductus arteriosus (PDA), was conducted. DuctOcclud was used in 35 patients (12 male and 23 female) for transcatheter occlusion of PDA between January, 1996, and April, 1997. The age of the patients ranged from 0.5 to 27.2 years (median 7.6 years) and weight from 6.3 to 70.0 kg (median 23.0 kg). The smallest diameter of PDA was 2.0+/-0.7 mm (range 1.0-3.3 mm). Pulmonary-systemic flow ratio (Qp/Qs) was 1.3+/-0.3 (range 1.0-2.2). The coils were successfully implanted in 32 (91%) patients. Of 31 patients who were followed 6 months after the procedure, 26 (84%) had no residual shunt and 5 (16%) had trivial residual shunt. One patient had infective endocarditis 1 month after the procedure but recovered completely. There were no incidences of coil embolization, hemolysis, late coil migration, or pulmonary artery stenosis. We conclude that DuctOcclud is a safe and effective device of transcatheter occlusion of PDA.

Signal distortion induced by Fresnel reflection in open-loop fiber-optic gyroscopes.

The signal distortion that is due to Fresnel reflection in open-loop fiber-optic gyroscopes was theoretically analyzed to determine the relationship between the reflection ratio and the scale factor error of the gyroscopes. The analysis showed that the in-phase component of each Fourier harmonic of the gyroscope signal deviates from the true sinusoidal function, a quadrature-phase component appears, and the pi/2 rotation rates of harmonic components disagree. We evaluated the degree of scale factor degradation by defining the harmonic distortion ratio, which can be used as a measure for the reflectional quality of the gyroscopic optical system. The theory was verified by the response of an experimental gyroscope. The Fresnel reflection was eliminated by optical and electrical means, and the signal distortion of the experimental gyroscope was suppressed.

Cardiovascular abnormalities in Noonan syndrome: the clinical findings and treatments.

The clinical findings and treatment of cardiovascular abnormalities in 33 patients with Noonan syndrome are reviewed. Major cardiovascular abnormalities were pulmonary valvular stenosis in 17 patients (51.1%), hypertrophic cardiomyopathy (HCM) in 11 (33.3%), and atrial septal defect in 9 (27.3%). Dysplastic pulmonary valve was seen in 6 (35.3%). Balloon pulmonary valvuloplasty was performed for 4 patients with dysplastic pulmonary valves. Two patients were successfully treated. Surgical treatment was performed in 13 patients, 11 alive and 2 died. Two patients with HCM and arrhythmia died suddenly. In conclusion, balloon pulmonary valvuloplasty should be the initial palliation for dysplastic pulmonary valve in Noonan syndrome, and HCM is the risk factor for sudden death in Noonan syndrome.

Multiplex in-cylinder pressure measurement utilizing an optical fiber with specific refractive-index composition.

An approach to multiplex in-cylinder pressure measurement that utilizes a single-mode optical fiber with specific refractive-index composition has been proposed. The sensing fiber has been designed to show a certain amount of optical power loss with a small change in the fiber-local-bend radius. Along with pressure-transferring diaphragms the sensing fiber was embedded into the head gasket of a four-cylinder gasoline engine. The internal-pressure change in each combustion chamber was detected on the basis of bending power loss in the fiber. Combustion pressure peaks for each cylinder were clearly observed.

Secondary-phase-modulation method for open-loop fiber-optic gyroscopes.

A proposed method of secondary phase modulation for open-loop fiber-optic gyroscopes is examined in general terms. To detect the rotation rate of a system through a beat-frequency channel, we employ linearly combined signals with different frequencies for the optical phase modulation. We find that the proper combinations of the modulation frequencies can optimize the sensitivity of gyroscopes. With this method we can employ a high-frequency band for optical phase modulations while keeping relative a lower-frequency band of the detection channel. The theoretically derived result is experimentally confirmed by using a lithium-niobate (LiNbO(3)) optical phase modulator. We also discuss the combination setup with an optical integrated-circuit device and digital signal processing.

Increased elastin-degrading activity and neointimal formation in porcine aortic organ culture. Reduction of both features with a serine proteinase inhibitor.

We investigated the association between tissue elastolytic activity and the development of neointimal formation using a previously described porcine aortic organ culture. Neointimal formation is associated with the presence of intact endothelium (nondenuded cultures) but is markedly reduced if endothelial cells are removed (denuded cultures). In nondenuded organ cultures, elastolytic activity assessed by using [3H]elastin increased sixfold at day 3 after initiation of the culture (P < .01), a time earlier than the previously published increase in intimal smooth muscle cells (ISMCs). Elastolytic activity did not increase from day 3 to day 7 despite doubling of ISMCs but did double by day 14 (P < .01) and remained elevated to day 28, correlating with increases in ISMCs. In denuded organ cultures, elastolytic activity was much lower than in nondenuded organ cultures at day 3 (P < .05) but increased fivefold in the presence of nondenuded organ culture conditioned medium (P < .01). Addition of alpha 1-proteinase inhibitor for 14 days caused a 60% decrease in elastolytic activity in nondenuded organ cultures and a 27% reduction in ISMCs compared with untreated controls (P < .05 for both). The elastolytic activity, resolved as lytic bands on an elastin substrate gel, reflected candidate enzymes, one at 76 kD and perhaps a doublet at 43 and 50 kD. Our study suggests that endothelial cells release a soluble agent that enhances elastin-degrading activity in the aorta and may at least partially account for the initiation of neointimal formation.

Post-cardiac transplant arteriopathy in piglets is associated with fragmentation of elastin and increased activity of a serine elastase.

In experimental piglets after heterotopic heart transplant, we observed an immune/inflammatory response in the coronary arteries with increased expression of interleukin-1 beta and accumulation of fibronectin and smooth muscle cells in the subendothelium (N. Clausell, S. Molossi, M. Rabinovitch, Am J Pathol 1993, 142, 1772-1786). Proteolytic enzymes including elastases regulate cytokine activity and are associated with the development of neointimal proliferation. We now report ultrastructural evidence of elastolytic activity in the donor compared to host coronary arteries judged by a fivefold increase in the breaks in the internal elastic lamina, (P < 0.01) correlating with a 10-fold increase in elastase activity per mg tissue (P < 0.01). The enzyme activity is serine elastase, i.e., inhibited by phenylmethyl sulfonyl fluoride, and elafin but not EDTA. Using a novel strategy that greatly increases the activity extractable from the tissue, we resolved the enzyme on an elastin substrate gel as a protein of approximately 23 kd. Ours is the first report and characterization of increased elastase activity associated with the development of the post-cardiac transplant coronary arteriopathy. The source may be inflammatory or smooth muscle cells, and elastase may play a pathophysiological role in neointimal proliferation by activating cytokines and growth factors and by release of chemotactic peptides.

Comparison of the incidence of intracranial hemorrhage following conventional mechanical ventilation and high frequency oscillation in beagle puppies.

Controversy exists as to whether high frequency oscillation (HFO) increases the risk of intraventricular hemorrhage (IVH) compared with conventional mechanical ventilation (CMV). We compared the risk of intracranial hemorrhage after phenylephrine-induced hypertension, combined with a hypovolemic, hypotensive insult followed by rapid volume replacement in two groups of newborn beagle puppies (one group on a piston pump HFO and the other on CMV). A total of 12 beagle puppies (6 on HFO and 6 on CMV) survived the protocol. Arterial blood gas analysis and arterial blood pressures through the study were of the same magnitude in both groups. The length of time for which the puppies remained hypertensive and hypotensive also did not vary significantly between the groups. Intraventricular hemorrhages were observed in two of six CMV puppies and two of six HFO puppies. One animal in each group had a white matter hemorrhage. Subarachnoid hemorrhages were seen in 4 animals on CMV and 3 on HFO. This study indicated that HFO does not increase the risk of any kind of intracranial hemorrhage, including IVH, in beagle puppies.

Two-dimensional pulsed Doppler echocardiographic technique for estimating pulmonary to systemic blood flow ratio in children with atrial septal defect and patent ductus arteriosus.

A two-dimensional pulsed Doppler echocardiographic method was evaluated for quantifying the pulmonary (Qp) to systemic (Qs) blood flow ratio. Twenty six patients were studied, 15 with atrial septal defect (ASD) and 11 with patent ductus arteriosus (PDA). An apical four-chamber view was used to measure the maximal Doppler flow velocities in the right and left ventricular inflow regions (RVIR and LVIR) and the maximal diameters of the tricuspid and mitral anuli at diastole. The two-dimensional pulsed Doppler pulmonary to systemic blood flow ratio (Qp/Qs) estimation involved calculating the area of the Doppler flow velocity signal along the time scale multiplied by the diameter of either the tricuspid or mitral anulus as measured on the apical four-chamber view. In ASD patients, Qp was measured at RVIR and Qs at LVIR. In PDA patients, Qp was calculated at LVIR and Qs at RVIR. Twenty-six healthy children comprised the control group. The areas of the Doppler flow velocity signals along the time scales of RVIR and LVIR were also quantified and the diameters of the tricuspid and mitral anuli were measured. In the control group, the linear correlation of the trans-mitral M(d)*M(a) to trans-tricuspid T(d)*T(a) value was r = 0.909, n = 26. The correlations between Doppler Qp/Qs ratio estimates and those obtained at cardiac catheterization were r = 0.902, n = 15 in ASD and r = 0.967, n = 11 in PDA. These results suggest a clinical application of this Doppler echocardiographic method in the noninvasive estimation of the cardiac shunt in ASD and PDA.

Evaluation and comparison of the axis of the interventricular septum by two-dimensional echocardiography among the patients with congenital heart disease (ASD, VSD, PDA, PS, TOF) and the normal subjects.

A two-dimensional echocardiographic method was applied to determine the axis of interventricular septum (IVS) in the horizontal plane. This study comprised 19 subjects with ASD, 15 subjects with VSD(I), 20 subjects with VSD(II), 13 subjects with PDA, 16 subjects with PS, 15 subjects with TOF and 99 normal children. Parasternal left ventricular short axis view was taken, and the IVS was recorded by using the polaroid prints. The axis of the IVS in the horizontal plane was measured from the recorded polaroid prints. The value of the angularity of IVS (IVS-A) expressed as means +/- one standard deviation (mean +/- 1S.D.) is 52.0 +/- 13.7 degrees in ASD, 42.2 +/- 9.7 degrees in VSD(I), 43.7 +/- 9.1 degrees in VSD(II), 41.6 +/- 11.4 degrees in PDA, 38.6 +/- 10.9 degrees in PS, 61.0 +/- 8.5 degrees in TOF and 40.1 +/- 8.2 degrees in normal controls. There was no significant difference among VSD(I), VSD(II), PDA, PS and normal controls but a highly significant difference was noted in ASD and TOF as compared to other groups. The correlation coefficient of the IVS-A with (1) the Qp/Qs ratio, (2) the magnitude of shunt (%), (3) the right ventricular pressure and (4) the hematocrits were evaluated among the patient groups. The IVS-A of ASD and VSD(II) had a good correlation with the shunt flow (r = 0.921 and 0.88 respectively) and/or the Qp/Qs ratio (r = 0.782 and 0.955 respectively); while that of VSD(I), PDA, and PS had a good correlation with the right ventricular pressure (r = 0.956, 0.953, 0.842 respectively) and that of TOF was mostly concerned with the hematocrits (r = 0.911). Besides, the IVS-A in each severe CHD subgroup was significantly (p less than 0.005 or a better value) higher than the normal control group. Thus an alternative method was validated for evaluating the severity of congenital heart disease by using a noninvasive two-dimensional echocardiographic technique.