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We evaluated the clinical significance of the configuration of right ventricular pressure curves after balloon valvoplasty in 35 patients with pulmonary valvar stenosis. Right ventricular pressures were measured with a fluidfilled catheter. We divided the subjects into two groups according to the pressure curves seen after balloon valvoplasty. In eight patients, two peaks were found in the curves, with the higher peak occurring at late systole. The remaining 27 patients had a single peak observed during early to mid systole. In all patients in the group with a single peak, the ratio of ventricular pressures decreased by more than half, and no residual narrowing was seen in right ventricular outflow tract, the diameter after valvoplasty increasing by more than half over the diameter before the procedure. In contrast, in five of eight patients in the group with double peaks in the pressure curves, the ratio between ventricular pressures remained higher than 0.5, and the diameter of the right ventricular infundibulum was reduced to less than half the diameter prior to balloon valvoplasty. In three of these patients with double peaked pressure contours, to whom propranolol was administered intravenously, the pressure configuration changed to one with a single peak and the ventricular pressure ratio fell to below 0.5. The degree of obstruction of the right ventricular infundibulum also decreased. These data suggest that a high right ventricular pressure and two peaks in the pressure curve with the higher peak at late systole after balloon valvoplasty indicate, first, the presence of a significant narrowing in the right ventricular outflow tract and, second, effective balloon valvoplasty.
Percutaneous transcatheter embolization of the arterial duct, using new detachable coils, was performed in 19 patients aged from two to 16 years. The minimal ductal diameter ranged from 0.5 to 2.7 mm. We used a 5 mm diameter coil, 8 cm in length and/or an 8 mm diameter coil, which was 10 cm in length. The coil was connected to a delivery wire with a screw system, and could be detached by rotation of the delivery wire. The coil was straightened by inserting a mandril, with loops then being formed by withdrawal of the mandril. In all patients, the coil was advanced retrogradely and either one or two coils were successfully implanted. Implantation was performed in four patients without the catheter entering the pulmonary trunk across the arterial duct. The ductal ampulla was either absent or very small in five patients, so we implanted a coil which had been cut short. Angiography revealed no residual shunting in 14 patients (74%) and trace residual shunting in five patients. Migration of the coils to the pulmonary arteries, or to a systemic artery, did not occur in any patient. Follow-up using Doppler color flow imaging showed complete closure of the arterial duct in all patients (100%), and no turbulence either in the left pulmonary artery or in the descending aorta in any patient. The use of the new detachable coil may improve the accuracy of placement of the device and reduce the incidence of its migration.
The triple-period (TP)-A and CuPt-A type ordering, which have been so far reported only for MBE grown alloys, were observed, in addition to CuPt-B type ordering, in Al0.5In0.5As alloys grown by MOVPE at 500°C. This indicates that (2×3) and (1×2) surface reconstructions occur on the surface even during MOVPE growth, although the (2×1) surface reconstruction and CuPt-B type ordering are dominant for the growth conditions examined.
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