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So as to understand better the pathogenesis of enlargement or hypoplasia of pulmonary arteries in congenital heart disease, we studied the dimensions of the pulmonary arteries in 74 fetuses with congenital heart disease induced by administration of bis-diamine to pregnant rats. The congenital malformations induced included 12 with large ventricular septal defect, 17 with tetralogy of Fallot, 15 with tetralogy together with severe valvar pulmonary stenosis and absence of the arterial duct, 17 with tetralogy with absent pulmonary valve syndrome and absence of the arterial duct, and 13 with common arterial trunk with a confluent segment supplying the pulmonary arteries. For comparison, 16 fetuses of the same gestational age with normal hearts were studied. After rapid whole-body freezing on the 21st day of gestation, the fetuses were studied by means of serial cross-sectional photographs of the thorax. The diameter of the right pulmonary artery of the fetus was of comparable dimensions in the normal hearts (480±10 µm) (mean±SEM), those with ventricular septal defects (470±10 µm), common arterial trunk (520±20 µm), and tetralogy of Fallot (500±10 µm). These findings suggest that the commonly observed enlargement of the right pulmonary artery in patients with ventricular septal defect and common arterial trunk, and hypoplasia of the right pulmonary artery in tetralogy of Fallot, occur postnatally in response to abnormal postnatal pulmonary blood flow.
We evaluated the physical characteristics of the pulmonary trunk in 32 patients with complete transposition after the arterial switch operation, calculating the pulmonary input impedance. In 6 of the patients, the characteristic impedance was equal to, or less than, the value in patients with ventricular septal defect. In those patients with an intact ventricular septum, or those with a ventricular septal defect who had undergone the arterial switch operation or banding of the pulmonary trunk before 3 months age, the frequency of the first modulus minimum also agreed with the values obtained in patients with ventricular septal defect. The value was high, however, in patients with complete transposition with ventricular septal defect who had undergone an arterial switch operation or banding of the pulmonary trunk after 4 months of age. Our data suggest decreased distensibility of the proximal pulmonary trunk after the arterial switch operation, and mild changes in the pulmonary vasculature in patients with complete transposition with ventricular septal defect who had undergone either an arterial switch operation or banding of the pulmonary trunk after 4 months of age. Long-term follow-up is needed clarify whether or not these features affect right ventricular function by means of an increase in afterload.
The purpose of this study was to clarify the clinical characteristics of interruption of the aortic arch associated with chromosome 22q11 deletion.
About half of patients with interruption of the aortic arch between the left common carotid and the left subclavian artery have deletion of chromosome 22q11.
In total, 20 patients with interruption of the aortic arch were studied with fluorescence in situ hybridization using peripheral lymphocytes and a DiGeorge syndrome chromosomal probe (Oncor N25). Cardiovascular anomalies in these patients were diagnosed by cross-sectional echocardiography and angiocardiography, and were confirmed at intracardiac repair.
Of 13 patients with interruption between the left common carotid artery and the left subclavian artery, seven had the deletion. All 7 also showed thymic hypoplasia and hypocalcemia, together with a nasal voice and peculiar facies. Six of the seven patients had complete deficiency of the muscular outlet septum, with the defect extending to the perimembranous area. Such complete absence of the muscular outlet septum was not present in any of the patients without the deletion.
Interruption of the aortic arch between the left common carotid and the left subclavian artery, absence of the thymus, and complete absence of the muscular outlet septum, were characteristic in Japanese patients with interruption of the aortic arch associated with deletion of chromosome 22q11.
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.
Deletion of chromosome 22 and DiGeorge syndrome are associated with inappropriate development of the neural crest and abnormalities of the ventricular outflow tracts. Bis-diamine induces comparable cardiac anomalies by inhibiting the normal development of the neural crest. In order to clarify the effect of damage on the development of the neural crest and its relation to the cardiac anomalies, the effects of giving a small dose of bis-diamine were compared with the results of a large dose of bis-diamine. A small dose of bis-diamine (20 mg), therefore, was administered to 40 pregnant rats on the 10th day of pregnancy, and 330 fetal hearts were studied on the 21st day with the rapid whole-body freezing method. Intracardiac anomalies were rare, being found in only 55 fetuses. The anomalies discovered were: aberrant origin of the subclavian artery in 88 fetuses, right aortic arch in 26 fetuses, interruption of the aortic arch in 23 fetuses, and high location of the aortic arch in 8 fetuses. Anomalies of the arterial duct were also common; with a vascular ring formed by the aortic arch and contra-lateral duct being seen in 21 fetuses, isolation of the right subclavian artery associated with either bilateral ducts (9 fetuses) or a right duct and absent left duct (9 fetuses), absent duct with tetralogy of Fallot in 7 fetuses, and with common arterial trunk in one fetus. In conclusion, a small dose of bis-diamine induced extra cardiac anomalies of the aortic arch and arterial duct, indicating a greater susceptibility of the aortic arch and the duct to inappropriate formation of the neural crest cells in the early developing embryo. Clinically, these anomalies of the aortic arch and the duct should be searched for in all patients suspected of having deletion of their 22nd chromosome.
We report a two-year-old boy with a rare combination of tetralogy of Fallot and aortic coarctation. The obstruction in this patient had an hourglass-like configuration, with a pressure difference of 15 mm Hg. There was a right aortic arch, bilateral brachiocephalic arteries, and persistent left superior caval vein. Percutaneous transluminal balloon angioplasty was performed to lower the resistance to the left ventricular ejection, considered a risk factor for subsequent corrective surgery of tetralogy. Six months later, he underwent combined repair of tetralogy of Fallot and coarctectomy with end-to-end anastomosis, thus avoiding the future potential for restenosis. During surgery, a ligament was found extending from the right subclavian artery to the distal side of the coarctation. The perioperative course was uneventful, indicating the success of the preoperative balloon angioplasty. We speculate that the embryogenesis of the coarctation could be related to an abnormal involution of the aortic arches.
We report a case of a fetus presenting intermittent ventricular tachycardia during midgestation, whose mother had long QT syndrome. The arrhythmia disappeared spontaneously, and the electrocardiogram of the baby after birth showed prolonged QTc. As far as we are aware, this is the first case in which ventricular tachycardia was documented during fetal life in a baby with long QT syndrome.
The size of the coronary arteries parallels the ventricular mass, thus it may be abnormal in complete transposition beyond infancy and could be influenced by the arterial switch operation. To investigate this possibility, we measured the diameters of the right, left main trunk, anterior descending, and circumflex coronary arteries before and three to seven years (mean 4.8) after the arterial switch operation in 17 patients with a “normal” distribution of the coronary arteries (so-called Shaher type 1). The values were compared with 18 controls who had Kawasaki disease with no apparent coronary arterial disease. The right, left anterior descending, and circumflex arteries were smaller than control values before the operation. The post-/preoperative ratios of the diameter were 1.16±0.11 for the right coronary artery, 1.18±0.16 for the left main trunk, 1.20±0.18 for the left anterior descending artery, and 1.22±0.26 for the circumflex artery. There were no significant differences among these values. After surgery, the right coronary artery was larger, but the left coronary arteries were smaller in the patients than in the controls: 2.5±0.3 vs 2.0±0.2 mm for the right coronary artery; 2.4±0.3 vs 2.7±0.1 mm for the left main trunk; 1.9±0.2 vs 2.4±0.2 mm for the left anterior descending artery; 1.6±0.4 vs 2.2±0.5 mm for the circumflex artery, respectively. The posterior descending coronary artery originated from the right coronary artery in all patients. The total cross-sectional area of the right coronary, left anterior descending, and circumflex arteries was 9.7±2.4 mm2 in the patients, and 11.8±2.9 mm2 in the controls (p>O. 1), suggesting that the increased size of the right coronary artery compensates for the small left coronary arteries. We conclude that the arterial system in complete transposition, with a large right coronary artery and small left coronary system, remains smaller than normal even at midterm follow-up after anatomic repair despite normalization of left ventricular volume and muscle mass.
We studied 28 fetal rats with atrioventricular septal defect with a common orifice produced from 300 fetuses treated with bis-diamine (200mg) on the ninth and tenth day of pregnancy. After undergoing rapid whole- body freezing on the 21st day, they were studied by means of serial cross-sectional photographs of the frozen thorax. Forty-one fetuses with normal hearts subsequent to treatment with bis-diamine served as controls. Atrioventricular septal defect was isolated in three, or was associated with either tetralogy of Fallot (n=14) or common arterial trunk (n=11). Fetal hydrops was associated with evidence of regurgitation of the atrioventricular valves. In a subgroup with larger right atrial volumes (increased by more than two standard deviation over the mean in the controls), the following parameters were significantly increased: subcutaneous edema, pericardial effusion, thickening of the left atrioventricular valve, cardiac chamber volumes and masses. The superior and inferior caval veins, and the descending aorta were significantly smaller in fetuses with atrioventricular septal defect than in controls. Fetal atrioventricular septal defect, therefore, was associated frequently with hydrops and increased volumes of the right atrium and both ventricles. Hydropic changes included cutaneous edema and increased pericardial, pleural, and peritoneal fluid.
We describe three children with chronic renal failure who developed mitral obstructive disease over a period when maintained on hemodialysis. The development and progression of the mitral disease was documented by cardiac catheterization in one child and by Doppler echocardiography in the other two children. These three patients had the lowest body weight among the 16 children undergoing chronic dialysis who were examined cardiologically in our hospital. Autopsy in one child who died from heart failure revealed marked thickening of the leaflets and subvalvar apparatus of the mitral valve with severe obliteration of the intercordal spaces. We found no sign of calcification at the mitral annulus nor at the attachments of the leaflets of the aortic valve, and no Ashoff bodies. We attempted percutaneous catheter balloon valvoplasty in one child which permitted successful renal transplantation after failure of an initial transplantation because of severe pulmonary venous congestion. We conclude that mitral obstructive disease could be a complication of long-term hemodialysis for chronic renal failure. Catheter intervention may serve to release the obstruction, although the procedure is not curative.
This study was designed to determine, first, the stiffness of the pulmonary arteries and, second, the relationship between the stiffness of the pulmonary arteries and the success rate of balloon angioplasty in patients with complete transposition after an arterial switch operation. Indexes of pulmonary arterial wall stiffness, percent change in the radius during a cardiac cycle and the pressure elastic modulus, were calculated from the pulmonary arterial pressure and radius measured from a cineangiogram. Of the patients, 13 had no significant stenosis, while 25 had significant stenoses and, therefore, underwent balloon angioplasty. In all, we dilated 33 stenotic lesions. In the presence or absence of postoperative pulmonary stenosis, the percent change in the radius of the pulmonary trunk was significantly less than the normal value. The pressure elastic modulus of the trunk and its branches was significantly greater than normal, and increased significantly with time after the operation. In patients without pulmonary stenosis, the systolic pulmonary arterial pressure increased concomitantly with the pressure elastic modulus. Balloon dilation was successful at 17 locations and unsuccessful at 16 locations. The percent change in radius was significantly less for the failures than for the successes. Prior to 3.5 years after the operation, the pressure elastic modulus was < 400 g/cm2 at most locations and balloon dilation was successful in 88%. More than 3.5 years after the operation, the pressure elastic modulus was < 400 g/cm2 in 11 of 15 locations, and balloon dilation was successful in only one location. The increased stiffness of the pulmonary artery may result in increased pulmonary systolic pressure in patients without pulmonary stenosis, and result in a low success rate for balloon angioplasty in patients with pulmonary stenosis.
The effect of enalapril, an inhibitor of angiotensin converting enzyme, was studied in 35 infants and children with congestive heart failure associated either with residual mitral or aortic regurgitation following intracardiac repair (24 patients) or with dilated cardiomyopathy (11 patients). Enalapril, at an average dose of 0.24 ±0.10 mg/kg, reduced the concentration of angiotensin II in the serum from 115 ± 67 pg/ml to 60 + 30 pg/ml and increased plasma renin activity from 25 + 24 ng/ml/hr to 45 ± 37 ng/ml/hr. There was a significant decrease in hepatomegaly, cardiothoracic ratio, heart rate and blood pressure in both groups of patients. Left ventricular end-diastolic dimension as evaluated by cross-sectional echocardiography, also decreased, whereas fractional shortening and systolic time intervals improved in both groups of patients. Adverse effects were noted in only one infant with postoperative mitral regurgitation who developed renal failure with oliguria, increase of blood urea nitrogen and serum creatinine. Renal function improved dramatically after discontinuation of enalapril. Hyperkalemia (>5mEq/ 1) was observed in four patients, three of whom were receiving spironolactone. Our results showed that enalapril is effective in improving hemodynamics in the relatively short-term treatment of infants and children with congestive heart failure due to postoperative volume overload or dilated cardiomyopathy. These conditions are poorly controlled with conventional medical therapy.
We report two autopsy proven cases of unguarded mitral orifice associated with mirror-imaged atrial arrangement, discordant atrioventricular connections, double outlet right ventricle, pulmonary valvar stenosis or atresia, and atrialisation of the morphologically left ventricle. The morphologically left atrioventricular junction was devoid of valvar leaflets, and there was no tension apparatus within the ventricle. To the best of our knowledge, this is the first description of this rare cardiac malformation
Balloon dilation was performed in four patients with postoperative pulmonary stenosis who had undergone surgical creation of a coronary arterial tunnel in the pulmonary trunk. Two patients had complete transposition in whom the arterial switch operation had been performed using the modified Aubert method. The other two patients had anomalous origin of the left coronary artery from the pulmonary trunk treated with the Takeuchi procedure. Balloon dilation was performed at 11 locations. The pressure gradient decreased from 48 ± 22 to 24 ± 14mmHg (p<0.01), and the diameter of the narrowest segment increased from 5.3 ± 2.5 to 7.5 ± 2.8mm (p<0.01), respectively. Of the 11 procedures, 8 (73%) were judged successful with use of the criterion of success as a greater than 50% decrease in pressure gradient, and/or a greater than 50% increase in diameter. The inflated balloon must have compressed the coronary arterial tunnel in the pulmonary trunk, but there was no apparent myocardial damage in any patient, although transient and mild ST-T changes appeared on electrocardiographic monitoring during the procedure in 2 patients. Rupture of the wall of the pulmonary trunk occurred in two patients, one of whom required elective surgical intervention. These data suggest that balloon dilation should be performed with caution for management of postoperative pulmonary arterial stenosis in patients with a surgically created intrapulmonary coronary arterial tunnel, since tearing the wall of the pulmonary trunk may occur.
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.
To clarify the contribution of afterload to left ventricular performance after repair of mitral regurgitation, we evaluated echocardiographically 8 children who had undergone surgical repair for isolated congenital mitral regurgitation. We examined the relationship between left ventricular systolic function and preload, afterload, and contractility. The left ventricular systolic function was strongly correlated with the afterload after the surgical repair. In the postoperative state, reducing afterload by vasodilators could be a useful means of treating cardiac failure, in addition to using catecholamines to increase the contractility.