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Biomedical subjects

R M Freedom

Publications and source records attributed to R M Freedom.

At least 163 records · Page 9Linked to original sources
PubMed1991

Spectrum of cardiovascular anomalies in Williams-Beuren syndrome.

This study is presented to identify and characterize the spectrum of the cardiovascular anomalies in children presenting with Williams-Beuren syndrome and cardiovascular anomalies at The Hospital for Sick Children, Toronto from 1966 to 1988. Forty-nine children were diagnosed and followed. The female to male ratio was 1.2:1. The age ranged from 1 month to 14 years at the time of diagnosis (mean 39 months), and follow-up periods were from 9 months to 20 years (mean 10 years). All patients having the typical features were also evaluated by geneticists. Based on cardiovascular findings four groups were identified. Group 1 had isolated supravalvular aortic stenosis (SVAS) (28 patients). There was follow-up in 24 of these children. Six had worsening of supravalvular narrowing and underwent surgery. One showed an increased gradient from 10-40 mmHg during 7 years. Seventeen had mild narrowing and showed no progression over a period of 75 months. Group 2 had isolated pulmonary artery branch stenosis (8 patients). Seven had mild narrowing which remained unchanged over a mean period of 16 months and one underwent surgery. Group 3 had combined lesions (11 patients). Six showed increased left-side narrowing, while right-side obstruction remained static or improved. Five showed improvement in narrowing in both outflow tracts. Five underwent surgery. Additional cardiovascular anomalies included peripheral artery stenosis in two patients, coronary artery abnormalities in three, mitral valve prolapse in three, and coarctation of the aorta in two. Group 4 had isolated lesions. One patient had isolated coarctation of the aorta and one isolated mitral prolapse.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormalities, Multiple↗
PubMed1991

Natural history of dilated cardiomyopathy in children.

To assess the natural history and potential risk factors in childhood dilated cardiomyopathy, we investigated 25 patients (ages 9.6 +/- 4.4 years) who presented after they were 2 years old. All patients had symptoms of congestive heart failure and reduced contractility with a dilated left ventricle at presentation. Two factors at presentation were significantly different between patients who died less than 1 year after the presentation (n = 14) and those who survived for more than 1 year (n = 9); cardiothoracic ratio (65.1% +/- 6.8% vs 57.1% +/- 6.1%, p less than 0.01) and left ventricular ejection fraction (31.3% +/- 7.0% vs 40.0% +/- 6.2%, p less than 0.05). Irrespective of intensive medical therapy, dilated cardiomyopathy in children had a poor prognosis; the actuarial survival rate was 41% at 1 year and 20% at 3 years. Other forms of therapy should be considered in the early stages of dilated cardiomyopathy in this high-risk group.

Cardiomyopathy, Dilated↗
PubMed1991

Results of the Fontan procedure for patients with univentricular heart.

One hundred twenty-four consecutive patients with univentricular heart undergoing the Fontan operation were reviewed. Patients with tricuspid atresia or biventricular heart with hypoplasia of one ventricle were excluded. Eighty-four patients had left ventricular morphology. Atrioventricular connection was double-inlet (n = 76), common (n = 29), absent left atrioventricular connection (n = 14), and absent right atrioventricular connection (n = 5). Actuarial survival was 77% (70% confidence limits, 73% to 81%) at 1 year, 66% (70% confidence limits, 60% to 72%) at 5 years, and 49% (70% confidence limits, 36% to 61%) at 10 years, indicating a continuing risk for premature death. Multivariate analysis identified preoperative ventricular function and hypertrophy as risk factors for survival. High postrepair right atrial pressure (greater than 15 mm Hg) emerged as a strong intraoperative predictor of survival. Logistic regression analysis of these factors predicts high probability of death for certain subgroups of patients after the Fontan operation. Forty-four percent (n = 53) of these original 124 patients are alive and in New York Heart Association class I at follow-up. Thirty-eight percent (n = 33) of survivors have worse ventricular function than preoperative. Long-term survival is disappointing. Certain identifiable subgroups of patients with univentricular heart have unacceptable risks for the Fontan operation and should have alternate management. High postrepair right atrial pressure is an ominous sign, and if it persists the Fontan should be fenestrated or taken down.

Adolescent↗
PubMed1991

Immunosuppressive therapy in the management of acute myocarditis in children: a clinical trial.

To assess whether steroid therapy influenced the clinical course of myocarditis in a pediatric population, findings in 13 consecutive infants and children (8 female, 5 male) with biopsy-proved myocarditis were reviewed. The mean age was 5.7 +/- 4.8 years (range 1.1 to 14.8). Congestive heart failure was present in all as were ST-T wave changes, cardiomegaly and pulmonary edema on chest roentgenogram. Echocardiography demonstrated pericardial effusion in five patients and mitral regurgitation in eight. Mean left ventricular ejection fraction was 34 +/- 12%. Prednisone was administered to all patients; one patient also received azathioprine. There was one death. All survivors showed clinical improvement with normalization of ECG changes, heart size and systolic function. No significant side effects occurred. Repeat myocardial biopsy in eight patients demonstrated improvement in all eight and elimination of the inflammatory infiltrate in six. Immunosuppressive therapy in this pediatric population appeared useful in improving the clinical course and cardiac function in acute myocarditis with no adverse side effects.

Azathioprine↗
PubMed1991

Repair of coarctation of the aorta in children: postoperative morphology.

To determine the morphologic sequelae after surgical repair of coarctation of the aorta, the authors retrospectively reviewed angiograms and hemodynamic and clinical data on 215 patients who underwent cardiac catheterization after surgical repair of coarctation of the aorta during a 13-year period. Ninety-seven patients (45%) underwent coarctation resection with end-to-end anastomosis; 92 (43%), subclavian-flap angioplasties; and 26 (12%), synthetic-patch repairs. Sixty-four patients (30%) had an "aneurysm," defined as a measurement ratio of repair site to diaphragmatic aorta greater than 1.5. Transverse-arch or isthmic hypoplasia or recoarctation was detected in 86 patients (40%) and was most commonly associated with septal defects or obstruction of the left ventricular outflow tract. Pullback systolic pressure gradients at catheterization were significantly higher (P = .0001) in the patients with transverse-arch hypoplasia and recoarctation than in those with ratios of transverse arch to diaphragmatic aorta greater than 0.9. Significant postoperative arch obstructions can be predicted with measurement ratios on the basis of the diameter of the abdominal aorta.

Adolescent↗
PubMed1991

Transcatheter occlusion of the persistently patent ductus arteriosus. Forty-month follow-up and prevalence of residual shunting.

BACKGROUND: Percutaneous closure of the persistently patent ductus arteriosus with the Rashkind prosthesis is an established effective therapeutic modality, although some patients are left with residual shunting. To evaluate this, a retrospective study of the prevalence of persistent shunting over a 40-month period in the first 190 patients was undertaken. METHODS AND RESULTS: All patients (male 45, female 145; mean age, 3.9 +/- 3.6 years; range, 5 months to 20 years) had serial clinical and color-flow echocardiographic follow-up at 6-12-month intervals (range, 6-40 months). Four patients required surgical removal of an embolized device, leaving a cohort of 186 patients in whom 196 procedures were performed, resulting in successful placement of 195 devices (43 17-mm [22%] and 152 12-mm [78%]). Complications occurred in seven of 195 procedures (3.6%). Nine of 10 attempted reocclusions (all with 12-mm devices) were successful. The prevalence of residual shunting was 38% at 1 year, 18% at 2 years, and 8% at 40 months. Patients with ductus measuring less than 4 mm had a higher success of initial occlusion. Thirty-four patients were left with residual shunting determined by color-flow Doppler study, but no anatomic or echocardiographic features were found predictive for residual shunting. All remain asymptomatic with 26 (76%) having no detectable murmur, two (6%) a continuous murmur, and six (18%) a systolic murmur. CONCLUSIONS: Catheter occlusion will obviate the need for surgery in the majority of patients presenting with persistently patent ductus arteriosus. Reocclusion has been found feasible in those with continuous murmurs (nine of nine) and should be offered early because it is unlikely for spontaneous closure to occur in this group. It appears prudent to follow those with small residual shunting because further spontaneous closure can occur.

Adolescent↗
PubMed1991

Thromboexclusion of the right ventricle in children with pulmonary atresia and intact ventricular septum.

Twelve children with pulmonary atresia and intact ventricular septum underwent closure of the tricuspid valve as a part of a new surgical procedure. In two cases a concomitant Fontan operation was performed. In each patient the right ventricle was very small and right ventricular pressure was higher than systemic pressure. Ventricle-coronary connections provided flow of desaturated blood from the right ventricle into the coronary arteries in 11 of 12 cases. Five of the 12 children did not survive operation and postmortem examination of each revealed severe acute and chronic myocardial ischemic damage and high-grade obstruction or interruption of the proximal left anterior descending coronary artery. Preoperative angiography demonstrated occlusive changes in the coronary arteries, resulting in right ventricular dependent circulation, in all five children who died and in one child who survived operation. Seven children who survived operation are well 4 months to 3.5 years later. Two have undergone subsequent successful Fontan operation and two others are considered suitable candidates for this operation. Tricuspid valve closure is recommended for a carefully selected group of infants with pulmonary atresia and intact ventricular septum provided a right ventricular-dependent coronary circulation can be excluded on the basis of preoperative coronary cineangiography.

Child↗
PubMed1991

[Truncal valve regurgitation and stenosis in persistent truncus arteriosus: echocardiographic evaluation of pre- and postsurgical states].

Twenty-four patients with persistent truncus arteriosus who underwent total surgical correction at The Hospital for Sick Children in Toronto, Canada between October 1984 and December 1987 were investigated to determine whether the postoperative course is satisfactory even without performing replacement of the truncal valve. All patients but one were less than 6 months of age. There were 9 operative deaths with a mortality rate of 37%. The most significant incremental risk factor was age of less than 30 days at the time of surgery (p < 0.01). The operative mortality did not correlate with the degree of preoperative truncal valve regurgitation nor stenosis. Among 15 hospital survivors, 14 patients were followed by echocardiography within one week after surgery, 4 of whom were reexamined within 2 weeks. Four patients without truncal valve regurgitation and stenosis underwent successful surgery, however, mild regurgitation developed in one 2 weeks after surgery. Among 4 patients with solitary truncal valve regurgitation, 2 improved and the other 2 did not. Among 5 patients with truncal regurgitation and stenosis, 3 improved in both truncal valve regurgitation and stenosis, but improvement was observed in only stenosis in the other 2 patients. One patient with stenosis improved, but developed mild regurgitation 2 weeks later. After radical surgery, 8 of the 10 patients (80%) with regurgitation and/or stenosis showed improvement without performing replacement of the truncal valve.

Age Factors↗
PubMed1991

Assessment of myocardial perfusion in patients after the arterial switch operation.

In 21 patients who had undergone the arterial switch operation, the adequacy of myocardial perfusion was evaluated by thallium-201 computed scintigraphy 2.6 +/- 2 (0.3-7) yr after surgery. Fourteen patients had undergone the arterial switch procedure after pulmonary artery banding and seven as a primary repair. Isoproterenol stress increased the heart rate by at least 55%. Tomographic imaging was performed at peak stress and 3 hr later in the reperfusion phase. Nine patients had perfusion defects. The perfusion defects were located at the left ventricular apex in four (with extension to the inferolateral wall in one), left ventricular anterolateral wall in two, ventricular septum in one, left ventricular inferior wall in one, and right ventricular free wall in one. Some of these defects could be due to myocardial damage at the time of surgery, but these results also raise concern about long-term adequacy of myocardial perfusion following the arterial switch procedure.

Child↗
PubMed1990

Natural history of cardiac rhabdomyoma in infancy and childhood.

Although spontaneous regression of cardiac rhabdomyoma has been reported, prognosis is still considered to be poor and surgery continues to be indicated. The experience with rhabdomyoma diagnosed in live infants over a 20-year period was reviewed. Diagnosis by angiography or echocardiography was accepted only if multiple tumors were present or if tuberous sclerosis was also diagnosed. Nine patients (3 diagnosed prenatally and the remaining 6 at age less than 8 months) were identified as having a total of 24 tumors. Measurements in 2 planes demonstrated at least some evidence of regression in 24 patients (100%), with 20 of 24 having complete resolution. One patient required delayed surgery for excision of a subaortic ridge that appeared at the site of a resolved tumor. Our findings suggest that pediatric cardiac rhabdomyoma is most often a benign condition in which spontaneous regression is the rule. Surgery is recommended only for patients with refractory dysrhythmias or severe hemodynamic compromise.

Child↗
PubMed1990

Echocardiographic evaluation of the spectrum of cardiac anomalies associated with trisomy 13 and trisomy 18.

To investigate the role that cardiac anomalies play in the early death frequently seen in the trisomy 13 and the trisomy 18 syndromes, two-dimensional and Doppler echocardiograms from 31 newborn infants with cytogenetic confirmation of these syndromes seen at one institution over a 4.5 year period (1983 to 1988) were reviewed. The mean age at echocardiography was 1.5 days, and the median age at death was 14 days. Significant cyanosis was present in 58%. Cardiac anomalies that would be considered lethal within the neonatal period were present in only 19% of patients. The most common lesions were atrial septal defect (81%), ventricular septal defect (61%) and patent ductus arteriosus (85%). Most ventricular septal defects and patent ductus arteriosus were large. Valvular dysplasia of one or more valves, graded as mild in most cases, was found in 68%, but was not associated with Doppler evidence of significant regurgitation or stenosis in any subject. Of the four valves, the pulmonary valve, followed by the tricuspid valve, was the most commonly dysplastic. Doppler evidence suggestive of elevated pulmonary artery pressure (low velocity bidirectional flow across the ventricular septal defect and patent ductus arteriosus), although expected, was accompanied by greater than normal mean right ventricular cavity and free wall dimensions in these patients. Thus, although the cardiac anomalies most frequently encountered in trisomy 13 and trisomy 18 are nonlethal, the combined findings of frequent cyanosis and increased right ventricular dimensions suggest that other factors such as pulmonary hypertension, perhaps related to maldevelopment of the pulmonary vasculature, may contribute to early death in some of these infants.

Abnormalities, Multiple↗
PubMed1990

Management of neonatal critical pulmonic stenosis in the balloon valvotomy era.

We evaluated our recent experience with management of neonatal critical pulmonic stenosis and intact ventricular septum between 1982 and 1988. Thirty-nine patients (aged less than 3 months) were treated initially by operation (group A, n = 19) or with balloon pulmonary valvotomy (group B, n = 20). Patients in group A were younger (5 +/- 1.3 versus 18 +/- 4 days in group B) (mean +/- standard error of the mean) and had a greater degree of hypoxia (oxygen tension, 55 +/- 4 versus 80 +/- 6 mm Hg) (p less than 0.05 for all variables). Ten patients in group A and 8 patients in group B had right ventricular hypoplasia, based on an angiographically determined index. Balloon pulmonary valvotomy was attempted in 20 patients at the time of the initial catheterization but was unsuccessful in 9 owing to inability to catheterize the hypoplastic right ventricular outflow tract (n = 8) and to recurrent infundibular stenosis (n = 1). Patients with failed balloon valvotomy were subsequently operated on within 24 hours. The early operative mortality (less than 30 days) was 25% (7 of 28); one death (9%) occurred after successful balloon valvotomy owing to associated critical aortic stenosis. The early postoperative gradient was 20 +/- 2 mm Hg; the post-balloon valvotomy gradient was 18 +/- 3 mm Hg. We conclude that balloon pulmonary valvotomy yields good results in patients with critical pulmonary stenosis with essentially normal-sized right ventricle, whereas surgical pulmonary valvotomy is required for patients with right ventricular hypoplasia.

Blood Pressure↗
PubMed1990

Common atrioventricular valve guarding double inlet atrioventricular connexion: natural history and surgical results in 76 cases.

We describe 76 patients in whom a double inlet atrioventricular connexion was guarded by a common atrioventricular valve. The atriums were connected to a dominant right ventricle in 42, to a left ventricle in 29 and to a solitary indeterminate ventricle in 5. The most common atrial arrangement was isomerism of the right atrial appendages, seen in 46% (35/76). Of these, there was associated anomalous pulmonary venous connexion in 72% and absence of the spleen in 63%. Double outlet right ventricle was the most frequent ventriculoarterial connexion, present in 37 cases. Abnormal atrioventricular valvar function could already be detected in 46% of cases at the time of initial presentation. A decrease of function was observed in 18 patients, in 14 of them 2 weeks to 16 years (mean 5.7 years) after palliative surgery. The majority of the palliative procedures were constructions of shunts, since 75% (57/76) of the patients showed obstruction to flow of pulmonary blood. Patients with double inlet ventricle guarded by a common atrioventricular valve have a high early mortality (37% died in the neonatal period). Management should be designed to protect the integrity of the pulmonary vascular bed. Definitive repair with a Fontan type procedure is the most suitable final approach.

Blood Vessel Prosthesis↗