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Biomedical subjects

R M Freedom

Publications and source records attributed to R M Freedom.

At least 253 records · Page 14Linked to original sources
PubMed1985

The investigation of abnormal pulmonary arteries in congenital heart disease.

Thorough investigation of the state of the pulmonary vascular bed is an important part of the preoperative assessment of patients with congenital heart disease. This article describes the imaging techniques applicable to anomalies and acquired changes of the pulmonary arteries, with emphasis on recent developments. The morphology and imaging of specific cardiovascular anomalies that involve the pulmonary arteries are described and illustrated.

Aortography↗
PubMed1984

Combined noninvasive assessment of the patent ductus arteriosus in the preterm infant before and after indomethacin treatment.

Fifteen preterm infants who weighed 0.7 to 2.0 kg and had clinical evidence of a patent ductus arteriosus (PDA) were studied by combined 2-dimensional and Doppler echocardiography before and after the administration of indomethacin. In 10 patients the PDA was widely patent at the time of the study and in 5 the lumen was narrow. In this latter group, the PDA was narrow at the pulmonary artery end in 2 patients, in the middle in 2 patients and at the aortic end and the middle in 1 patient. After the administration of intravenous indomethacin, the PDA closed completely in 12 patients and constricted in 3. The patterns of closure could be documented in those in whom serial studies were performed. In 3 patients, closure occurred after a single dose of indomethacin, in 3 after 2 doses and in the rest after a full course of 3 doses. Doppler interrogation at the aortic and pulmonary artery end of the PDA demonstrated the shunting patterns and provided a reliable assessment of patency after the ductal lumen was outside the range of lateral resolution following constriction. In no case did the PDA reopen after the course of indomethacin. This combined approach is a reliable method of assessing a PDA before and after a course of indomethacin. It should provide the means to answer many of the questions regarding the effect of various manipulations on the PDA in the preterm infant.

Ductus Arteriosus, Patent↗
PubMed1984

Complete transposition of the great arteries and coarctation of the aorta.

Thirty-two patients with complete transposition of the great arteries (TGA) and coarctation of the aorta (C of A) were seen at The Hospital for Sick Children, Toronto, Canada, between 1963 and 1983. Three patients had only mild C of A and have not required coarctectomy (Group I); 29 had a severe form of C of A (Group II). Two patients in Group I and 21 in Group II had a ventricular septal defect. Subaortic obstruction was present in 5 patients in Group II. The mechanisms included anterior deviation of the infundibular ventricular septum, anomalous right ventricular muscle bundles, and abnormal ventriculoinfundibular fold. Five patients in Group II had a hypoplastic right ventricle. Coarctectomy was performed in 25 patients, and 5 died (20% mortality rate). Sixteen patients had repair for TGA (13 Mustard, 2 Jatene , 1 Rastelli), and 2 died (12% mortality rate). Life-table analysis shows that only 68% of the patients with TGA and C of A survived the first month of life. The 5-year survival in this group was 57%. In the same period, 94% of patients with uncomplicated TGA survived the first month of life and the 5-year survival rate was 89%.

Aortic Coarctation↗
PubMed1984

Coarctation of the aorta or subaortic stenosis with atrioventricular septal defect.

Thirty patients are reported with atrioventricular (AV) septal defect and either coarctation of the aorta (C of A) or subaortic stenosis (SAS) or both. All patients had normal left ventricles as assessed by angiography (21 of 30 patients) or necropsy (9 of 30). Three groups were recognized. Groups I and II included 19 patients with AV septal defect (12 complete, 7 partial) and C of A with or without SAS, 11 patients with AV septal defect (5 complete, 6 partial) and SAS. In Group I, preductal C of A was diagnosed in 16 of 19 patients. Concomitant angiographic evidence of SAS was present in 2 cases, the mechanism being exaggerated anterior displacement of the left AV valve. In Group III, at the time of diagnosis left ventricular-aortic peak systolic pressure gradients of greater than 20 mm Hg were present in 9 patients, 2 of whom had gradients greater than 50 mm Hg. Angiographic diagnoses were: discrete fibrous diaphragm in 4, fibromuscular obstruction in 5, dynamic tunnel in 1, and chordae from left AV valve to LV outflow tract in 1. Thus, SAS in AV septal defect is most often due to a discrete anatomic lesion. Hemodynamic data show that SAS can be progressive, both before and after the surgical management of the AV septal defect.

Abnormalities, Multiple↗
PubMed1984

Bilateral ductus arteriosus (or remnant): an analysis of 27 patients.

Bilateral ductus arteriosus (DA) was clinically recognized in 27 patients studied angiographically from 1963 through May 1983. Distal bilateral DA origin of non-confluent pulmonary arteries was identified in 15 patients, ectopic or distal ductal origin of 1 pulmonary artery in 9 patients (5 without evidence of intracardiac disease) and isolation of the left subclavian artery in 3 (all 3 of whom had a right aortic arch). Other conditions reported to be associated with bilateral DA include interruption of the aortic arch with isolation of a subclavian artery, aortic atresia with interruption of the aortic arch in which bilateral DA supports the entire systemic circulation, bilateral DA complicating forms of congenitally malformed hearts other than those just stated, and, rarely, bilateral DA in isolation. Understanding the symmetric or paired nature of the primitive aortic arch system in the developing human heart facilitates recognition of the patterns of fourth and sixth arch anomalies seen with bilateral DA.

Angiography↗
PubMed1984

Surgical management of critical pulmonary stenosis in the neonate.

Experience with 36 consecutive neonates less than 1 month of age with critical pulmonary stenosis (PS) with intact ventricular septum was analyzed to define the role of pulmonary valvotomy and of a concomitant systemic-pulmonary shunt as well as the impact of prostaglandin E1 (PGE1) therapy in the management of this disorder. Operative procedures included pulmonary valvotomy as an isolated procedure (Group 1, N = 22), pulmonary valvotomy plus a systemic-pulmonary shunt (Group 2, N = 8), pulmonary valvotomy with PGE1 therapy (Group 3, N = 5), and one miscellaneous procedure. The hospital mortality (+/- 70% confidence limits [CL]) by treatment group was as follows: Group 1, 54% (CL, 41-67%) (12/22); Group 2, 25% (CL, 9-50%) (2/8); and Group 3, 0 (CL, 0-32%); Group 1 versus Group 2 plus Group 3 (p less than or equal to 0.05). Patients managed with a shunt or perioperative administration of PGE1 experienced a significant improvement in early survival. Late postoperative angiography demonstrated exemplary right ventricular growth in the majority of patients, although important residual abnormalities of the outflow tract necessitating operative repair were frequently present (5-year and 10-year actuarial freedom from reoperation, 73 +/- 10% and 42 +/- 16%, respectively [+/- standard error of the mean]). This review illustrates the limitations of pulmonary valvotomy as an isolated therapeutic method in neonates with critical PS. Provision of a systemic extracardiac source of pulmonary blood flow, accomplished by a systemic-pulmonary shunt or PGE1 infusion continued postoperatively, is the most important determinant of early survival in this disorder.

Alprostadil↗
PubMed1984

Surgical palliation of subaortic stenosis in the univentricular heart.

Seventeen patients with a univentricular atrioventricular connection and subaortic stenosis at the outlet foramen level were seen from 1974 until 1983. The ventricular anatomy was of a single left ventricle with an outlet chamber, and the great arteries were transposed. This condition often followed pulmonary artery banding (15 cases) but also occurred with pulmonic stenosis (one) or pulmonary atresia (one). The median interval to the detection of subaortic stenosis after banding was 2.3 years (range 11 days to 15 years). Thirteen patients had a resting gradient to 118 mm Hg and three a gradient only with isoprenaline infusion. The following surgical procedures have been performed: (1) insertion of a conduit between the left ventricle and aorta (one patient); (2) creation of an aorticopulmonary window proximal to the band and tightening of the band (three patients); (3) enlargement of the ventricular septal defect (three patients); (4) Fontan procedure (five patients); and (5) Fontan procedure plus arterial switch (two patients). All of the procedures but the last one have met with significant mortality in this difficult group of patients.

Abnormalities, Multiple↗
PubMed1984

Serous fluid leakage: a complication following the modified Blalock-Taussig shunt.

Polytetrafluoroethylene tubular grafts are useful in performing a systemic-to-pulmonary artery shunt (modified Blalock-Taussig). They allow a controlled-volume shunt, avoid kinking of the pulmonary artery, and preserve distal flow in the subclavian artery. Unfortunately, occasionally excessive serous fluid will drain through the interstices of the fabric. This results in excessive and prolonged chest tube drainage and/or localized seroma formation around the graft. This complication occurred in 26 children, an incidence of 18.8% of the 138 modified Blalock-Taussig operations. Repeat thoracotomy was required in four of these children--for evacuation of seroma mass in three and for relief of cardiac tamponade in one. Four other children required reinsertion of pleural or pericardial chest drains for excessive serous drainage persisting as long as 6 weeks after operation. Wrapping of the graft with silicone sheeting to facilitate subsequent takedown of the shunt led to seroma formation in five of nine children. We believe this practice should be abandoned. Excessive drainage of serous fluid through the interstices of PTFE grafts in almost 20% of our patients has compromised an otherwise satisfactory result of the modified Blalock-Taussig operation.

Blood Vessel Prosthesis↗
PubMed1983

Ventricular septal defect and subaortic stenosis: an analysis of 41 patients.

Forty-one patients with subaortic stenosis (SAS) and ventricular septal defect (VSD) were identified from the cardiac records of the Hospital for Sick Children, Toronto, Ontario. The diagnosis of an associated SAS was made clinically in only 1 patient, who had findings of left ventricular (LV) hypertrophy with strain on the electrocardiogram. There was a delay of 3.1 years between initial presentation and detection of SAS. The SAS was not diagnosed at initial catheterization in 17 patients and was confirmed at subsequent catheter studies in 8 patients, surgery in 5 and autopsy in 4. Associated defects included coarctation of the aorta in 12 patients, mitral valve abnormalities in 4, and right-sided obstructions, including anomalous right ventricular muscle bundles in 6 patients, tetralogy in 4 and pulmonic stenosis in 1 patient. The mean gradient across the LV outflow tract was 25 mm Hg. Nineteen patients had serial catheters without intervening surgery, and the outflow gradient increased from a mean of 9 to 36 mm Hg. The mechanism of SAS consisted of fibrous diaphragm and fibromuscular obstruction in 31 cases, muscular narrowing in 4, protruding tricuspid valve leaflet in 2, hypertrophic cardiomyopathy in 2, anterolateral twist in 1 patient and redundant tissue tag in 1. Thirty-eight patients had a perimembranous VSD, 19 of whom had an associated so-called aneurysm of the membranous septum; 2 had an infundibular VSD and 1 patient had a central muscular defect. Although the SAS was located below the VSD in 30 cases, the associated heart failure and reduced cardiac output can mask the presence or severity of associated SAS.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiocardiography↗
PubMed1983

Pulmonary vein wedge angiography: indications, results, and surgical correlates in 25 patients.

Pulmonary vein wedge angiography was applied to 25 patients ranging in age from 4 months to 16 years. The indications for this technique include (1) determination of the presence or absence of central (intrapericardial or mediastinal) pulmonary arteries in patients with pulmonary atresia where standard anterograde injections of contrast medium do not demonstrate these, (2) determination of the patency and caliber of a nonvisualized pulmonary artery when there is distal "occlusion" by a systemic-to-pulmonary artery anastomosis, (3) determination of the patency and caliber of a nonvisualized pulmonary artery when previous pulmonary arterial banding has led to acquired pulmonary artery atresia, and (4) determination of the presence of a mediastinal pulmonary artery in patients with so-called isolated congenital unilateral absence of a pulmonary artery. Surgical correlates to the interpretation of pulmonary vein wedge angiograms are provided in 18 patients. The present data suggest that pulmonary vein wedge angiography is a safe technique that provides considerable information about (1) the caliber of the parenchymal pulmonary arteries, (2) their sizes at the hilum of the lung, and (3) the presence or absence of a mediastinal confluence of pulmonary arteries. This technique may also complement those anatomic findings derived from anterograde injection of contrast material in patients with pulmonary atresia of a congenital or acquired nature.

Adolescent↗
PubMed1983

Palliative right ventricular outflow tract construction for patients with pulmonary atresia, ventricular septal defect, and hypoplastic pulmonary arteries.

From December, 1977, through June, 1981, 15 patients with pulmonary atresia, ventricular septal defect, and hypoplastic pulmonary arteries underwent a palliative right ventricular outflow tract construction. In seven (Group A) this was the first surgical procedure, whereas in the remaining eight (Group B) previous systemic-pulmonary artery anastomoses had been performed. A high morbidity of the pulmonary arteries was present in Group B, resulting in part from the previous shunting procedures. The left pulmonary artery was severely hypoplastic in five patients; the right was hypoplastic in seven of the eight patients and was severely stenotic or atretic in three. All the patients in Group A survived the palliative right ventricular outflow tract reconstruction, and only one in Group B died. Almost all patients had an increase in the aortic PO2 and oxygen saturations after palliative right ventricular outflow tract construction, with a concomitant fall in hemoglobin concentration. Three of the five patients in Group A who underwent postoperative angiography were found to have proximal left pulmonary artery stenosis, and three had lesser involvement of the proximal right pulmonary artery as well. Three of the six patients in Group B who were studied postoperatively also had severe stenosis or proximal atresia of the right pulmonary artery, and three patients had stenosis and hypoplasia of the left pulmonary artery as well, two severe. Thus in no patient in this series were normal pulmonary arteries achieved by palliative right ventricular outflow tract construction will provide the potential for ultimate complete repair. The rather constant finding of severe proximal left pulmonary artery stenosis and hypoplasia in Group A is disappointing.

Adolescent↗
PubMed1983

Axial angiocardiography in the critically ill infant. Indications and contraindications.

Axial projections provide a new and important dimension to cardiac angiography. These techniques, however, must not be used blindly. There are several contraindications to their use as an initial approach, for example, the distortion of the usual spatial relationships between ventricles. But these projections are well suited for imaging the atrial septum, atrioventricular septal defects, anomalies of the atrioventricular junction, and other diseases.

Angiocardiography↗
PubMed1983

The Mustard procedure in transposition of the great arteries associated with juxtaposition of the atrial appendages with and without dextrocardia.

Left-sided juxtaposition of the right atrial appendage (LJRAA) was seen in 10 patients in a series of 361 consecutive Mustard procedures for transposition of the great arteries (TGA). Dextrocardia complicated LJRAA in four cases. Right atrial capacity and free atrial wall size were smaller than normal in all patients, and a Mustard intra-atrial baffle repair was performed in all instances. Direct caval cannulation or cannulation of either atrial appendage facilitated intra-atrial repair. Nine patients in whom the pulmonary venous atrium was enlarged with a patch survived. One child who did not have a right atrial patch died 1 hour postoperatively of pulmonary edema. Two late deaths occurred 1 year postoperatively. Seven children survived and are well. In one child, superior vena caval baffle obstruction is controlled by digoxin and diuretic therapy. TGA associated with juxtaposition of the atrial appendages (JAA) and dextrocardia may be successfully repaired by the Mustard procedure, provided that the tricuspid valve and right ventricle are normal, an adequate superior vena caval channel is created, and patch enlargement of the pulmonary venous atrium is undertaken.

Abnormalities, Multiple↗
PubMed1982

The atrioventricular junction in the univentricular heart: a two-dimensional echocardiographic analysis.

The atrioventricular junction of 40 patients with univentricular heart was evaluated by two-dimensional echocardiography. The apical 4 chamber view optimally imaged the atrioventricular junction, and allowed determination of the type of atrioventricular connection: double inlet, common atrioventricular orifice, and absent right or left atrioventricular connection. When double inlet to 1 ventricle was demonstrated, the 4 chamber view allowed immediate comparison of the form and function of the right and left atrioventricular valves. Because anomalies of the atrioventricular valves frequently complicate the univentricular heart, two-dimensional echocardiographic assessment is a most important adjunct to the preoperative investigation of these patients.

Adolescent↗