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Biomedical subjects

R M Freedom

Publications and source records attributed to R M Freedom.

At least 19 recordsLinked to original sources
PubMed1992

Percutaneous pericardial catheter drainage in childhood.

The clinical course of 41 consecutive pediatric patients (mean age 7.6 +/- 5.8 years, weight 27 +/- 22 kg) who underwent percutaneous pericardial drain placement during a 3-year period were reviewed. The most common diagnoses were malignancy (20%), postpericardiotomy syndrome (17%), aseptic pericarditis (12%), and patients recovering from a Fontan type of operation (12%). Indications for drainage included increasing effusion size determined by 2-dimensional echocardiogram (48%), clinical deterioration (33%) and echocardiographic evidence of hemodynamic compromise (12%). Only 3 (7%) patients had clinical evidence of cardiac tamponade. Drainage catheter placement was accomplished percutaneously from the subxiphoid approach. Insertion was successful in all but 1 patient (98%) and successful evacuation of the pericardial space was achieved in 93% of patients. There was 1 death in a critically ill 2-week-old infant and 4 complications, 3 of which occurred in patients aged less than 2 years. Drainage catheters remained in position from 1 to 18 days (mean 3 +/- 3 days) with no late complications. There were 3 instances (7%) of drainage catheter occlusion. These data support the notion that placement of a percutaneous pericardial catheter is safe and effective in providing definitive drainage of the pericardial space in the pediatric age group. Children younger than age 2 years may be at increased risk for complications.

Catheters, Indwelling↗
PubMed1992

Clinical impact of balloon angioplasty for branch pulmonary arterial stenosis.

The clinical impact of percutaneous balloon angioplasty on the management of patients with native or postoperative pulmonary arterial stenosis was reviewed. Seventy-four patients underwent 110 angioplasty procedures. Mean age at dilation was 6.7 +/- 5.3 years (range 0.2 to 18.1), 17 patients were aged less than 1 year, mean follow-up was 37.7 +/- 22.8 months (range 16 to 96), and 34 patients (44%) had follow-up angiography. Pulmonary artery dilation was acutely successful in 53% of patients, 17% had recurrent stenosis, and 5% had complications. The impact on subsequent care was favorably influenced in 26 of 74 patients (35%) with either complete resolution of stenosis (n = 7), optimizing future surgical conditions (n = 14), reduction in right ventricular pressure by greater than 20% (n = 3), or improvement of ipsilateral lung perfusion (n = 2). No patient previously considered inoperable was subsequently considered suitable for surgical repair owing to the intervention. No correlation was found between success and cardiac diagnosis (p = 0.48), site of stenosis (p = 0.78), balloon-vessel ratio (p = 0.42), or whether the stenotic area consisted of native or synthetic material (p = 0.22). No predictive factors for success could be defined, and often there was only a transient clinical impact. Due to the low complication risk and potential for a beneficial result, it still appears prudent to offer angioplasty as an initial therapeutic modality in this setting.

Adolescent↗
PubMed1992

Balloon atrial septostomy under transesophageal echocardiographic guidance.

Balloon atrial septostomy is an established method of palliation for several forms of congenital heart disease. Previously performed under fluoroscopic x-ray control, recent reports have demonstrated the utility of transthoracic echocardiographic monitoring. We report the first application of uniplane transesophageal echocardiography (TEE) (6.7-mm probe) as an alternative imaging modality for control of balloon atrial septostomy on neonates in the intensive care unit.

Catheterization↗
PubMed1992

Acute renal failure complicating pediatric cardiac surgery: a comparison of survivors and nonsurvivors following acute peritoneal dialysis.

The outlook for patients with cardiac surgery complicated by acute renal failure (ARF) is poor, with a reported mortality of 50-67%. In addition to assessing the impact of recent advances in pediatric cardiac surgery on the mortality rate and renal outcome of surgery complicated by ARF requiring peritoneal dialysis (PD), this study compares preoperative, operative, and postoperative variables in patients who survived surgery and those who did not survive. From 1982 through 1988, 44 postoperative cardiac patients developed ARF, and 40 (age: 2 days to 15 years) required PD. Seventeen of 40 patients survived (mortality 57.5%) and 16 of these patients recovered normal renal function. Preoperative variables, including operative age and weight, did not appear to directly influence survival. Operative profiles, including length of cardiopulmonary bypass, aortic cross-clamp time, and hypotension immediately off bypass, did not distinguish surviving patients from those that did not survive. Postoperative variables, such as postoperative hypotension treatment, arrhythmias, hematologic status, cardiac arrest with resuscitation, did not differentiate survivors from nonsurvivors. The mean duration of PD was less than 2 weeks, and complications were infrequent. Renal status following PD in survivors was usually normal. We conclude that recent advances in pediatric cardiac surgery have not further increased the high mortality of surgery complicated by ARF. Survival is associated with renal recovery and thus aggressive treatment using PD is warranted.

Acute Kidney Injury↗
PubMed1992

Congenitally corrected transposition of the great arteries associated with hypoplasia of the morphological left ventricle in the setting of atrial situs inversus.

Hypoplasia of the morphological left ventricle associated with severe pulmonic stenosis and an intact ventricular septum in the setting of congenitally corrected transposition of the great arteries is a rare lesion. We report the clinical and echocardiographic findings of this lesion in a patient with atrial situs inversus.

Abnormalities, Multiple↗
PubMed1992

Intravascular stent prosthesis for right ventricular outflow obstruction.

OBJECTIVES: This study was designed to assess the impact of implantation of balloon-expandable stents on right ventricular outflow obstruction in children with congenital heart disease. BACKGROUND: Intravascular stenting has been established as a useful treatment in adults with coronary and peripheral vascular disease. Its application in the treatment of infants and children with pulmonary, systemic and right ventricular conduit obstruction resistant to balloon angioplasty is limited. METHODS: A total of 24 stainless steel stents were implanted in 17 patients. Five stents were placed within right ventricular to pulmonary artery conduits, 17 in branch pulmonary arteries and 1 in an aortopulmonary collateral vessel. Follow-up time has ranged from 1 to 14 months, with 6 patients having hemodynamic and angiographic studies greater than 1 year after stent placement. The mean age at implantation was 7.4 +/- 5.6 years and the mean weight 33 +/- 16 kg. RESULTS: Optimal stent position was obtained in 22 of 24 implantations. In one patient the stent slipped from the delivery balloon and was left positioned in the inferior vena cava. No embolization or thrombotic event has been documented. Among patients with right ventricular to pulmonary artery conduit obstruction, the gradient was immediately reduced from 85 +/- 30 mm Hg to 35 +/- 20 mm Hg after stent implantation; however, three patients required conduit replacement because of persistent obstruction with elevated right ventricular pressures (82 +/- 16 mm Hg). In 10 of 11 patients with pulmonary artery stenosis, clinical improvement was noted in association with enlargement of vessel diameter by 92% +/- 90% (range 17% to 355%) and the gradient reduction of 22 +/- 24 mm Hg to 3 +/- 4 mm Hg. CONCLUSIONS: These data support the view that intravascular stenting will become an important adjunct in the management of children with congenital heart disease.

Child↗
PubMed1992

Serial analysis of regional left ventricular wall motion by two-dimensional echocardiography in patients with coronary artery enlargement after Kawasaki disease.

OBJECTIVES: This study was designed to assess the temporal relation between early coronary artery abnormalities and left ventricular function in Kawasaki disease. BACKGROUND: Although late segmental wall motion abnormalities may be seen in patients with Kawasaki disease who have coronary artery stenosis, the impact of early coronary artery abnormalities is unclear. METHODS: Regional left ventricular wall motion was assessed by two-dimensional echocardiography in 18 patients with Kawasaki disease and echocardiographic evidence of coronary artery enlargement at 3 weeks and 3 months and at either 6 or 12 months after the onset of fever. Four patients had a persistent left coronary artery aneurysm, four had regression of their aneurysm, two had persistent left coronary artery ectasia and eight had regression of ectasia. Left ventricular wall motion was assessed by measuring regional area change in parasternal and apical views. After planimetry of an end-systolic and an end-diastolic frame, the ventricle was divided into eight equal segments and the percent area change was calculated. A floating system correcting for translation and rotation was applied. The measurements in the patient group were compared with values previously obtained in 55 normal age-matched infants and children. RESULTS: A transient regional wall motion abnormality 3 and 6 months after the onset of fever was discovered in the inferolateral wall of one patient with a persistent left coronary artery aneurysm. One patient with regression of coronary artery ectasia had a persistent wall motion abnormality in the anterolateral left ventricular wall. There was no correlation between the extent of coronary artery enlargement and the presence or absence of wall motion abnormalities. CONCLUSIONS: These early changes are most likely secondary to associated myocarditis rather than coronary artery abnormalities.

Child↗
PubMed1992

Ventricular performance before and after Fontan repair for univentricular atrioventricular connection: angiographic and radionuclide assessment.

OBJECTIVES: This study was designed to evaluate changes in ventricular volume, mass and cardiac function before and after creation of an atrial to pulmonary connection in patients with a univentricular atrioventricular connection. BACKGROUND: Intact systolic and diastolic performance is critical for successful establishment of an atrial dependent circulation, and few studies are available comparing cardiac performance before and after creation. METHODS: With the use of radionuclide blood pool imaging and ventricular cineangiography, 54 patients (mean age 6.4 +/- 3.4 years) were studied. Twenty-eight patients were investigated preoperatively and 36 greater than 1 year after repair and compared with a control population. RESULTS: Before operation, end-diastolic volume and wall mass were significantly increased compared with those of control subjects; however, the mass/volume ratio was normal (1.08 +/- 0.31 g/ml for the preoperative group; 0.97 +/- 0.19 for control subjects). Although end-diastolic volume returned to normal after the procedure, wall mass remained elevated and contributed to an elevated mass/volume ratio (1.20 +/- 0.38 g/ml). After the procedure, systemic vascular resistance index was significantly elevated compared with that before surgery or with that of control subjects (1,199 +/- 373, 2,120 +/- 645, 1,556 +/- 275 dynes.s.cm-5.m2: pre- and postrepair and control subjects, respectively). Radionuclide studies demonstrated that preoperative ejection fraction (52 +/- 9, 50 +/- 9, 60 +/- 8%), peak ejection (2.58 +/- 0.66, 2.95 +/- 0.81, 3.73 +/- 0.70 EDV/s) and peak filling rates (2.84 +/- 0.75, 2.75 +/- 0.79, 3.84 +/- 0.51 end-diastolic volumes [EDV/s]) were significantly reduced compared with those of control subjects and remained so after surgery. CONCLUSIONS: These data suggest that systolic and diastolic function is depressed preoperatively in these patients, remains unchanged after the creation of an atrial-dependent circulation and is associated with an increased systemic vascular resistance. Long-term issues addressing preservation of cardiac function need to be prospectively studied.

Child↗
PubMed1992

Outcome of coronary artery aneurysms after Kawasaki disease.

From 1974 through 1991, a total of 583 children with Kawasaki disease were seen at the Hospital for Sick Children, in Toronto, of whom 80 (13.7%) had coronary artery involvement. There were 55 boys and 25 girls, whose mean age at onset was 2.9 +/- 2.5 years, followed for a mean period of 4.0 +/- 3.6 years. Giant aneurysms (maximum diameter > or = 8 mm) were found in 22 children, moderate-sized aneurysms (> or = 4 to < 8 mm) in 44, and dilation lesions (< 4 mm) in 14. Myocardial infarction occurred in 9 (1.5%), all of whom had giant aneurysms. The persistence rate for aneurysms was 72% at 1 year and 41% at 5 years of follow-up. In multivariate analysis, the regression of an aneurysm was significantly related to the severity of coronary artery lesions, initial treatment, and gender. Although > 80% of small or moderate-sized aneurysms regressed within 5 years, giant aneurysms did not regress during the follow-up period. In patients who received immune globulin therapy, coronary lesions tended to resolve more rapidly than in those treated with salicylate therapy alone, because 91% of the lesions in the former were small or moderate. These findings suggest that the severity of coronary artery involvement during the initial stages of Kawasaki disease influences the regression of these lesions, and that immune globulin treatment may improve outcome by reducing the incidence of severe lesions.

Adolescent↗
PubMed1992

The relation between ventricular hypertrophy and clinical outcome in patients with double inlet left ventricle after atrial to pulmonary anastomosis.

To clarify differences between pre- and postoperative volumetric and hemodynamic variables from patients with clinically good and poor outcomes after a Fontan procedure, 40 patients with univentricular heart (double inlet left ventricle) (mean age: 5.7 +/- 3.3 years) were studied using the ventricular cineangiography. According to postoperative clinical findings, patients were classified into two groups: 26 patients with good outcomes and 14 patients with poor outcomes (including five with early and two with intermediate deaths) and compared with a control population. Age at surgery, pre-operative cardiac index, wall mass and systolic ejection phase parameters were not different between the two patient groups, however, end-diastolic volume index in poor outcomes was significantly smaller than those with good outcomes (100 +/- 24, 78 +/- 22, 64 +/- 14 ml/m2: good, poor outcomes and controls, respectively, p less than 0.05), and the mass/volume ratio in this group significantly elevated (1.00 +/- 0.18, 1.19 +/- 0.33, 0.97 +/- 0.19 g/ml, p less than 0.05). Postoperatively, both ventricular volume and mass in good outcomes returned toward the normal and the mass/volume ratio remained within normal range (1.07 +/- 0.22). In contrast, the hypertrophied ventricular mass in those patients with poor outcomes did not decrease in parallel with ventricular volume, thus contributing to a further increased ratio (1.48 +/- 0.19). Although there were no significant differences between pre-operative hemodynamic variables among the two groups, the mass/volume ratio in those with poor outcomes was increased pre-operatively and further increased after the Fontan procedure due to rapid and acute reduction of preload.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

The recognition, identification of morphologic substrate, and treatment of subaortic stenosis after a Fontan operation. An analysis of twelve patients.

Twelve children were identified with subaortic stenosis after Fontan's operation. All had absent resting and isoproterenol-provoked pressure gradient before the Fontan procedure. Six had a univentricular heart of left ventricular morphology, three had a single ventricle of right ventricular morphology, one had tricuspid atresia with transposition of the great arteries, one had pulmonary atresia, intact ventricular septum, and hypoplastic right ventricle, and one had corrected transposition with hypoplastic systemic ventricle. The median interval between the Fontan operation and the recognition of subaortic stenosis was 2.5 years. Ten patients underwent surgical treatment after a prior Fontan operation: Five had myectomy and enlargement of ventricular septal defect with two operative deaths; two had placement of a valved conduit from the ventricular apex to the descending aorta, and both died postoperatively; two with single ventricle had subaortic myectomy, and one had enlargement of ventricular septal defect and pulmonary aortic connection. Complete heart block developed in only one patient. Postoperative testing with Doppler echocardiography with color flow imaging demonstrated good relief of subaortic stenosis. All six children who survived the operation are well 4 months to 4 years later. Subaortic stenosis is a progressive lesion that may develop after a Fontan operation. Its surgical treatment continues to carry a significant mortality. Myectomy and enlargement of ventricular septal defect achieve direct relief of the obstruction with minimal risk of heart block.

Adolescent↗
PubMed1992

Failure of cryopreserved homograft valved conduits in the pulmonary circulation.

BACKGROUND: This study evaluates our experience with the cryopreserved homograft valved conduit used for reconstruction of the pulmonary circulation in patients with congenital heart disease. METHODS AND RESULTS: Between July 1, 1985, and December 31, 1990, 219 patients had cryopreserved homograft extracardiac valved conduits placed in the pulmonary circuit. Average age at operation was 7.2 years. Of these, 132 patients had a pulmonary homograft, and 87 had an aortic homograft. Twenty-four patients (11%) died in hospital. Hospital survivors (n = 195) have been followed an average of 29.8 months (SD, +/- 18.4 months). Fourteen patients died during follow-up, almost all related to the complexity of their original cardiac malformation. Thirty-two patients (15%) have required reoperation for conduit-related problems. Actuarial freedom from conduit reoperation is 55 +/- 12% at 5 years. The most common indication for reoperation was calcific stenosis (n = 27). Other indications for reoperation were pseudoaneurysm (n = 2), conduit infection (n = 2), and pulmonary insufficiency (n = 1). Reoperation rate for patients with aortic homografts (16 of 87) compared with that for pulmonary homografts (16 of 132) was not significantly different by the actuarial method. CONCLUSIONS: Long-term function of cryopreserved homograft valved conduits in the pulmonary circulation is disappointing.

Actuarial Analysis↗
PubMed1992

Surgical connections from ventricle to pulmonary artery. Comparison of four types of valved implants.

BACKGROUND: Four types of valved conduits used to correct venous ventricle to pulmonary artery (V-PA) discontinuity were compared. METHODS AND RESULTS: Four hundred fifty-seven patients with congenital heart defects requiring a V-PA connection during the past 25 years were reviewed. Age at implant varied from 1 day to 64 years (mean, 9.1 years). Four types of valved prostheses were used: 1) homograft conduit (HC, n = 178), 2) valved Dacron conduit (VDC, n = 126), 3) polystan conduit (PC, n = 47), and 4) orthotopic pulmonary valve implant (PVI, n = 106). There were 83 early deaths (18.2%) and 34 late deaths (8.5%). Follow-up ranged from 1 month to 22 years (mean, 3.5 years). One hundred eight conduit replacements were performed in 93 patients (21%). The overall patient survival was 73 +/- 2.3%, 67 +/- 3.2%, and 56 +/- 6.8% at 5, 10, and 15 years, respectively. Factors predictive of patient survival were diagnosis (p < 0.001) and valve size (p < 0.001). Age at operation (p < 0.001) and type of valve (p < 0.001) were the only risk factors for valve survival. At 5 years, survival of PVI (89 +/- 5%) and VDC (89 +/- 4%) was significantly better than survival of HC (46 +/- 13%) or PC (57 +/- 9%). CONCLUSIONS: Patients who survived the initial construction of a V-PA conduit had a reasonable long-term survival. A PVI was the most durable prosthesis. A Dacron porcine-valved conduit had significantly better durability than either a cryopreserved homograft or a PC.

Actuarial Analysis↗
PubMed1992

Evaluation of ventricular diastolic function in normal children using equilibrium radionuclide angiography.

Twenty children, aged 10.3 +/- 4.5 (3.3 to 17.5) years, were studied by equilibrium radionuclide angiography to establish a normal range for diastolic parameters. Ejection fraction (EF), peak ejection rate (PER) and time to peak ejection rate (TPER), peak filling rate (PFR) and time to peak filling rate (TPFR) were obtained from ventricular time-activity curves and their first derivative curves, and PFR and TPFR were considered as the diastolic parameters. Normal ranges obtained were as follows: EF, 60 +/- 8%; PER, 3.73 +/- 0.70 EDV-1; TPER, 109 +/- 25 ms; PFR, 3.84 +/- 0.51 EDVs-1; TPFR, 136 +/- 21 ms. There were significant correlations between PER and EF (P less than 0.001), PFR and EF (P less than 0.05), while age and heart rate had no influence upon these variables. Such normal ranges will be useful for evaluation of systolic and diastolic function in children with heart disease.

Adolescent↗
PubMed1992

Late results after repair of aortic insufficiency associated with ventricular septal defect.

The late results of 70 patients aged 1.96 to 35.9 (mean 10.1) years who had repair of ventricular septal defect and aortic insufficiency from 1968 to 1988 were reviewed. The ventricular septal defect was subcristal in 50 and subpulmonary in 20 patients. Two thirds were situated immediately below some part of the right coronary leaflet with prolapse of that leaflet. Most of the remainder were below the right commissure or the anterior part of the noncoronary leaflet with prolapse of one or both adjacent leaflets. Associated structural defects, usually including some fusion at a commissure, were present in 18 of the 70 patients and occurred more often with a ventricular septal defect in or below the commissure between the right and noncoronary leaflets (p less than 0.001). Follow-up ranged from 1.9 to 19.6 (mean 9.8) years. There were no early deaths or cases of atrioventricular block, but there were two late deaths. Patient survival rate was 96% at 10 years. Freedom from valvuloplasty failure and freedom from reoperation were 76% and 85%, respectively, at 10 years. The major predictor for failure by multivariate analysis was the presence of an associated structural defect (p less than 0.01). Age at repair and position of the ventricular septal defect were not significant risk factors. We conclude that aortic valvuloplasty produces good palliation in most children. The few failures occurred early and chiefly in patients with associated structural valve defects that occurred more frequently in children who had a ventricular septal defect in the right commissure, where both the right and noncoronary leaflets may be affected.

Adolescent↗
PubMed1991

Percutaneous implantation of a balloon-expandable endoprosthesis for pulmonary artery stenosis: an experimental study.

Conventional therapy to treat peripheral pulmonary artery stenosis (surgery or balloon angioplasty) has been frustrating. Recently a variety of peripheral vascular stenoses, in which conventional approaches are disappointing, have become amenable to therapy with the use of a balloon-expandable endovascular stent. This experimental study was designed to assess the application of such a prosthesis in artificially created pulmonary artery stenoses. In 9 of 12 2-week old pigs, left pulmonary artery stenosis was surgically created (3.9 +/- 1.1 mm diameter and 7 +/- 1 mm Hg mean gradient). At 6.8 +/- 1 weeks of age (13 +/- 4 kg), percutaneous (femoral venous) implantation of a 3-cm long balloon-expandable (maximal diameter 18 mm) stent (three placed into normal pulmonary artery branches) using a 3-cm x 10-mm balloon dilating catheter was achieved without technical difficulties. Stenoses were enlarged to 8.3 +/- 1.4 mm with a decrease in mean gradient to 1 +/- 1 mm Hg that was maintained through 3.5 months of follow-up. Histologic and electron micrographic studies identified normal-appearing neoendothelial layering over stent struts without intraluminal or peripheral thrombus formation and nonobstructed side branching to lung subsegments. These findings support the application of this approach in the treatment of pulmonary stenosis that is not amenable to conventional therapy.

Animals↗