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Biomedical subjects

R M Freedom

Publications and source records attributed to R M Freedom.

At least 37 records · Page 2Linked to original sources
PubMed2000

Non-confluent pulmonary arteries in a patient with pulmonary atresia and intact ventricular septum: ? A 5th aortic arch with a systemic-to-pulmonary arterial connection.

Major abnormalities of pulmonary circulation are uncommon in the patient with pulmonary atresia and intact ventricular septum. Non-confluent pulmonary arteries have only rarely been described in this setting. In this case report, we describe a patient in whom the pulmonary arteries are non-confluent, with the right pulmonary artery supplied through a right-sided arterial duct, and the left pulmonary artery most likely through a fifth aortic arch, thus providing a systemic-to-pulmonary arterial connection. We discuss the various forms of non-confluent pulmonary arteries in the setting of pulmonary atresia and intact ventricular septum.

Aorta, Thoracic↗
PubMed2000

Independent factors associated with longevity of prosthetic pulmonary valves and valved conduits.

OBJECTIVE: To evaluate the age dependence of variables predictive of pulmonary valve prosthesis replacement, we conducted the following analysis. METHODS: Retrospective analysis of 945 operations in 726 patients undergoing placement of pulmonary valve prostheses was performed. Age was identified as a strong independent predictor of valve failure. The database was stratified into age-based subsets and predictors of valve replacement were identified within each subset. RESULTS: For the entire cohort, freedom from valve replacement at 5 years was 81%. Younger age was strongly associated with decreased time to valve replacement by multivariable analysis (hazard ratio: 0.71/log-year, P <.001). Other independent factors included diagnosis, type of prosthesis, and time-dependent requirement for pulmonary valve stent placement. Important predictors of valve failure varied among age groups and are as follows: for Age Less Than 3 Months: valve type; for Age 3 Months To Less Than 2 Years: smaller normalized valve prosthesis size; for Age 2 Years To Less Than 13 Years: sex, smaller normalized valve prosthesis size, placement of endovascular stents, and valve type; for Age 13 Years To 65 Years: smaller normalized valve prosthesis size, placement of endovascular stents, and increased number of previous valve placements. CONCLUSION: Age is a dominant risk factor predictive of pulmonary valve prosthesis failure. A significant interaction exists between age and the effects of diagnosis, valve type, and size on prosthetic pulmonary valve longevity.

Adolescent↗
PubMed2000

Noninvasive imaging in congenital heart disease.

Imaging algorithms in congenital heart disease, as in the patient with acquired heart diseases continue to evolve, with more and more information gleaned noninvasively. The emphasis will be on the newer aspects of imaging, not cross sectional echocardiography with color Doppler.

Adrenergic beta-Agonists↗
PubMed2000

Transcatheter closure of atrial septal defects using the Cardio-Seal implant.

OBJECTIVE: To review the outcomes of transcatheter closure of atrial septal defects using the Cardio-Seal implant. DESIGN: A prospective interventional study. SETTING: Tertiary referral centre. PATIENTS: The first 50 patients (median age 9.7 years) who underwent attempted percutaneous occlusion. INTERVENTIONS: Procedures were done under general anaesthesia and transoesophageal guidance between December 1996 and July 1998. MAIN OUTCOME MEASURES: Success of deployment, complications, and assessment of right ventricular end diastolic diameter, septal wall motion, and occlusion status by echocardiography. RESULTS: The median balloon stretched diameter was 14 mm. Multiple atrial septal defects were present in 11 patients (22%) and a deficient atrial rim (< 4 mm) in 19 (38%). In four patients (8%), a second device was implanted after removal of an initially malpositioned first implant. There were no significant immediate complications. All patients except one were discharged within 24 hours. At the latest follow up (mean 9.9 months) a small shunt was present in 23 patients (46%), although right ventricular end diastolic dimensions (mean (SD)) corrected for age decreased from 137 (29)% to 105 (17)% of normal, and septal motion abnormalities normalised in all but one patient. No predictors for a residual shunt were identified. Supporting arm fractures were detected in seven patients (14%) and protrusion of one arm through the defect in 16 (32%), the latter being more common in those with smaller anterosuperior rims. No untoward effects resulted from arm fractures or protrusion. There were no complications during follow up, although five patients (10%) experienced transient headaches. CONCLUSIONS: The implantation of the Cardio-Seal device corrects the haemodynamic disturbances secondary to the right ventricular volume overload, with good early outcome.

Adolescent↗
PubMed2000

Angiographic findings of persistent primitive hepatic venous plexus with underdevelopment of the infrahepatic inferior vena cava in pediatric patients.

OBJECTIVE: We describe the angiographic diagnosis and significance of persistence of the primitive hepatic venous plexus with underdevelopment of the infrahepatic inferior vena cava. CONCLUSION: We recommend that inferior venacavography be performed in routine assessment before surgery of patients with azygos or hemiazygos continuation of the inferior vena cava, in whom redirection of systemic venous blood to the pulmonary artery is contemplated.

Adolescent↗
PubMed1999

Stent implantation to create interatrial communications in patients with complex congenital heart disease.

A restrictive interatrial communication can complicate the management of complex congenital heart disease. The purpose of this report is to present a new technique to achieve a patent and reliable interatrial communication by using an endovascular stent. A stent was successfully implanted across a fenestrated extracardiac conduit in two patients with low cardiac output after Fontan operations and across the interatrial septum in a patient with double inlet left ventricle and severe left atrioventricular stenosis. The procedures were uncomplicated and all patients showed immediate hemodynamic improvement. Cathet. Cardiovasc. Intervent. 47:310-313, 1999.

Child, Preschool↗
PubMed1999

Aortic atresia with a ventricular septal defect: modified single-stage neonatal biventricular repair.

BACKGROUND: The spectrum of hypoplastic left heart disease is diverse but the surgical repair is strictly dichotomous, culminating in either a univentricular or a biventricular surgical repair. Although aortic atresia with a ventricular septal defect historically has been managed by conversion to a univentricular physiology, a biventricular repair occasionally has been attempted in stages or in conjunction with the implantation of multiple allografts or prosthetic conduits. Our repair strategy recently has evolved to the use of a modified single-stage biventricular repair using only autologous tissues without conduits. METHODS: Retrospective analysis (1989 to 1997) of neonates with aortic atresia with a ventricular septal defect. RESULTS: Five neonates underwent repair of aortic atresia with a ventricular septal defect. One died in the hospital. The mean age and weight of the neonates who underwent repair were 7.8 days (range, 2 to 17 days) and 3.2 kg (range, 3 to 3.6 kg), respectively. Three neonates had a univentricular repair and 2 had a modified biventricular repair. The latter two procedures were successful and the patients were discharged from the hospital. CONCLUSIONS: Long-term results are lacking to attest to this surgical modification's superiority over either the standard multistage univentricular operation or the single-stage biventricular repair using multiple conduits. However, we are optimistic that routine use of this modification will enable a greater percentage of neonates to undergo a biventricular repair without the need for serial conduit revisions or future aortoplasty.

Aorta↗
PubMed1999

Direct neonatal ventriculo-arterial connections (REV): early results and future implications.

BACKGROUND: Is the time-honored supposition correct that insertion of a competent prosthetic conduit or homograft is necessary to achieve right ventricular (RV) to pulmonary artery continuity in neonates? A direct ventriculo-arterial connection, or réparation à l'étage ventriculaire (REV), has been successfully used to achieve RV to pulmonary artery continuity in neonates without mortality or major morbidity. Acute RV function is preserved even in the face of free pulmonary insufficiency, but scrupulous preservation of pulmonary artery patency (unobstructed pathway) must be achieved. METHODS: We retrospectively reviewed the cases of 6 neonates who underwent direct ventriculo-arterial connection to achieve RV to pulmonary artery continuity during open heart procedures in the last 3 years. RESULTS: The 6 neonates had a mean age of 12.3 days (range, 2 days to 6 weeks) and a mean weight of 3.2 kg (range, 2.7 to 3.6 kg) at operation. Two of them had a diagnosis of aortic atresia + ventricular septal defect and successfully achieved an in-series circulation. Two had pulmonary atresia + ventricular septal defect and 2, double-outlet right ventricle + transposition of the great arteries + ventricular septal defect + pulmonary atresia. Follow-up is a mean of 16 months (range, 6 to 22 months). Surgical reintervention was required in 3 neonates and resulted in excellent hemodynamics in 2 of them. In the other patient, who had bilateral long-segment branch pulmonary artery hypoplasia, stents were placed without hemodynamic benefit. All children are currently alive with preserved RV function even in the presence of free pulmonary insufficiency. CONCLUSIONS: Although the creation of a direct ventriculo-arterial connection has routinely been used for children older than 1 year with satisfactory initial results, its application in neonate is very limited. Why have neonates been denied this viable alternative? Perhaps the answer involves legitimate concerns about the consequent free pulmonary insufficiency and the presumed acute RV diastolic dysfunction.

Double Outlet Right Ventricle↗
PubMed1999

Minimally invasive surgery with cardioscopy for congenital heart defects.

BACKGROUND: Minimally invasive cardiac surgery remains a burgeoning discipline lacking adequate instrumentation and perfusion circuitry, particularly for the pediatric population. Cardioscopy, utilizing first generation imaging equipment with a variety of different angled lenses, provides a unique opportunity to expand the realm for the diagnosis and treatment of congenital heart disease. METHODS: Sixty-eight children with a mean weight of 23 +/- 11 kg (range 8-62 kg) who underwent repair of atrial septal defects (ASD) using a minimally invasive approach (MINI group) were compared to 25 consecutive children undergoing ASD repair via a full median sternotomy (CONT group). In addition, mini-sternotomy with or without cardioscopy allowed for the diagnosis and treatment of more complex congenital lesions in 24 children. RESULTS: The mean age in the MINI group was 7 +/- 3 years (range 1-15 years) compared to 4 +/- 4 years in the CONT group (p = 0.009). The mean body surface area of the MINI group (0.8 +/- 0.2 m2; range 0.4-1.6 m2) was larger than the CONT group (mean 0.6 +/- 0.3 m2; range 0.2-1.6 m2; p = 0.04). Ischemic times and cardiopulmonary bypass times were similar in both groups. Postoperative hospital stay was shorter in the MINI group (3 +/- 2 versus 4 +/- 1 days; p = 0.014). CONCLUSIONS: Minimally invasive cardiac surgery can be performed safely even in small children with congenital heart defects. In addition to improved cosmetic results, these techniques can reduce the utilization of hospital resources. Future advances in cardioscopic technology should permit minimally invasive repair of most complex congenital heart lesions and should obviate the need for full sternotomy in the majority of children undergoing cardiac surgery.

Adolescent↗
PubMed1999

Surgical treatment of aortic arch hypoplasia in infants and children with biventricular hearts.

BACKGROUND: Results of aortic arch reconstruction in the setting of biventricular physiology are well documented in the adult population, however, in children, surgical outcome of this subgroup of patients is less clear. METHODS: We studied the clinical outcomes of 37 children aged 8 days to 15 years (median 26 months), who underwent aortic arch reconstruction for arch hypoplasia from 1982 to 1997. The children were divided into three groups: Group 1 (20 patients) had isolated aortic arch lesions, Group 2 (13 patients) had associated intra-cardiac pathology yet conserving a biventricular physiology, Group 3 (4 patients) had Williams Syndrome. Previous interventions for coarctation had been performed in 30 patients (81%). Arch repair consisted of a patch aortoplasty in the majority of patients (35 of 37 children). RESULTS: Operative mortality occurred in 5 children, 4 in Group 2 (31%), 1 in Group 3 (25%) and none in Group 1. Permanent neurological complications occurred in 2 children (5 %). During the follow-up, which ranged from 1 month to 8 years, balloon angioplasty for arch obstruction was required in 1 child. There was one late death, associated with a subsequent intra-cardiac repair. CONCLUSIONS: Aortic arch surgery in children with isolated arch hypoplasia, is associated with excellent early and late survival in addition to a low reintervention rate. Alternative perfusion and operative strategies must be implemented in infants with associated intra-cardiac anomalies to improve results.

Adolescent↗
PubMed1999

Endovascular stent implantation for the management of postoperative right ventricular outflow tract obstruction: clinical efficacy.

OBJECTIVE: Extracardiac conduits between the right ventricle and pulmonary arteries commit patients to multiple reoperations. We reviewed our experience with stent implantation in obstructed conduits. METHODS: Between 1990 and 1997, stents were implanted across 43 conduits. The median age at procedure was 6 years (0.5-17 years), and the median interval between conduit insertion and stent implantation was 2.4 years (0.3-14 years). RESULTS: Mean systolic right ventricular pressures and gradients, respectively, decreased from 71 +/- 18 mm Hg and 48 +/- 19 mm Hg before to 48 +/- 15 mm Hg and 19 +/- 13 mm Hg after stent placement. Mean percentage of predicted valve area for body surface area increased from 26% +/- 12% to 48% +/- 17% after stent placement. Fifteen patients underwent a second transcatheter intervention (dilation or additional stent), and 2 patients, a third, allowing further postponement of surgery in 8 patients. One sudden death occurred 2.8 years after stent placement. Surgical conduit replacement has occurred in 20 patients. Body growth was maintained during follow-up. Freedom from surgical reintervention was 86% at 1 year, 72% at 2 years, and 47% at 4 years. Higher right ventricular pressure and gradient before and after stent placement and lower percentage of predicted valve area for body surface area after stent placement were associated with shorter palliation. CONCLUSION: Endovascular stent placement across obstructed conduits is a safe and effective palliation that allows for normal body growth.

Cardiac Catheterization↗
PubMed1999

Impact of diaphragmatic paralysis after cardiothoracic surgery in children.

OBJECTIVES: We sought to determine the prevalence and clinical impact of diaphragmatic paralysis caused by phrenic nerve injury after cardiothoracic surgery in children. METHODS: A search of cardiology, radiology, and hospital databases identified 170 episodes of diaphragmatic paralysis after cardiothoracic surgery in 168 children operated on from 1985 to 1997. Medical records were reviewed to determine demographics, details of the operation and postoperative course, diagnostic features and management of diaphragmatic paralysis, and follow-up status. RESULTS: The prevalence of diaphragmatic paralysis was 1.6% (95% confidence interval 1.4%-1.8%). Median age at operation was 6 months (range <1 day-14.4 years). Median time from the operation to the initial investigation was 5 days (range <1 day-61 days), with 57% of patients receiving mechanical ventilation at diagnosis. Diaphragmatic plication was performed in 40% of the patients at a median interval from the initial investigation of 15 days (range 3 days-11.1 months). Significant independent factors associated with increased postoperative hospital stay were lower patient weight at operation, previous cardiothoracic operations, bilateral diaphragmatic paralysis, increased interval from operation to investigation, mechanical ventilation at the time of investigation, and diaphragmatic plication. Confirmed recovery of diaphragmatic function was noted before hospital discharge in only 15 episodes. CONCLUSIONS: Diaphragmatic paralysis complicating cardiothoracic surgery continues to occur in the current era, with a significant impact on morbidity. Smaller patients with bilateral hemidiaphragmatic paralysis, requiring mechanical ventilation, may represent a higher risk subgroup to target for increased diagnostic suspicion and more aggressive management; early spontaneous recovery is rare.

Adolescent↗
PubMed1999

Atrioventricular discordance: results of repair in 127 patients.

OBJECTIVE: The conventional management of patients with atrioventricular discordance is directed at associated lesions, taking advantage of physiologic "correction"; however, the morphologic right ventricle and tricuspid valve support the systemic circulation. Questions surrounding survival using this approach led us to analyze our institutional results. METHODS: All patients with atrioventricular discordance undergoing biventricular repair were analyzed (n = 127, 1959-1997), excluding those with functionally univentricular hearts. The ventriculoarterial connection associated with atrioventricular discordance varied and was most commonly discordant (87%), but occasionally concordant (6%), double-outlet right ventricle (6%), or double-outlet left ventricle (1%). At initial presentation, the most common lesions associated with atrioventricular discordance were ventricular septal defect (86%), pulmonary stenosis (64%), tricuspid regurgitation (28%), and atrioventricular block (12%). Nine patients underwent a double switch procedure to create ventriculoarterial concordance and the remainder were managed conventionally without correcting discordant connections. RESULTS: Operative mortality was 6% and did not vary by associated lesion. Twenty years after repair, survival was 48%. Within 20 years, 56% of patients required reoperation, usually for atrioventricular valve incompetence (n = 16), pulmonary stenosis (n = 16), or both (n = 3). Pacemakers were required in 50 patients, 4 before repair, 40 within 2 months of repair, and 6 remotely after repair. In early follow-up, the double switch procedure (n = 9) had equivalent mortality and a high pacemaker requirement for atrioventricular block. CONCLUSIONS: Analysis of conventional management of atrioventricular discordance revealed cumulative increases in mortality, systemic atrioventricular valve (tricuspid) replacement, complete atrioventricular block, and incidence of reoperation. Alternative management should be examined.

Adolescent↗
PubMed1999

Interventional cardiac catheterization.

Over the past decade, transcatheter interventions have become increasingly important in the treatment of patients with congenital heart lesions. These procedures may be broadly grouped as dilations (e.g., septostomy, valvuloplasty, angioplasty, and endovascular stenting) or as closures (e.g., vascular embolization and device closure of defects). Balloon valvuloplasty has become the treatment of choice for patients in all age groups with simple valvar pulmonic stenosis and, although not curative, seems at least comparable to surgery for congenital aortic stenosis in newborns to young adults. Balloon angioplasty is successfully applied to a wide range of aortic, pulmonary artery, and venous stenoses. Stents are useful in dilating lesions of which the intrinsic elasticity results in vessel recoil after balloon dilation alone. Catheter-delivered coils are used to embolize a wide range of arterial, venous, and prosthetic vascular connections. Although some devices remain investigational, they have been successfully used for closure of many arterial ducts and atrial and ventricular septal defects. In the therapy for patients with complex CHD, best results may be achieved by combining cardiac surgery with interventional catheterization. The cooperation among interventional cardiologists and cardiac surgeons was highlighted in a report of an algorithm to manage patients with tetralogy of Fallot or pulmonary atresia with diminutive pulmonary arteries, involving balloon dilation, coil embolization of collaterals, and intraoperative stent placement. In this setting, well-planned catheterization procedures have an important role in reducing the overall number of procedures that patients may require over a lifetime, with improved outcomes.

Adolescent↗
PubMed1999

Factors associated with outcomes of persistent truncus arteriosus.

OBJECTIVES: The purpose of this study was to identify trends and factors associated with outcomes of persistent truncus arteriosus (PTA). BACKGROUND: Although there have been significant improvements, PTA continues to be associated with significant morbidity and mortality. METHODS: We undertook a review of all consecutive cases of PTA (n = 205) presenting at our institution from 1953 to 1997. Data were collected regarding demographics, anatomy, management (surgical palliation and repair) and outcomes (mortality and reoperation). RESULTS: Significant trends (p < or = 0.001) related to groups defined by year of birth were as follows: number of cases (1953-1967, n = 13; 1968-1977, n = 42; 1978-1987, n = 69; 1988-1997, n = 81), median age at first assessment (8 months, 42 days, 7 days and 2 days, respectively), proportion who did not have any surgery (58%, 27%, 22% and 11%), proportion who had an initial palliative procedure (25%, 37%, 6% and 2%), proportion who underwent PTA repair (31%, 59%, 72% and 88%), median age at PTA repair (11.2 years, 1.1 years, 1.6 months and 12 days) and proportion dying before hospital discharge after repair (50%, 63%, 56% and 41%). Since 1995, mortality before hospital discharge after repair has further decreased to 2/11 (18%). Increasing time to initial conduit replacement in hospital survivors was significantly related to larger sized conduit at repair (p = 0.02) and use of pulmonary homografts (vs. aortic homografts or xenografts; p = 0.002). Interventional catheterization to address conduit obstructions significantly increased conduit longevity. CONCLUSIONS: Significant improvements in PTA outcomes are evident with trends toward earlier age at assessment and complete repair.

Child, Preschool↗
PubMed1999

Equivalent survival following cavopulmonary shunt: with or without the Fontan procedure.

OBJECTIVES: In 1992, an analysis of our experience with the cavopulmonary shunt (CPS) demonstrated equivalent long-term survival, with or without subsequent conversion to a Fontan circulation. Before 1992 (era 1) intervention was deferred until mandated by clinical deterioration. Since 1992 (era 2), timing of both CPS and Fontan was compressed in an effort to improve survival. Survival following CPS is analyzed to ascertain whether Fontan confers any survival advantage over no further definitive intervention. METHODS: From 1962 to 1997 inclusive, 490 patients underwent CPS, excluding those who had a CPS concomitant with a Fontan. In 55 patients the CPS was performed at or after a biventricular repair (BVR), or after a Fontan, and these patients are excluded. The 435 patients remaining followed a surgical protocol which included a subsequent BVR (n = 28), or a subsequent Fontan operation (n = 220), or no further definitive surgery (CPS only, n = 187). Between eras the mean age at surgery decreased for all procedures. RESULTS: Long-term survival 20 years after a CPS in 435 patients is 56 +/- 5%. Survival at 20 years among the 220 patients who were subsequently converted to a Fontan circulation is 65 +/- 8% compared to 50 +/- 11% for the 187 patients who did not have a Fontan. However, most of their survival difference is because all early deaths after a CPS occurred in the non-Fontan group. Multivariable analysis demonstrated that proceeding to a Fontan did have a small survival advantage which was not evident by univariate analysis. Independent risk factors for death, at any time, are a common atrioventricular valve, or pulmonary artery banding. The era had no effect on survival. CONCLUSIONS: The single ventricle circulation appears to have a limited durability of, an average, 30-40 years. There is a slight survival advantage in converting patients after a CPS to a Fontan circulation. A marked reduction in age at CPS and at Fontan has, as yet, not improved survival.

Adolescent↗