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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
PubMed2003

Transcatheter management of residual shunts after initial transcatheter closure of a patent arterial duct.

OBJECTIVES: To assess the efficacy and safety of transcatheter reocclusion of persistent leaks following previously attempted transcatheter occlusion of persistent arterial duct. DESIGN: Retrospective study. SETTING: Tertiary pediatric cardiology centre. PATIENTS: From February 1987 through October 1996, trans-catheter occlusion of a residual ductal shunt was attempted in 42 consecutive patients at a median age of 5.0 years (range 1.6 years to 16.2 years). INTERVENTIONS: Fourty patients had successful placement of a double umbrella occluder (n=27) or coils (n=13) across residual shunts. Complications included device embolization in two patients and hemolysis in one patient. OUTCOME MEASURES AND RESULTS: Mean z-score for left ventricular end-diastolic dimension (LVEDD) at initial echocardiography was +2.55 +/- 1.89 (P<0.0001 versus normal); z-score for left pulmonary artery (LPA) diameter was +2.00 +/- 1.52 (P<0.0001). Mean LPA to right pulmonary artery (RPA) diameter ratio was 1.05 +/- 0.18. At follow-up echocardiogram, a median of two years (range six months to 7.7 years) after the second procedure, a shunt was persistent in 3% of the patients. Mean LVEDD and LPA diameter z-value, and mean LPA to RPA diameter had dropped significantly to +0.42 +/- 1.31, +0.07 +/- 1.15 and 0.86 +/- 0.14 (P<0.001), respectively. LPA flow acceleration was present in 25% of patients. Three of nine patients, in whom lung perfusion scan was performed, had left lung perfusion below 40%. Small weight and age at catheterization were significant risk factors for LPA flow disturbance. CONCLUSIONS: Repeat transcatheter occlusion is safe and successful in eliminating residual shunt across the arterial duct. Attention should, however, be addressed to the potential for LPA stenosis and growth, and flow should be regularly assessed.

Adolescent↗
PubMed2001

Comparison of two transcatheter closure methods of persistently patent arterial duct.

A randomized trial of arterial duct occlusion with a double umbrella (DU) or wire coil (WC) was undertaken for patients <18 years of age, weighing >10 kg with isolated ducts < or = 3 mm in diameter. Baseline, procedural, and outcome characteristics were compared in an intention-to-treat analysis according to randomization group. From 40 consecutively screened patients, 2 were not enrolled due to a ductal diameter of >3 mm on initial aortography, 38 patients were randomized to either the DU (n = 20) or WC (n = 18) groups. The groups did not differ significantly with respect to age, weight, gender, duct size, type, or branch pulmonary artery diameters. Crossover occurred only in the DU group, where 4 patients (20%) had a ductal diameter of < or = 1 mm and could not be entered for umbrella placement. All remaining DU group patients had ductal diameters of > or = 1.3 mm (p <0.0001). There were no embolizations or secondary implants in the DU group, but in the WC group there was 1 early and 1 late embolization, with 6 patients (33%) with > or = 2 coils. Mean times for the procedure (DU 68+/-19 minutes; WC 65+/-27 minutes; p = 0.70) and fluoroscopy (DU 14+/-4 minutes; WC 11+/-6 minutes; p = 0.22) did not differ significantly. Angiographic duct closure was documented in 4 of 13 patients (31%) of the DU group and 4 of 18 patients (22%) of the WC group (p = 0.69). Combined with an echocardiogram, closure in 11 of 17 patients with DU (65%) and 13 of 18 patients with WC (72%) (p = 0.64) was documented before hospital discharge. One WC group patient received thrombolytic therapy for a femoral artery thrombus. Follow-up at a median of 6.5 months (range 3.2 to 37) showed closure by Doppler echocardiography in 15 of 19 patients with DU (79%) versus 14 of 18 patients with WC (78%) (p = 1.0). Thus, with a tendency toward similar procedural characteristics and outcomes, the higher cost of the DU system compared with coil implants favors the use of coils for closure of the small arterial duct.

Analysis of Variance↗
PubMed2001

Total cavopulmonary connections in children with a previous Norwood procedure.

BACKGROUND: Outcomes of the Fontan operation in children initially palliated with the modified Norwood procedure are incompletely defined. METHODS: From August 1993 to January 2000, 45 patients (mean age 2.6 +/- 1.1 years, weight 12.7 +/- 2.8 kg) who were palliated with staged Norwood procedures (hypoplastic left heart syndrome, n = 32; nonhypoplastic left heart syndrome, n = 13) underwent a modified Fontan operation. Preoperative features included moderate/severe atrioventricular valve regurgitation (n = 5, 11%), reduced ventricular function on echocardiography in 11 patients, McGoon index 1.56 +/- 0.38, and pulmonary artery distortion in 18 patients (40%). RESULTS: A lateral tunnel (n = 16) or an extracardiac conduit (n = 29) connection with fenestration in 38 patients (84%) was used. Concomitant procedures included pulmonary artery reconstruction (n = 24, 53%), atrioventricular valve repair (n = 4, 9%) or replacement (n = 1). Before Fontan, 12 patients (27%) had an intervention to address neoaortic obstruction, and 7 patients required balloon dilation/stenting of the left (n = 5) or right pulmonary artery (n = 5). Intraoperatively, left (n = 5) or right pulmonary artery (n = 1) stenting was performed in 5 patients (11%). On follow-up, 8 patients required additional interventional procedures to address left pulmonary artery narrowing (n = 5), or venous (n = 5) or arteriopulmonary collaterals (n = 1). Perioperative mortality was 4.4% (n = 2). There were 2 late deaths at a mean follow-up of 39 +/- 20 months. CONCLUSIONS: In relatively high-risk patients, midterm results of the Fontan operation for children initially palliated with the Norwood procedure were good. Combined interventional-surgical treatment algorithms can lead to improved outcomes.

Child↗
PubMed2001

Extracardiac conduit versus lateral tunnel cavopulmonary connections at a single institution: impact on outcomes.

OBJECTIVE: To compare outcomes of extracardiac conduit and lateral tunnel Fontan connections in a single institution over a concurrent time period. METHODS: Between January 1994 and September 1998, 60 extracardiac conduit and 47 lateral tunnel total cavopulmonary connections were performed. Age, sex, and weight did not differ between the 2 groups. Compared with the lateral tunnel group (LT group), patients undergoing the extracardiac conduit procedure (EC group) had a trend to a higher incidence of morphologically right ventricle (EC group 48% vs LT group 32%; P <.09), a higher incidence of isomerism/heterotaxy syndrome (EC 22% vs LT 0%; P <.001), worse atrioventricular valve regurgitation (EC 11% moderate-plus vs LT 0%; P <.06), and lower McGoon indices (EC 1.8 +/- 0.5 vs LT 2.1 +/- 0.5; P <.03). Preoperative arrhythmias, transpulmonary gradients, room air oxygen saturations, ejection fractions, ventricular end-diastolic pressure, and pulmonary artery distortion did not differ between groups. Cardiopulmonary bypass times and fenestration usage were similar in both groups. RESULTS: Overall operative mortality was 5.6% and did not differ between groups. The LT group had a significantly higher incidence of postoperative sinoatrial node dysfunction (45% vs EC group 15%; P <.007), supraventricular tachycardia (33% vs EC group 8%; P <.0009), and need for temporary postoperative pacing (32% vs 12%; P <.01). Median duration of intensive care unit stay (EC 2 days, range 1-10 days, vs LT 2.8 days, range 1-103 days; P <.07) and ventilatory support (EC 1 day, range 0.25-10 days, vs LT 1 day, range 0.25-99 days; P <.03) were all longer in the LT group. Median chest tube drainage (EC 8 days, LT 9 days) was similar in both groups. Follow-up averaged 2.5 +/- 1.4 years in the EC group and 2.8 +/- 1.9 years in the LT group. There were 2 late deaths. Overall survival is 94% at 1 month, 92% at 1 year, and 92% at 5 years. Late ejection fraction or atrioventricular valve function did not differ between groups. Intermediate follow-up Holter analysis showed a higher incidence of atrial arrhythmias in the LT group (23% vs 7%; P <.02). Multivariable analysis showed that (1) prolonged cardiopulmonary bypass time was the only independent predictor for perioperative mortality, prolonged ventilation and intensive care unit length of stay, and increased time to final removal of chest tube drains and (2) lateral tunnel Fontan connection is an independent predictor of early postoperative and intermediate atrial arrhythmias. CONCLUSIONS: Although patients in the EC group were at higher preoperative risk, their outcomes were comparable with those of the LT group. Use of the extracardiac conduit technique for the modified Fontan operation reduces the risk of early and midterm atrial arrhythmia.

Arrhythmias, Cardiac↗
PubMed2000

What is the optimal age for repair of tetralogy of Fallot?

BACKGROUND: Controversy regarding the timing for the repair of tetralogy of Fallot centers around initial palliation versus primary repair for the symptomatic neonate/young infant and the optimal age for repair of the asymptomatic child. We changed our approach from one of initial palliation in the infant to one of primary repair around the age of 6 months, or earlier if clinically indicated. We examined the effects of this change in protocol and age on outcomes. METHODS AND RESULTS: The records of 227 consecutive children who had repair of isolated tetralogy of Fallot from January 1993 to June 1998 were reviewed. The median age of repair by year fell from 17 to 8 months (P:<0.01). The presence of a palliative shunt at the time of repair decreased from 38% to 0% (P:<0.01). Mortality (6 deaths, 2. 6%) improved with time (P:=0.02), with no mortality since the change in protocol (late 1995/early 1996). Multivariate analysis for physiological outcomes of time to lactate clearance, ventilation hours, and length of stay, but not death, demonstrated that an age <3 months was independently associated with prolongation of times (P:<0.03). Each of the deaths occurred with primary repair at an age >12 months. The best survival and physiological outcomes were achieved with primary repair in children aged 3 to 11 months. CONCLUSIONS: On the basis of mortality and physiological outcomes, the optimal age for elective repair of tetralogy of Fallot is 3 to 11 months of age.

Age Distribution↗
PubMed2000

Balloon angioplasty of native coarctation: clinical outcomes and predictors of success.

OBJECTIVES: We sought to investigate the clinical impact of balloon angioplasty for native coarctation of the aorta (CoA) and determine predictors of outcome. BACKGROUND: Balloon dilation of native CoA remains controversial and more information on its long-term impact is required. METHODS: Hemodynamic, angiographic and follow-up data on 69 children who underwent balloon angioplasty of native CoA between 1988 and 1996 were reviewed. Stretch, recoil and gain of CoA circumference and area were calculated and related to outcomes. RESULTS: Initial systolic gradients (mean +/- SD, 31+/-12 mm Hg) fell by -74+/-27% (p < 0.001), with an increase in mean CoA diameters of 128+/-128% in the left anterior oblique and 124+/-87% in the lateral views (p < 0.001). Two deaths occurred, one at the time of the procedure and one 23 months later, both as a result of an associated cardiomyopathy. Seven patients had residual gradients of >20 mm Hg. One patient developed an aneurysm, stable in follow-up, and four patients had mild dilation at the site of the angioplasty. Freedom from reintervention was 90% at one year and 87% at five years with follow-up ranging to 8.5 years. Factors significantly associated with decreased time to reintervention included: a higher gradient before dilation, a smaller percentage change in gradient after dilation, a small transverse arch and a greater stretch and gain, but not recoil. CONCLUSION: Balloon dilation is a safe and efficient treatment of native CoA in children. Greater stretch and gain are factors significantly associated with reintervention, possibly related to altered elastic properties and vessel scarring.

Angioplasty, Balloon↗
PubMed2000

Repair of isolated multiple muscular ventricular septal defects: the septal obliteration technique.

BACKGROUND: Isolated multiple ventricular septal defects (mVSDs) remain a surgical challenge. The dilemma of whether to perform a complete repair ultimately rests with the surgeon, who must decide if all significant septal defects can be located. Avoidance of a pulmonary arterial band (as part of a two-stage repair) will negate the need for future pulmonary arterial reconstruction and will reduce the incidence of late right ventricular diastolic dysfunction. METHODS: We performed a retrospective analysis of hospital and echocardiographic data of eight children who underwent a septal obliteration technique (SOT) as part of their correction of mVSDs (with and without coarctation of the aorta). RESULTS: Eight children with a mean age of 10.5 months (range 1.5 to 36 months), and weight of 6.2 kg (range 2.1 to 13.5 kg), respectively, underwent correction of mVSDs. All had a single, large, perimembranous defect, additional VSDs within the muscular trabecular septum (juxtaposed to the moderator band), and apical mVSDs. All VSDs were repaired via the right atrium, with avoidance of either a right or left ventriculotomy. The posterior and apical defects were excluded from the right ventricular cavity with a pericardial patch (SOT). The follow-up period remains limited to a mean of 20.9 months (8 to 39 months). Two children repaired with SOT had previous pulmonary artery bands (neonatal coarctation repair). All children were successfully discharged home with a mean postoperative Qp:Qs of 1.09:1. One pacemaker was required, but this child has since reverted back to normal sinus rythm. CONCLUSIONS: Our initial experience using the SOT in the treatment of apical VSDs as a component of isolated mVSDs has been rewarding. All children are currently alive, in normal sinus rhythm, and have no residual significant left-to-right shunts.

Cardiac Surgical Procedures↗
PubMed2000

Preservation of the pulmonary valve complex in tetralogy of fallot: how small is too small?

BACKGROUND: Surgical repair of congenital lesions associated with right ventricular outflow tract obstruction frequently requires the destruction of pulmonary valve (PV) components including the valve annulus. The resultant pulmonary insufficiency may lead to late functional deterioration of right ventricular performance. Acute right ventricular dysfunction has been associated with poor pulmonary runoff, tricuspid valve regurgitation, and pulmonary hypertension. Preservation of PV competence may prevent both early and late right ventricular failure. However, the recent trend towards earlier repair of tetralogy of Fallot (TOF) may preclude preservation of the PV in favor of a transannular patch. We reviewed our experience with surgical repair of TOF to determine if age and/or body size affected the ability to repair the PV. METHODS: We reviewed the clinical records of 50 consecutive children who underwent surgical repair of TOF by one surgeon. The latter 27 patients underwent repair with an intention to preserve their pulmonary valve. In total, 28 patients underwent repair with preservation of their pulmonary valve, and form the basis of this study. Serial echocardiographic assessments were performed early (3 to 6 months) and late (12 months) after surgery. RESULTS: Pulmonary valve preservation was possible in the majority of children (89%) in whom it was intended. Pulmonary valve competence was observed in 68% of children, with only 5 (16%) children demonstrating severe insufficiency at follow-up. Residual right ventricular outflow tract obstruction was present in only 1 child who underwent repair with pulmonary valve preservation at greater than 2 years of age. CONCLUSIONS: Our data suggest that earlier repair of TOF does not preclude preservation of the pulmonary valve and may indeed facilitate repair. The pulmonary valve remains competent at 12 months, with acceptable gradients, and should participate in somatic growth. Pulmonary valve preservation during repair of TOF may prevent free pulmonary insufficiency, progressive right ventricular dilation, and the need for future prosthetic pulmonary valve replacement.

Age Factors↗
PubMed2000

Single coronary artery and complete transposition of the great arteries: a technical challenge resolved?

BACKGROUND: The origin of the coronary arteries from a single aortic sinus remains a rare congenital anomaly, once regarded as having little clinical significance. Contemporary surgical practice, however, frequently demands precise coronary reimplantation. In this article we emphasize a prophylactic surgical technique found especially helpful in the repair of D-transposition of the great arteries (D-TGA)/single coronary artery. METHODS: We reviewed the institutional cardiac registry. RESULTS: Since 1985, 398 neonates with D-TGA were repaired with the arterial switch procedure. A mortality rate of 38% was encountered in "simple" D-TGA (n = 174)/single coronary (2.9% left facing sinus (IRLCx), 7.5% right facing sinus (IIRLCx)) and 41% in neonates with D-TGA (n = 224)/single coronary (3.6% IRLCx, 12% IIRLCx). During the past 3.5 years the surgical mortality rate of neonates (n = 6) treated with origin of the coronary arteries from a single aortic sinus has dropped to 0%. CONCLUSIONS: The surgical repair of D-TGA/single coronary artery continues to trouble surgeons. The implantation of a well-mobilized coronary "button" into a previously anastomosed neoaorta remains a key prophylactic technique in the achievement of good technical results.

Cardiac Surgical Procedures↗
PubMed2000

Influence of perioperative factors on outcomes in children younger than 18 months after repair of tetralogy of Fallot.

BACKGROUND: There has been a trend toward advocating earlier repair of tetralogy of Fallot and avoiding palliative procedures. The impact of this trend on perioperative outcomes has not been adequately documented. METHODS: Data from consecutive patients undergoing repair of tetralogy of Fallot at less than 18 months of age from May 1987 to September 1994 were reviewed. Independent factors associated with duration of stay in the intensive care unit were sought. RESULTS: Repair was performed in 89 infants at a median age of 13 months (range, 15 days to 18 months). A systemic-pulmonary artery shunt was present in 24% of patients. Mean duration of cardiopulmonary bypass was 119+/-37 minutes; 63% of patients received a transannular patch. There were six deaths (7%), all occurring less than 48 hours after repair. The median duration of stay in the intensive care unit was 5 days (range, 1 day to 8 months). Significant independent factors associated with increasing length of intensive care unit stay included younger age at repair, previous shunt, malformation syndrome, increased total dose and number of inotropic agents used, and respiratory complications. Hemodynamic variables serially recorded in the first 48 hours after repair were independently associated with death or prolonged (>7 days) duration of stay. CONCLUSIONS: Although outcomes after repair of tetralogy of Fallot in infants are good, both younger age at repair and previous palliative procedures were associated with longer duration of stay in the intensive care unit.

Age Factors↗
PubMed2000

Outcomes of left atrial isomerism over a 28-year period at a single institution.

OBJECTIVES: We determined long-term outcomes in a large cohort with left atrial isomerism (LAI). BACKGROUND: Left atrial isomerism is associated with a complex spectrum of cardiac and noncardiac anomalies that may impact on outcomes. METHODS: The records of all patients with LAI, born between 1970 and 1998, and treated at one center were reviewed. Kaplan-Meier survival was estimated, and independent factors associated with time-related death were identified. RESULTS: There were 163 patients (63% women), and extracardiac anomalies were noted in 36%, including biliary atresia in 10%. Cardiac defects included interrupted inferior caval vein in 92%, anomalous pulmonary veins in 56%, atrioventricular septal defect in 49%, pulmonary atresia or stenosis in 28% and aortic coarctation in 16%, with congenital atrioventricular block in 7%. Of 22 patients with a normal heart, 18% died of extracardiac anomalies. Of 71 patients with hearts suitable for biventricular repair, 62 (87%) had surgery, with survival of 80% at one year, 71% at five years, 66% at 10 years and 63% after 15 years. Of 70 patients with unbalanced cardiac defects suitable for single-ventricle palliation, 47 (67%) had surgery, with survival of 73% at one year, 61% at five years, 53% at 10 years and 48% at 15 years (p < 0.001). Independent factors associated with time-related death included congenital atrioventricular block, aortic coarctation, single ventricle, biliary atresia and other gastrointestinal malformations. CONCLUSIONS: Both cardiac and noncardiac anomalies contribute to a high mortality with LAI. Cardiac transplantation may need to be a considered a primary option for selected high-risk patients.

Abnormalities, Multiple↗
PubMed2000

A novel repair for patients with atrioventricular septal defect requiring reoperation for left atrioventricular valve regurgitation.

OBJECTIVE: Left atrioventricular valve regurgitation (LAVVR) is the most frequent indication for reoperation following atrioventricular septal defect (AVSD) repair. We estimate from our experience that within 10 years of initial repair, 14% of patients undergoing repair of atrioventricular septal defect (AVSD) require reoperation for this complication. We have developed a novel leaflet augmentation technique for LAVVR which may avoid failure of conventional repair and/or the need for valve replacement. METHOD: The novel technique consists of insertion of a glutaraldehyde-treated autologous pericardial patch to augment the bridging leaflets of the atrioventricular valve. We describe the outcome of eight patients in whom this technique was used and compared them to 68 other patients with AVSD undergoing reoperation for LAVVR by either conventional repair (n=54) or valve replacement (n=14). RESULTS: There were no early deaths or major complications following patch repair. The mean follow-up is 2.3 years (range 1-8.5 years) during which there were no late deaths. Two patients underwent reintervention at 3.5 and 5 years after patch repair for LAVVR and were successfully rerepaired. Mild residual LAVVR was seen at last echocardiography in six patients and mild to moderate in two. These results compare favorably with the 68 patients who underwent conventional surgery. The 3-year freedom from reoperation was 86% for both repair groups. Dysplastic valve tissue appears to be a major risk factor for failure of conventional repair or for valve replacement. Failure of conventional valve repair led to valve replacement in six of seven patients. CONCLUSIONS: For patients with late LAVVR after AVSD repair, pericardial leaflet augmentation is durable and may avoid failure of conventional repair or valve replacement in patients with dysplastic valves.

Adolescent↗
PubMed2000

A most peculiar coronary circulation in a patient with pulmonary atresia and intact ventricular septum.

A patient with pulmonary atresia and intact ventricular septum was found to have a right ventricular-dependent coronary circulation. In this infant both coronary arteries lacked their normal proximal connection with the aorta, perhaps the most egregious form of this prejudicial coronary circulation. Even more interesting was a direct collateral vessel originating from the descending thoracic aorta and connecting with the coronary circulation. This patient has undergone bilateral modified Blalock-Taussig shunts, and left ventricular function seems preserved.

Angiocardiography↗
PubMed2000

Non-invasive determination of the systolic peak-to-peak gradient in children with aortic stenosis: validation of a mathematical model.

Doppler derived systolic pressure gradients have become widely applied as noninvasively obtained estimates of the severity of aortic valvar stenosis. There is little correlation, however, between the Doppler derived peak instantaneous gradient and the peak-to-peak gradient obtained at catheterisation, the latter being the most applied variable to determine severity in children. The purpose of this study was to validate a mathematical model based on data from catheterisation which estimates the peak-to-peak gradient from variables which can be obtained by noninvasive means (Doppler derived mean gradient and pulse pressure), according to the formula: peak-to-peak systolic gradient = 6.02+/-1.49*(mean gradient)-0.44*(pulse pressure). Simultaneous cardiac catheterization and Doppler studies were performed on 10 patients with congenital aortic valvar stenosis. Correlations between the gradients measured at catheter measured, and those derived by Doppler, were performed using linear regression analysis. The mean gradients correlated well (y = 0.67 x +11.11, r = 0.87, SEE = 6 mm Hg, p = 0.001). The gradients predicted by the formula also correlated well with the peak-to-peak gradients measured at catheter (y = 0.66 x +14.44, r = 0.84, SEE = 9 mm Hg, p = 0.002). The data support the application of the model, allowing noninvasive prediction of the peak-to-peak gradient across the aortic valvar stenosis.

Adolescent↗
PubMed2000

Outcomes for children with cardiomyopathy awaiting transplantation.

OBJECTIVE: To determine factors associated with outcomes after listing for transplantation in children with cardiomyopathies. BACKGROUND: Childhood cardiomyopathies form a heterogeneous group of diseases, and in many, the prognosis is poor, irrespective of the etiology. When profound heart failure develops, cardiac transplantation can be the only viable option for survival. METHODS: We included all children with cardiomyopathy listed for transplantation between 12/89 and 4/98 in this historical cohort study. RESULTS: We listed 31 patients, 15 male and 16 female, 27 with dilated and 4 with restrictive cardiomyopathy, for transplantation. The median age at listing was 5.7 years, with a range from fetal life to 17.8 years. Transplantation was achieved in 23 (74%), with a median interval from listing of 54 days, and a range from zero to 11.4 years. Of the patients, 14 were transplanted within 30 days of listing. Five patients (16%) died before transplantation. Within the Canadian algorithm, one of these was in the third state, and four in the fourth state. One patient was removed from the list after 12 days, having recovered from myocarditis, and two remain waiting transplantation after intervals of 121 and 476 days, respectively. Patients who died were more likely to be female (5/5 vs. 11/26; p=0.04) and to have been in the third or fourth states at listing (5/5 vs. 15/26; p=0.04). The use of mechanical ventricular assistance, in 10 patients, was not a predictor of an adverse outcome. While not statistically significant, survival to transplantation was associated with treatment using inhibitors of angiotensin converting enzyme, less mitral regurgitation, a higher mean ejection fraction and cardiac index, and lower right ventricular systolic pressure. CONCLUSIONS: Children with cardiomyopathy awaiting transplantation have a mortality of 16% related to their clinical state at the time of listing.

Adolescent↗