Biomedical subjects
Publications and source records attributed to R M Freedom.
Many hearts, although considered morphologically biventricular, may not be candidates for a biventricular repair. Such patients are best placed on a Fontan algorithm. This article reviews in broad principles those hearts that, despite being biventricular, do not lend themselves to a two-ventricle repair.
BACKGROUND: Recent reports have cited improving results for surgical management of isolated total anomalous pulmonary venous drainage. Complex cases (with other cardiac anomalies) are less frequently reported and are associated with higher mortality. METHODS: Retrospective review identified 170 consecutive patients treated for total anomalous pulmonary venous drainage from 1982 to 1996: 44 cases were "complex" (with significant associated cardiac lesions) and 126 cases were "simple." RESULTS: Operative mortality for simple cases decreased from 26% to 8%, and mortality for complex cases remained constant at 52%. Age, size, and the presence of atrial isomerism were univariate predictors of mortality. Multivariable analysis identified only univentricular hearts and associated cardiac lesions as predictors of operative mortality. Pulmonary artery (n = 16) and arteriopulmonary (n = 7) shunting strategies for complex cases resulted in less than 30% long-term survival. CONCLUSIONS: Despite improvement in survival for simple cases, management of total anomalous pulmonary venous drainage with single-ventricle hearts or other associated cardiac lesions remains problematic.
BACKGROUND: Progressive stenosis of the pulmonary veins after repair of total anomalous pulmonary venous drainage is frequently refractory to surgical therapy. METHODS: Retrospective review of 170 consecutive patients treated for total anomalous pulmonary venous drainage identified 13 patients with postrepair pulmonary vein stenosis. Preoperative and operative data were analyzed to define the patterns of progression and efficacy of surgical techniques. RESULTS: Seventeen reoperations were performed in 13 patients. Postrepair pulmonary vein stenosis was most common in the infracardiac and mixed subtypes (p < 0.02). All 4 patients with unilateral stenosis, 2 of whom had progression of stenosis resulting in nearly complete unilateral pulmonary vein occlusion, survived. Six of 9 patients with bilateral disease died (p < 0.05 versus unilateral); 2 of the 3 survivors were repaired with a novel technique creating a sutureless neoatrium without evidence of restenosis at 1.8 years' follow-up. Stenting was uniformly unsuccessful. CONCLUSIONS: In unilateral stenosis, progression of disease may be survivable with loss of single-lung perfusion. Although bilateral disease is lethal in most cases, creation of a sutureless neoatrium has demonstrated short-term freedom from disease progression.
OBJECTIVES: The purpose of this study was to determine the incidence, risk factors, and outcomes of acquired stenosis of the neopulmonary valve after the neonatal arterial switch operation. METHODS: Reviewed were the preoperative and follow-up echocardiograms from 136 of 288 patients undergoing the arterial switch operation for whom adequate studies were available. Pulmonary stenosis was defined as a thickened and doming pulmonary valve and a pressure gradient of 20 mm Hg or more. Transposition of the great arteries was present with intact ventricular septum in 91 patients, with a ventricular septal detect in 39, with an aortic coarctation in 5, and with double-outlet right ventricle in 1 patient. No patient had preoperative valvular abnormalities (i.e., a bicuspid valve). RESULTS: During a median follow-up of 18 months (range <1 to 90 months), 32 patients (24%) had the development of supravalvular pulmonary stenosis, 15 (11%) with associated pulmonary valve stenosis (group I). Kaplan-Meier estimates of freedom from any intervention were 94% (95% confidence interval, 90% to 99%) at 1 year and 79% (95% confidence interval, 64% to 94%) at 5 years. The valve anulus before the arterial switch operation was significantly larger (p < 0.03) in those in whom neopulmonary valve stenosis did not develop (group II) than it was in those in whom it did (group I). At follow-up, the pulmonary valve anulus had decreased significantly in diameter in group I (p < 0.0005) and had remained larger in group II (p = 0.06) compared with normal diameter. Group I patients had the development of significant pulmonary valve hypoplasia (p < 0.03) whereas group II patients continued to have significantly larger valves compared with normal size (p < 0.0001). CONCLUSIONS: Neopulmonary valve stenosis after the arterial switch operation is not uncommon and is associated with growth failure of the valve anulus often associated with supravalvular pulmonary stenosis.
OBJECTIVES: We sought to determine, in a large series of patients with right atrial isomerism, factors associated with mortality. BACKGROUND: Right atrial isomerism is associated with complex congenital heart disease and high morbidity and mortality. METHOD: All data from patients diagnosed with right atrial isomerism between January 1970 and March 1996 were reviewed. RESULTS: A total of 91 consecutive patients (54 male) were identified. Most patients (89%) presented within the first month of life, 62% at birth. Cardiac abnormalities included common atrioventricular (AV) valve (81%), ventricular hypoplasia or single ventricle (73%), abnormal ventriculoarterial connections (96%), pulmonary outflow tract obstruction (84%), anomalous pulmonary venous drainage (87%) and pulmonary vein obstruction (30%). The overall mortality rate was 69%. No interventions were planned or performed in 24%, 95% of whom died. The mortality rate for patients requiring their first cardiovascular operation in the neonatal period was 75% versus 51% for those with later first operations (p < 0.05). The surgical mortality rate for patients undergoing pulmonary vein repair was 95%. Overall survival estimates were 71% at 1 month, 49% at 1 year and 35% at 5 years. Independent risk factors for decreased time to death included the absence of pulmonary outflow obstruction (relative risk [RR] 2.23, p < 0.03), presence of major AV valve anomaly (RR 5.23, p < 0.03) and obstructed pulmonary veins (RR 5.43, p < 0.0001). CONCLUSIONS: Right atrial isomerism continues to have an associated high mortality despite surgical innovations. Management of pulmonary vein obstruction remains a serious problem and is associated with high mortality.
OBJECTIVES: To determine the prevalence of systemic venous collaterals after the bidirectional cavopulmonary anastomosis and the factors associated with their development. BACKGROUND: Systemic venous collaterals have been found after cavopulmonary anastomosis. Methods. Cardiac catheterization was performed in 103 patients before and after a bidirectional cavopulmonary anastomosis. RESULTS: After surgery, 51 venous collaterals were identified in 32 patients (31%). Collateral development was associated with an abnormal superior vena caval connection (56% incidence vs. 26% with a single right superior vena cava, p = 0.01) and postoperative factors including pulmonary artery distortion (53% incidence vs. 22% without distortion, p = 0.002); increased superior vena caval mean pressure (14 +/- 5 mm Hg versus 11 +/- 4 mm Hg with no collaterals, p = 0.0002); increased pulmonary artery mean pressure (13 +/- 4 mm Hg vs. 11 +/- 4 mm Hg with no collaterals, p = 0.02); lower right atrial mean pressure (5 +/- 2 mm Hg vs. 6 +/- 3 mm Hg with no collaterals, p = 0.04); and increased mean gradient between superior vena cava and right atrium (8 +/- 3 mm Hg vs. 5 +/- 4 mm Hg with no collaterals, p = 0.0002). Using multiple logistic regression, only this last factor was independently associated with collateral development with an odds ratio per 1 mm Hg of 1.33 (95% CI 1.12-1.58, p = 0.001) for their presence. CONCLUSIONS: Systemic venous collaterals occur frequently after a bidirectional cavopulmonary anastomosis and are found postoperatively when a significant pressure gradient occurs between cava and right atrium.
OBJECTIVES: We reviewed the factors contributing to or causing death before surgery in neonates with d-transposition of the great arteries (TGA) despite anatomy suitable for the arterial switch operation (ASO) to develop strategies to minimize preoperative attrition. BACKGROUND: Currently the ASO for neonates with TGA carries a low operative mortality. However, there is a paucity of information regarding the patients who die before the ASO. Strategies to ensure survival to operation are of importance to improve overall outcome. METHODS: We reviewed all neonates with TGA and patent forearm ovale (PFO) < or = 2 mm, a birthweight <2 kg, or who died before surgery, between 1988 and 1996. RESULTS: We identified 12 out of 295 neonates with TGA (4.1%) with anatomy suitable for the ASO who died prior to surgery. All had TGA/intact ventricular septum (IVS) and presented with a severely restrictive PFO. In 11 of 12 cases the cause of death was attributed to the sequelae of profound hypoxemia from inadequate mixing. Contributing factors were prematurity, 41.7%; severe respiratory distress syndrome, 25%; and persistent pulmonary hypertension of the newborn (PPHN), 16.7%. All patients received prostaglandin E1 (PGE1) infusion. Urgent balloon atrial sepstostomy (BAS) was performed in 66.7% with improved oxygenation. No cases were diagnosed prenatally. In contrast, all patients with a PFO < or = 2 mm who survived to ASO had a significantly better response to PGE1 infusion (p=0.03) than nonsurvivors. The ASO was accomplished without mortality in four of nine with a weight <2 kg. CONCLUSIONS: Of those neonates admitted with TGA, 4.1% died before surgery. Eleven of 12 (3.7%) died due to consequences of inadequate interatrial mixing despite PGE1 infusion. Earlier diagnosis and BAS are critically important in determining survival. Early ASO may improve survival in patients weighing <2 kg. Prenatal diagnosis with delivery in a high-risk obstetrical unit with facilities for immediate BAS and supportive therapy for pulmonary hypertension and ventricular failure may be necessary to salvage this group of patients.
OBJECTIVES: The aim of this study was to determine the relative risks of pediatric diagnostic, interventional and electrophysiologic catheterizations. BACKGROUND: The role of the pediatric catheterization laboratory has evolved in the last decade as a therapeutic modality, although remaining an important tool for anatomic and hemodynamic diagnosis. METHODS: A study of 4,952 consecutive pediatric catheterization procedures was undertaken. RESULTS: Patient ages ranged from 1 day to 20 years (median 2.9 years). One or more complications occurred in 436 studies (8.8%) and were classified as major in 102 and minor in 458, with vascular complications (n=189; 3.8% of procedures) the most common adverse event. Arrhythmic complications (n=24) were the most common major complication. Death occurred in seven cases (0.14%) as a direct complication of the procedure and was more common in infants (n=5). Independent risk factors for complications included a young patient age and undergoing an interventional procedure. CONCLUSIONS: Complications continue to be associated with pediatric cardiac catheterization. Efforts should be directed to improving equipment for flexibility and size, and finding alternative methods for vascular access. Patient age and interventional studies are risk factors for morbidity and mortality.
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UNLABELLED: Anomalous origin of one pulmonary artery from the ascending aorta is an uncommon lesion with an uncertain outcome. We reviewed 16 consecutive children (9 males) presenting with this lesion over a 36 year period at a single institution. Median age at presentation was 2 days (range, birth to 3.2 years). The anomalous pulmonary was the right in 12 and the left in 4, all originating from the proximal ascending aorta, with no patient having stenosis at the origin of the anomalous pulmonary artery. Associated cardiac anomalies were noted in 9 patients. No intervention was attempted in 2 patients: one was deemed inoperable due to complex associated lesions and pulmonary vascular obstructive disease, while the other one died before repair. Surgical intervention was attempted in 14 patients, with 3 intraoperative deaths (21%). Of 11 operative survivors, 8 developed pulmonary arterial stenosis graded severe in 2, moderate in 1 and mild in 5. Patients with severe stenosis required surgical angioplasty, 1 after unsuccessful dilation combined with placement of an endovascular stent. One patient with moderate, and one with mild, stenosis underwent successful transcatheter balloon dilation. The remaining 4 patients with mild stenosis remain unchanged during follow-up. One patient had biopsy evidence of pulmonary vascular obstructive disease at 3.3 years of age. There were no late deaths, giving a total mortality of 25% (4/16). CONCLUSION: While early diagnosis and repair of anomalous origin of one pulmonary artery from the ascending aorta is necessary, restenosis of the site of repair is common.
Persistent left superior vena cava (SVC) is a not uncommon finding in patients with congenital heart disease. This anatomical variant must be recognised before doing a Glenn anastomosis, bidirectional cavopulmonary connection or a Fontan-type procedure. Following these procedures, reopening of a left SVC leading to clinical cyanosis can occur. Five cases are described in whom persisting left SVCs were excluded before performing a bidirectional cavopulmonary connection or Fontan procedure but (re-)opened after surgery, leading to cyanosis either by reducing effective pulmonary blood flow (bidirectional cavopulmonary connection) or by an obligatory right to left shunt (Fontan). These observations suggest that, embryologically, the lumen of the left SVC obliterates rather than disappears. Balloon occlusion angiography of the innominate vein before cavopulmonary connections or Fontan procedures might improve detection of these collateral vessels.
BACKGROUND: Minimally invasive pediatric cardiac surgical techniques continue to evolve and remain challenged by technologic advances in percutaneous devices developed to treat congenital heart disease exclusive of cardiopulmonary bypass. Public tenacity for "incisionless" operations, however, must remain balanced scrupulously against the collective safety of the surgical procedure. METHODS: Twenty-three pediatric patients underwent repair of atrial septal defects through a partial sternal split and a limited skin incision (5 to 7 cm) at our institution between July 1995 and October 1996. RESULTS: The average age of the patients was 6 years and 2 months (range, 19 months to 15 years) and the average weight was 23.3 kg (range, 11.3 to 61.7 kg). The average bypass time was 35 minutes (range, 19 to 81 minutes). Fourteen patients had a single dose of blood cardioplegia administered, whereas 9 had ventricular fibrillation electrically induced. Twenty-two patients had ostium secundum defects and 1 had a sinus venosus defect. The average length of the hospital stay was 3.6 days (range, 3 to 6 days). There were no operative or late deaths. CONCLUSIONS: Modifications of this technique continue to evolve as an effective cosmetic alternative to submammary and thoracotomy approaches. Advantages of this modification include excellent cosmetic results in all age groups and the concomitant security and familiarity of mediastinal access and full sternotomy when required.
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BACKGROUND: Several perioperative risk factors influence outcomes after repair of complete atrioventricular septal defects. This study was conducted to determine their association with perioperative mortality and need for reoperation. METHOD AND RESULTS: Between July 1982 and February 1995, 363 children underwent defect repair (median age, 8.3 months; mean, 17.4+/-1.3). Tetralogy of Fallot was present in 21 patients, double-outlet right ventricle in 4, subaortic stenosis in 8, ventricular hypoplasia in 8, coarctation in 5, atrial isomerism in 2, and other congenital anomalies in 9. Down's syndrome was present in 235 (65%). One-patch technique was applied in 99, two-patch in 243. During repair, the anterior bridging leaflet was divided in 12, the posterior bridging leaflet in 31, both leaflets in 71, and neither in 249. Left atrioventricular valve (LAVV) cleft was closed partially in 181 and completely in 112. Early mortality was 10.5%; 10-year survival, 83% (95% confidence interval, 0.79 to 0.87). At 10 years, freedom from reoperation for LAVV repair was 86%; LAVV replacement, 90%; subaortic stenosis, 95%; residual ventricular septal defect, 97%; permanent pacemaker insertion, 98%; and other types of reoperation, 95%. At the time of operation, greater age, shorter ischemic time, absence of a double-orifice LAVV, and cleft closure were found to be significant independent predictors of survival. CONCLUSIONS: Repair of atrioventricular septal defects has acceptable early and late mortality and a low incidence of reoperation. Double-orifice LAVV remains a risk factor. Repairs that include complete cleft closure may confer better survival.
The clinical impact of transcatheter perforation and dilatation of the right ventricular outflow tract in neonates with pulmonary atresia and intact ventricular septum was reviewed. Between April 1992 and December 1994, 8 neonates underwent transcatheter perforation of the right ventricular outflow tract. Radiofrequency energy was employed in 6 patients and wire perforation in 2 patients. Mean patient age at intervention was 1.9 +/- 0.6 days and weight 3.4 +/- 0.5 kg. Median tricuspid valve annulus was 10.9 mm (range: 4.0-13.0 mm) and Z-value -0.85 (range: -4.5-1.0). The mean right ventricular systolic pressure fell from 117 +/- 16 to 55 +/- 15 mm Hg (P < 0.0001), and the right ventricular to aortic pressure ratio decreased from 1.81 +/- 0.33 to 0.82 +/- 0.28 (P < 0.0001). The arterial duct was patent in all. No acute complications occurred. Aortopulmonary shunts were performed in 7 patients at a median 6 days (range: 3-23 days) following catheterization. One patient developed sepsis and died after surgical resection of infected tissue, while a second patient died of a blocked aortopulmonary shunt 17 months following discharge. Median follow-up for the 6 surviving patients was 8 months (range: 4-32 months). One patient has achieved and a second is awaiting biventricular repair. Transcatheter perforation appears to be a promising form of therapy in selected patients with pulmonary atresia, and potentially facilitates algorithms leading to a biventricular repair.
An increase in the incidence of primary cardiac tumors has been reported since the development or enhancement of noninvasive imaging modalities. We identified 56 children with primary cardiac tumors. Forty-four (78%) children had rhabdomyomas, 6 (11%) fibromas, 1 (2%) pericardial teratoma, 1 (2%) epicardial lipoma, 1 (2%) multicystic hamartoma, and 3 (5%) unspecified tumors. The mean age at diagnosis was 19 +/- 35 months (median 4.7 months, range 0.03 to 204 months), excluding 12 patients who were given the diagnosis before birth. Among 27,640 patients assessed for cardiac disease, the incidence of tumors was 0.06% (1980 to 1984), 0.22% (1985 to 1989), and 0.32% (1990 to 1995). Diagnosis was made in 55 of 56 patients by echocardiography. Catheterization was performed in five patients and magnetic resonance imaging in nine. No tumor-related deaths occurred. Nine patients had surgery because of hemodynamically significant obstruction or arrhythmias. Partial or complete regression occurred in 24 (54%) of 44 patients with rhabdomyomas. Overall, the prognosis was excellent. Individualized surgery allowed early safe treatment of symptomatic tumors.
BACKGROUND: Children with pulmonary atresia and an intact ventricular septum show a heterogeneous spectrum of cardiac anomalies. A biventricular repair is attainable in some; a Fontan procedure or a one-and-a-half ventricle is the only possible repair for others. Children with right ventricle-to-coronary artery connections, with or without right ventricle-dependent coronary artery blood flow, are a high-risk group. METHODS: Between May 1980 and December 1994, 22 children underwent a Fontan operation for the treatment of pulmonary atresia with an intact ventricular septum at The Hospital for Sick Children, Toronto. The mean age was 5.8 years (median, 4.9 years). All children had had at least one pre-Fontan palliative procedure; 19 had two, and 7 of these had three or more. Right ventricle-to-coronary artery connections were present in 15 children, including 5 with right ventricle-dependent coronary artery blood flow. Thromboexclusion of the right ventricle was done in 10 children, with 7 undergoing it before and 3 at the time of the Fontan procedure. RESULTS: There were three early deaths (13.6%) and one late death. The actuarial survival at 10 years after the Fontan operation was 80%. Early postoperative complications occurred in 4 children. Follow-up was completed in all children at a mean of 4 years (range, 1 to 12.5 years) after the Fontan operation. Atrial arrhythmia occurred in 3 children, and permanent pacemakers were required in 4. CONCLUSIONS: Results of the Fontan operation for the treatment of pulmonary atresia with an intact ventricular septum are satisfactory. Thromboexclusion of the right ventricle is indicated in the presence of right ventricle-to-coronary artery connections without right ventricle-dependent coronary artery blood flow. The right ventricle should not be decompressed or thromboexcluded in children with right ventricle-dependent coronary artery blood flow, and at the Fontan operation, saturated blood must enter the right ventricle.
BACKGROUND: Pulmonary valve incompetence is usually well tolerated after tetralogy of Fallot repair but may result in late progressive right heart failure as manifested by increasing fatigue, dyspnea, and frequently arrhythmias. METHODS: All patients who underwent pulmonary valve replacement in our center late after repair of tetralogy of Fallot were reviewed. RESULTS: Eighty-five patients had elective pulmonary valve replacement late (median, 9.3 years) after repair. Operative risk was low (1.1%). Ninety percent of survivors are in New York Heart Association class I. Survival 10 years after pulmonary valve replacement is 95%, with 86% of the patients free of reoperation for valve failure. CONCLUSIONS: Pulmonary valve replacement is infrequently required after repair of tetralogy of Fallot. Pulmonary valve replacement may be performed electively with little risk; it improves symptoms of right heart failure and provides satisfactory long-term survival with low risk of early valve failure. As the population of patients who have had repair of tetralogy of Fallot ages, pulmonary valve replacement will become a more frequent consideration.