Biomedical subjects
Publications and source records attributed to V R Zales.
We report the case of a child with hypoplastic left heart syndrome who developed pulmonary arteriovenous (AV) malformations after superior cavopulmonary anastomoses. Resolution of the pulmonary AV malformations occurred following a completion Fontan procedure. This phenomenon has been reported previously, but only in patients with heterotaxy and polysplenia.
A rare case of truncus arteriosus associated with mitral valve atresia, hypoplastic left ventricle, and intact ventricular septum is reported. Successful medical management and surgical palliation of this defect is described. The possible embryology, pertinent hemodynamics, and clinical concerns with this unusual case are discussed.
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Pediatric coronary artery bypass has been done mostly for ischemic complications of Kawasaki disease. We reviewed our clinical experience between 1987 and 1994 with internal thoracic artery-coronary artery bypass in one infant and five children for varying indications. Indications for coronary bypass included Kawasaki disease (2), congenital left main coronary ostial stenosis, iatrogenic coronary cameral fistula, anomalous origin of the left coronary artery from the pulmonary artery, and single coronary artery traversing between the great arteries in a patient after cardiac transplantation. An additional cohort of 34 control patients of various ages and weights (1 day to 16.1 years, 2.6 kg to 62 kg) had angiographic measurements of the right coronary, left coronary, and left internal thoracic arteries with respect to the feasibility of performing coronary artery bypass. All six patients survived internal thoracic artery-left anterior descending coronary artery bypass without evidence of perioperative myocardial infarction. Postoperative angiographic studies in five and color Doppler echocardiography in one showed graft patency. Retrospective angiographic measurements in the 34 control patients showed that internal thoracic and coronary arteries are proportionately quite large in neonates and infants compared with those in older children and adolescents. Internal thoracic artery-coronary artery bypass should be considered for the expanding indications presented herein and when emergency intraoperative life-threatening situations present themselves. Long-term patency and reoperation rates have yet to be determined.
BACKGROUND: Ultrasonographic tissue characterization is the assessment of physical properties of biologic tissue on the basis of quantitative analysis of its acoustic characteristics. Abnormalities in microscopic structure that occur with cardiac allograft rejection may result in characteristic alterations in myocardial acoustics. Ultrasonographic tissue characterization may allow noninvasive detection of rejection. METHODS: Findings in 22 pediatric heart transplant patients undergoing routine surveillance for rejection by endomyocardial biopsy were prospectively evaluated. Off-line ultrasonographic tissue characterization analysis was done on transthoracic echocardiograms obtained at each biopsy. Within patients, tissue characterization texture measures derived from the ultrasonographic image data were compared with histologic findings. Univariate multiple regression analysis was used to identify texture measures associated with acute allograft rejection in a subgroup (n = 8) with at least one biopsy-proven episode of moderate rejection. RESULTS: Measures of homogeneity (co-occurrence matrix correlation and heterogeneity (run-length nonuniformity) decreased with moderate rejection (p < 0.03). Homogeneity measures decreased if the patient had a previous episode of rejection. Several measures of heterogeneity (gray level difference and run-length statistics) were affected by the presence of edema. Run-length nonuniformity was the only measure that differentiated moderate rejection from edema. Discriminant analysis on all 22 patients correctly identified 96% of first rejection episodes (sensitivity 80%, specificity 64%), 93% of moderate and severe rejection episodes (sensitivity 71%; specificity 62%), and 69% of all rejection episodes (sensitivity 51%, specificity 91%). CONCLUSIONS: Histologic changes associated with moderate and severe pediatric allograft rejection as reflected by characteristic alterations in myocardial acoustics can be assessed with ultrasonographic tissue characterization. Histologic changes associated with transplantation itself (resolution of rejection and edema) also affect myocardial acoustics and must be taken into account in rejection surveillance.
BACKGROUND: The first successful surgical repair of coarctation of the aorta (CoAo) was performed in 1944, but during the years that followed a high incidence of recoarctation was seen, ranging from 20% to 86%. In response to that problem, the patch aortoplasty was introduced in 1957; however, true aneurysms were found in the aortic wall opposite the patch after Dacron patch aortoplasty, particularly when the coarctation ridge was excised. The purpose of our review was to evaluate the results of patch aortoplasty for CoAo using a relatively new material, polytetrafluoroethylene (PTFE), and an operative technique that does not involve resection of the coarctation ridge. METHODS AND RESULTS: Between 1979 and 1993, 125 infants and children underwent PTFE patch aortoplasty for CoAo; 111 of the procedures were primary repairs, and 14 were reoperations. Diagnoses were isolated CoAo (96 patients), CoAo and ventricular septal defect (15 patients), and CoAo with complex intracardiac anomaly (14 patients). Patient age at the time of repair ranged from 4 days to 17 years (mean age, 5.1 +/- 4.5 years). There were no instances of intraoperative mortality or paraplegia. There were 4 deaths from 10 to 40 days postoperatively, all in neonates (mean age, 33 days) who received additional intracardiac procedures for complex associated anomalies. Follow-up has ranged from 6 months to 12.5 years (mean, 4.5 +/- 3.2 years). All children had postoperative chest roentgenograms, 80 (66%) patients have had a postoperative echocardiogram and 16 (13%) a cardiac catheterization. One patient had successful repair of a false aneurysm 4 months postoperatively. No patient has developed a late true aneurysm. Of the patients < 1 month of age at the time of CoAo repair (12 patients), 6 patients had recurrent CoAo (gradient > 20 mm Hg) compared with only 4 recurrences in 97 patients > 1 month of age at the time of repair (P < .001). CONCLUSIONS: For children > 1 year of age, PTFE patch aortoplasty remains our procedure of choice for CoAo repair because of the low mortality rate, low recoarctation rate, and absence of late true aneurysms. We have stopped using this technique for infants < 1 month of age because of the high recurrence rate.
This report describes a child with tetralogy of Fallot and acquired pulmonary valve atresia in whom the pulmonary blood flow was provided solely by retrograde flow from an anomalous right coronary artery originating from the main pulmonary artery. Complete repair with preservation of the native pulmonary valve and implantation of the right coronary artery into the ascending aorta is described.
BACKGROUND: Between 1983 and 1994, 115 infants and children underwent repair of a complete atrioventricular canal defect with the two-patch technique and routine mitral valve "cleft" closure. METHODS: A retrospective review of these 115 patients was performed. Age at the time of repair ranged from 1 month to 108 months (mean age, 14.2 +/- 16.5 months; median age, 8 months). Preoperative cardiac catheterization in 113 patients revealed a mean pulmonary to systemic flow ratio of 3.37 +/- 1.8, a mean pulmonary artery systolic pressure of 71.1 +/- 15.7 mm Hg, and a mean pulmonary vascular resistance of 4.9 +/- 3.3 units. Associated anomalies included Down's syndrome (99 patients), patent ductus arteriosus (47), and coarctation of the aorta (4). Rastelli classification was A (76 patients), B (10), C (24), and unknown (5). Twenty-four patients had intraoperative epicardial or transesophageal echocardiography. RESULTS: Although there was a trend toward increasing mean preoperative pulmonary vascular resistance with age from 2.1 +/- 0.9 units (0 to 3 months) to 4.0 +/- 2.6 units (4 to 6 months) to 5.7 +/- 3.0 units (7 to 12 months), the mean pulmonary vascular resistance of each age group was not significantly different from that of the main group. The operative survival rate was 94% (seven early deaths) and the overall survival rate, 91% (three late deaths). Intraoperative echocardiography altered the surgical therapy for 1 patient. No patient has required reoperation for a residual ventricular septal defect. Four patients (3.5%) had heart block requiring permanent pacemakers. Eight patients (7%) required reoperation for mitral insufficiency; 6 of whom had successful repair of a residual cleft. CONCLUSIONS: For infants with complete atrioventricular canal defect, repair using the two-patch technique with routine mitral valve cleft closure at 4 to 6 months of age results in a low operative mortality, a low incidence of permanent heart block, and a low reoperation rate for mitral insufficiency.
BACKGROUND: Endothelium-derived nitric oxide (NO) is a potent vasodilator and a major mediator of pulmonary vascular tone. METHODS: Five infants underwent a trial of inhaled NO with hemodynamic monitoring in the operating room after atrioventricular canal repair. An additional 15 patients with congenital heart disease and refractory pulmonary hypertension were treated with inhaled NO for 1 day to 10 days postoperatively. RESULTS: In the 5 infants with atrioventricular canal, corrective surgical intervention and conventional therapy (hyperventilation, inspired oxygen fraction of 0.80, and inotropic agents) lowered mean pulmonary artery pressure from 49.5 +/- 10.5 to 20.0 +/- 2.2 mm Hg (p < 0.001). Adding inhaled NO further decreased mean pulmonary artery pressure to 18.0 +/- 2.8 mm Hg (p = not significant). Inhaled NO had no effect on ventricular function curves (inflow occlusion) in this group. In the 15 patients with refractory postoperative pulmonary hypertension, 11 had a favorable response to inhaled NO, with a decrease in mean pulmonary artery pressure from 30.9 +/- 5.8 to 23.1 +/- 5.4 mm Hg (p < 0.01) in 8 patients with pulmonary artery catheters. CONCLUSIONS: These studies demonstrate that inhaled NO has minimal beneficial effect on pulmonary artery pressure or cardiac output in infants after repair of atrioventricular canal. Inhaled NO is effective in decreasing PAP postoperatively in select patients with congenital heart disease and pulmonary hypertension refractory to conventional therapeutic modalities.
OBJECTIVES: The aim of this study was to retrospectively evaluate the sensitivity of noninvasive surveillance (physical examination, echocardiography) of rejection in accurately predicting histologically documented rejection episodes. Additionally, the usefulness of routine scheduled biopsy and its safety in pediatric patients was explored. BACKGROUND: Endomyocardial biopsy has been utilized as the standard for rejection surveillance after heart transplantation in adults, but its role in documenting clinically suspected rejection and in routine surveillance of pediatric patients has not been agreed upon. METHODS: Heart transplantation was performed in 14 neonates and 21 children. The immunosuppressive regimen consisted of cyclosporine, azathioprine and prednisone. All patients underwent routine noninvasive rejection surveillance that included clinical examination and echocardiography. In the neonates, biopsy was performed quarterly beginning 6 months after transplantation, after cessation of prednisone therapy. In the children, biopsy was performed 15 times in the 1st year. A minimum of five biopsy samples were interpreted using the Working Formulation for Heart Transplant Rejection. RESULTS: In the neonates, 37 biopsies were performed. Evidence of rejection was present in only three biopsy samples obtained during eight episodes (38%) of clinically suspected rejection. In 29 biopsies performed when rejection was not clinically suspected, each biopsy was free of cellular infiltrate. In the children, 291 biopsies were performed. Evidence of rejection was present in only seven biopsies (41%) from 17 episodes of clinically suspected rejection. Cellular rejection was discovered during routine rejection surveillance biopsies in asymptomatic patients in 23 (8.4%) of 274 biopsies. CONCLUSIONS: In neonates with clinically suspected rejection, endomyocardial biopsy identified which patients did not require rejection therapy. Endomyocardial biopsy surveillance did not detect any unsuspected cases of rejection. In children, noninvasive rejection surveillance was less reliable even in asymptomatic patients, suggesting that periodic endomyocardial biopsy should be utilized.
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BACKGROUND: Accelerated coronary atherosclerosis after heart transplantation (TCAD) is a major cause of late death. It is progressive and eventually fatal, and currently no therapy exists. The purpose of this study was to determine the incidence as well as the clinical and age-dependent characteristics of pediatric patients with TCAD. METHODS AND RESULTS: Pediatric heart transplantation centers were surveyed on patient outcome and incidence of TCAD from August 1974 to March 1993. A follow-up questionnaire was sent to examine patient-specific details, including age at transplantation and at death, time to diagnosis, and rejection history. Data on coronary angiography and autopsy findings were requested. Replies were received from 17 US centers that performed 815 pediatric heart transplantations (including 188 neonates), with 560 survivors (69%). TCAD was identified in 58 patients (7.3%) by either coronary angiography, autopsy, or both. Detailed data were available for 45 patients. The mean age at diagnosis of TCAD was 9.9 years (0.2 to 26 years), and mean posttransplantation time was 2.2 years (0.1 to 7.7 years). TCAD occurred in 16 patients who received transplants before age 2 years. Many deaths were sudden and unexpected. Only 9 of 58 patients are alive, including 5 who had a second transplant. Four or more treated cellular rejection episodes and one or more courses of monoclonal antibody were used in 60% of patients with TCAD. Angiography was performed in 45 and was normal in 15 patients who later died of TCAD. An autopsy, performed in 36 of the 49 who died, showed severe coronary stenosis in 28 (78%) and concurrent cellular rejection in 26 (72%). CONCLUSIONS: TCAD is a serious problem in transplant recipients and may affect patients of any age, even neonates. Diagnosis is difficult, and incidence of TCAD may be under-estimated. TCAD appears to be associated with cellular rejection; thus, higher surveillance in patients with frequent rejection episodes is indicated. Better surveillance methods, such as intravascular ultrasound and quantitative analysis of angiographic data, are needed to improve detection and assess new treatment strategies.
BACKGROUND: The adaptive growth of the transplanted heart within the growing child may contribute to long-term cardiac performance. The ability to achieve increased ventricular volume and appropriate muscle mass in the face of immunosuppression and cardiac denervation has not been studied. We previously reported normal left ventricular (LV) volume growth over a 3-year period after cardiac transplantation. This study was designed to assess changes in LV mass and mass/volume ratio and their relation to LV end-diastolic pressure (LVEDP) 1 to 4 years after cardiac transplantation. METHODS AND RESULTS: Cardiac transplantation was performed in 18 patients, age 7 days to 18 years (median, 3.7 years). The indications for cardiac transplantation were cardiomyopathy (8 patients), hypoplastic left heart syndrome (7 patients), and postoperative structural congenital heart disease with ventricular failure (3 patients). The mean follow-up was 48 months, with a range from 29 to 70 months. Serial annual catheterizations were performed after 1 year (16 patients), 2 years (18 patients), 3 years (15 patients), and 4 years (8 patients). Cardiac index (Fick), LVEDP (baseline and after 10-mL/kg saline infusion delivered over 5 minutes), and systemic vascular resistance (SVR) were measured. LV diastolic volume index (LVDVI), LV mass index, and mass/volume ratio were determined angiographically according to the method of Lange and Rackley. The data were analyzed by repeated-measures ANOVA. Least-squares means and group SEM were calculated. No change in cardiac index, SVR, or baseline LVEDP was noted. The LVEDP doubled after fluid challenge, suggesting a restrictive process. The LVDVI remained near 60 mL/m2. The LV mass/volume ratio remained one. CONCLUSIONS: Appropriate increases in muscle mass occurred after cardiac transplantation, preserving normal mass/volume ratios despite somatic growth deficits associated with immunosuppressive therapy and denervation of the donor heart.
Between 1989 and 1991, 17 children underwent 18 right ventricle-to-pulmonary artery conduit placement operations using a composite of an aortic or pulmonary valved homograft and a Hemashield extension to the ventricle. Hemashield is a collagen-coated knitted Dacron graft with excellent compliance and hemostatic properties. Diagnoses included tetralogy of Fallot with pulmonary atresia (7), truncus arteriosus (6), and complex transposition of the great arteries (4). Mean age at conduit placement was 4.9 +/- 4.2 years, and all patients survived. At a mean follow-up of 14 +/- 4 months, postoperative Doppler echocardiographic gradients between the ventricle and pulmonary artery ranged from less than 20 to 60 mm Hg. At cardiac catheterization 13 +/- 3 months postoperatively (6 patients), the systolic pressure gradient across the conduits ranged from 14 to 90 mm Hg (mean gradient, 59 +/- 29 mm Hg). Conduit obstruction, when present, was demonstrated angiographically to be in the Hemashield portion and led to early conduit replacement six times in 5 patients (33% of operations) within 10 to 18 months (mean time, 14 months) after insertion of the original conduit. Pathologic examination of the explanted conduits revealed the obstruction to be a thick neointimal peel that was impossible to separate from the Hemashield graft. Failure of the Hemashield as an extension for ventricle-to-pulmonary artery conduits secondary to accelerated neointimal formation has led us to abandon its use in clinical practice.
Historically, indications for ventricular septal defect closure have included congestive heart failure, pulmonary hypertension, aortic insufficiency with or without aortic valve prolapse, and prior bacterial endocarditis. However, controversy exists as to how the lifetime risk of an isolated, nonoperated restrictive ventricular septal defect compares with the risk of surgical closure in an asymptomatic child. Between 1980 and 1991, cardiac catheterization and elective ventricular septal defect closure (age > 1 year, pulmonary to systemic flow ratio < 2.0) were performed in 141 patients aged 1 to 23 years (mean age, 6.1 +/- 4.7 years). Mean systolic pulmonary artery pressure was 26.9 +/- 13.0 mm Hg, and mean pulmonary to systemic flow ratio was 1.6 +/- 0.3. Aortic valve prolapse was present in 63 patients (45%), aortic insufficiency was present in 25 (18%), and 5 (3.5%) had prior bacterial endocarditis. There were no early or late deaths or major morbidity. No patient required a ventriculotomy to accomplish ventricular septal defect closure. Mean postoperative intensive care unit stay was 1.3 +/- 0.9 days, and mean hospital stay was 5.5 +/- 1.9 days. There were no instances of permanent complete atrioventricular dissociation, reoperations for bleeding, postoperative wound infections, or reoperations for residual or recurrent ventricular septal defect. These improved results justify a reevaluation of historic indications for ventricular septal defect closure.(ABSTRACT TRUNCATED AT 250 WORDS)
We describe two patients with acute myocarditis temporally associated with an acute Shigella sonnei gastroenteritis. This association has not been described in children and should be considered in children with shigellosis who do not respond to rehydration therapies.
Since the advent of cyclosporine A, cardiac transplantation has been offered routinely for adolescents and children with cardiomyopathy refractory to medical management. Recently, cardiac transplantation has been offered to neonates with severe structural congenital heart disease. This article reviews the indications, pretransplant evaluation, and post-transplant management of neonates and infants undergoing cardiac transplantation.
BACKGROUND: Transplant coronary artery disease (CAD) is characterized by severe myointimal proliferation causing vascular stenosis. Nontransplant vascular injury models have shown that angiotensin converting enzyme (ACE) inhibitors reduce myointimal proliferation and preserve lumen integrity. We examined the effect of the ACE inhibitor captopril on graft CAD in a Lewis to F344 rat heterotopic cardiac transplantation model. METHODS AND RESULTS: Twenty-five control rats (group 1) were observed without captopril administration after heterotopic cardiac transplantation, and the other 19 rats (group 2) were administered captopril (50 mg/kg per day in drinking water) after heart transplantation. Graft survival 3 months after transplantation was significantly (P < .02) higher in group 2 (18 of 19, 95%) than that in group 1 (16 of 25, 64%). Cellular rejection grades of the heart allografts were significantly higher in group 1 than those in group 2 both at 3 months (grades, 2.5 +/- 0.4 vs 1.3 +/- 0.7; P < .01) and 6 months (grades, 2.4 +/- 0.9 vs 0.8 +/- 0.5; P < .05) after transplantation. The grades of graft CAD (vascular rejection) were also significantly higher in group 1 than those in group 2 both at 3 months (grades, 2.3 +/- 0.7 vs 0.9 +/- 0.9; P < .05) and 6 months (grades, 3.0 +/- 0.9 vs 0.9 +/- 0.3; P < .01) after transplantation. The cardiac allographs in group 2 showed minimal intimal proliferation, intact elastic laminae, and reduced smooth muscle cell proliferation. CONCLUSIONS: These results suggest that the ACE inhibitor captopril may be effective in prevention of accelerated graft CAD.