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Biomedical subjects

C E Canter

Publications and source records attributed to C E Canter.

At least 37 records · Page 2Linked to original sources

Recognition and management of nonpenetrating cardiac trauma in children.

OBJECTIVE: To characterize the evaluation and clinical course of children with nonpenetrating injury to the heart. METHODS: We reviewed the medical records for children admitted to St. Louis Children's Hospital between the years 1987 to 1992 with traumatic cardiac injury. Patients with penetrating trauma were excluded; eight children, ages 4 to 13 years, were the study subjects. Chest x-ray studies, electrocardiograms, and serum creatine kinase values were obtained on admission. Two-dimensional echocardiography was performed when indicated by unexplained hemodynamic instability or abnormal radiographic findings. RESULTS: All children with nonpenetrating cardiac trauma were involved in a motor vehicle accident. The principal cardiac diagnoses were ventricular septal defect (1), mitral regurgitation (1), pericardial effusion (2), contusion (3), and arrhythmia (1). Multisystem injury was present in each case, but cardiac injury was not suspected at the time of admission in seven of the eight patients. The hemodynamic status of four children was compromised 12 to 48 hours after admission; echocardiography was diagnostic in each instance, but the electrocardiogram and creatine kinase values were nonspecific. Two patients eventually required cardiac surgery. CONCLUSIONS: Recognition of blunt cardiac trauma in children may be confounded by associated multisystem injury and the delayed onset of clinical manifestations. Echocardiography is a sensitive diagnostic tool for hemodynamically significant disease, and should be performed promptly when patients have unexplained hypotension or diminished peripheral perfusion.

Accidents, Traffic↗

Echocardiographic characteristics of biopsy-proven cellular rejection in infant heart transplant recipients.

BACKGROUND: Echocardiography has been used as a primary means to detect cellular rejection in infant heart transplant recipients. There is, however, limited information correlating echocardiography and biopsy-proven rejection in this age group. METHODS: Between September 1989 and July 1994, 32 consecutive heart transplantations were done in infants younger than 20 months old, who were followed up for 2 to 58 months (mean 28 months) with concurrent endomyocardial biopsy and M-mode echocardiography with digitization. M-mode data from all 16 episodes of rejection (International Society for Heart and Lung Transplantation grade 3A or greater) that occurred in 12 grafts were compared with data from the same grafts with histologic resolution of rejection 2 weeks after treatment and with data from biopsy-proven nonrejecting control grafts matched for sex, time after transplantation, donor weight, and donor age. RESULTS: Left ventricular mass index increased in rejection (86 +/- 9 gm/m2) versus resolution (64 +/- 6 gm/m2) and versus that in nonrejecting control grafts (59 +/- 8 gm/m2). Left ventricular shortening fraction increased in rejection (40% +/- 2%) versus resolution (38% +/- 10%). Septal thickening fraction decreased in rejection (33% +/- 9%) versus nonrejection (68% +/- 16%). These changes became significant only in grafts transplanted more than 1 month before study. Substantial overlap of measurements prevented identification of threshold values. Intraobserver and interobserver variabilities for standard M-mode data were 7% to 8% and 12% to 22%, respectively, whereas those for digitized parameters were markedly elevated at 37% to 71% and 51% to 81%, respectively. CONCLUSIONS: We found (1) left ventricular mass index increases in cellular rejection but may be unreliable less than 1 month after transplantation and (2) significant interobserver and intraobserver variability may limit the applicability of digitized echo parameters to the detection of rejection in infant heart transplant recipients.

Acute Disease↗

Lung transplantation in infancy and early childhood.

BACKGROUND: Experience with lung transplantation in infants and young children is limited. Small size, vulnerability to infection, and limited modalities for rehabilitation and surveillance of the transplanted lung make this group particularly challenging. METHODS: We reviewed the course of all children up to the age of 25 months who underwent lung transplantation at two centers between July 1990 and February 1995. RESULTS: Lung transplantation was performed in 17 patients under the age of 25 months, with concurrent cardiac repair in 14. Prior thoracic surgery had been performed in 12; six patients had mechanical ventilation, and three were supported with extracorporeal membrane oxygenation while waiting for lungs. The mean waiting time was 37 days (range 1 to 197 days). Hospital survival was 12 of 17 (71%); there was one late death. Early deaths were due to hemorrhage (two patients), cytomegalovirus and lymphoproliferative disease (one patients), and viral pneumonitis (two patients). The one late death was due to overwhelming gastroenteritis of unknown origin. One additional patient had graft failure caused by viral pneumonitis and underwent successful retransplantation. Bronchial stenosis occurred at 3 of 33 anastomoses. At a mean follow-up of 22 months, surviving patients were well, without supplemental oxygen, and, although small in stature, had normal linear growth. CONCLUSIONS: Lung transplantation is a reasonable therapy for very young patients with limited life expectancy and no other therapeutic alternative, with outcomes comparable with those achieved in older patients. Early recognition of lung transplant candidates and advances in the prevention, diagnosis, and treatment of viral illness may improve survival in these patients.

Actuarial Analysis↗

Infant and donor organ growth after heart transplantation in neonates with hypoplastic left heart syndrome.

BACKGROUND: There is little published data regarding somatic growth and changes in allograft size after heart transplantation in infants with hypoplastic left heart syndrome. METHODS: We evaluated the somatic growth of 26 infants with hypoplastic left heart syndrome who underwent heart transplantation over a 5-year period and measured changes in left ventricular dimensions in 22 of those infants. Age at transplantation was 27 +/- 17 days (mean +/- standard deviation), and the follow-up period was 43 +/- 14 months. Growth and echocardiographic data were converted to standard deviation (Z) scores for comparison with normal populations. RESULTS: Height and weight were always within normal limits (two standard deviations), with a trend toward smaller size throughout the follow-up period. The somatic growth of infants on low-dose maintenance steroids was not significantly different from that of infants withdrawn from chronic steroid regimens. Initial left ventricular posterior wall and septal dimensions were greater than two standard deviations (+4.3 and +6, respectively), probably the result of routine use of oversized donors, but the dimensions decreased to within the normal range during the first year. They then remained within normal limits during follow-up. With one exception at 2 years after transplantation, left ventricular diastolic dimensions were always within two standard deviations of the mean. Left ventricular dimensions of patients with hypertension, rejection, or acute graft failure were not significantly different from patients without these complications. CONCLUSIONS: Neonates with hypoplastic left heart syndrome who undergo heart transplantation can be expected to have somatic growth within normal limits. However, the trend toward growth retardation is worrisome. Left ventricular wall dimensions adjust to smaller recipient size during the first year after transplantation and then remain appropriate for the recipient's size over time.

Analysis of Variance↗

Lung transplantation in children and young adults with cardiovascular disease.

Single or bilateral lung transplantation was performed in 20 patients with pulmonary hypertension or an inadequate pulmonary vascular bed; all but 1 had congenital heart disease. The average age was 6.3 years (range, 3 months to 23.9 years). All were in New York Heart Association class IV, and 6 were hospitalized and receiving intensive support before transplantation. Hospital survival was 70% (14/20), with three additional deaths at 7, 11, and 27 months. A prior thoracic operation contributed to three of six hospital deaths from hemorrhage. All late deaths were due directly or indirectly to obliterative bronchiolitis. At a mean follow-up of 19 months (range, 2 to 48 months), 10 of 11 survivors are in New York Heart Association class I. Survival after hospital discharge and incidence of obliterative bronchiolitis are similar in a contemporary group of 41 patients of comparable age who underwent lung transplantation for pulmonary disease (p = not significant). Single or bilateral lung transplantation is an acceptable therapy for children with pulmonary hypertension, congenital heart disease, or both. Further investigation in the areas of pretransplantation survival, operative risk factors, and long-term outcome of single-lung recipients and recipients with hemodynamically insignificant intracardiac lesions are needed to develop optimal decision-making strategies for these patients.

Adolescent↗

Comparison of ventricular mass and function in early versus late repair of coarctation of the aorta.

Left ventricular (LV) mass and function in 11 patients (group I) with coarctation of the aorta repaired at a mean age of 35 days were compared with that of 14 patients (group II) who underwent repair at a mean age of 8 years. Each group was compared to age- and sex-matched normal control subjects. All patients were normotensive and had resting arm-leg peak systolic blood pressure gradients < 20 mm Hg. Quantitative M-mode echocardiography was used to determine LV mass index and systolic performance. Magnetic resonance imaging was performed to assess residual narrowing of the descending aorta. LV mass index was increased in both groups when compared with control subjects (group I p = 0.01; group II p = 0.007). Whereas systolic performance in group I was similar to its control group, group II patients had enhanced LV systolic performance as measured by shortening fraction (p = 0.007). Multiple regression analysis of combined group I and II patients demonstrated a significant positive correlation of residual aortic narrowing with LV mass index (p = 0.01). Thus, LV mass remains increased in normotensive patients without major blood pressure gradients after repair of coarctation of the aorta in infancy or childhood. Small degrees of residual aortic narrowing were associated with increased postoperative LV mass regardless of the age at repair.

Adolescent↗

Predictors of operative mortality and morbidity after infant heart transplantation.

We retrospectively analyzed the impact of recipient, donor, and operative factors on the operative mortality and morbidity of 36 consecutive infant heart transplantations. Operative survival was excellent at 94%. Among 34 survivors, operative morbidity in 12 patients included acute severe allograft failure with or without prolonged ventilatory support. The cohort was characterized by age less than 4 months (32 of 36), a diagnosis of hypoplastic left heart syndrome (29 of 36), and the use of circulatory arrest (27 of 36); these variables were colinear and could not be used to predict operative mortality or morbidity. None of the remaining recipient, donor, or operative characteristics predicted survival or acute severe allograft failure. A donor-to-recipient weight ratio greater than 2 and a circulatory arrest time greater than 39 minutes predicted the need for prolonged ventilatory support. Despite the need for aggressive or prolonged support after 12 of 36 transplantations, operative survival was high at 94% (34 of 36 procedures, 32 of 34 patients). The use of less restrictive donor criteria combined with aggressive management of acute allograft failure can result in excellent operative survival after infant heart transplantation.

Female↗

Early results after pediatric cardiac transplantation with triple immunosuppression therapy.

Pediatric heart transplant recipients were previously reported to have higher early mortality and morbidity than do adult patients treated with triple immunosuppression therapy (steroids, azathioprine and cyclosporine). Nineteen patients (11 infants and 8 older children) underwent orthotopic transplantation using triple immunosuppression therapy. Surveillance for cellular rejection and coronary arteriopathy was performed with endomyocardial biopsy and selective coronary angiography in all patients, with continuous monitoring for hypertension and serious infection. Seventeen of 19 patients (89%; 10 infants and 7 older children) are current survivors, with a median follow-up of 29 months (range 17 to 94). There were 5 and 7 episodes of rejection in the first 12 months after transplantation in the infant and older groups, respectively, for actuarial freedom-from-rejection rates of 65% at 3 months and 54% at 12 months. Severe coronary arteriopathy was detected in 1 infant 11 months after transplantation. In the first 12 months after transplantation, there were 3 hospitalizations for infection, and 2 patients needed treatment for hypertension in the infant group, compared with 1 hospitalization for infection, and 4 patients on antihypertensives in the older group. An increased prevalence of noninfectious complications in the infant group led to significantly longer postoperative stays than in the older group (mean 27.3 vs 19.4 days; p < 0.05). The results indicate that cardiac transplantation using triple immunosuppression therapy in infants, children and adolescents is associated with a high survival rate, and low rates of rejection and serious infection.

Actuarial Analysis↗

Repair of coarctation of the aorta in infancy: comparison of surgical and balloon angioplasty.

Surgical repair of coarctation of the aorta in infancy has recently been challenged by some investigators who suggest that balloon angioplasty results in a lower mortality rate and similar risk of restenosis. Over a 44-month period, 37 consecutive infants with a mean age of 33 days (median, 15 days; range, 1 to 200 days) and mean and median weight of 3.7 kg (range, 2.4 to 5.4 kg) underwent surgical repair of coarctation of the aorta with either an end-to-end anastomosis (24 patients) or subclavian flap angioplasty (13 patients). There were no operative deaths (95% confidence interval, 0% to 10%). Four patients died late (> 30 days) after surgery (11%). Four patients (11%) (95% confidence interval, 3% to 25%) had residual gradients greater than 20 mm Hg. A review of the recent literature on treatment of native coarctation in infants with surgical repair (18 reports, 1189 patients) and balloon angioplasty (8 reports, 57 patients) reveals a similar early mortality rate but a much higher rate of recoarctation in infants who were treated with balloon dilation (57%) as compared with those who underwent surgical repair (14%). Because of the incidence of restenosis, balloon dilation as compared with surgical repair does not yet offer an improved outcome for native coarctation of the aorta in infancy.

Abnormalities, Multiple↗

Technique of transplantation for hypoplastic left heart syndrome with left superior vena cava.

The presence of a left superior vena cava in infants with hypoplastic left heart syndrome complicates the technical performance of orthotopic cardiac transplantation. In this report we describe a modification of the recipient cardiectomy to maintain patency of the left superior vena cava, leaving the recipient coronary sinus as a conduit for it into the right atrium and avoiding complex venous reconstructions.

Echocardiography↗

Damus-Kaye-Stansel with cavopulmonary connection for single ventricle and subaortic obstruction.

Infants with single ventricle and transposition of the great arteries with or without aortic arch obstruction have a poor prognosis due in large part to the development of systemic outflow obstruction, a frequent consequence of pulmonary artery banding. Thus, the initial palliation and long-term treatment options are critical in terms of surgical choices and timing. We report our experience with 9 patients managed by neonatal pulmonary artery banding and early debanding, a Damus-Kaye-Stansel procedure, and either a modified Glenn shunt or a modified Fontan procedure. Some evidence of subaortic stenosis developed in every patient as manifested by a resting gradient across the systemic outflow tract (21.4 +/- 4.2 mm Hg), a small ventricular septal defect relative to the body surface area (1.57 +/- 0.39 cm2/m2), and a small ventricular septal defect relative to the aortic root cross-sectional area (0.70 +/- 0.04 cm2/m2). There were 1 early death and 1 late death after the Damus-Kaye-Stansel procedure. With the exception of 1 patient, the in-hospital course of the survivors was relatively uncomplicated. Two patients with levotransposition of the great arteries have required pacemakers. None of the survivors have residual systemic outflow obstruction. There is trivial or mild pulmonic insufficiency in 5 patients, which is not progressing. One patient had mild to moderate pulmonic insufficiency but died late presumably of an arrhythmia. We conclude that neonatal pulmonary artery banding coupled with planned early debanding, a Damus-Kaye-Stansel procedure, and cavopulmonary anastomosis is a relatively low-risk course for patients with this complex physiology.

Anastomosis, Surgical↗

Restrictive atrial septal communication as a determinant of outcome of cardiac transplantation for hypoplastic left heart syndrome.

BACKGROUND: Infant cardiac transplantation for hypoplastic left heart syndrome (HLHS) can be performed with a high success rate, but it remains unclear whether variations in anatomy or degree of illness before transplantation can affect ultimate survival. METHODS AND RESULTS: We analyzed the initial echocardiograms and pretransplant courses of 21 infants whose families chose transplantation as a primary therapy option for factors influencing survival. Sixteen of 21 were transplanted (mean wait, 18 days; range, 3 to 97 days) with 15 current (6- to 36-month) survivors, leading to a survival rate from presentation of 71% (70% confidence limit [CL], 61% to 81%) and an operative survival of 94% (70% CL, 81% to 99%). Seven of 20 listed for transplant (35%) had a severely restrictive interatrial communication, defined as a color flow jet width of 3 mm or less across the interatrial septum. Three of these 7 infants died at 4 (2) and 7 (1) weeks from congestive heart failure and progressive hypoxemia before transplantation. One died 2 months after transplant with an autopsy demonstrating pulmonary venous hypertensive disease, leading to a significantly higher relative risk for death (relative risk = 7.4, P = .01) for those infants with a severely restrictive interatrial communication versus those infants without severe restriction. The size and function of the right ventricle, left atrium, aorta, and tricuspid valve, as well as the magnitude of support on presentation, were not related to ultimate survival. CONCLUSIONS: A severely restrictive interatrial communication is a frequent component of HLHS. When primary cardiac transplantation is the chosen therapy for HLHS, it is a significant negative risk factor for death primarily before transplantation.

Echocardiography↗

Extracorporeal life support in cyanotic congenital heart disease before cardiovascular operation.

From July 1988 to March 1991, extracorporeal membrane oxygenation (ECMO) was used in 8 infants (newborn to 16 months old) with unoperated cyanotic congenital heart disease and cardiopulmonary collapse, associated with hypercyanotic spells (4 infants), pulmonary hypertensive crises (3) and sepsis (1). Indications for ECMO support were arterial saturations less than or equal to 60% accompanied by hypotension and metabolic acidosis unresponsive to mechanical ventilation with 100% oxygen, paralysis and sedation, and pharmacologic support with inotropes or vasodilators, or both. Venoarterial bypass by carotid/jugular cannulation with flow rates of 100 to 840 ml/kg/min (mean 460) stabilized all patients. Duration of ECMO support ranged from 15 to 840 hours and was associated with transient seizures (1 patient) and renal failure (1). Seven patients underwent palliative (3 patients) or corrective (4) surgical procedures while on ECMO or within 48 hours of decannulation, including 1 patient bridged to double-lung transplantation with a long (840 hours) duration of ECMO. There was 1 operative and 2 late (greater than 1 month after decannulation) deaths, for an overall survival rate of 62%. These 5 survivors all have normal growth and development, and patent neck vessels at the site of cannulation. These early results indicate that ECMO can be effective mechanical support in cardiovascular crises untreatable with maximal conventional medical therapy and can be used as a bridge to successful surgical palliation or repair.

Cohort Studies↗

Increased stiffness and persistent narrowing of the aorta after successful repair of coarctation of the aorta: relationship to left ventricular mass and blood pressure at rest and with exercise.

Fifteen children and adolescents who had repair of coarctation of the aorta before age 15, who were not hypertensive at rest, and who had resting arm-leg blood pressure gradients of less than 20 mm Hg underwent noninvasive evaluation of left ventricular structure and function, aortic stiffness, and residual coarctation as well as bicycle exercise testing. These results were compared with those in 15 age- and sex-matched control subjects. The mean resting age-related systolic blood pressure percentiles (63% versus 46%), transverse aortic stiffness measured by the elastic modulus (Ep) (42.1 versus 23.2 kPa), stiffness index beta (beta) (3.66 versus 2.17), echocardiographic left ventricular fractional shortening (0.42 versus 0.36), left ventricular mass index (99.3 versus 81.0 gm/m2), maximum exercise right arm systolic blood pressure (173 versus 156 mm Hg), and exercise arm-leg blood pressure gradient (35 versus 6 mm Hg) were significantly increased in the coarctectomy patients compared with controls. Univariate correlations in the coarctectomy group showed significant relationships of residual aortic narrowing with left ventricular mass index (r = 0.68, p less than 0.01) and resting systolic blood pressure percentile for age (r = 0.55, p less than 0.05). Residual aortic narrowing did not significantly correlate with aortic stiffness, resting blood pressure gradient, or exercise blood pressure gradient. Neither left ventricular mass index nor resting systolic blood pressure percentile significantly correlated with age of repair or years after repair. These results demonstrate persistent abnormalities in aortic stiffness and left ventricular mass and function after successful repair of coarctation of the aorta in childhood and adolescence.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Primary surgical closure of large ventricular septal defects in small infants.

Herein, a policy of primary surgical closure of large ventricular septal defects in infants is reviewed. Forty-eight infants met criteria for inclusion in the study, and were divided into two groups based on weight: group 1 infants weighted 4 kg or less (n = 23), and group 2 infants weighed more than 4 kg (n = 25). Both groups had similar variation in ventricular septal defect location (paramembranous versus muscular) and number (single versus multiple), as well as incidence of major associated extracardiac diseases. No early deaths occurred in group 1, compared with 1 infant (4%) in group 2. Major complications occurred similarly in both groups (9% versus 12%). There were two late deaths in group 1 (9%) and none in group 2. No surviving patients have required a second ventricular septal defect operation, and the majority no longer receive anticongestive therapies. These results indicate that primary surgical closure of large ventricular septal defects, even multiple muscular defects, can be performed in very small infants with no difference in mortality or serious complication rates compared with larger infants. Protracted medical efforts to achieve larger size before primary repair and palliative pulmonary artery banding are not necessary.

Body Weight↗

Pediatric lung transplantation for pulmonary hypertension and congenital heart disease.

Five children underwent lung transplantation for end-stage pulmonary hypertension and respiratory insufficiency associated with congenital heart disease. One (17 mo) had pulmonary hypertension with a patent ductus arteriosus and required two periods of preoperative extracorporeal membrane oxygenation before successful bilateral sequential lung transplantation. One (21 mo) required bilateral lung transplantation for pulmonary hypertension and bronchopulmonary dysplasia associated with iatrogenic injury to the left pulmonary artery. This child also had patent ductus arteriosus ligation and preoperative catheter closure of an atrial septal defect. Extracorporeal membrane oxygenation was required for early postoperative pulmonary support. One child underwent right single-lung transplantation and closure of an atrial septal defect for pulmonary hypertension. Two patients had single-lung transplantation for Eisenmenger's syndrome: 1 with muscular inlet ventricular septal defect closure, atrial septal defect closure, and right single-lung transplantation; 1 with ventricular septal defect closure, patent ductus arteriosus ligation, right ventricular outflow tract patch repair, and single-lung transplantation. All patients survived operation, with one late death (lymphoproliferative disease). The 4 survivors are all ambulatory without oxygen and have evidence of normal pulmonary artery pressure 9 to 12 months after transplantation.

Adolescent↗