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Biomedical subjects

C E Canter

Publications and source records attributed to C E Canter.

At least 55 records · Page 3Linked to original sources
PubMed1991

Evaluation of congenital heart disease by three-dimensional magnetic resonance imaging.

This study was undertaken to compare electrocardiographically gated magnetic resonance imaging (MRI) to established imaging modalities in the detection of complex intra- and extracardiac morphologic defects. Twenty-three patients with congenital cardiac abnormalities were imaged by four methods: cardiac catheterization, echocardiography, two-dimensional (2D) transaxial MRI, and three-dimensional (3D) MRI surface reconstruction. Observers with experience in congenital cardiac disease diagnosis (two for echo, one for catheterization, two for 2D MR, and three for 3D MR) evaluated the images in a blinded fashion, and the results were analyzed with receiver operating characteristic (ROC) analysis. Overall, cardiac catheterization had the best diagnostic performance. The diagnostic value of routine 2D cardiac MR images and 3D MR reconstruction images were similar to that of echocardiography. All of the modalities performed poorly in the diagnosis of extracardiac defects and atrial septal defects.

Cardiac Catheterization↗
PubMed1991

Coronary artery disease in pediatric cardiac transplant recipients receiving triple-drug immunosuppression.

Although triple-drug immunosuppression (cyclosporine, azathioprine, and prednisone) has reduced the incidence of acute rejection after pediatric cardiac transplantation, its effect on the development of coronary artery disease, which may be the major determinant of long-term survival in these patients, is not well defined. We reviewed 42 coronary angiograms obtained annually in 17 cardiac transplant recipients, aged 6 months to 18 years (mean, 12.4 years) at the time of transplantation, who had been maintained on triple-drug immunosuppression and had survived at least 1 year after transplantation. Each angiogram was reviewed for luminal irregularities or discrete stenoses, for the loss of third-order branching, and for the presence of myocardial bridging or calcification of vessels. Patient files were reviewed for donor and recipient age, sex, and ABO blood group, for postoperative episodes of rejection or cytomegalovirus infection, for hypertension, and for cholesterol and triglyceride values. No recipient in our series has died or undergone retransplantation because of coronary artery disease. Six of 17 (35%) patients have developed angiographically identifiable coronary artery abnormalities: four by the first year and two additional recipients by the second and third years, respectively, after transplantation. Development of coronary artery abnormalities approached a significant correlation when related to posttransplantation cytomegalovirus infection (p = 0.11) and older recipient age (p = 0.056) but not to any other factors studied, including episodes of rejection (p = 1.0). Angiographically identifiable coronary artery abnormalities can occur in pediatric recipients within the first year after cardiac transplantation in spite of a low incidence of acute rejection. Although the abnormalities may be mild initially, they can progress and require intervention.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗
PubMed1991

Surveillance for rejection by echocardiographically guided endomyocardial biopsy in the infant heart transplant recipient.

Echocardiographically guided endomyocardial biopsy via percutaneous right internal jugular vein puncture has been performed 98 times in six patients 5-16 years of age at our institutions. The use of this approach was extended for rejection surveillance in seven infants transplanted at 2 weeks to 15 months of age (median, 2 months; mode, 2 weeks). A total of 35 consecutive biopsies were performed under heavy sedation in these infants (lowest weight, 3.0 kg) with the use of a 5F semirigid bioptome through a 5.0-cm 5F sheath. There was no case of entrance failure. A median of four biopsies was performed on each child (range, one to 14). Four to seven tissue pieces per biopsy were obtained using an apical four-chamber view for bioptome guidance. Ten instances of clinically suspected rejection were not confirmed by biopsy, and two cases of unsuspected rejection were found. The only complication was one instance of new mild tricuspid regurgitation in this group compared with one instance of increased tricuspid regurgitation after biopsy in the older child group. These preliminary results suggest that echocardiographically guided endomyocardial biopsy from the right internal jugular approach is a reliable and safe means for rejection surveillance in the infant and young child.

Biopsy↗
PubMed1991

Noninvasive diagnosis of right-sided extracardiac conduit obstruction by combined magnetic resonance imaging and continuous-wave Doppler echocardiography.

Right-sided extracardiac conduits are frequently complicated by obstruction over time. We compared the utility of two-dimensional and Doppler echocardiography and magnetic resonance imaging in the diagnosis of postoperative right-sided obstruction with cardiac catheterization and angiography in 10 patients with xenograft or homograft conduits. Correlation (r = 0.95) between continuous-wave Doppler estimates and catheter pullback pressure gradients across the conduits was excellent. Echocardiography could only visualize five of 10 conduits in their entirety. Magnetic resonance imaging visualized all conduits and showed statistically significant (kappa = 0.58) agreement with angiography in the localization and estimation of severity of a variety of right-sided obstructions in these patients. However, flow voids created by the metallic ring around xenograft valves led to a false negative diagnosis of valvular stenosis in four patients when magnetic resonance imaging was used alone. Doppler studies correctly indicated obstruction in these patients. The combination of magnetic resonance imaging studies and continuous-wave Doppler echocardiography can be useful to noninvasively evaluate right-sided obstruction in postoperative patients with right-sided extracardiac conduits.

Adolescent↗
PubMed1990

Rejection and infection after pediatric cardiac transplantation.

Cardiac transplantation has only recently become an accepted therapeutic modality for children and adolescents with end-stage cardiomyopathy. Long-term survival, the incidence of rejection, and the incidence of infection are still being defined. From 1985 to 1989, 21 children aged 6 months to 19 years (average age, 11.2 years) underwent cardiac transplantation at our institutions. Eighteen survived the operative period and have been followed for 5 to 49 months (average follow-up, 24 months). All operative survivors have received triple-drug immunosuppression consisting of cyclosporine, azathioprine, and prednisone. During follow-up, 7 patients have been treated on 12 occasions for rejection as documented by endomyocardial biopsy. Eight (67%) of the 12 episodes of rejection occurred in the presence of subtherapeutic cyclosporine levels. Two of the 7 patients treated for rejection have subsequently died of ongoing cardiac rejection and arrhythmia. There have been no perioperative or late deaths from infection. Bacterial sepsis was identified and treated twice during follow-up, viral infections on five occasions, and fungal infection once. Actuarial 1-year survival and 3-year survival of the 18 operative survivors are 94% and 78%, respectively. In the first 7 months after cardiac transplantation, 73% of patients were free from rejection and 83% were free from serious bloodborne infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

Evaluation of pulmonary arterial morphology in cyanotic congenital heart disease by magnetic resonance imaging.

Before and after surgical therapy, the anatomy of the pulmonary arteries in cyanotic congenital heart disease is often distorted. Pulmonary arterial anatomy was evaluated by magnetic resonance imaging (MRI) and angiography in 20 patients, ages 3 months to 20 years, with cyanotic heart disease associated with decreased pulmonary blood flow. Excellent correlation between MRI and angiographic estimates of pulmonary artery diameter was obtained (main pulmonary artery, r = 0.96; right pulmonary artery, r = 0.93; left pulmonary artery, r = 0.96). A similar excellent correlation (kappa = 0.83) was found in the assessment of the presence and severity of proximal pulmonary arterial stenoses. However, stenoses in the peripheral pulmonary arteries visualized with angiography were missed with MRI. MRI and angiography showed complete agreement in determining the patency of 11 surgical shunts. MRI did not demonstrate all of the systemic collateral vessels present with angiography, and the distal connections of collaterals were not detected with MRI. MRI is comparable to angiography in the evaluation of central pulmonary arterial anatomy over a wide range of ages. These findings suggest an important role for noninvasive MRI in the serial evaluation of pulmonary artery morphology in patients with cyanotic congenital heart disease before and after surgical repair.

Adolescent↗
PubMed1989

Cardiac cycle-dependent variation of integrated backscatter is not distorted by abnormal myocardial wall motion in human subjects with paradoxical septal motion.

To define the dependence of cardiac cycle-dependent variation of integrated backscatter on regional myocardial wall motion, 8 children mean age 10.6 +/- 1.3 y with congenital cardiac lesions associated with paradoxical septal motion were studied (study group). Six healthy children mean age 9.0 +/- 0.3 y with no history of cardiac disease served as controls (control group). Subjects in the study group had paradoxical septal motion but normal septal wall thickening detected by conventional two-dimensional and M-mode echocardiography. The control group had normal septal motion evident by conventional echocardiographic criteria. The percentage of systolic septal thickening was 46 +/- 4.5% and 42 +/- 5.9% in the study and control groups (p = NS). Cyclic variation was measured in parasternal long-axis views from several septal sites in each subject. Mean values of the magnitude of cyclic variation from independent septal sites were averaged to yield a regional average value for each subject. The average regional magnitude of cyclic variation was 8.3 +/- 1.0 dB and 5.7 +/- 0.4 dB in the study and control groups (p = NS). The results indicate that the measurement of cyclic variation of integrated backscatter is not distorted by altered regional wall motion, and that it reflects intrinsic contractile function.

Child↗
PubMed1989

Intraoperative evaluation of atrioventricular septal defect repair by color flow mapping echocardiography.

Despite improving survival rates after repair of atrioventricular septal defect, many patients require reoperation because of postoperative heart failure. We used intraoperative color flow mapping echocardiography to assess the results of surgical repair of atrioventricular septal defect in 19 consecutive patients and compared those findings with results three to five days and 3 to 11 months after repair. There was close correlation between intraoperative and postoperative color flow mapping echocardiography in estimating the presence and severity of left atrioventricular valve regurgitation. All patients survived surgical repair, but in 4 (21%), postoperative congestive heart failure due to left atrioventricular valve regurgitation developed. The need for reoperation was significantly correlated with the severity of left atrioventricular valve regurgitation (r = 0.68) as estimated by intraoperative echocardiography and preoperative aberrancies in the atrioventricular valve (r = 0.68). Age, weight, additional congenital heart disease, preoperative pulmonary vascular resistance, preoperative atrioventricular valve regurgitation, and postoperative mean pulmonary arterial or left atrial pressure were not significantly correlated with the need for reoperation. Intraoperative color flow mapping echocardiography can accurately predict the development of early postoperative heart failure and subsequent reoperation after surgical repair of atrioventricular septal defect.

Child↗
PubMed1989

Management and follow-up of arterial thrombosis in the neonatal period.

The management and follow-up of 12 patients with major aortic thrombus formation occurring in the neonatal period between 1982 and 1987 are reported. Umbilical arterial catheters were inserted in 8 of the 12 patients before thrombus formation. Two patients had congenital thrombi. Hypertension, oliguria, hematuria, and elevated blood creatinine concentration were found at the time of diagnosis of the thrombus; nine of the patients had a patent ductus arteriosus. Supportive care was instituted in seven patients who were hemodynamically stable. Five of the patients had congestive heart failure, shock, or both, and were treated with surgical thrombectomy. Thrombolytic therapy was not used in either group. The five surgically treated patients and six of seven medically treated patients survived. Ultrasound examination suggested resolution of the thrombus in all survivors in 6 to 30 days. Sequelae from thrombus formation were present in all patients at the time of discharge and included hypertension in 9 of the 11 survivors and decreased renal function in six of them. Follow-up at 1 to 3 years revealed normal blood pressure, good growth, and good renal function in 10 of the survivors.

Anticoagulants↗
PubMed1989

Tetralogy of Fallot: MR findings.

Surgical treatment of patients with tetralogy of Fallot requires accurate definition of all anatomic structures, particularly the central pulmonary arteries. Magnetic resonance (MR) images of 22 patients with tetralogy of Fallot were studied to assess their usefulness in providing information regarding the spectrum of anatomic abnormalities in this condition. MR findings were compared with information obtained at catheterization (in 16 patients) and at surgery (in nine patients), both of which were performed within 3 months of MR imaging. Ventricular chamber enlargement and wall hypertrophy were clearly delineated in most of the 17 patients who were examined before definitive surgical repair, and ventricular septal defects were visualized in all 17. Palliative systemic-to-pulmonary shunts were visualized in 11 patients and could be evaluated for patency. Most important, the morphology and size of the right ventricular outflow tract and central pulmonary arteries could be accurately assessed. Pulmonary artery measurements obtained from MR images demonstrated excellent correlation with angiographic measurements. In six patients examined after complete surgical repair, MR images accurately reflected changes in pulmonary artery outflow tract morphology and complications, such as residual pulmonary artery stenosis and thrombosis. The findings suggest that MR imaging can complement or obviate catheterization in the evaluation of tetralogy of Fallot with regard to suitability for definitive surgical repair.

Adult↗
PubMed1988

Three-dimensional magnetic resonance imaging of congenital heart disease.

Three-dimensional surface reconstruction images of the heart and great vessels have been produced from contiguous sequences of EKG-triggered MRI scans in more than 35 patients with congenital heart disease and 5 normal subjects. The scan data was semiautomatically processed to separate the epi- and endocardial surfaces and to define the outlines of the enclosed blood volumes on a slice by slice basis. Surface reconstruction images aid communication with clinicians, establish the size and location of intracardiac defects, and image the pulmonary venous drainage. The method is practical for use in the evaluation of cardiac morphologic abnormalities, especially for planning cardiac surgery.

Adult↗
PubMed1975

Induction of extra nephrons in unilaterally nephrectomized immature rats (38525).

The normal number of glomeruli per kidney in the rat rises from about 10-4 at birth to approximately 35 times 10-3 at 50 days of age. When one kidney is removed at birth the remaining one produces an average of 63% more nephrons than normal by 70 days. Unilateral nephrectomy of successively older rats results in progressively less augmentation of the nephron complement in the remaining kidney up to 50 days, beyond which age the kidney loses its ability to produce new nephrons.

Age Factors↗
PubMedDate not supplied

Prospective single-arm protocol of carvedilol in children with ventricular dysfunction.

The objective of this study was to evaluate the safety and efficacy of carvedilol in pediatric patients with stable moderate heart failure. We performed a single-arm prospective drug trial at three academic medical centers and the results were compared to historical controls. Patients were 3 months to 17 years old with an ejection fraction <40% in the systemic ventricle for at least 3 months on maximal medical therapy including ACE inhibitors. Treated patients were started on 0.1 mg/kg/day and uptitrated to 0.8 mg/kg/day or the maximal tolerated dose. Echocardiographic parameters of function were prospectively measured at entry and at 6 months. Two composite endpoints were recorded: severe decline in status and significant clinical change. Adverse events were reviewed by a safety committee. Data were also collected from untreated controls with dilated cardiomyopathy meeting entry criteria, assessed over a similar time frame. Twenty patients [12 dilated cardiomyopathy (DCM) and 8 congenital] with a median age of 8.4 years (range, 8 months to 17.8 years) were treated with carvedilol. Three patients discontinued the drug during the study. At entry, there was no statistical difference in age, weight, or ejection fraction between the treated group and controls. The ejection fraction of the treated DCM group improved significantly from entry to 6 months (median, 31 to 40%, p = 0.04), with no significant change in ejection fraction in the control group [median, 29 to 27%, p = not significant (NS)]. The median increase in ejection fraction was larger for the treated DCM group than for the untreated DCM controls (7 vs 0%, p = 0.05). By Kaplan-Meier analysis, time to death or transplant tended to be longer in treated patients (p = 0.07). The difference in the proportion of patients with severe decline in status or significant clinical change in the treated group was not significant compared to the controls (5 vs 12%, p = NS). We conclude that in this prospective protocol of pediatric patients, the use of adjunct carvedilol in the DCM group improved ejection fraction compared to untreated controls and trended toward delaying time to transplant or death.

Adolescent↗