Safety and efficacy of intravenous contrast imaging in pediatric echocardiography.

This study was performed to determine the safety and efficacy of intravenous contrast echocardiography in children attending a tertiary cardiac center. This was a prospective study to evaluate the use of Optison contrast agent in children with severely limited transthoracic echocardiographic windows. Twenty children (median age, 15 years; range, 9-18) underwent fundamental imaging (FI), harmonic imaging (HI), and HI with intravenous contrast (Optison FS-069). Endocardial border delineation was determined based on a visual qualitative scoring system (0, none: 4, excellent). Endocardial border definition was significantly improved in all patients using contrast echocardiography (FI vs Optison, p < 0.001 for each). Improved border definition was most dramatic in the apical and left ventricular (LV) free wall regions. Left ventricular ejection fraction (LVEF) was measurable in 20 patients (100%) using contrast compared to 11 (55%) with FI or HI (p < 0.05). The echocardiographic diagnosis was correctly delineated in 1 patient with a severely dyskinetic LV segment only with use of intravenous contrast and HI. No patients suffered adverse hemodynamic effects, changes in taste, or flushing episodes. Three patients experienced transient headaches. Intravenous contrast echocardiography offers an additional tool in evaluating children with very poor transthoracic echocardiographic windows. Such a strategy increases diagnostic accuracy and allows accurate LVEF determination. Adverse hemodynamic effects related to intravenous contrast are exceedingly rare.

Echocardiographic predictors of adverse clinical events in children with dilated cardiomyopathy: a prospective clinical study.

OBJECTIVES: To compare tissue Doppler (TD) velocities between patients with dilated cardiomyopathy (DCM) and normal controls and to determine whether TD velocities, Tei index, right ventricular fractional area change, and left ventricular ejection fraction (LVEF) predict adverse clinical outcomes in children with DCM. METHODS: Prospective evaluation of children with DCM. RESULTS: 54 children with DCM and 54 age and sex matched control group participants were studied. Mitral inflow velocities were similar for both groups except for decreased mitral deceleration time in patients with DCM. Systolic and diastolic TD velocities at the mitral annulus (septal and lateral sides) and tricuspid annulus were significantly reduced in children with DCM compared with controls (p < 0.001 for each). By multivariate analysis, after adjustment for Tei index and right ventricular fractional area change, decreased LVEF and tricuspid velocity during early diastole (Ea) were predictors of the primary end point (PEP), a composite end point consisting of need for hospitalisation or the outcome transplantation or death. Tricuspid Ea velocity < 8.5 cm/s had 87% specificity and 60% sensitivity for reaching the PEP. LVEF < 30% had 68% specificity and 74% sensitivity for the PEP. Combined LVEF < 30% and tricuspid Ea < 11.5 cm/s had 100% specificity and 44% sensitivity for the PEP. CONCLUSIONS: Children with DCM have significantly lower TD velocities than normal controls. In such cases, lower LVEF (< 30%) is more sensitive but less specific than lower tricuspid Ea velocities (< 8.5 cm/s) in predicting which patients are at risk of hospitalisation, transplantation, or death.

Autoregulation of cerebral blood flow in fetuses with congenital heart disease: the brain sparing effect.

Fetuses with congenital heart disease (CHD) have circulatory abnormalities that may compromise cerebral oxygen delivery. We believe that some CHD fetuses with decreased cerebral oxygen supply have autoregulation of blood flow that enhances cerebral perfusion (brain sparing). We hypothesize that cerebral autoregulation occurs in CHD fetuses, and the degree of autoregulation is dependent on the specific CHD and correlates with intrauterine head circumferences. CHD fetuses were compared to normal fetuses. Data included cardiac diagnosis, cerebral and umbilical artery Doppler, head circumference, weight, and gestational age. The cerebral-to-placental resistance ratio (CPR) was assessed as a measure of cerebral autoregulation. CPR = cerebral/umbilical resistance index (RI) and RI = systolic-diastolic/systolic velocity (normal CPR > 1). CPR > 1 was found in 95% of normal vs 44% of CHD fetuses. The incidence of CPR < 1 was greatest in hypoplastic left or right heart fetuses. Compared to normal, cerebral RI was decreased in CHD fetuses. The CPR vs gestational age relationship, and the relationship among weight, head circumference, and CPR differed across normal and CHD fetuses. Fetuses > 2 kg with CHD and a CPR < 1 had smaller head circumferences than normal. Brain sparing occurs in CHD fetuses. Fetuses with single ventricular physiology are most affected. Inadequate cerebral flow in CHD fetuses, despite autoregulation, may alter brain growth.

Early detection of cardiac dysfunction: use of the myocardial performance index in patients with anorexia nervosa.

OVERVIEW: Patients with anorexia nervosa have functional cardiac abnormalities secondary to their nutritionally depleted state. These abnormalities include decreased left ventricular (LV) mass and varying degrees of LV systolic dysfunction. Assessment of LV diastolic function and quantitative assessment of right ventricular function are not routinely performed. The myocardial performance index (MPI) is a relatively new, simple, quantitative measure of global myocardial function. The purpose of this study was to evaluate left and right ventricular function in 13 patients with anorexia nervosa with the MPI and compare it to more commonly used echocardiographic measures of ventricular function.

Unusual finding of cor triatriatum in a newborn with hypoplastic left heart syndrome.

Cor triatriatum is a rare anomaly in which the left atrium is partitioned into 2 distinct chambers with a variable degree of obstruction to left atrial inflow. This anomaly often occurs in isolation but can occur in combination with other cardiac lesions. The association of cor triatriatum with hypoplastic left heart syndrome has not been reported. We describe a newborn with hypoplastic left heart syndrome who also had the unusual finding of cor triatriatum sinistrum.

Quantitative assessment of fetal ventricular function: establishing normal values of the myocardial performance index in the fetus.

OBJECTIVE: Assessment of ventricular function in the fetus has been limited for many reasons, including relative cardiac size and atypical orientation of fetal cardiac structures. A myocardial performance index (MPI) has been described in adult and pediatric populations as an echocardiographic measure of global (systolic and diastolic) ventricular performance. Because the MPI is a Doppler index, it is independent of ventricular geometry and can be applied to both left and right ventricular function. This study attempts to define the MPI in a group of normal fetuses and compare these data to other published studies of this index. STUDY DESIGN: The right ventricular (RV) and left ventricular (LV) MPI were measured in 125 normal fetuses (20--40 weeks gestation, mean age 28 weeks). These fetuses were divided into five gestational age groups for comparison. These data were compared to 152 normal children (age 3--18 years, mean age 9.3 years). RESULTS: In normal fetuses, the LV MPI was 0.36 +/- 0.06 and the RV MPI was 0.35 +/- 0.05. This was not statistically different from the group of normal children in whom the LV MPI was 0.35 +/- 0.03 and the RV MPI was 0.32 +/- 0.03. In addition, no significant change in the fetal MPI was seen with advancing gestational age. CONCLUSION: This study demonstrates that fetal ventricular function can be quantitatively measured with the MPI. The MPI provides an easily obtainable and reproducible measure of fetal ventricular performance that can be readily incorporated into all fetal echocardiographic examinations.

Unusual association of hypertrophic cardiomyopathy with complete atrioventricular canal defect and Down syndrome.

Hypertrophic cardiomyopathy typically presents as an isolated cardiac lesion. Transient hypertrophic cardiomyopathy in infancy has been described as a result of exposure to maternal metabolic disorders or to corticosteroids. In addition, hypertrophic cardiomyopathy has been described in association with genetic syndromes and, in rare cases, as a primary lesion associated with other congenital heart defects. We describe the unusual association of hypertrophic cardiomyopathy and complete atrioventricular canal defect in an infant with trisomy 21.

Usefulness of the myocardial performance index for assessing right ventricular function in congenital heart disease.

Quantitative assessment of ventricular function in patients with congenital heart disease is often challenging due to distorted ventricular geometry. A myocardial performance index (MPI) has been reported in adults and children that is a Doppler-derived nongeometric measure of ventricular function. The MPI measures the ratio of isovolumic time intervals (isovolumic contraction time and isovolumic relaxation time) to ventricular ejection time. The effects of altered ventricular preload or afterload on the MPI have yet to be determined. This study assesses the impact of altered preload or afterload on right ventricular (RV) function and the RV MPI in the clinical setting of congenital heart disease. Patient groups were compared with normal pediatric and adult populations before and after repair of their congenital heart lesion. Patients with large atrial septal defects (ASDs) represented the clinical setting of increased ventricular preload, whereas patients with isolated pulmonary valve stenosis represented increased RV afterload. Patients with congenitally corrected transposition of the great arteries (CC-TGA) with severe left atrioventricular valve regurgitation represented a combined increase in RV preload and afterload. The RV MPI in 152 normal children (ages 3 to 18 years) and 37 adults (ages 18 to 51 years) was 0.32 +/- 0.03 and 0.28 +/- 0.04, respectively. In pediatric patients (n = 45) and adult patients (n = 40) with ASD, the RV MPI was 0.35 +/- 0.09 (p = NS) and 0.38 +/- 0.04 (p < 0.01 compared with normal adults), respectively. Patients with pulmonary stenosis (n = 21, ages 1 day to 19 years) had a RV MPI of 0.32 +/- 0.06 (p = NS). CC-TGA patients had a RV MPI of 0.72 +/- 0.17 (p < 0.001). No significant change in the RV MPI was seen in any postoperative patient group despite relief of RV volume or pressure overload. Thus, the MPI is a quantitative measure of RV performance that is appears to be relatively independent of changes in preload or afterload in the clinical setting.

Gaining vascular access in pediatric patients: use of the P.D. access Doppler needle.

This article describes our initial experience with the P.D. Access Doppler needle for obtaining vascular access in pediatric patients. Patients were considered for use of the P.D. Access Doppler needle (Escalon Vascular Access, New Berlin, WI) if they had a history of difficult access or body habitus limitations to vascular access. An 18-, a 20-, or a 22-gauge bare needle with an inserted Doppler stylet was utilized. The time from initial subcutaneous entry of the Doppler needle until wire placement into the vessel lumen was recorded. Initial attempts to cannulate were performed with standard Seldinger technique. If attempts with the standard technique were unsuccessful, then P.D. Access was utilized. However, P.D. Access was used primarily in small children for internal jugular vein cannulation or in patients with coarctation who had absent/diminished femoral pulses. P.D. Access cannulation was attempted 39 times (31 patients). Median age is 23 months (range, 1 day to 15 years). Median weight is 10.5 kg (range, 1.7-57 kg). These patients had a mean of two prior cardiac catheterizations and/or surgeries (range, 0-6 procedures). Use of P.D. Access resulted in successful cannulation in 35/39 (90%) attempts. In successful outcomes, the time from initial subcutaneous entry to cannulation is 6.5+/-4.9 min. In unsuccessful outcomes, failure was due to prior hematoma formation, operator inexperience, or prior vessel occlusion. Successful use of P.D. Access shortens the duration of vascular access in difficult pediatric patients. In our cardiac catheterization laboratory, this technique has become the preferred initial entry technique for cannulation of the internal jugular vein in small children. In addition, this technique was particularly useful for femoral artery cannulation in patients with coarctation of the aorta with absent/diminished femoral pulses.

Extended end-to-end repair and enlargement of the entire arch in complex coarctation.

BACKGROUND: Treatment of hypoplasia of the entire arch in coarctation is a surgical challenge. The current approaches have technical difficulties, high recurrence rates, and increased morbidity and mortality. METHODS: Over a 14-month period, a combined extended end-to-end repair with patch enlargement of the concavity of the entire arch was performed in 6 neonates and 1 infant. Through a midsternotomy and using cardiopulmonary bypass and hypothermia, extended end-to-end repair was performed initially leaving the proximal anastomosis open. The enlarging polytetrafluoroethylene patch was then sutured starting at the incised descending aorta distal to the extended end-to-end repair and continued retrogradely through the transverse arch to the ascending aorta proximal to the aortic cannulation site. One neonate had a patent ductus arteriosus and another had ventricular septal defect closure. One neonate had arterial switch and 3 had Norwood-type procedures performed with the enlarging patch extended to the pulmonary artery anastomosis. The remaining infant had arch enlargement performed after an arterial switch procedure and extended end-to-end repair. RESULTS: All patients did well and showed no residual gradient up to 1 year follow-up. Two patients successfully had bidirectional Glenn shunt at 9 months of age, and one had closure of residual arterial septal defect at 8 months of age. CONCLUSION: The combined extended end-to-end repair and arch enlargement procedure should minimize recurrence rates because of a tension-free enlargement of the entire aortic arch and elimination of the coarctation ridge and ductile tissues. Combined with the arterial switch and Norwood-type procedures, the approach results in a large neoaorta.

Semilunar valve switch procedure: autotransplantation of the native aortic valve to the pulmonary position in the Ross procedure.

BACKGROUND: The Ross procedure has gained wide acceptance in young patients with aortic valve disease. The durability of the pulmonary autograft in the aortic position has been proved, with up to 24 years of follow-up. The homograft pulmonary valve, however, has limited longevity. To circumvent this problem we harvested, repaired, and reimplanted the native aortic valve with intact commissures in the pulmonary position in 13 patients undergoing the Ross procedure for aortic insufficiency. METHODS: The cause of aortic insufficiency was rheumatic in 6 patients, congenital in 4, post-aortic valvotomy in 2, and bacterial endocarditis in 1. Patient age ranged from 5 to 45 years (mean, 17+/-9 years). Root replacement technique with coronary artery reimplantation was used. In the first 4 patients, the native aortic valve was sutured into the right ventricular outflow tract, and a polytetrafluorethylene patch was used to reconstruct the main pulmonary artery. In the last 9 patients, the aortic valve and polytetrafluorethylene patch were made into a conduit by another surgeon while the left-sided reconstruction was performed. RESULTS: All patients had marked reduction of left ventricular dilation and good function of the reimplanted native aortic valve, with up to 50 months of follow-up (mean, 29.9+/-14.2 months; range, 12 to 50 months). Two patients died 15 and 26 days, respectively, of a false aneurysm rupture at the distal aortic anastomosis. In the remaining 11 patients, 9 (82%) had mild or absent, and 2 (18%) had mild to moderate, neoaortic valve regurgitation. Similarly, 9 patients (82%) had mild or absent, and 2 (18%) had mild to moderate, neopulmonary valve regurgitation. Mild neopulmonary valve stenosis was present in 6 patients (54%) (mean gradient, 29+/-4 mm Hg; range, 25 to 35 mm Hg). All surviving patients are in functional New York Heart Association functional class I. CONCLUSIONS: We conclude that use of the native aortic valve with the Ross procedure makes the procedure attractive and potentially curative. The diseased aortic valve works well in the pulmonary position because of lower pressure and resistance. The valve leaflets should remain viable and grow in both the pulmonary and aortic positions because they derive nutrition directly from the blood.

Resolution of neonatal hypertrophic cardiomyopathy in an infant with an affected mother.

Hypertrophic cardiomyopathy (HCM) in infancy has been described in association with many medical disorders. The genetic location and mode of transmission of HCM in families also has been reported extensively. We present an infant with nonobstructive hypertrophic cardiomyopathy whose mother also had HCM. Regression of septal hypertrophy was documented in this patient by 1 year of age despite a positive family history.

Nongeometric quantitative assessment of right and left ventricular function: myocardial performance index in normal children and patients with Ebstein anomaly.

Assessment of ventricular systolic function has been based on the geometric models of ventricular shape. This study was designed to define normal values for a nongeometric myocardial performance index (MPI) in children and to evaluate the utility of MPI in congenital heart disease. The MPI measures the ratio of total time spent in isovolumic activity (isovolumic contraction time and isovolumic relaxation time) to the ejection time. The right ventricular (RV) and left ventricular (LV) MPI were measured in 152 normal children (ages 3 to 18 years) and 45 preoperative patients with Ebstein anomaly (age 1 week to 52 years). In normal children, the RV MPI was 0.32+/-0.03 and the LV MPI was 0.35+/-0.03. In the Ebstein group, both RV and LV MPI were abnormally increased compared with age-matched normal subjects (Ebstein group: RV MPI=0.49+/-0.12, LV MPI=0.42+/-0.09, P < .001). Increasing RV dysfunction was associated with progressively increasing (abnormal) values of RV MPI (P < .001). The myocardial performance index quantitatively reflects ventricular performance in patients with complex ventricular geometry (ie, Ebstein anomaly). In the absence of a geometric solution, this nongeometric index is particularly appealing for the assessment of RV or LV performance.

Anomalous right coronary artery from the pulmonary artery in Taussig-Bing anomaly.

The presence of associated anomalies in patients with double-outlet right ventricle can significantly alter surgical intervention. Preoperative delineation of these anomalies can facilitate surgical planning and improve outcome. We describe a case in which the right coronary artery and anterior descending coronary artery arose from the pulmonary artery in a patient with double-outlet right ventricle with subpulmonary ventricular septal defect (Taussig-Bing anomaly). Recognition of this important anomaly prevented significant intraoperative myocardial damage by altering techniques of cardioplegia administration for myocardial preservation.