Claudio Ramaciotti

Prevalence of spontaneous closure of the ductus arteriosus in neonates at a birth weight of 1000 grams or less.

OBJECTIVE. Ductus arteriosus (DA) closure occurs within 96 hours in >95% of neonates >1500 g in birth weight (BW). The prevalence and postnatal age of spontaneous ductal closure in neonates ≤1000 g in BW (extremely low birth weight [ELBW] neonates) remain unclear, as does the incidence of failure to close with indomethacin. Therefore, we prospectively examined the prevalence, postnatal age, and clinical variables associated with spontaneous DA closure, occurrence of persistent patent DA, and indomethacin failure in ELBW neonates. METHODS. Neonates delivered at Parkland Memorial Hospital from February 2001 through December 2003 were studied. Those with congenital heart defects or death <10 days postnatally were excluded. Echocardiograms were performed 48 to 72 hours postnatal and every 48 hours until 10 days postnatally. RESULTS. We studied 122 neonates with BW of 794 ± 118 (SD) g and estimated gestational age (EGA) of 26 ± 2 weeks. Spontaneous permanent DA closure occurred in 42 (34%) neonates at 4.3 ± 2 days postnatally, with 100% closure by 8 days. These neonates were more mature, less likely to have received antenatal steroids or have hyaline membrane disease (HMD; 52% vs 79%), and more likely to be growth restricted (31% vs 5%) and delivered of hypertensive women. Using regression analysis, EGA and absence of antenatal steroids and HMD predicted ductal closure. Ten (8%) neonates with early DA closure reopened and required medical/surgical closure. Eighty neonates had persistent patent DA; 7 were surgically ligated, and 5 remained asymptomatic, with 4 of 5 closing after 10 days postnatally. Sixty-eight (85%) received indomethacin at 6.2 ± 4 days postnatally; 41% failed therapy and had no distinguishing characteristics. CONCLUSIONS. Spontaneous permanent DA closure occurs in >34% of ELBW neonates and is predicted by variables related to maturation, for example, EGA and an absence of HMD, whereas indomethacin failure could not be predicated.

Chloral Hydrate Sedation for Pediatric Echocardiography: Physiologic Responses, Adverse Events, and Risk Factors

OBJECTIVE. The physiologic responses to chloral hydrate sedation in the setting of a pediatric echocardiography laboratory have not been well documented; neither has the population at risk been identified adequately. The purpose of this study was to describe the physiologic responses to chloral hydrate sedation, to report the occurrence of adverse events, and to identify any risk factors that predicted these adverse events in children who underwent sedation for echocardiography at our institution. METHODS. We analyzed retrospectively 1095 patients who were sedated for echocardiography. Vital signs and oxygen saturations were recorded every 5 minutes, and adverse events were noted. Potential risk factors for sedation-related adverse events were analyzed. RESULTS. Thirty-eight percent of patients were classified as American Society of Anesthesiologists class 3 or 4, reflecting the significant comorbidity in the study population. Hemodynamic responses to chloral hydrate sedation included ≥20% decreases in heart rate (24% of the patients) and blood pressure (59% of the patients). There were no deaths or permanent morbidity. Adverse events occurred in 10.8% of patients and included apnea (n = 3 [0.3%]), airway obstruction (n = 15 [1.4%]), hypoxia (n = 65 [5.9%]), hypercarbia (n = 40 of 603 [6.6%]), hypotension with poor perfusion (n = 4 [0.4%]), vomiting (n = 4 [0.4%]), and prolonged sedation (n = 36 [3.3%]). No intervention was required in 92.5%, minor interventions were necessary in 7%, and major interventions were required in 0.5% of all patients. Multivariate analysis identified only age younger than 6 months as a predictor for adverse events, whereas cyanosis, hospitalization, American Society of Anesthesiologists class, fasting time, oxygen requirement, and use of additional sedation were not predictors. CONCLUSIONS. Moderate decreases in heart rate and blood pressure, in the absence of clinical deterioration, are expected responses to chloral hydrate sedation in this pediatric population. The majority of adverse events were minor, and major events were uncommon. Infants who were younger than 6 months were found to be at higher risk for serious adverse events.

Magnetic resonance and echocardiographic imaging of pulmonary artery size throughout stages of Fontan reconstruction.

BackgroundBecause pulmonary artery size is considered by most investigators to be a major prognosticator of outcome in patients undergoing staged Fontan reconstruction, the objective of the present study was to determine the efficacy of noninvasive measures in determining pulmonary artery size. Methods and ResultsThis study analyzed the T1-weighted, spin-echo magnetic resonance and echocardiographic images of 36 functional single-ventricle patients throughout stages of Fontan reconstruction (prebidirectional and postbidirectional cavopulmonary anastomosis and after Fontan) and compared them with angiography images at cardiac catheterization. Magnetic resonance imaging had a high degree of agreement with angiography, with the McGoon index agreeing better than the Nakata index and absolute right and left pulmonary diameters. Although echocardiography had fair agreement with angiography, it agreed less well and had a wider standard deviation than magnetic resonance imaging for all indexes and measurements and, based on the prediction interval, would be a poorer prospective measure of pulmonary artery size in this population. In addition, echocardiography was a poorer measure of pulmonary artery size as the size of the vessel increases. Magnetic resonance imaging correctly detected five of five patients with nonconfluent branch pulmonary arteries and six of six patients with stenoses, whereas echocardiography was unable to visualize any of the patients with nonconfluent branch pulmonary arteries with certainty and only two of six (33%) with stenoses. ConclusionsMagnetic resonance imaging is a useful, noninvasive tool to determine pulmonary artery size in patients undergoing Fontan reconstruction and is superior to echocardiography. Echocardiography was a fair predictor of pulmonary artery size, but magnetic resonance imaging agreed with angiography better than echocardiography and outperformed echocardiography in diagnosing branch pulmonary artery discontinuity and stenoses. Magnetic resonance imaging may avoid unnecessary cardiac catheterization, especially in older patients, and may obviate the need for jugular or subclavian catheterization in those who have undergone bidirectional cavopulmonary anastomosis.

Importance of (perimembranous) ventricular septal aneurysm in the natural history of isolated perimembranous ventricular septal defect

Records were reviewed of 247 patients found to have isolated perimembranous ventricular septal defect (VSD) on cross-sectional echocardiography. Patients were separated into 2 groups: those in whom a perimembranous ventricular septal aneurysm (VSA) was associated with the VSD (group A, 77% of patients) and those in whom a VSA was not present (group B, 23%). The VSD was assessed by clinical (125 in group A, 24 in group B) and hemodynamic criteria (65 in group A, 33 in group B). The median follow-up period was 27 months (range 3 months to 25 years). In group A, the VSD closed spontaneously in 11% of the patients, improved clinically in 33% and required surgical closure in 11%. In group B, the VSD closed spontaneously in only 2%, improved clinically in 16% and required surgical closure in 47%. When considering larger VSDs only, 28% required surgery in group A, whereas 84% required surgery in group B (p less than 0.001). The VSA was found at the first echocardiographic examination in 94% of the studies. Thus, VSA is found in a large proportion of patients with perimembranous VSD. It occurs as an early phenomenon and is an important mechanism of closure. The presence of a VSA appears to confer a more favorable prognosis in perimembranous VSD except in patients with Downs syndrome.

Prevalence, relation to spontaneous closure, and association of muscular ventricular septal defects with other cardiac defects

Previous studies on muscular ventricular septal defect (VSD) have not taken into account the specific defect location in the septum. We retrospectively reviewed all patients with a muscular VSD, with and without associated malformations, diagnosed over 32 months to determine the prevalence and rate of spontaneous closure of single defects in relation to location in the muscular septum. Defects were classified into 4 groups: midmuscular, apical, anterior, and posterior. Two hundred seven patients were identified, of whom 125 had a single defect. The relative prevalence of single muscular VSD was: midmuscular 55 (44%), apical 31 (25%), anterior 33 (26%), and posterior 6 (5%). Thirty patients had signs of spontaneous closure and only 1 underwent surgery. There was no difference in rate of closure with respect to anatomic locations. Patients with multiple muscular VSD were either referred for surgery in the first year of life or had a course similar to patients with a single VSD. Muscular VSD associated with other cardiac malformations was more often encountered in patients with conoventricular VSD and coarctation of the aorta. The distribution of anatomic groups of muscular VSD in association with malformations was similar to the single VSD.

Coarctation index: identification of recurrent coarctation in infants with hypoplastic left heart syndrome after the Norwood procedure

Assessment of recurrent coarctation after the Norwood procedure by routine measures is complicated by the unusual physiology caused by the presence of a modified Blalock-Tausig shunt with distal aortic arch obstruction. We present a new index that uses 2-dimensional measurement of the reconstructed aortic arch, which is highly sensitive and specific in identifying recurrent coarctation after the Norwood procedure in children with hypoplastic left heart syndrome.

Echocardiography, not chest radiography, for evaluation of cannula placement during pediatric extracorporeal membrane oxygenation

Objective: Optimal cannula position is essential during extracorporeal membrane oxygenation (ECMO). We hypothesize that echocardiography is superior to chest radiography in diagnosing abnormal cannula position during ECMO. Design: Retrospective. Setting: Pediatric hospital. Patients: 100 pediatric patients requiring ECMO. Measurements and Main Results: We reviewed the medical records of all ECMO patients (n = 100), including reports of all echocardiograms (n = 326), during the years 2002–2004. Of the 91 patients who had echocardiograms while on ECMO, 33 had at least 1 echocardiogram for cannula-position evaluation. Of the remaining 58 patients with echocardiograms for reasons other than cannula-position evaluation, 4 (7%) were found to have abnormal cannula position. These included arterial cannula (AC) within 2–4 mm of the aortic valve (n = 2), AC across the aortic valve into the left ventricle (n = 1), and venous cannula (VC) abutting the atrial septum (n = 1). Of the 33 patients with echocardiograms for evaluation of cannula position, 8 (24%) required intervention. Of those 8 patients, 4 required cannula repositioning due to VC in the coronary sinus (n = 1), VC abutting atrial septum (n = 1), AC in left subclavian artery (n = 1), and AC within 3 mm of aortic valve (n = 1). The remaining 4 with normal cannula position required upsizing of the VC (n = 2), increased circuit flow (n = 1), or intravascular volume administration (n = 1). Overall, 12 of 91 patients (13%) required intervention based on echocardiographic findings. Chest radiography did not detect abnormalities of ECMO cannula position in any of the 8 patients with this problem, nor were any additional patients with abnormal cannula position identified by chest radiography. Conclusions: Echocardiography appears to be superior to chest radiography for assessing ECMO cannula position in our institution. A prospective study, including cost analysis, comparing chest radiography and echocardiography, is needed to definitely determine the preferred diagnostic test or sequence of tests to establish ECMO cannula position.

The four-chamber view and its sensitivity in detecting congenital heart defects.

We sought to determine the sensitivity of detecting congenital heart defects with routine antenatal ultrasound including the four-chamber view in a population at low risk for cardiac anomalies. Neonatal outcome and anomaly databases were reviewed to identify cases of morphologic cardiac defects from 1988–1992. Of 176 cases identified, 62 (35%) had routine antenatal ultrasound including the four-chamber view. Thirteen of these 62 (21%) were diagnosed by ultrasound and 18 of the 116 (15%) total defects present were seen. Of these, only 16 of 25 (64%) defects reasonably expected to be seen by the four-chamber cardiac view alone were detected. The routine ultrasound four-chamber cardiac evaluation is limited and detection depends on the type of cardiac defect present.

Cardiac Findings in Congenital Muscular Dystrophies

Cardiac involvement (CI) in congenital muscular dystrophies (CMDs) has been only rarely investigated so far. By means of a systematic literature search we reviewed the literature about CI in CMD and found that CI is apparently absent in Ullrich CMD or CMD with integrin deficiency and only mild in Bethlem CMD. CI in merosin deficiency includes dilated cardiomyopathy and systolic dysfunction. CI in dystroglycanopathies seems most prevalent among all CMDs and includes dilated cardiomyopathy, systolic dysfunction, and myocardial fibrosis in Fukuyama CMD. Among the nonspecified dystroglycanopathies, CI manifests as dilated cardiomyopathy, hypertrophic cardiomyopathy (CMP) or systolic dysfunction. With CMD type 1C, as well as with limb-girdle muscular dystrophy 2I, up to half of the patients develop dilated cardiomyopathy. In rigid-spine syndrome, predominantly the right heart is affected secondary to thoracic deformity. In patients who carry LMNA mutations, CI may manifest as dilated cardiomyopathy, hypertrophic cardiomyopathy, or fatal ventricular arrhythmias. Overall, CI in patients with CMD varies considerably between the different CMD types from absent or mild CI to severe cardiac disease, particularly in merosin deficiency, dystroglycanopathies, and laminopathies. Patients with CMD with CI require regular cardiologic surveillance so that severe, treatable cardiac disease is not overlooked.

Echocardiographic predictors of symptomatic patent ductus arteriosus in extremely-low-birth-weight preterm neonates

Objective:Identify echocardiographic parameters at ⩽4 day postnatal that predict the subsequent need for closure of a clinically significant patent ductus arteriosus (sPDA) in extremely-low-birth-weight neonates (ELBW).Study Design:Serial echocardiograms obtained in 115 ELBW at ⩽10 day postnatal were examined to estimate PDA size using the PDA:left pulmonary artery (LPA) diameter ratio: ⩾1 indicated a large PDA, <1 but ⩾0.5 moderate, and <0.5 small. Sensitivity, specificity, and positive predictive values (PPV) were determined for ELBW <27 weeks and ⩾27 weeks gestational age.Result:Neonates with moderate to large PDA at ⩽4 day had 15-times greater likelihood of requiring treatment for sPDA than those with a small PDA (95% confidence interval (CI): 5.6–41). Sensitivity, specificity and PPV of the PDA:LPA at <27 weeks was 80, 86 and 92%, respectively.Conclusion:A moderate to large PDA determined from the PDA:LPA ratio at ⩽4 day postnatal identifies neonates <27 week gestation who subsequently require closure of a PDA.