Marcus S. Schamberger

Course of Right and Left Ventricular Function in Patients with Pulmonary Insufficiency After Repair of Tetralogy of Fallot

Abstract. Surgical repair of tetralogy of Fallot (TOF) frequently results in pulmonary valve insufficiency. Nevertheless, no serial information is available on the long-term impact of the valvular insufficiency on right and left ventricular function. Right and left ventricular ejection fraction was measured serially by radionuclide angiocardiography in 21 patients with at least moderate pulmonary insufficiency after repair of TOF. A baseline study was obtained an average of 1.2 years after repair, and a follow-up study was performed an average of 10.2 years after surgery. Changes in ventricular function over time and deviations from the normal range were analyzed. At baseline evaluation the mean right ventricular ejection fraction (RVEF; 0.52 ± 0.10) and left ventricular ejection fraction (LVEF; 0.68 ± 0.10) were normal. At the time of follow-up the mean RVEF had significantly decreased to 0.45 ± 0.09 (p < 0.01). The mean LVEF had decreased to 0.60 ± 0.11 (p < 0.02). This change was independent of the RVEF (r=−0.13). Eleven patients (52%) had an abnormal RVEF or LVEF at follow-up. Nineteen patients (90%) showed a decrease of 0.05 or more in RVEF, LVEF, or both between studies. These data suggest a negative impact of long-standing pulmonary insufficiency on right and left ventricular systolic function after repair of TOF. Therefore, continued surveillance of biventricular function in this patient population appears warranted.

Large left-to-right shunts and congestive heart failure increase total energy expenditure in infants with ventricular septal defect ☆

T purpose of the present study was to determine the effect of congestive heart failure (CHF) and/or left-to-right shunting on resting and total energy expenditure, energy intake (caloric intake), and the energy expenditure of physical activity in a group of 3to 4-month-old infants with ventricular septal defect (VSD) and a group of healthy age-matched controls. We hypothesized that infants with VSD being treated for CHF would exhibit significantly higher rates of total energy expenditure (TEE) than infants with VSD without CHF or healthy infants. We also hypothesized that the magnitude of left-to-right shunting (Qp:Qs) would positively correlate with TEE. • • • Threeto 5-month old infants with VSD were identified in the cardiology clinic, confirmed by echocardiography, and recruited for the study population. This age group was chosen because pulmonary vascular resistance in these infants with heart defects had generally decreased enough so that a large left-to-right shunt should be apparent and growth problems may have been manifested, but most did not have surgical intervention. Seventeen infants (6 males and 11 females) with VSD and 13 (8 males and 5 females) healthy control infants were studied. Infants with other heart lesions or chromosomal defects were excluded. Infants who had undergone palliative procedures (pulmonary artery banding) or other surgical procedures, or who had been hospitalized within 6 weeks from the study were also excluded. The patient group was subdivided into 2 groups. Ten patients were being treated for CHF (CHF group) and 7 patients were not (non-CHF group). The diagnosis of CHF was based on clinical parameters such as tachypnea, hepatomegaly, or increases in medications to control symptoms. The study was approved by the institutional review board of Indiana University-Purdue University at Indianapolis. Written informed consent was obtained from parents or guardians before enrollment in the study. Infant characteristics are listed in Table 1. There were no significant differences between birth weight, gestational age, or age at the time of the study. However, there was a significant difference between weights at the time of the study. All 10 patients in the CHF group received lasix and digoxin; 4 infants also received aldactone. None of the infants in the control group was taking medications. Five of the CHF group infants received higher calorie formula or fortified breast milk (25 to 30 cal/oz); the non-CHF group infants received 20 cal/oz of formula, and all control infants received regular 20 cal/oz of formula or breast milk. Anthropometric measurements were obtained on day 1 of the study. Weight, crown-heel length, head and mid-arm circumference, triceps, and subscapular skinfold thicknesses were measured in each infant. All measurements were taken in triplicate and mean value was used. Open circuit indirect calorimetry was used to measure resting energy expenditure (REE). This was performed on day 1 of the study for approximately 30 minutes while the infants were asleep and within 1 hour of the last feeding. Infants were not sedated. A Plexiglas hood (Rohm and Haas Co., Philadelphia, Pennsylvania) was placed over the infant’s head, and a suction pump was used to draw air through the hood. Oxygen consumption and carbon dioxide (CO2) production were determined from the oxygen and CO2 gradients across the face during a steady-state period, correcting for room temperature and atmospheric pressure.1 The respiratory quotient was calculated as respiratory quotient 5 CO2/oxygen consumption [VCO2/VO2], where VCO2 and VO2 are the volumes of CO2 produced and oxygen consumed, respectively. REE was calculated using the modified Weir formula.2 The doubly labeled water method was used to measure TEE, energy intake, and total body water over a 1-week period. This method is based on the premise that oxygen exits the body as water and CO2, while hydrogen exits solely as water. The difference between the elimination rates of O and H reflects the rate of CO2 production. From the rate of CO2 production and the respiratory or food quotient, the TEE can be calculated from the Weir formula.2 After collection of a baseline urine sample, an oral dose of Oand H-labeled water was administered to the infant (2.0 g H2 O/kg and 0.08 g H2O/kg).3 Serial urine samples were obtained over the next 24 hours to measure the total body water pool size. Daily urine samples were collected over the next 7 days to measure elimination rates of O and H. Samples were From the Section of Pediatric Cardiology and Neonatal-Perinatal Medicine, Department of Pediatrics, James Whitcomb Riley Hospital for Children, Indiana University Medical Center, Indianapolis, Indiana. This work was supported in part by Grants S10-RR-07269 and M01RR-750 from the National Institutes of Health, Bethesda, Maryland, and the James Whitcomb Riley Memorial Association, Indianapolis, Indiana. Dr. Leitch’s address is: Indiana University School of Medicine, Department of Pediatrics, Riley Hospital for Children, 699 West Drive, RR 208, Indianapolis, Indiana 46202-5210. E-mail: cleitch@ iupui.edu. Manuscript received August 31, 2000; revised manuscript received and accepted November 22, 2000.

Utilizing a Collaborative Learning Model to Promote Early Extubation Following Infant Heart Surgery

Objective: To determine whether a collaborative learning strategy-derived clinical practice guideline can reduce the duration of endotracheal intubation following infant heart surgery. Design: Prospective and retrospective data collected from the Pediatric Heart Network in the 12 months pre- and post-clinical practice guideline implementation at the four sites participating in the collaborative (active sites) compared with data from five Pediatric Heart Network centers not participating in collaborative learning (control sites). Setting: Ten children’s hospitals. Patients: Data were collected for infants following two-index operations: 1) repair of isolated coarctation of the aorta (birth to 365 d) and 2) repair of tetralogy of Fallot (29–365 d). There were 240 subjects eligible for the clinical practice guideline at active sites and 259 subjects at control sites. Interventions: Development and application of early extubation clinical practice guideline. Measurements and Main Results: After clinical practice guideline implementation, the rate of early extubation at active sites increased significantly from 11.7% to 66.9% (p < 0.001) with no increase in reintubation rate. The median duration of postoperative intubation among active sites decreased from 21.2 to 4.5 hours (p < 0.001). No statistically significant change in early extubation rates was found in the control sites 11.7% to 13.7% (p = 0.63). At active sites, clinical practice guideline implementation had no statistically significant impact on median ICU length of stay (71.9 hr pre- vs 69.2 hr postimplementation; p = 0.29) for the entire cohort. There was a trend toward shorter ICU length of stay in the tetralogy of Fallot subgroup (71.6 hr pre- vs 54.2 hr postimplementation, p = 0.068). Conclusions: A collaborative learning strategy designed clinical practice guideline significantly increased the rate of early extubation with no change in the rate of reintubation. The early extubation clinical practice guideline did not significantly change postoperative ICU length of stay.

After Repair, Atrioventricular Valve Regurgitation During Cardiac Extracorporeal Membrane Oxygenation Predicts Survival

BACKGROUND When echocardiography is used to follow up cardiac patients on extracorporeal membrane oxygenation (ECMO), ejection fraction as a measure of ventricular function has been used to determine likelihood of survival after decannulation. We hypothesized that systemic atrioventricular (AV) valve regurgitation while on ECMO may be a better predictor of survival. METHODS From February 1995 to March 2001, 64 patients required ECMO postoperatively. Three were removed from ECMO owing to brain death, so 61 patients formed our study group. Retrospective chart review was performed with systemic AV valve regurgitation and ejection fraction while on ECMO recorded from echocardiography reports. Patients alive 1 month after decannulation were considered survivors. RESULTS There were 29 survivors (47.5%). Ejection fraction in survivors (mean 41% +/- 0.13%) was not significantly different from that of nonsurvivors (41% +/- 0.18%; p < or = 0.839) but severity of systemic AV valve regurgitation was significantly different. Only 2 survivors (6.8%) had at least moderate AV valve regurgitation compared with 17 of the 32 nonsurvivors (53%). Patients with moderate to severe regurgitation while on ECMO were less likely to survive for 1 month after decannulation, with an odds ratio of 16.63 (95% confidence interval 3.08, 89.70; p = 0.001). Also female sex increased the odds of death by a factor of 5.43 (95% confidence interval 1.45, 20.36; p = 0.012). CONCLUSIONS Severity of systemic AV valve regurgitation on ECMO is a more reliable predictor than ejection fraction for survival at 1 month after decannulation. Patients with less than moderate AV valve regurgitation have a significantly better chance of survival.

Resolution of Acquired Pulmonary Arteriovenous Malformations in a Patient with Total Anomalous Systemic Venous Return

An 11-year-old male with total anomalous systemic venous return had surgical repair except for the hepatic venous return, which drained to the left atrium. He developed progressive cyanosis and fatigue and was diagnosed with large pulmonary arteriovenous malformations (PAVMs) during cardiac catheterization with the use of bubble contrast echocardiography. After surgical redirection of hepatic venous flow to the right heart and pulmonary arterial system, resolution of these PAVMs was demonstrated clinically and by contrast echocardiography. This unique case report demonstrates the development of PAVMs with exclusion of hepatic venous return through the pulmonary vascular bed while pulsatile pulmonary blood flow remains intact. It reinforces the likelihood of the absence of an as yet unidentified hepatic vasoactive substance as the source for development of PAVMs.

Increase of B‐type Natriuretic Peptide from Baseline Increases the Risk of Death or Retransplant in Pediatric Cardiac Transplant Patients, Midterm Results

UNLABELLED BACKGROUND; Several studies have demonstrated the utility of B-type natriuretic peptide (BNP) in the months following cardiac transplant. The purpose of this study was to analyze longitudinal BNP data in pediatric cardiac transplant patients and determine the efficacy of BNP in routine follow-up of transplant to help predict the adverse event of death or re-transplant. METHODS From October 2002 to July 2007, 53 pediatric cardiac transplant patients were treated in an unmatched case-control study. Along with routine studies, BNP values were obtained at regular intervals. Six patients were excluded due to recent transplant, and three patients were excluded due to poor compliance. A baseline BNP was established for each subject utilizing the mean of all BNP values during year 2 post-transplant, or the first year of measured BNP in those patients whose transplant preceded the study by more than 1 year (time from transplant to first BNP 7.0 +/- 3.5 years). The median BNP of all data points since transplant was utilized as an additional surrogate baseline. Univariate logistic regression was used to evaluate BNP versus other covariates on cardiac death. RESULTS Forty-four patients provided 1254 BNP data points spanning 173 patient years. Nine (20.5%) had an adverse event. Patients who experienced an adverse event had a higher baseline BNP (mean 365 +/- 290; median 375 +/- 352)) when compared to patients without an event (mean 128 +/- 78; median 121 +/- 62; p = 0.04 and p = 0.06)). All subjects with adverse events had a BNP value >or= 250 during the 90 days preceding the event compared to 32.4% of those who did not (odds ratio: 23.13, p < 0.01). A log fold increase in the BNP value compared to the baseline median BNP is a risk for cardiac death in the subsequent 90-day period (OR: 6.82, 95% confidence interval: 1.25-37.11, p = 0.03). CONCLUSION Routine BNP monitoring in the post-cardiac transplant pediatric patient allows for the determination of a median BNP, which can be used as a baseline. A log fold increase from the median BNP, or a BNP value >or= 250, increases the risk of death or re-transplant and suggests a 90-day period of heightened clinical surveillance, perhaps necessitating increased medication or re-listing for repeat transplant.

Quality of life following paediatric heart transplant: are age and activity level factors?

BACKGROUND We evaluated whether quality of life correlates to age and activity in children following heart transplantation. In addition, quality of life in children following heart transplantation was compared with previously reported values in children with congenital heart disease. Quality of life remains an important aspect of therapy. METHODS The Pediatric Quality of Life Inventory Generic Core Scales and Cardiac Module were administered to 14 children who had previously undergone heart transplantation. Patients wore a pedometer for 7 days to assess daily activity. RESULTS The age at assessment was 13.1±1.9 years. The patients were 7.1±5.7 years post heart transplantation. There was a negative correlation between age at first heart transplantation and emotional (r=-0.64; p<0.05) and school function (r=-0.57; p<0.05). A negative correlation between patients age at assessment and perceived physical appearance existed (r=-0.53; p<0.05). Daily steps negatively correlated with cognitive (r=-0.58; p<0.05), physical (r=-0.63; p<0.05), emotional (r=-0.62; p<0.05), and school function (r=-0.66; p<0.01). Heart transplantation patients reported better scores for treatment and symptoms (p<0.05) but lower physical health scores (p<0.01) than those with moderate congenital heart disease. CONCLUSIONS Paediatric heart transplantation patients reported overall similar quality of life as patients with moderate congenital heart disease. Children receiving heart transplants at an older age may require additional emotional and educational support. Heart transplantation patients with higher activity levels may be more aware of their physical, emotional, and cognitive limitations, and thus score lower on these quality of life indicators.

Use of Cardiac Magnetic Resonance Imaging to Determine Myocardial Viability in an Infant with In Utero Septal Myocardial Infarction and Ventricular Noncompaction

We describe the use of cardiac magnetic resonance imaging (CMRI) to determine myocardial viability and subsequently clinical prognosis in a patient with in utero septal myocardial infarction (MI) and dilated cardiomyopathy. MI is most commonly associated with congenital heart disease. These lesions include aortic atresia and stenosis, interrupted aortic arch, hypoplastic left ventricle (LV), and total anomalous pulmonary venous return (TAPVR) [3]. Within the last decade, it has been clearly established that systolic dysfunction is not always a definitive status after MI [10]. In the presence of residual viable myocardium and an adequate myocardial perfusion, contractility might normalize—this process being related to a remarkable prognostic benefit [10]. Until the use of CMRI, myocardial viability has been poorly characterized by other imaging modalities, thus making prognosis difficult to predict. Using myocardial delayed-enhancement CMRI, this patient was shown to have a dilated left ventricle with noncompaction, longitudinal midwall hyperenhancement consistent with nonviable tissue, and severely diminished left ventricular function. In conclusion, CMRI is the only imaging modality that can define anatomy, function, and tissue characterization simultaneously. In the future, CMRI could circumvent the need for more invasive diagnostic procedures in determining the cause and prognosis of patients with dilated cardiomyopathy and myocardial infarction.

Resolution of inferior venous baffle leak and total venous occlusion using a bare stent and the gore(®) excluder( ®) aortic extension in transposition of the great arteries after mustard procedure.

We present a patient with a history of Mustard repair for transposition of the great arteries. The patient presented with complete inferior venous baffle obstruction and a large baffle leak after several years of cyanosis. Complete relief of the obstruction and exclusion of the baffle leak were accomplished with the use of a combination of bare metal stenting and the Gore® Excluder® aortic extender. To our knowledge, this represents the first reported use of the Gore® Excluder® aortic extender in the setting of inferior venous baffle leak and associated total inferior vena cava obstruction.

Cyanosis and Stroke due to Functional Cor Triatriatum Dexter in a Neonate

Small remnants of the right valve of the sinus venosus are commonly found in adults, but the incidence and risk associated with these embryonic remnants in neonates are not well studied. The following report describes a cyanotic neonate with a large Eustachian valve remnant creating a functional cor triatriatum dexter who was initially diagnosed with persistent pulmonary hypertension of the newborn. The cyanosis in this infant improved over the first postnatal week with conservative management, but she suffered multifocal subcortical stroke, likely related to her intracardiac shunt. The clinical presentation and questions regarding long-term management of this rare diagnosis are explored.