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Biomedical subjects

Anthony C Chang

Publications and source records attributed to Anthony C Chang.

At least 19 recordsLinked to original sources
PubMed2006

Autologous Ross operation for congenital aortic stenosis.

Congenital aortic stenosis is a relatively common cardiac anomaly encountered in approximately 5% of all children with heart disease. The Ross procedure is increasingly used for replacement of the aortic valve in children. We report a 12-year-old boy who was born with congenital aortic stenosis secondary to a bicommissural aortic valve. The patient underwent open valvotomy in infancy and aortic valvuloplasty 2 years later. Residual/recurrent stenosis prompted referral for aortic valve replacement, and he underwent an autologous Ross procedure, in which the aortic root was replaced with a pulmonary autograft and the repaired aortic valve was used to restore right ventricular-to-pulmonary artery continuity. The postoperative course was unremarkable. Nitroprusside, esmolol, and labetolol were used to control postoperative hypertension. He was discharged 4 days after surgery on oral furosemide and aspirin, and he has had no cardiovascular symptoms during follow-up. Recent echocardiography demonstrated mild right ventricular outflow tract obstruction with a peak velocity of 3.6 m/sec, with a gradient of 42 mmHg and moderate pulmonary insufficiency. There was no left ventricular outlet tract obstruction or aortic insufficiency.

Anastomosis, Surgical↗
PubMed2006

Future pharmacologic agents for treatment of heart failure in children.

The addition of new agents to the armamentarium of treatment options for heart failure in pediatric patients is exciting and challenging. Administration of these therapies to pediatric patients will require careful scrutiny of the data and skilled application. Developmental changes in drug metabolism, excretion, and distribution are concerning in pediatric patients, and inappropriate evaluation of these parameters can have disastrous results. Manipulation of the neurohormonal pathways in heart failure has been the target of most recently developed pharmacologic agents. Angiotensin receptor blockers (ARBs), aldosterone antagonists, beta-blockers, and natriuretic peptides are seeing increased use in pediatrics. In particular, calcium sensitizing agents represent a new frontier in the treatment of acute decompensated heart failure and may replace traditional inotropic therapies. Endothelin receptor antagonists have shown benefit in the treatment of pulmonary hypertension, but their use in heart failure is still debatable. Vasopressin antagonists, tumor necrosis factor inhibitors, and neutral endopeptidase inhibitors are also targeting aspects of the neurohormonal cascade that are currently not completely understood. The future of pharmacologic therapies will include pharmacogenomic studies on new and preexisting therapies for pediatric heart failure. The education and skill of the practitioner when applying these agents in pediatric heart failure is of utmost importance.

Adrenergic beta-Antagonists↗
PubMed2006

An alternative treatment strategy for pump thrombus in the DeBakey VAD Child: use of clopidogrel as a thrombolytic agent.

Our institution has used the DeBakey VAD Child as a bridge to heart transplantation in select pediatric patients. Pump thrombus is a potentially serious complication with few available treatment options. Only surgical device exchange or the use of tissue plasminogen activator are reported in the literature. We report the use of clopidogrel as an alternative thrombolytic agent in the presence of pump thrombus in an adolescent patient with a DeBakey VAD Child heart pump.

Adolescent↗
PubMed2006

Perioperative management of ventricular assist devices in children and adolescents.

Ventricular assist devices are an integral part of therapy for patients with end-stage heart failure. Devices can either bridge to recovery or to transplantation. Options for ventricular assist devices include those that are centrifugal, pulsatile, and new rotary/axial devices. Care of the patient on a ventricular assist device is multifaceted, involving pharmacologic or mechanical support of the right ventricle, management of systemic vascular resistance, and manipulation of the hematologic system to avoid bleeding or thrombosis. In addition, care of these patients involves support of all end organs and avoidance of infectious complications. Care of these patients is complex, requiring a highly integrated team for optimal outcome.

Adolescent↗
PubMed2006

Arterial pulse wave analysis: An accurate means of determining cardiac output in children.

OBJECTIVE: Cardiac output is a useful measure of myocardial performance. Standard methods of determining cardiac output are not without risk and can be problematic in children. Arterial pulse wave analysis (PulseCO), a novel, minimally invasive cardiac output determination technique, offers the advantage of continuous monitoring, convenience, and low risk. This technique has not been validated in children. The purpose of this study was to validate PulseCO as an accurate means of noninvasively determining real-time cardiac output in children. DESIGN: Prospective, single-center evaluation. SETTING: Children's hospital. PATIENTS: Any child with a structurally normal heart, undergoing hemodynamic evaluation in the cardiac catheterization laboratory, was included. INTERVENTIONS: A prograde right heart catheterization was performed, and cardiac output was determined using the thermodilution technique, via placement of a pulmonary arterial catheter. MEASUREMENTS AND MAIN RESULTS: Thermodilution results were compared with continuous real-time cardiac output measurements obtained with the PulseCO system, and they were then analyzed by standard correlation techniques and Bland-Altman analysis. Twenty patients were evaluated with a median age of 10.5 yrs and a median weight of 25 kg. The mean thermodilution cardiac index was 3.3 +/- 0.9 L/min/m, whereas the mean PulseCO cardiac index was 3.1 +/- 0.9 L/min/m. Standard Pearson correlation tests revealed a correlation coefficient of .94 (p < .001). Bland-Altman analysis revealed excellent clinical agreement with a mean difference of 0.19 L/min/m and a precision of 0.28 L/min/m at 2 sd. CONCLUSIONS: Arterial pulse wave analysis by the PulseCO system provides a novel, minimally invasive method of determining real-time cardiac output in children.

Adolescent↗
PubMed2006

Complex pulmonary atresia in a neonate: successful surgical palliation for right pulmonary artery arising from the right main coronary artery.

We describe the case of a 3-week-old infant who was diagnosed with pulmonary atresia, a ventricular septal defect, and discontinuous pulmonary arteries. The pulmonary artery anatomy was delineated by angiography: the right pulmonary artery arose from the proximal right coronary artery, and the left pulmonary artery arose from a left ductus arteriosus. This case illustrates the importance of careful delineation of the anatomy in complex pulmonary atresia before surgical intervention.

Abnormalities, Multiple↗
PubMed2005

Neonates with aortic coarctation and cardiogenic shock: presentation and outcomes.

BACKGROUND: Some neonates with coarctation of the aorta (COA) present with cardiogenic shock and secondary end-organ injury. The management of this subgroup imposes unique challenges. We review our perioperative strategy and outcomes for neonates with COA who presented with cardiogenic shock. METHODS: Neonates (younger than 30 days) with isolated COA or COA with aortic arch hypoplasia were identified. Retrospective review was performed to identify and characterize patients who presented with cardiogenic shock, defined as impaired left ventricular (LV) or right ventricular (RV) systolic function, or both, respiratory failure requiring tracheal intubation, and metabolic acidosis. RESULTS: Thirteen neonates presented in cardiogenic shock and underwent surgical repair. No patients required catheter or surgical reintervention for recoarctation. There were no deaths at a mean follow-up of 54 months. Group I neonates (isolated COA, n = 7) underwent end-to-end anastomosis through left thoracotomy. The mean age and pH at presentation were 9 (+/-1.1) days and 7.07 (+/-0.21), respectively. The mean preoperative and postoperative LV myocardial performance indices (MPI) were 0.81 (+/-0.22) and 0.37 (+/-0.16), respectively (p = 0.002). Group II neonates (COA with arch hypoplasia +/- ventricular septal defect, n = 6) underwent aortic arch advancement and ventricular septal defect closure through median sternotomy. The mean time from diagnosis to surgery in group II was 5.5 (+/-1.9) days versus 2.4 (+/-1.5) days in group 1 (p = 0.01). The mean age and pH at presentation were 11.8 (+/-9.3) days and 7.02 (+/-0.21), respectively. The mean preoperative and postoperative LV MPI were 0.46 (+/-0.13) and 0.35 (+/-0.11), respectively (p = 0.02). The total hospital length of stay in group II patients was 18 (+/-6.23) days versus 11.3 (+/-5. 7) days in group I (p = 0.04). CONCLUSIONS: Timely intervention with a strategy individualized to the patient anatomy can be performed with excellent outcomes in neonates with COA and cardiogenic shock. Neonates with isolated COA had worse preoperative LV MPI, which reflects more significant global left ventricular systolic dysfunction in this subgroup. The elapsed time from diagnosis to surgery was decreased in neonates with isolated COA.

Aortic Coarctation↗
PubMed2005

Lessons learned from the first application of the DeBakey VAD Child: an intracorporeal ventricular assist device for children.

We report and describe the design and the first clinical implantation of the DeBakey ventricular assist device (VAD) Child, a pediatric intracorporeal left ventricular assist device, in a 6-year-old girl. The risk-benefit of novel technologies in advanced heart failure and the lessons learned by our experience are important to consider in hopes that other centers (where this device is now available) may benefit.

Cardiomyopathies↗
PubMed2005

Altered expression of dystrophin within the thoracic aorta in coarctation.

Although persisting endothelial dysfunction has been established in the vasculature of patients following surgical repair of coarctation, it is unknown whether there are alterations in the cytoskeleton of the aorta in such patients. We compared staining of N-terminus dystrophin in the smooth muscle of the aortic wall of a patient with coarctation to that in a patient without coarctation, the latter undergoing surgical treatment of a double aortic arch. There was a marked difference in the pattern of expression of dystrophin between the two, with the coarcted specimen demonstrating marked fragmentation but normal intensity of staining. As far as we are aware, ours is the first report to demonstrate the presence of dystrophin in the smooth muscle of the aorta. Alterations in the cytoskeletal structure may account for underlying aberrations in endothelial function in such patients, and is a topic that warrants further investigation.

Aorta, Thoracic↗
PubMed2005

Hemodynamic effects of rescue protocol hydrocortisone in neonates with low cardiac output syndrome after cardiac surgery.

OBJECTIVE: To assess the hemodynamic effects and safety of hydrocortisone in neonates with low cardiac output syndrome requiring high levels of inotropic support and fluid resuscitation after cardiac surgery. DESIGN: Retrospective chart review. SETTING: Fifteen-bed pediatric cardiovascular intensive care unit. PATIENTS: Twelve neonates with low cardiac output syndrome after cardiac surgery to whom hydrocortisone was administered according to one of two dosing regimens (100 mg/[m.day] for 2 days, 50 mg/[m.day] for 2 days, and 25 mg/[m.day] for 1 day or 100 mg/[m.day] for 1 day, 50 mg/[m.day] for 2 days, and 25 mg/[m.day] for 2 days) were identified from the Department of Pharmacy database between September 2002 and January 2004. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The mean and systolic blood pressure increased significantly 3 hrs after hydrocortisone treatment from the values preceding hydrocortisone administration. The mean blood pressure increased from 44.0+/-3.0 to 55.4+/-2.3 mm Hg (p=.01) and the systolic blood pressure increased from 64.2+/-4.7 to 78.3+/-3.4 mm Hg (p=.04). Comparable beneficial changes were also seen in the heart rate, which decreased from 168.3+/-4.6 to 148.3+/-5.6 beats/min (p=.004) after 24 hrs of hydrocortisone administration and remained at this level during the 72 hrs of follow-up. Significant weaning of epinephrine infusions was possible, from a mean dose of 0.16 to 0.06 microg/(kg.min) (p=.008), within 24 hrs after the initiation of steroid administration, and this reduction was not offset by increases in other inotropic agents. hydrocortisone administration caused nonsignificant increases in mean blood glucose concentration (from 116.2+/-20.6 to 156.0+/-25.6 mg/dL; p=.64), mean white blood cell count (from 16.6+/-1.6 to 18.9+/-2.6 x 10 U/L; p=.35), and sodium level (from 144.7+/-1.3 to 145.3+/-1.3 mmol/L; p=.51). Ten of the 12 patients (83.3%) survived. CONCLUSION: Most of the hemodynamically compromised neonates who were unresponsive to high doses of inotropic agents and fluid resuscitation after heart surgery responded to hydrocortisone with improvement of hemodynamic parameters and a decrease in inotropic requirements.

Anti-Inflammatory Agents↗
PubMed2005

A noninvasive estimation of mixed venous oxygen saturation using near-infrared spectroscopy by cerebral oximetry in pediatric cardiac surgery patients.

BACKGROUND: Near-infrared spectroscopy (NIRS) is a noninvasive optical monitor of regional cerebral oxygen saturation (rSO2). The aim of this study was to validate the use of NIRS by cerebral oximetry in estimating invasively measured mixed venous oxygen saturation (SvO2) in pediatric postoperative cardiac surgery patients. METHODS: Twenty patients were enrolled following cardiac surgery with intraoperative placement of a pulmonary artery (PA) or superior vena cava (SVC) catheter. Five patients underwent complete biventricular repair--complete atrioventricular canal (n=3) and other (n=2). Fifteen patients with functional single ventricle underwent palliative procedures--bidirectional Glenn (n=11) and Fontan (n=4). Cerebral rSO2 was monitored via NIRS (INVOS 5100) during cardiac surgery and 6 h postoperatively. SvO2 was measured from blood samples obtained via an indwelling PA or SVC catheter and simultaneously correlated with rSO2 by NIRS at five time periods: in the operating room after weaning from cardiopulmonary bypass, after sternal closure, and in the CICU at 2, 4, and 6 h after admission. RESULTS: Each patient had five measurements (total=100 comparisons). SvO2 obtained via an indwelling PA or SVC catheter for all patients correlated with rSO2 obtained via NIRS: Pearson's correlation coefficient of 0.67 (P<0.0001) and linear regression of r2=0.45 (P<0.0001). Separate linear regression of the complete biventricular repairs demonstrated an r=0.71, r2=0.50 (P<0.0001). Bland-Altman analysis showed a bias of +3.3% with a precision of 16.6% for rSO2 as a predictor of SvO2 for all patients. Cerebral rSO2 was a more accurate predictor of SvO2 in the biventricular repair patients (bias -0.3, precision 11.8%), compared with the bidirectional Glenn and Fontan patients. CONCLUSIONS: Regional cerebral oximetry via NIRS correlates with SvO2 obtained via invasive monitoring. However, the wide limits of agreement suggest that it may not be possible to predict absolute values of SvO2 for any given patient based solely on the noninvasive measurement of rSO2. Near-infrared spectroscopy, using the INVOS 5100 cerebral oximeter, could potentially be used to indicate trends in SVO2, but more studies needs to be performed under varying clinical conditions.

Brain Chemistry↗
PubMed2005

Preterm infants with congenital heart disease and bronchopulmonary dysplasia: postoperative course and outcome after cardiac surgery.

OBJECTIVE: Success in treatment of premature infants has resulted in increased numbers of neonates who have bronchopulmonary dysplasia (BPD) and require surgical palliation or repair of congenital heart disease (CHD). We sought to investigate the impact of BPD on children with CHD after heart surgery. METHODS: This was a retrospective, multicenter study of patients who had BPD, defined as being oxygen dependent at 28 days of age with radiographic changes, and CHD and had cardiac surgery (excluding arterial duct ligation) between January 1991 and January 2002. Forty-three infants underwent a total of 52 cardiac operations. The median gestational age at birth was 28 weeks (range: 23-35 weeks), birth weight was 1460 g (range: 431-2500 g), and age at surgery was 2.7 months (range: 1.0-11.6 months). Diagnoses included left-to-right shunts (n = 15), conotruncal abnormalities (n = 13), arch obstruction (n = 6), univentricular hearts (n = 4), semilunar valve obstruction (n = 3), Shone syndrome (n = 1), and cor triatriatum (n = 1). RESULTS: Thirty-day survival was 84% with 6 early and 6 late postoperative deaths. Survival to hospital discharge was 68%. There was 50% mortality for patients with univentricular hearts and severe BPD. The median duration of preoperative ventilation was 76 days (range: 2-244 days) and of postoperative ventilation was 15 days (range: 1-141 days). The median duration of cardiac ICU stay was 7.5 days (range: 1-30 days) and of hospital stay was 115 days (range: 35-475 days). Current pulmonary status includes on room air (n = 14), O2 at home (n = 4), and ventilated at home (n = 4) or in hospital (n = 4), and 5 patients were lost to follow-up. CONCLUSIONS: BPD has significant implications for children who have CHD and undergo cardiac surgery, leading to prolonged ICU and hospital stays, although most survivors are not O2 dependent. Postoperative mortality was highest among patients with univentricular hearts and severe BPD. Optimal timing of surgery and strategies to improve outcome remains to be delineated.

Bronchopulmonary Dysplasia↗