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Biomedical subjects

William T Mahle

Publications and source records attributed to William T Mahle.

31 records · Page 2Linked to original sources
PubMed2004

Neurodevelopmental outcomes in hypoplastic left heart syndrome.

Infants with hypoplastic left heart syndrome (HLHS) are now surviving to school age and early adulthood because of surgical palliation with either staged reconstruction or transplantation. Although in some respects these patients are doing remarkably well, recent investigations have shown that they are at risk for cognitive, neuromotor, and psychosocial problems. This article examines the neurodevelopmental outcome for children and adolescents with HLHS. In addition, hemodynamic and genetic factors unique to this patient population that may impact longer-term outcome are explored. The continued evolution of the pre-, intra- and post-operative care of the patient with HLHS has significantly improved early survival. Concomitant changes in care, such as selective cerebral perfusion and neurologic monitoring, aimed at reducing neurologic insult may also favorably impact later neurodevelopmental status.

Adolescent↗
PubMed2004

Economic analysis of palivizumab in infants with congenital heart disease.

OBJECTIVE: Palivizumab has been shown to reduce the number of respiratory syncytial virus (RSV)-related hospitalizations by 45% in children with congenital heart disease (CHD). The American Academy of Pediatrics has recommended that infants with hemodynamically significant CHD be considered for palivizumab. However, the economic implications of palivizumab prophylaxis in the CHD population have not been evaluated. In the present study, we sought to examine the cost savings and cost utility of RSV prophylaxis with palivizumab in children with CHD. METHODS: Probabilities of hospitalization and efficacy of prophylaxis were based on published results. Costs of hospitalization were derived from a published analysis of bronchiolitis hospitalization costs from a consortium of children's hospitals. A hypothetical cohort of 10,000 CHD patients (half of whom would receive palivizumab) was created to calculate cost-savings and cost-utility. To assess cost utility, we assumed that by reducing hospitalization, palivizumab would reduce RSV-related hospital mortality, generally reported to be 3% in CHD patients. Sensitivity analysis was performed. RESULTS: On the basis of a protocol of 5 monthly doses of palivizumab, the cost of prophylaxis for 1 RSV season was calculated as 6160 dollars per patient. After accounting for impact on direct and indirect costs of hospitalization, administration of palivizumab to 5000 CHD patients would result in a net loss of 20,415,753 dollars. If one assumes that palivizumab confers a survival benefit, then the cost of life-year saved is 100,338 dollars and cost of quality-adjusted life-year saved is 114,337 dollars. CONCLUSIONS: The cost of palivizumab prophylaxis was high relative to benefits realized. Given the large number of CHD patients who might be considered candidates for RSV prophylaxis (>6000 patients per year in United States) routine use of palivizumab in young children with hemodynamically significant CHD needs to be evaluated further.

Antibodies, Monoclonal↗
PubMed2004

De Vega tricuspid annuloplasty for systemic tricuspid regurgitation in children with univentricular physiology.

BACKGROUND AND AIM OF THE STUDY: Significant tricuspid valve regurgitation (TR) is problematic in children with univentricular physiology and a systemic tricuspid valve occasionally requiring tricuspid (systemic atrioventricular) valve replacement. Since 1998, the De Vega tricuspid annuloplasty technique has been applied for TR in these children. METHODS: Twelve children (median age 2.2 years; range: 6 months to 17 years) with moderate or severe systemic TR underwent a De Vega tricuspid annuloplasty during a bidirectional Glenn anastomosis (n = 3), Fontan procedure (n = 8) or aortic valve replacement late after a Fontan procedure (n = 1). Nine patients (75%) had prior Norwood palliation for hypoplastic left heart syndrome. Four patients had simultaneous repair of an abnormal tricuspid valve in addition to the De Vega procedure. RESULTS: There were no deaths during a mean follow up of 2.0 +/- 1.4 years (range: 6 months to 5.1 years). One child required pacemaker implantation early after operation, and one child with a Glenn anastomosis underwent cardiac transplantation 21 months postoperatively. In the remaining 11 patients, the most recent echocardiogram showed mild or no TR in eight children, mild-to-moderate TR in one child, and moderate TR in two children. No child had symptomatic TR (including the two with moderate TR), significant tricuspid stenosis, or late pacemaker implantation. CONCLUSION: The De Vega tricuspid annuloplasty safely provides excellent relief of systemic TR in children with univentricular physiology, with a majority of patients (73%) having mild or less residual TR at follow up examination. This simple technique is preferred to tricuspid (systemic) valve replacement in these children.

Adolescent↗
PubMed2003

Tricuspid regurgitation in patients with repaired Tetralogy of Fallot and its relation to right ventricular dilatation.

In a cohort of 56 school-aged children with repaired tetralogy of Fallot, significant (moderate to severe) tricuspid regurgitation was common (32% of patients) and was related to both tricuspid annulus dilatation and structural valve abnormalities that were potentially related to previous surgery. Even after adjusting for pulmonary regurgitation, tricuspid regurgitation was significantly correlated with right ventricular volume (r= 0.39, p = 0.009), suggesting that tricuspid regurgitation as well as pulmonary regurgitation may contribute significantly to progressive right ventricular dilatation in this population.

Cardiac Volume↗
PubMed2003

Early experience with a modified Norwood procedure using right ventricle to pulmonary artery conduit.

BACKGROUND: A recent modification to the Norwood procedure involves the use of a right-ventricle (RV) to pulmonary artery (PA) conduit to provide pulmonary blood flow for patients with hypoplastic left heart syndrome (HLHS). This modification is thought to provide more stable hemodynamics by avoiding the diastolic "run-off" that occurs with a Blalock-Taussig shunt. METHODS: We reviewed our experience with the first 11 patients undergoing the RV-PA conduit modification of the Norwood operation and compared their outcomes with those of the preceding 22 patients who underwent a conventional Norwood procedure. RESULTS: Between July 1999 and March 2002, 33 patients with HLHS underwent the Norwood procedure at a median age of 5 days (range 1 to 31 days). Aortic atresia was present in 28 (85%). No significant difference was noted between the RV-PA (n = 11) and conventional Norwood (n = 22) groups with respect to measures of morbidity such as duration of mechanical ventilation or hospital stay. Patients who underwent the conventional Norwood procedure did have significantly lower diastolic blood pressure in the early postoperative period (38.4 +/- 4.4 mm Hg versus 49.5 +/- 4.3 mm Hg, p = 0.001). The operative and 1-year survival rates were 81% and 81%, respectively, for patients with the RV-PA modification, which was not significantly different from those of patients who underwent the conventional procedure, 81% and 73% (p = 1.00 and p = 0.36). Two patients developed a pseudoaneurysm of the RV infundibulum after placement of RV-PA conduit. Four sudden deaths occurred after hospital discharge, all occurring in the conventional Norwood group. CONCLUSIONS: The RV-PA conduit modification of the Norwood procedure results in excellent early survival. By avoiding low diastolic blood pressure this modification may provide superior perfusion to the coronary vascular bed and potentially reduce the risk of sudden unexpected death.

Cardiac Surgical Procedures↗
PubMed2003

Deletion of chromosome 22q11.2 and outcome in patients with pulmonary atresia and ventricular septal defect.

BACKGROUND: The 22q11.2 deletion (del22q) is present in many patients with conotruncal abnormalities including pulmonary atresia with ventricular septal defect (PA/VSD). We sought to determine the impact of the del22q on outcome in subjects with PA/VSD. METHODS: We reviewed the experience for all patients with PA/VSD who were born between January 1993 and April 2002 and presented to our institution. Patients with conotruncal defects were routinely evaluated for genetic disorders including del22q. Fluorescence in situ hybridization was used to test for del22q. RESULTS: There were 67 subjects with PA/VSD who presented during that time period; testing for del22q was performed in 58 of 67 (87%) and these 58 patients comprised the study population. The 22q11.2 deletion was present in 20 of 58 (34%) patients tested. Major aortopulmonary collaterals were defined by angiography and were present in 27 (47%). These collaterals were significantly more common among subjects with del22q (13 of 20, 65%; p = 0.04). The median cross sectional area of the pulmonary arteries, the Nakata index, was significantly less for patients with del22q (41 versus 142 mm(2)/m(2); p = 0.006). There were 3 subjects, all of whom had del22q, who did not undergo surgery owing to markedly hypoplastic pulmonary arteries. Of the remaining 55 patients, 53 had arteriopulmonary shunt with or without unifocalization as the initial procedure and 35 patients have undergone complete repair. There were 8 operative deaths and 1 nonoperative death. The 5-year survival was 36% for patients with del22q versus 90% for patients without del22q. The 22q11.2 deletion was a significant risk factor for death, even after adjusting for the presence of major aortopulmonary collaterals (p = 0.004). There was no significant difference between the two groups with respect to the incidence of serious viral, bacterial, or fungal infections in the perioperative period. CONCLUSIONS: Patients with del22q and PA/VSD are at increased risk for death owing to a variety of factors including less favorable pulmonary artery anatomy. A better understanding of del22q, pulmonary artery anatomy, and outcome is required.

Abnormalities, Multiple↗
PubMed2003

Results with the freestyle porcine aortic root for right ventricular outflow tract reconstruction in children.

BACKGROUND: The ideal choice for valved reconstruction of the right ventricular outflow tract (RVOT) in children is undetermined. This study explores the Freestyle porcine aortic root for these patients. METHODS: From January 1998 to December 2002, 56 patients ages 1.6 to 29.9 years old (mean 11.8 years old) underwent RVOT reconstruction using a Freestyle porcine aortic root. The patients averaged 1.9 prior operations (range 0 to 5) for tetralogy of Fallot +/- pulmonary atresia (28 patients), critical pulmonary stenosis (10 patients), Ross procedure (5 patients), pulmonary atresia/intact ventricular septum (4 patients), complete atrioventricular septal defect +/- tetralogy of Fallot (4 patients), and others (5 patients). At time of RVOT reconstruction, 42 patients (75%) had additional procedures including the following: tricuspid or mitral repair (24 patients), pulmonary arterioplasty +/- Glenn (12 patients), ventricular septal defect closure (5 patients), aortic valve replacement (3 patients), placement of a cardioverter/defibrillator or pacemaker (3 patients), and others (8 patients). RESULTS: One patient developed mediastinitis; another was treated for Candida endocarditis (his excised homograft unexpectedly grew Candida). All patients are well on follow-up from 2 to 60 months (mean 30 +/- 20 months) with no deaths. The patient with endocarditis underwent conduit replacement for recurrent pulmonary stenosis 3.5 years postoperatively. Echocardiography revealed mild or no pulmonary insufficiency in 93%. The calculated mean peak systolic RVOT gradient by echocardiography was 19.7 +/- 15.4 mm Hg. CONCLUSIONS: These data demonstrate excellent results with the Freestyle bioprosthesis for RVOT reconstruction in children. This valve may serve as a readily available alternative to homograft valves in RVOT reconstruction, particularly since early insufficiency seems to be less problematic. Questions of long-term durability and significance of echocardiographic stenosis remain unanswered.

Adolescent↗
PubMed2003

Reduction of tricuspid annular doppler tissue velocities in pediatric heart transplant patients.

BACKGROUND: Orthotopic heart transplantation is a life-saving therapy for children with end-stage heart disease. However, 50% of these transplanted children die or require re-transplantation 12 years later. Progressive deterioration of cardiac function is a common feature of long-term survivors; however, quantitative evaluation of the state of the right ventricle has been lacking. Tissue Doppler imaging (TDI) has been used to measure alterations in right ventricular (RV) function in other illnesses. The purpose of this study was to quantitate abnormalities in tricuspid annular systolic and diastolic velocities as an indicator of RV dysfunction, and to evaluate if time since transplantation and the presence of tricuspid regurgitation are associated with quantitative changes in tricuspid annular velocities in pediatric heart transplant recipients. METHODS: TDI was performed and velocities recorded during systole and early and late diastole at the tricuspid annulus, septum and mitral annulus in transplanted patients and in a control group with normal hearts. Pulsed wave Doppler mitral and tricuspid inflows were also measured and the severity of tricuspid regurgitation was estimated using color flow mapping. Patients with biopsy evidence of active cellular rejection or left ventricular ejection fraction of <60% were excluded from study. RESULTS: Thirty-five patients were divided into a normal heart group (n = 14) and a transplant group (n = 21), aged from 1 to 23 years. Systolic and early diastolic velocities at the tricuspid annulus and septum in the transplant group were reduced significantly compared with the normal group (p < 0.05): tricuspid annular systolic, 5.8 +/- 1.4 vs 9.4 +/- 1.7 cm/sec; early diastolic, -6.4 +/- 2.6 vs -9.7 +/- 2.6 cm/sec; septum systolic, 3.9 +/- 1.5 vs 5.8 +/- 1.4 cm/sec; and early diastolic, -6.3 +/- 2.4 vs -9.1 +/- 2.5 cm/sec. Patients were divided into early (<5 years) and late (>5 years) term groups since transplantation. Tissue velocities at the tricuspid annulus in the late term group had further reduction in systole, 4.9 +/- 1.4 vs 6.4 +/- 1.1 cm/sec, and early diastole, -5.3 +/- 1.5 vs -7.1 +/- 2.9 cm/sec (p < 0.05). Patients with severe tricuspid regurgitation had systolic and early diastolic velocities at the tricuspid annulus that were further reduced. Left ventricular mitral inflow Doppler early/late diastolic ratios became significantly different from the normal group 5 years after transplantation (p < 0.05). CONCLUSIONS: TDI demonstrated that tricuspid annular systolic and early diastolic velocities were abnormal in children after transplantation and became significantly more abnormal with prolonged time after transplantation. These alterations were not dependent on the presence of severe tricuspid regurgitation but appeared to be exacerbated by its presence. Evidence of diastolic left ventricular dysfunction was not detected before 5 years after transplantation in this unselected group. A prospective study may be required to define the evolution and progression of right and left ventricular dysfunction in children after heart transplantation.

Adolescent↗
PubMed2003

A population-based study of the 22q11.2 deletion: phenotype, incidence, and contribution to major birth defects in the population.

OBJECTIVES: Although several studies describe the 22q11.2 deletion, population-based data are scant. Such data are needed to evaluate properly the impact, distribution, and clinical presentation of the deletion in the population. Our goals were to assess the population-based birth prevalence of the 22q11.2 deletion and its associated phenotype and its impact on the occurrence of heart defects. METHODS: We evaluated data on infants who were born from 1994 through 1999 to women who resided in metropolitan Atlanta. We matched records from the Metropolitan Atlanta Congenital Defects Program (a population-based registry with active case ascertainment), the Sibley Heart Center at Children's Healthcare of Atlanta, and the Division of Medical Genetics at Emory University. We used birth certificate data for the denominators of the rates. RESULTS: We identified 43 children with laboratory-confirmed 22q11.2 deletion among 255 849 births. The overall prevalence was 1 in 5950 births (95% confidence interval: 1 in 4417 to 1 in 8224 births). The prevalence was between 1 in 6000 and 1 in 6500 among whites, blacks, and Asians and 1 in 3800 among Hispanics. Most affected children (81%) had a heart defect, and many (1 in 3) had major extracardiac defects (other than velopalatal anomalies), including anomalies of the central nervous system. Overall, the deletion contributed to at least 1 of every 68 cases of major heart defects identified in the total birth cohort and, in particular, to 1 of every 2 cases diagnosed with interrupted aortic arch type B, 1 of every 5 with truncus arteriosus, and 1 of every 8 with tetralogy of Fallot. CONCLUSIONS: The 22q11.2 deletion was common in this birth population. The clinical phenotype included a wide and variable spectrum of major cardiac and extracardiac anomalies. From these population-based data, one can estimate that at least 700 affected infants are born annually in the United States. Population-based estimates such as these should be useful to medical professionals and policy makers in planning for the optimal care of people with the 22q11.2 deletion.

Abnormalities, Multiple↗
PubMed2002

An MRI study of neurological injury before and after congenital heart surgery.

BACKGROUND: Neurological deficits are observed in patients with congenital heart disease (CHD) before and after neonatal surgery, the etiology being multifactorial. To understand the impact of preoperative events and to characterize the evaluation of neurological injury, we performed serial magnetic resonance imaging (MRI) studies of the brain in a cohort of neonates undergoing open-heart surgery. METHODS AND RESULTS: Twenty-four term neonates with CHD were studied prospectively with brain MRI: before surgery, within 2 weeks of surgery, and several months after surgery. Preoperative MRI examinations showed periventricular leukomalacia (PVL) in 4 patients (16%) and infarct in 2 subjects (8%). MR spectroscopy was performed in 19 subjects preoperatively and revealed elevated brain lactate in 53%. An early postoperative MRI (n=21) identified new PVL in 48%, new infarct in 19%, and new parenchymal hemorrhage in 33%. New lesions or worsening of preoperative lesions occurred in 67% of subjects. No patient- or procedure-related factors for the development of early postoperative lesions were identified. A late postoperative MRI (n=17) demonstrated resolution of early lesions in 8 and mild cerebral atrophy in 2. CONCLUSIONS: Mild ischemic lesions, primarily in the form of PVL, occur in a number of neonates with CHD before surgery and >50% of patients postoperatively. Resolution of these lesions is common 4 to 6 months after surgery. Longer-term follow-up is needed to determine the significance of perioperative ischemic lesions on functional outcome.

Brain↗
PubMed2002

Risk factors for mortality after the Norwood procedure.

OBJECTIVES: Recent studies have suggested that survival following the Norwood procedure is influenced by anatomy and is worse for patients with hypoplastic left heart syndrome (HLHS), particularly aortic atresia (AA), as compared to other forms of functional single ventricle and systemic outflow tract obstruction. The current study was undertaken to evaluate our recent experience with the Norwood procedure and to evaluate potential predictors of operative and 1-year mortality. METHODS: A retrospective study of risk factors for operative and 1-year mortality in 158 patients undergoing the Norwood procedure between January 1, 1998 and June 30, 2001. RESULTS: HLHS was present in 102 patients (70 with AA) and other forms of functional single ventricle with systemic outflow tract obstruction in the remaining 56. Operative survival was 77% (122/158), 78% for patients with HLHS and 75% for patients with other diagnoses. Multivariable analysis identified birth weight (odds ratio (OR) 0.18/kg, 95% confidence limit (CL) 0.08-0.42, P<0.001), associated cardiac anomalies (OR 4.45, 95% CL 1.50-13.2, P=0.001), total support time (OR 1.02/min, 95% CL 1.01-1.03, P=0.004), and extracorporeal membrane oxygenation (ECMO) or ventricular assist device (VAD) support (OR 17.8, 95% CL 4.40-71.0, P<0.001) as predictors of operative mortality. The anatomic diagnosis (HLHS versus non-HLHS) was not a predictor of mortality, P=0.6). The Kaplan-Meier survival estimate at 1 year was 66% (95% CL 58-73%) and was not different for patients with HLHS compared to non-HLHS, P=0.5. For patients who have survived the Norwood procedure, survival to 1 year was 86% (95% CL 78-91%). Presence of an extra-cardiac anomaly or genetic syndrome (OR 2.70, 95% CL 0.98-7.41%, P=0.05) and presence of an additional cardiac defect (OR 3.99, 95% CL 1.67-9.57, P=0.002) were predictors of worse survival in the first year of life. CONCLUSIONS: The Norwood procedure is currently being applied to a heterogeneous group of patients. Operative and 1-year survival are equivalent for patients with HLHS and those with other cardiac defects. The presence of additional cardiac or extra-cardiac anomalies are predictors of poor outcome.

Cardiac Surgical Procedures↗
PubMed2002

Predictors of outcome after the Fontan operation: is hypoplastic left heart syndrome still a risk factor?

OBJECTIVE: This study was undertaken to evaluate factors contributing to a decrease in early mortality and morbidity after the Fontan procedure between January 1, 1992, and December 31, 1999. METHODS: Outcomes evaluated were early survival, duration of pleural effusions, and duration of hospitalization. Potential predictors evaluated included anatomic diagnosis, presence of a common atrioventricular valve, preoperative pulmonary artery pressure, type of Fontan operation, type of intentional right-to-left shunt or baffle fenestration, and use of modified ultrafiltration. RESULTS: The modified Fontan procedure was performed in 332 patients at a median age of 22 months (range, 11-380 months) and a median weight of 11 kg (range, 5.8-120 kg). Prior stage I reconstructive surgery for classic or variant hypoplastic left heart syndrome had been performed in 205 (53%) of 332 patients, and 318 (96%) had undergone an interim superior cavopulmonary connection. A lateral-tunnel Fontan operation was performed in 281 patients, and an extracardiac conduit Fontan operation was performed in 51 patients. An intentional right-to-left shunt was created in 298 (90%) patients. Between 1992 and 1999, the outcome after the modified Fontan operation improved significantly. Overall mortality was 6.6% (22/332), with only 2 deaths since 1994. Morbidity was also reduced, with a decreased duration of pleural effusions and decreased hospital stay. In a multivariable analysis of the entire cohort, only the presence of a common atrioventricular valve (odds ratio, 7.64; 95% confidence limits, 2.07-28.14; P =.0002) and increased preoperative pulmonary artery pressure (odds ratio, 1.46/1 mm Hg increase; 95% confidence limits, 1.2-1.78; P <.001) increased the risk of early death, whereas use of a single-punch fenestration in a lateral-tunnel Fontan (odds ratio, 0.06; 95% confidence limits, 0.01-0.65; P =.02) and use of modified ultrafiltration (odds ratio, 0.14; 95% confidence limits, 0.03-0.72; P =.019) decreased the risk of death. The risk of prolonged pleural effusions (>3 days) was increased in patients with hypoplastic left heart syndrome (odds ratio, 1.73; 95% confidence limits, 1.07-2.81; P =.03) and was decreased by use of a single-punch fenestration in a lateral-tunnel Fontan operation (odds ratio, 0.17; 95% confidence limits, 0.07-0.4; P <.001), as well as by the use of modified ultrafiltration (odds ratio, 0.25; 95% confidence limits, 0.15-0.40; P <.01). CONCLUSIONS: In a contemporary series of Fontan operations performed largely in patients with hypoplastic left heart syndrome or variants, systemic ventricle morphology had no effect on mortality. Some patient characteristics, however, continue to influence outcome. The decrease in mortality and morbidity in the current era is attributed to changes in management strategies, specifically the use of modified ultrafiltration and baffle fenestration.

Cohort Studies↗