Anthony Azakie

Temporal and Anatomic Risk Profile of Brain Injury With Neonatal Repair of Congenital Heart Defects

Background and Purpose— Brain injury is common in newborns with congenital heart disease (CHD) requiring neonatal surgery. The purpose of this study is to define the risk factors for preoperative and postoperative brain injuries and their association with functional cardiac anatomic groups. Methods— Sixty-two neonates with CHD were studied with preoperative MRI, and 53 received postoperative scans. Clinical and therapeutic characteristics were compared in newborns with and without newly acquired brain injuries. A subset of 16 consecutive patients was monitored with intraoperative cerebral near-infrared spectroscopy. Results— Brain injury was observed in 56% of patients. Preoperative brain injury, seen in 39%, was most commonly stroke and was associated with balloon atrial septostomy (P=0.002). Postoperative brain injury, seen in 35%, was most commonly white matter injury and was particularly common in neonates with single-ventricle physiology and aortic arch obstruction (P=0.001). Risk factors associated with acquired postoperative brain injury included cardiopulmonary bypass (CPB) with regional cerebral perfusion (P=0.01) and lower intraoperative cerebral hemoglobin oxygen saturation during the myocardial ischemic period of CPB (P=0.008). In a multivariable model, new postoperative white matter injury was specifically associated with low mean blood pressure during the first postoperative day (P=0.04). Conclusions— Specific modifiable risk factors can be identified for preoperative and postoperative white matter injury and stroke associated with neonatal surgery for CHD. The high incidence of postoperative injury observed despite new methodologies of CPB indicates the need for ongoing evaluation to optimize neurological outcome.

Evolving strategies and improving outcomes of the modified Norwood procedure: a 10-year single-institution experience

BACKGROUND This study reviews our 10-year experience with the modified Norwood procedure to determine its early and midterm outcomes. The focus is on the impact of evolving management strategies and accumulated institutional experience. METHODS A modified Norwood operation was performed in 171 infants over a 10-year period. Sixty-eight percent of the infants were male, the median age at operation was 6 days (range 1 to 175 days), and the median weight was 3.3 kg (range 1.7 to 4.8 kg). The 10-year period was divided into three eras: era I; 1990 through 1993; era II; 1994 through 1997; and era III; 1998 into 2000. Outcomes and risk factors for mortality were sought. RESULTS Hypoplastic left heart syndrome or a variant was the primary diagnosis in 118 infants (69%). The overall 5-year survival rate was 43%. Multivariate analysis revealed that only need of preoperative ventilatory support, earlier date of operation, and lower weight at operation were significant independent predictors of increased time-related mortality. Morphologic features such as a diagnosis other than hypoplastic left heart syndrome, ascending aortic size, and noncardiac anomalies were not significantly associated with an increased risk of death. The hospital survival rate for stage-one palliation in era III was 82%, significantly better than that in the preceding eras (p < 0.001). Attrition between stages one and two accounted for a 15% mortality rate among hospital survivors. CONCLUSIONS With increasing experience and improvements in perioperative care and surgical technique, good outcomes can be expected for the first-stage modified Norwood procedure. Greater monitoring of patients in the interstage period may reduce interval mortality and improve overall survival.

Regional and central venous oxygen saturation monitoring following pediatric cardiac surgery: concordance and association with clinical variables.

Objective: To compare changes in regional cerebral or flank oxygen saturation measured by near-infrared spectroscopy with changes in central venous oxygen saturation (Scvo2) and to determine clinical variables associated with these changes. Design: Prospective observational cohort study. Setting: University tertiary care center, pediatric cardiac intensive care unit. Patients: Seventy postoperative congenital cardiac surgical patients (median age 0.3 yrs; interquartile range 0.02–0.46 yrs). Interventions: None. Measurements and Main Results: We measured temporally correlated regional oxygen saturation (rSo2) with hematologic (hematocrit), biochemical (arterial blood gas, Scvo2, and lactate) and physiologic (temperature, heart rate, mean blood pressure, and pulse oximetry) variables in the first postoperative day. Cerebral and flank rSo2 were strongly correlated with Scvo2, in both cyanotic or acyanotic patients and single- or two-ventricle physiology with and without aortic arch obstruction (all p < .001). However, individual values had wide limits of agreement on Bland-Altman analysis. The correlations of change in these measurements were weaker but still significant (all p < .0001), again with wide limits of agreement. Similar direction of change in cerebral rSo2 and Scvo2 was present 64% (95% confidence interval, 55–73%) of the time. Change in arterial pressure of carbon dioxide (&Dgr;Paco2) was associated with cerebral &Dgr;rSo2 (&Dgr;Paco2 &bgr; = 0.35, p < .0001) but not flank &Dgr;rSo2 or &Dgr;Scvo2. A pattern of relative cerebral desaturation (flank rSo2 > cerebral rSo2) was noted in a majority of patients (81%) with two-site monitoring regardless of bypass method or age. Conclusions: Neither individual values nor changes in rSo2 are interchangeable measures of Scvo2 in postoperative pediatric cardiac patients. The unique relationship between changes in Paco2 and cerebral rSo2 supports the hypothesis that cerebral near-infrared spectroscopy monitors regional cerebral oxygenation. Clinical application of this monitor must include recognition of the clinical variables that affect regional brain oxygenation.

Anatomic repair of anomalous left coronary artery from the pulmonary artery by aortic reimplantation: early survival, patterns of ventricular recovery and late outcome

BACKGROUND To determine the early and late outcomes of patients presenting with anomalous left coronary artery from the pulmonary artery who had repair by aortic reimplantation. METHODS From January 1952 to July 2000, 67 patients presented with anomalous coronary artery from the pulmonary artery. Forty-seven patients who had repairs performed by aortic reimplantation are the subject of this study. The median age at repair was 7.7 months. Before repair, 10 infants (21%) presented in extremis requiring ventilatory and inotropic support, and 38 infants (80%) presented in heart failure. Autologous pericardial hood coronary arterioplasty was used in 4 patients, and concomitant mitral valve repair was used in 1 patient. RESULTS Hospital survival was 92%. Five children required postoperative extracorporeal membrane oxygenation for a median of 4 days (range, 2 to 8 days). Patients who had extracorporeal membrane oxygenation were significantly more likely to have presented in critical condition (40% vs 3% if no extracorporeal membrane oxygenation; p = 0.006) or with ventricular arrhythmias (67% vs 7%; p = 0.027), to have presented with significantly lower preoperative repair median ejection fraction (10%, n = 5 vs 40%, n = 38; p = 0.01) or to have presented with more severe left ventricular dilatation (p = 0.03). Within a 15-year or less follow-up (mean, 4.7 years) there were no late deaths. Kaplan-Meier survival was 91% at 5 years, and freedom from reoperation was 93% at 10 years. At late follow-up, echocardiography demonstrated significant improvements in mean ejection fraction (64% +/- 9% vs 33% +/- 21% preoperatively, p < 0.0001); moderate mitral regurgitation (9% vs 38% preoperatively, p < 0.02); and wall motion abnormalities (15% vs 81% preoperatively, p < 0.002). The ratio of measured left ventricular end-diastolic dimension to the 95th percentile of normal declined from 1.4 +/- 0.3 to 1.0 +/- 0.1 (p < 0.0006). Children who had extracorporeal membrane oxygenation had normal ejection fractions and ventricular dimensions at follow-up (n = 3). Repeated measures of mixed linear regression analysis demonstrated that normalization of ejection fraction and left ventricular function occurred within 1 year of repair. Improvements in mitral regurgitation lagged behind normalization of ejection fraction and left ventricular dilatation. CONCLUSIONS Anatomic repair of anomalous left coronary artery from the pulmonary artery by aortic reimplantation yields excellent early survival and late functional outcomes even in critically ill infants.

Surgical management of subclavian-vein effort thrombosis as a result of thoracic outlet compression

BACKGROUND There is considerable variability and controversy in the current management of subclavian-vein effort thrombosis. The purpose of this study was to determine the long-term effectiveness and the functional outcome of our preferred treatment strategy of early thrombolysis/recanalization and prompt extensive supraclavicular decompression. PATIENTS AND METHODS Thirty-three patients who ranged in age from 15 to 60 years underwent operative decompression of 34 primary subclavian-vein thromboses, one of which was bilateral. There were 21 patients with acute thrombosis 7 of whom had had prior unsuccessful balloon venoplasty, 1 with stent placement and 8 patients with chronic/recurrent thrombosis 5 of whom had had 9 unsuccessful prior operations for attempted decompression. Four patients had high-grade symptomatic stenosis and positional occlusion. A supraclavicular approach was used in 32 cases and, in 23 cases, was complemented by an infraclavicular (n = 21) or transaxillary (n = 2) incision. Complete subclavian-vein decompression was achieved by first-rib resection (n = 31), scalenectomy (n = 33), and circumferential venolysis (n = 34). RESULTS Follow-up was obtained in 30 patients at a mean of 31 months. Twenty of the 21 patients with acute thrombosis had a complete resolution of symptoms with a return to full activity; the other patient was lost to follow-up. Four of the 8 patients with chronic thrombosis reported a mild relief of symptoms but still had limitations of activities of daily living. All of the patients with high-grade symptomatic stenosis with positional occlusion had a complete relief of symptoms and a return to full activity. CONCLUSION The optimal management of acute effort thrombosis of the subclavian vein includes anticoagulation therapy, thrombolysis/recanalization, confirmatory positional venography, and early supraclavicular decompression of the subclavian vein. In the patients with chronic subclavian-vein thrombosis and positional venographic evidence of compression of first-rib bypass graft collaterals, the initial anticoagulation therapy should be followed by the surgical decompression of the collaterals. The supraclavicular approach alone or with an infraclavicular incision provides optimal exposure for scalenectomy, total first-rib resection, and circumferential venolysis.

Clinically silent preoperative brain injuries do not worsen with surgery in neonates with congenital heart disease.

OBJECTIVE Preoperative brain injury, particularly stroke and white matter injury, is common in neonates with congenital heart disease. The objective of this study was to determine the risk of hemorrhage or extension of preoperative brain injury with cardiac surgery. METHODS This dual-center prospective cohort study recruited 92 term neonates, 62 with transposition of the great arteries and 30 with single ventricle physiology, from 2 tertiary referral centers. Neonates underwent brain magnetic resonance imaging scans before and after cardiac surgery. RESULTS Brain injury was identified in 40 (43%) neonates on the preoperative magnetic resonance imaging scan (median 5 days after birth): stroke in 23, white matter injury in 21, and intraventricular hemorrhage in 7. None of the brain lesions presented clinically with overt signs or seizures. Preoperative brain injury was associated with balloon atrial septostomy (P = .003) and lowest arterial oxygen saturation (P = .007); in a multivariable model, only the effect of balloon atrial septostomy remained significant when adjusting for lowest arterial oxygen saturation. On postoperative magnetic resonance imaging in 78 neonates (median 21 days after birth), none of the preoperative lesions showed evidence of extension or hemorrhagic transformation (0/40 [95% confidence interval: 0%-7%]). The presence of preoperative brain injury was not a significant risk factor for acquiring new injury on postoperative magnetic resonance imaging (P = .8). CONCLUSIONS Clinically silent brain injuries identified preoperatively in neonates with congenital heart disease, including stroke, have a low risk of progression with surgery and cardiopulmonary bypass and should therefore not delay clinically indicated cardiac surgery. In this multicenter cohort, balloon atrial septostomy remains an important risk factor for preoperative brain injury, particularly stroke.

Brain injury and development in newborns with critical congenital heart disease.

Objective: To determine the relationship between radiologically identifiable brain injuries and delayed brain development as reflected by brain metabolic and microstructural integrity. Methods: Term newborns with congenital heart disease (CHD) (120 preoperatively and 104 postoperatively) were studied with MRI to determine brain injury severity (BIS), microstructure reflected by fractional anisotropy (FA) and average diffusivity (Dav), and metabolism reflected by N-acetylaspartate (NAA)/choline (Cho) and lactate/Cho. Brain development is characterized by increasing NAA/Cho and white matter FA, and by decreasing Dav and lactate/Cho. Results: Newly acquired brain injury was common (41% preoperative, 30% postoperative). Lower white matter FA (p = 0.005) and lower NAA/Cho (p = 0.01) were associated with increasing preoperative BIS. Higher neonatal illness severity scores (p = 0.03), lower preoperative oxygen saturation (p = 0.002), hypotension (p < 0.001), and septostomy (p = 0.002) were also predictive of higher preoperative BIS. Preoperative FA, Dav, and NAA/Cho did not predict new postoperative BIS. Increasing preoperative BIS predicted higher postoperative Dav (p = 0.002) and lactate/Cho (p = 0.008). Within the postoperative scan, new brain injuries were associated with lower white matter FA (p = 0.04). Postoperative BIS (new lesions) was associated with lower postoperative systolic (p = 0.03) and mean (p = 0.05) blood pressures. Conclusions: Brain injuries in newborns with CHD are strongly related to abnormalities of brain microstructural and metabolic brain development, especially preoperatively. Both newly acquired preoperative and postoperative brain injuries are related to potentially modifiable clinical risk factors.

Improving outcomes of the Fontan operation in children with atrial isomerism and heterotaxy syndromes

BACKGROUND The historic outcome of the Fontan procedure in children with single ventricle and heterotaxy syndrome has been poor, and in the current era it has been incompletely described. METHODS From January 1993 through April 2000, 30 patients (age range, 5.3 +/- 3.6 years) had total cavopulmonary connection for single ventricle and isomerism and heterotaxy syndrome. Right atrial isomerism and heterotaxy (n = 19) or left atrial isomerism and heterotaxy (n = 11) were associated with a morphologic right ventricle (n = 26), a common atrioventricular valve (n = 25), pulmonary atresia (n = 9) or stenosis (n = 17), anomalous pulmonary venous drainage (partial, n = 7; total, n = 11; obstructed, n = 4), and interrupted inferior vena cava (n = 13). A previous systemic to pulmonary artery shunt had been performed in 21 patients, and 3 patients had previous pulmonary artery banding. The Fontan procedure was staged in all but 3 patients at a median age of 12 months (range, 3 to 114 months). Before the Fontan procedure, atrial arrhythmia was present in 7 patients (23%). RESULTS An extracardiac conduit was constructed in 22 patients (median diameter, 20 mm; range, 16 to 27 mm), and a lateral tunnel was constructed in 4 patients. Associated procedures included pulmonary artery augmentation (n = 17), repair of anomalous pulmonary venous drainage (n = 7), and repair of a regurgitant atrioventricular valve (n = 2). The mean cardiopulmonary bypass time was 134 +/- 57 minutes. Cardioplegic cardiac arrest was used in 12 patients for a mean duration of 62 +/- 28 minutes. There were four hospital deaths (13%), three that occurred in children having concomitant repair of anomalous pulmonary venous drainage (previously undetected in one). Thirteen children (41%) developed early postoperative atrial arrhythmias, 11 of the 13 children required temporary pacing. There was one late death. Follow-up (3.4 +/- 2.7 years) was available on 24 of 25 survivors. All but 2 patients were in sinus rhythm. CONCLUSIONS Early and midterm outcomes after the Fontan procedure in this patient group improved and may be further ameliorated by detecting and repairing associated obstruction to pulmonary venous flow and performing atrioventricular valvuloplasty before the Fontan procedure.

Ruptured sinus of valsalva aneurysm: early recurrence and fate of the aortic valve

BACKGROUND We reviewed our experience with congenital ruptured sinus of Valsalva aneurysms (RSVA) to determine patterns of early recurrence and the fate of the aortic valve (AV). METHODS Over a 28-year period, RSVA was identified in 34 patients, (mean age 31.6 years). Primary closure of the RSVA was performed in 10 patients, and a patch employed in 24. Aortic insufficiency was present in 24 patients. AV replacement (AVR) was performed in 5 patients; AV repair in 6. RESULTS Follow-up of 9.2 +/- 8.3 years (6 months to 24 years) was complete in all but 2 patients. Five early fistula recurrences (in 4 patients) correlated with primary rather than patch closure (p < 0.03). Kaplan-Meier survival at 10 years is 90 +/- 7%. Freedom from reoperative AVR at 10 years is 83 +/- 9%. Late AVR was performed in 6 patients for progressive aortic insufficiency due to bicuspid valve (n = 3), cusp disease of affected sinus (n = 2), or aortic root dilatation (n = 2). CONCLUSIONS Patch closure of the RSVA should be routinely employed. A bicuspid valve may be associated with the late need for AVR.

Outcomes of intraoperative device closure of muscular ventricular septal defects

BACKGROUND The surgical management of muscular ventricular septal defects (mVSD) in the small infant is a challenge particularly when multiple and associated with complex cardiac lesions. Devices for percutaneous implantation have the advantage of ease of placement and for the double umbrella designs a wide area of coverage. We reviewed our experience and clinical outcomes of intraoperative mVSD device closure for such defects in small infants. METHODS Since October 1989, intraoperative VSD device closure was a component of the surgical strategy in 14 consecutive patient implants (median age, 5.5 months; range, 3 to 11 kg), whose defects were thought difficult to approach using conventional techniques. Nine patients had associated complex cardiac lesions, 10 multiple mVSDs, and 4 patients had a previous pulmonary artery banding. RESULTS There were 2 early deaths, 1 in a severely ill child who preoperatively had pulmonary hypertension and left ventricular failure and another in a patient with a hypoplastic left heart. Mean pulmonary to systemic flow ratio before device insertion was 3.5:1. Complete closure was achieved in 5 patients and clinically insignificant residual shunts persisted in 7. In 2 infants with significant residual lesions concomitant pulmonary artery banding was required. Postoperative mean pulmonary to systemic flow ratio was 1.7:1. In follow-up of the 12 surviving infants (mean, 41 months), 8 had complete closure and 3 persistent residual shunts. One patient with no residual shunting required heart transplantation for progressive ventricular failure 9 years after operation. All devices were well positioned on postoperative echocardiograms. There was 1 late death due to aspiration in a patient with a tiny residual shunt. CONCLUSIONS Infants requiring operative intervention with mVSDs are difficult to manage and have an increased mortality and morbidity. Intraoperative VSD device placement for closure of mVSDs is feasible, can avoid ventriculotomy, division of intracardiac muscle bands, and is ideally suited for the neonate or infant.