Faculty Bibliography

The outlook for newborns with hypoplastic left heart syndrome has been dramatically altered in the past decade with the successful application of staged reconstructive techniques. Once considered a uniformly fatal condition, refinements in operative technique and perioperative care have been largely responsible for this improved survival. The first stage in the reconstructive process, the Norwood procedure, continues to carry the most significant risk. The Norwood procedure must provide: unobstructed systemic and coronary blood flow from the right ventricle; unobstructed pulmonary venous return across the atrial septum; and sufficient pulmonary blood flow without significant volume overload. Although the postoperative management of these patients must achieve the proper ratio of systemic and pulmonary vascular resistance, a properly performed reconstruction should result in a largely uncomplicated recovery. The second stage procedure, the hemi-Fontan operation, is performed between 4 and 6 months of age. This step results in removal of the ventricular volume overload imposed by the systemic shunt and the connection of the superior vena cava to the pulmonary arteries. Augmenting the central pulmonary arteries, avoiding conduction disturbances, and constructing a potential connection for the inferior vena cava to the pulmonary arteries are essential components of this procedure. The Fontan procedure is performed at approximately 1.5-2 years of age. Inferior vena cava return is channeled to the pulmonary arteries through the previously constructed atriocaval connection to complete the separation of the pulmonary and systemic circulations. Although the current techniques have resulted in substantial improvements in the quantity and quality of survival, efforts to refine each stage of the process continue to evolve with increasing follow-up and evaluation

BACKGROUND: It is widely held that the postoperative course of patients with hypoplastic left heart syndrome (HLHS) after stage 1 palliation is characterized by hemodynamic instability, which in part may be due to excessive pulmonary blood flow. Hence, avoidance of alkalosis and the use of minimally oxygen-enriched inspiratory gas are thought by many to be important, although there is little pertinent published data. This study was undertaken to characterize the postoperative course and to determine whether the FIO2 and blood pH are related to indices of hemodynamic stability in these infants. METHODS AND RESULTS: The postoperative course of 25 consecutive infants undergoing first stage palliation for HLHS were retrospectively reviewed and the following data were obtained: arterial pressure, arterial blood gas measurements, the inotropic agents used, and multiple respiratory parameters. There was one operative death, and 2 patients died within 2 days, but 22 were extubated (mean, 5.2 +/- 4.1 days after surgery). Hospital mortality was 24%. Mean pH was > or = 7.51 for the first 9 hours after surgery and was > or = 7.45 for the entire period. The mean FIO2 was > or = 50% for the first 18 hours. The PaO2 was appropriate (37 +/- 6 mm Hg at 1 hour after surgery, increasing to 45 +/- 5 mm Hg by hour 73). Only modest inotropic support was needed to maintain appropriate blood pressure. CONCLUSIONS: These data suggest that neither alkalosis nor relatively high inspired oxygen necessarily cause hemodynamic instability in these patients. To what extent these results are generalizable is unclear, but they suggest that there is nothing inherent with HLHS that mandates postoperative hemodynamic instability or unacceptable mortality

Since September 1991, 14 consecutive patients with tetralogy of Fallot, pulmonary atresia, and diminutive pulmonary arteries have undergone staged repair. All patients had multiple aortopulmonary collateral arteries and the ductus arteriosus was absent in 11. Mean sizes of the right and left pulmonary arteries were 2.2 +/- 0.7 mm and 1.9 +/- 0.8 mm, respectively (range 0.5 to 3.0 mm). Eight patients (57%) have subsequently received complete repair. Age at initial procedure (shunt, right ventricle-pulmonary artery conduit, or direct aorta-pulmonary artery anastomosis) in this group was 5.3 +/- 6.8 months. The number of operative procedures to achieve complete repair was 2.9 +/- 0.8 per patient (range 2 to 4). Intraoperative postrepair peak right ventricle-left ventricle pressure ratio was 0.57 +/- 0.17. Six of 8 patients (75%) required additional interventional procedures (mean 1.5 +/- 1.2 per patient) for angioplasty of peripheral pulmonary artery stenoses, coil embolization of aortopulmonary collateral arteries, or intra-operative insertion of intravascular pulmonary artery stents. Mean follow-up from complete repair was 8.7 +/- 8.3 months (range 0.5 to 23.8 months) and is complete. There was one in-hospital death at 45 days, and one late cardiac death at 20.3 months. Six patients had initial palliative operations (unifocalization, right ventricle-pulmonary artery conduit, direct aorta-pulmonary artery anastomosis, or transannular outflow patch) but have not undergone complete repair. Age at initial procedure in this group was 27.9 +/- 56.9 months (range 0.27 to 155 months), and mean follow-up from initial procedure was 10.9 +/- 11.2 months (range 0 to 31.4 months). The operative mortality rate was 33% (2 of 6 patients). There was one late noncardiac death at 5.3 months. Three patients are awaiting further intervention or repair. This experience suggests that complete repair is feasible even in patients with extremely diminutive pulmonary arteries (< or = 3.0 mm). Pulmonary artery growth is facilitated by early (3 to 6 month) establishment of central pulmonary artery flow by right ventricle-pulmonary artery conduit (pulmonary arteries > 1.5 mm) or by direct ascending aorta-pulmonary artery anastomosis (pulmonary arteries < 1.5 mm). Subsequent interventional catheterization and operative procedures as required for pulmonary artery stenoses and coil embolization of collateral arteries allow continued recruitment of central pulmonary arteries and may obviate or minimize the need for unifocalization procedures

The effectiveness of a single-stage anterior approach for the repair of aortic arch obstruction and associated intracardiac defects has not been well evaluated. We therefore reviewed our experience with 60 neonates (median age 8 days, range 1 to 28) who underwent a single-stage repair by way of a median sternotomy at our institution between 1986 and 1994. Nineteen (32%) had coarctation with ventricular septal defect, 18 (30%) had interrupted aortic arch with ventricular septal defect, and 23 (38%) had coarctation or interrupted aortic arch with complex intracardiac anatomy. The arch obstruction was repaired using resection and primary anastomosis in 54 patients, synthetic patch aortoplasty in 3, subclavian flap aortoplasty in 2, and an interposition gortex graft placement in 1. Total circulatory arrest time was 48 +/- 3 minutes (mean +/- SEM). There were 7 early postoperative deaths (11.7%; 70% confidence limit 8% to 16.6%). The 53 survivors were followed for a mean of 23 months (range 1 to 78), for a total of 1,219 patient-months. Recurrent arch obstruction > or = 20 mm Hg has occurred in 2 of 53 patients (3.8%; 70% confidence limit 1.9% to 7.5%); both underwent successful balloon angioplasty. There were 2 late deaths, 1 of which was noncardiac. We conclude that repair of aortic arch obstruction and intracardiac defects by a single-stage approach through median sternotomy can be accomplished with low mortality in infancy, even with associated complex intra-cardiac anatomy. Recurrent coarctation is relatively uncommon and can be successfully managed with balloon angioplasty

From July 1988 through September 1993, 30 neonates with symptomatic tetralogy of Fallot underwent complete repair. Sixteen patients had tetralogy and pulmonary stenosis, 9 had pulmonary atresia, 3 had nonconfluent pulmonary arteries, and 2 had both pulmonary atresia and nonconfluent pulmonary arteries. The median age at operation was 11 days (mean +/- standard error of the mean, 12.6 +/- 2.9 days), with a mean weight of 3.1 +/- 0.1 kg (range 1.5 to 4.4 kg). Preoperatively, 14 patients were receiving an infusion of prostaglandin, 13 were mechanically ventilated, and 6 required inotropic support. Right ventricular outflow tract obstruction was managed by a limited transannular patch in 25 patients, infundibular muscle division with limited resection in 15, and insertion of a right ventricle-pulmonary artery valved aortic homograft conduit in 5 patients. Follow-up was complete at a median interval of 24 months (range 1 to 62 months). There were no hospital deaths and two late deaths, for 1-month, 1-year, and 5-year actuarial survivals of 100%, 93%, and 93%, respectively. The hazard function for death had a rapidly declining single phase that approached zero by 6 months after the operation. Both late deaths occurred in patients with tetralogy of Fallot and pulmonary atresia who had undergone aortic homograft conduit reconstruction, so that the only independent risk factor for death was the use of a valved homograft conduit (p < or = 0.005). Eight patients required reoperation, resulting in 1-month, 1-year, and 5-year freedom from reoperation rates of 100%, 93%, and 66%, respectively. Indications for reoperation were branch left pulmonary artery stenosis in 5 patients, residual right ventricular outflow tract obstruction in 2 patients, and severe pulmonary insufficiency in 1 patient. Independent risk factors for reoperation included an intraoperative pressure ratio between the right and left ventricles of 0.75 or greater (p = 0.01), Doppler residual left pulmonary artery stenosis of 15 mm Hg or more, or Doppler right ventricular outflow tract obstruction gradient of 40 mm Hg or more at hospital discharge (p = 0.002 and 0.02, respectively). This series demonstrates the safety of early hemodynamic repair of symptomatic tetralogy of Fallot in neonates. It also emphasizes the importance of relieving all sources of right ventricular outflow tract obstruction at the initial operation, particularly that located at the site of insertion of the ductus arteriosus, which may be difficult to diagnose in the neonate before ductal closure occurs. The safety and efficacy of valved aortic homograft conduits in neonates requires further investigation

The optimal treatment of critical aortic stenosis in the neonate and infant remains controversial. We compared transventricular dilation using normothermic cardiopulmonary bypass and percutaneous balloon aortic valvuloplasty with respect to early and late survival, relief of aortic stenosis, degree of aortic insufficiency, left ventricular function, and freedom from reintervention. Between July 1987 and July 1993, 30 neonates and infants underwent transventricular dilation or balloon aortic valvuloplasty for critical aortic stenosis. The patients in the transventricular dilation group (n = 21) ranged in age from 1 to 59 days (mean age 18.0 days +/- 19.1 days) and the balloon aortic valvuloplasty group (n = 9) from 1 to 31 days (mean age 10.0 days +/- 9.0 days). There were no significant differences in weight, body surface area, or aortic anulus diameter between the two groups (p = 1.0). Associated cardiovascular anomalies were more common in the transventricular dilation group (48%) than in the balloon aortic valvuloplasty group (11%). After intervention, the degree of residual aortic stenosis and insufficiency was equivalent in the two groups as assessed by postprocedural Doppler echocardiography. Ejection fraction improved within both groups (transventricular dilation 39% +/- 20.2% versus 47% +/- 22.0%; balloon aortic valvuloplasty 51% +/- 16.1% versus 62% +/- 8.4%), and there was no significant difference between groups. The left ventricular mass/volume ratio increased within both groups (p < 0.05) but with no significant difference between groups (transventricular dilation 1.4 +/- 0.5 gm/ml versus 1.8 +/- 0.6 gm/ml; balloon aortic valvuloplasty 1.1 +/- 0.6 gm/ml versus 1.7 +/- 0.4 gm/ml). Early mortality in the transventricular dilation group was 9.5% and in the balloon aortic valvuloplasty group, 11.1%. There was one late death in the transventricular dilation group. Four patients from the transventricular dilation group (19%) and two patients from the balloon aortic valvuloplasty group (22%) required reintervention for further relief of aortic stenosis. We conclude that both transventricular dilation and balloon aortic valvuloplasty provide adequate and equivalent relief of critical aortic stenosis. The treatment strategy adopted should depend on other factors, including associated cardiovascular anomalies, vascular access, preoperative condition, and the technical expertise available at each institution