Faculty Bibliography

BACKGROUND: Bidirectional superior cavopulmonary connection (BSCC) has become widely used in patients with univentricular AV connections. However, concerns remain about perioperative morbidity and mortality and about the adequacy of oxygenation after cavopulmonary connection in very young patients. This report examines our experience with BSCC in young infants to evaluate whether young age affects operative outcome, to examine the effect of young age on postoperative oxygenation, and to define the lower age limit for successful use of the procedure. METHODS AND RESULTS: The records of the 85 consecutive patients < 6.5 months old who underwent BSCC from December 1990 through February 1995 were reviewed. The average patient age was 4.8 +/- 1.4 months (range, 5 weeks to 6.5 months), with 13 patients being < 3 months old. There were 5 hospital deaths (6%; 70% confidence limits, 3% to 10%). Pulmonary artery thrombosis occurred in 3 patients (4%; 70% confidence limits, 2% to 7%). Younger age was significantly associated with pulmonary artery thrombosis but not with operative death. Oxygenation (arterial PO2, and oxygen saturation) improved significantly and spontaneously over the first 48 hours after BSCC. Younger age had a significant adverse effect on oxygenation in the early postoperative period (first 48 hours). CONCLUSIONS: BSCC can be performed successfully in infants < 6 months old and as young as 5 weeks old. Within this patient population, younger age is not associated with perioperative death but is associated with pulmonary artery thrombosis and postoperative hypoxemia. We suggest that BSCC may be performed any time beyond the neonatal period in symptomatic patients and may be delayed until 4 to 6 months of age if completely elective

BACKGROUND: During induced ischemia for cardiac surgery inefficient anaerobic energy mechanisms predominate. Sustaining aerobic metabolism with perfluorocarbon-supplemented blood cardioplegia theoretically could lead to improved postischemic recovery. Therefore we studied functional recovery after myocardial ischemia, comparing perflubron (C8F17Br) supplemented blood cardioplegia to standard blood cardioplegia. METHODS: Nineteen dogs underwent 15 minutes of 37 degrees C global ischemia on cardiopulmonary bypass, followed by 90 minutes of cardioplegic arrest by use of blood cardioplegia with or without perflubron and then 30 minutes of 37 degrees C reperfusion. During ischemia myocardial oxygen tension, temperature, and pH were measured. Postischemic left ventricular recovery was assessed by means of preload recruitable stroke work, exponential end-diastolic stress-strain regression, and preservation of adenosine triphosphate and energy charge. RESULTS: The addition of perflubron, a new shorter half-life, lecithin-emulsified perfluorocarbon, provided superior myocardial protection when compared with standard blood cardioplegia. This benefit was evidenced by significantly increased recovery of preload recruitable stroke work slope (71% +/- 8% versus 42% +/- 9%), decreased myocardial edema, and enhanced end ischemic myocardial oxygen and pH levels. CONCLUSIONS: The reliable oxygen delivery system and endothelial-preserving properties of the perfluorocarbons may prove to be an invaluable asset in addition to standard blood cardioplegia in the preservation of postischemic ventricular function. These data support the further investigation of perfluorocarbon-enriched blood cardioplegia

Hospital charges for coil occlusion were significantly less than for surgical closure of patent ductus arteriosus, and were reduced over time as experience permitted refinement of the coil occlusion protocol. The expected hospital charges for closure by a coil occlusion strategy, including the charges for surgical closure in patients with failed coil occlusion, was less than the hospital charges for surgical closure strategy under any reasonable estimate of coil occlusion efficacy

Increased myocardial collagen accompanies pressure overload of the adult left ventricle. This phenomenon is poorly understood in infants. This study compares the myocardial volume fraction of collagen in infants who did not have primary heart disease with infants with isolated pressure overload of the right ventricle (tetralogy of Fallot [ToF]), and with infants with combined volume and pressure overload (aortic valve atresia [AVA]). The distribution of collagen in the neonatal myocardium was also determined. We measured the volume fraction of collagen from right ventricular biopsy specimens of cadaver hearts in normal infants (1 to 9 months old; n = 7), infants with ToF (1 day to 9 months old; n = 9), newborns with AVA (AVA-NB) (1 to 4 days old; n = 5), and older patients with AVA (AVA-I) (5 to 8 months old; n = 5). Myocardium from 3 patients undergoing repair of ToF (6 to 8 months old) was also analyzed. Specimens were stained with Masson's trichrome and myocardial volume fraction of collagen determined by point counting. Myocardial volume fraction of collagen was significantly higher (p = 0.02) in AVA-I patients (8.0 +/- 3.5%) versus normal (3.3 +/- 2.7%), ToF (3.2 +/- 1.8%), and AVA-NB (3.5 +/- 2.3%) patients. There was a tendency for increased collagen in the subendocardium, especially in AVA-I patients (p > 0.05). We conclude that patients with AVA-I have increased collagen relative to normal subjects, patients with ToF, and patients with AVA-NB, and that this increase is greatest in the subendocardium

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