Faculty Bibliography

OBJECTIVE: The relationship between volume and outcome in many complex surgical procedures is well established. BACKGROUND: No published data has examined this relationship in pediatric cardiac transplantation, but low-volume adult heart transplant programs seem to have higher early mortality. METHODS: The United Network for Organ Sharing (UNOS) provided center-specific data for the 4647 transplants performed on patients younger than 19 years old, 1992 to 2007. Patients were stratified into 3 groups based on the volume of transplants performed in the previous 5 years at that center: low [<19 transplants, n = 1135 (24.4%)], medium [19-62 transplants, n = 2321(50.0%)], and high [>/=63 transplants, n= 1191 (25.6%)]. A logistic regression model for postoperative mortality was developed and observed-to-expected (O:E) mortality rates calculated for each group. RESULTS: Unadjusted long-term survival decreased with decreasing center volume (P<0.0001). Observed postoperative mortality was higher than expected at low-volume centers [O:E ratio 1.39, 95% confidence interval (CI) 1.05-1.83]. At low volume centers, high-risk patients (1.34, 0.85-2.12)--especially patients 1 year old or younger (1.60, 1.07-2.40) or those with congenital heart disease (1.36, 0.94-1.96)--did poorly, but those at high-volume centers did well (congenital heart disease: 0.90, 0.36-1.26; age<1 year: 0.75, 0.51-1.09). Similar results were obtained in the subset of patients transplanted after 1996. In multivariate logistic regression modeling, transplantation at a low-volume center was associated with an odds ratio for postoperative mortality of 1.60 (95% CI, 1.14-2.24); transplantation at a medium volume center had an odds ratio of 1.24 (95% CI, 0.92-1.66). CONCLUSION: The volume of transplants performed at any one center has a significant impact on outcomes. Regionalization of care is one option for improving outcomes in pediatric cardiac transplantation

OBJECTIVES: Temporary epicardial pacing wires are commonly placed during pediatric cardiac surgery. Data are sparse on postoperative pacing in this population. The objective of this study was to determine the frequency of use and identify predictors for the use of temporary epicardial pacing wires. METHODS: Perioperative data were prospectively collected on all patients who underwent cardiac surgery at our institution (n = 162). RESULTS: A total of 117 (72%) patients had temporary epicardial pacing wires placed. Postoperatively, 23 (20%) of 117 patients had hemodynamic improvement with the use of temporary epicardial pacing wires. Indications for pacing were slow junctional rhythm (11/23 [48%]), junctional ectopic tachycardia (7/23 [31%]), pace termination of supraventricular tachycardia (3/23 [13%]) and atrial flutter (1/23 [4%]), and complete heart block (1/23 [4%]). By using univariate analysis, single-ventricle anatomy, heterotaxy, the Fontan procedure, use of circulatory arrest, intraoperative arrhythmia, pacing in the operating room, and use of vasoactive medications were predictors for hemodynamic improvement with the use of temporary epicardial pacing wires (P < .05). On multivariate analysis, the Fontan procedure, circulatory arrest, and intraoperative arrhythmias were independent predictors (P < .01). When excluding all patients with any of these 3 risk factors, only 2% were paced. Patients with clinically significant pacing had longer chest tube drainage (P < .01) and intensive care unit length of stay (P < .01). There were no complications associated with temporary epicardial pacing wires. CONCLUSIONS: The Fontan procedure, use of circulatory arrest, and intraoperative arrhythmias were associated with hemodynamic improvement with postoperative pacing and might represent indications for empiric intraoperative placement of temporary epicardial pacing wires. Patients without these risk factors were less likely to require pacing. Temporary epicardial pacing wires were safe and useful in the management of arrhythmias after pediatric cardiac surgery.

Application of the Fontan procedure has allowed the survival of many patients with univentricular cardiac lesions into mid adulthood. Despite its ingenious design, implementation, and thoughtful modifications, its attendant hemodynamic perturbations persist; central venous hypertension and reduced cardiac output. These aberrations in physiology have led to pernicious changes in organ function. A more thorough understanding of these derangements and attempts at Fontan revision have temporized, yet the morbidity and patient attrition persists. Mechanical assistance to normalize the circulation is being investigated and holds some promise. At present, cardiac transplantation remains the last stage of palliation for many.

BACKGROUND: The neonatal repair of interrupted aortic arch and ventricular septal defect (IAA/VSD) presents a surgical challenge. Although one-stage repair has become well established, left ventricular outflow tract obstruction (LVOTO) continues to be an important factor affecting survival and reintervention rates after IAA/VSD repair. We investigated the relationship between the preoperative aortic annulus and the rates of reoperation for LVOTO. METHODS: Between July 1994 and July 2006, 38 patients with IAA/VSD have undergone complete single-stage repair. Patients with single ventricle physiology, transposition of the great arteries, or truncus arteriosus were excluded. Surgical technique involved the aortic arch reconstruction and VSD closure. Three patients underwent subaortic resection at the time of first operation and one patient underwent Yasui operation. The patients were divided into two groups according to whether the aortic annulus is greater than the patient's weight (kg) + 1.5 mm or less. RESULTS: The average follow-up was 7.9 +/- 4.2 years. Among the patients with small aortic annulus (n = 12), there was one hospital death and 6 reoperations for LVOTO, and one late death. There was only one reoperation for LVOTO among the patients with larger aortic annulus (n = 26, p < 0.001). The patients whose aortic annulus is less than patient's weight (kg) + 1.0 mm had poor outcomes if the LVOTO is not addressed at the time of the first operation. CONCLUSIONS: Neonatal single-stage repair for IAA/VSD achieves excellent survival. For the patients whose aortic annulus is greater than patient's weight (kg) + 1.5 mm, low reoperation rate for LVOTO is expected. For the patient whose aortic annulus is less than patient's weight + 1.5 mm, almost half of them needed reoperation. An LVOT bypass procedure (Yasui or Norwood) is recommended if the aortic annulus is less than the patient's weight + 1.0 mm.

Although cardiac tumours are rare, such tumours are increasingly being diagnosed with increasing frequency and great accuracy by antenatal ultrasound. Cardiac haemangiomas account for less than one-twentieth of all primary cardiac tumours, with most being diagnosed in the neonatal period. We report 3 instances of successful neonatal resection of cardiac haemangioma subsequent to prenatal diagnosis. Such diagnosis is important in perinatal management, since early surgical intervention provides a good prognosis

OBJECTIVE: Substantial controversy persists regarding the need and efficacy of a routine myectomy in the treatment of discrete subaortic stenosis. Although some believe myectomy more effectively relieves subaortic narrowing, this is uncertain, and complications, including heart block and aortic valve injury, are concerns. The aims of the study were as follows: (1) to analyze the role of enucleation for relief of subaortic stenosis and the risk factors associated with recurrence and reoperation and (2) to delineate the characteristics of the patients who might benefit from enucleation alone. METHODS: From January 1990 through May 2007, 221 patients with subaortic stenosis underwent biventricular repair. Of those, 106 patients had discrete subaortic stenosis. The preoperative peak left ventricular outflow tract gradient, as determined by means of transthoracic echocardiographic analysis, was 67.3 +/- 29 mm Hg. Forty patients had previous operations for other intracardiac anomalies. Mean age at repair was 7 years. Sixty-one patients underwent isolated enucleation, and 45 patients underwent concomitant myectomy. Patients with recurrent subaortic stenosis whose first operation was performed elsewhere were excluded from analysis. RESULTS: There was 1 early death and 1 late death. The postoperative peak left ventricular outflow gradient decreased to 12.5 +/- 12.9 mm Hg (P < .001). No patient had development of heart block or required a pacemaker. A recurrent gradient of greater than 30 mm Hg was found in 26 (27%) patients, and 8 (7.5%) patients had reoperations. Actuarial freedom from reoperation rates at 5, 10, and 15 years were 94.7% +/- 1.8%, 89.6% +/- 3.5%, and 84.8% +/- 4.9%, respectively.Of those patients who had not undergone a previous cardiac operation, there were no significant differences in the rates of recurrence (28% vs 27%) or reoperation (4.7% vs 4.4%) between the enucleation group and the concomitant myectomy group. For the patients who had a previous cardiac operation, the concomitant myectomy group had a significantly lower rate of recurrence (44% for enucleation vs 13% for enucleation plus myectomy, P = .031). CONCLUSIONS: For those patients undergoing primary operations for discrete subaortic stenosis, routine myectomy does not offer superior relief of left ventricular outflow tract obstruction; enucleation alone provides good results in this selected population. However, in those patients with associated cardiac anomalies, concomitant additional myectomy is recommended

OBJECTIVE: To determine the incidence of vasodilatory shock (VDS) in children after cardiopulmonary bypass (CPB), and to describe this syndrome of post-CPB VDS in children. DESIGN: Prospective, observational. SETTING: Pediatric and neonatal intensive care units in a tertiary care, children's hospital. PATIENTS: Three hundred children undergoing CPB. INTERVENTION: None. MEASUREMENTS AND MAIN RESULTS: Three hundred subjects undergoing CPB were evaluated for clinical evidence of VDS following CPB. The incidence of post-CPB VDS was 3%. Characteristics of children who developed VDS: higher peak lactate (6.2 +/- 2.6 vs. 3.0 +/- 2.1 mmol/L; p = 0.0002), higher peak serum blood urea nitrogen (18.5 +/- 4.6 vs. 15.6 +/- 7.2 mg/dL; p = 0.04), lower urine output (1.7 +/- 0.8 vs. 2.6 +/- 0.2 mL/kg/hr; p = 0.04), and fewer intensive care unit free days (14.9 +/- 9.0 vs. 21.1 +/- 7.2 days; p = 0.01). Univariate predictors for the development of post-CPB VDS included children who had heart transplantation (HT) (relative risk [RR], 9.8; 95% confidence interval [CI], 2.7-35.2) or ventricular assist device (VAD) placed (RR, 17.9; 95% CI, 3.8-84.1), a cardiomyopathy diagnosis (RR, 8.5; 95% CI, 2.3-31), age >12 years (RR, 4.5; 95% CI, 1.2-17.0), CPB time >180 minutes (RR, 7.1; 95% CI, 1.9-26.2), and preoperative ventricular dysfunction (RR, 3.7; 95% CI, 1.0-13.4). By stratified analysis, the only independent predictor for the development of VDS was undergoing HT/VAD. CONCLUSIONS: Post-CPB VDS is uncommon in children. However, children who undergo HT or VAD placement are at high risk for developing post-CPB VDS. Recognition that the overall incidence of post-CPB is low-except in the HT/VAD population-may help guide therapy in the pediatric post-CPB patient