Lester Permut

Association of thymectomy with infection following congenital heart surgery.

Background: Congenital absence of the thymus can lead to profound immunodeficiency, suggesting that thymic function during fetal development is essential to normal lymphocyte development. How vital the thymus after birth is to human immune competence and regulation is not known. Routine thymectomy, especially at an early age, may influence immunity, and therefore the risk of infection, autoimmunity, or malignancy. Methods: A retrospective review of cardiac surgery patients followed at Seattle Children’s Hospital was performed. The primary outcome was rate of serious infections requiring hospitalization. Secondary analyses included age, type of infection, cardiac diagnosis, surgical procedure, and comorbidities. Results: Patients fell into 2 groups: 60 with complete thymectomy and 35 with partial or no thymectomy. There was no statistical difference between groups in the overall prevalence of serious infections (16.7% vs 17.2%, P = 1.0). There was a nonsignificant trend toward reduced time between surgery and onset of first infection in patients in the total thymectomy group versus those without thymectomy (1.7 years vs 4.6 years, P = .07). Total thymectomy before 6 months of age also tended to increase infection rate, but the effect was not significant (0.09/year vs 0.02, P = .14). Gastroesophageal reflux in patients with total thymectomy increased the risk of infection (P = .013), suggesting a cumulative effect. Conclusions: Though infections occurred frequently in the childhood cardiac surgery population, total thymectomy was not associated with increased risk of serious infection. Comorbid conditions may be more important contributing factors increasing the risk of infection in this complex and vulnerable population.

Significance of Positive Mediastinal Cultures in Pediatric Cardiovascular Surgical Procedure Patients Undergoing Delayed Sternal Closure

BACKGROUND Many pediatric cardiac surgery centers obtain mediastinal cultures at the time of delayed sternal closure (DSC). There are no recommendations regarding how to treat patients with positive cultures. We explored the clinical significance of positive mediastinal cultures with regard to surgical site infections (SSI). METHODS A retrospective study was performed on all patients who underwent DSC at our institution between December 2006 and December 2011. National Healthcare Safety Network criteria were used to prospectively identify SSIs. Univariate and multivariate logistic regression analyses were performed to evaluate potential risk factors for SSI and predictors for positive mediastinal cultures obtained at DSC. RESULTS A total of 178 patients underwent DSC during the study period; 155 patients met the eligibility criteria for the study and were included in the analysis. Of the 155 included patients, 11 patients (7.1%) experienced SSI. Patients with a positive mediastinal culture obtained at DSC were more likely to experience SSI than were patients with a negative culture (p=0.003). In univariate analysis, a positive mediastinal culture was the only factor associated with SSI (odds ratio [OR], 7.4; 95% confidence interval [CI], 2.1 to 26.7). In multivariate analysis, age at operation≥2 weeks (adjusted OR [aOR], 4.9; 95% CI, 1.84 to 12.8), receipt of stress-dosed hydrocortisone while the chest was open (aOR, 2.9; 95% CI, 1.1 to 7.6), and gestational age≤37 weeks (aOR, 2.7; 95% CI, 1.01 to 7.27) were independent predictors for a positive mediastinal culture. CONCLUSIONS Patients with positive mediastinal cultures obtained at DSC had a significantly higher rate of subsequent SSI, and a positive mediastinal culture was the only statistically significant predictor of SSI.

Absent Aortocoronary Connections in a Neonate With Pulmonary Atresia and an Intact Ventricular Septum

m t i w t o f p M g p a a a I n o v m ( m t URING FETAL DEVELOPMENT, pulmonary atresia can cause important changes in the growth and function of he right ventricle (RV). If there is no ventricular septal defect ie, if the fetus has pulmonary atresia with an intact ventricular eptum [PA-IVS]), the RV becomes severely hypertrophic and he RV cavity develops into a small, high-pressure chamber.1-3 resumably, the high RV pressure promotes maintenance and rowth of RV to distal coronary artery communications (venriculocoronary arterial connections) and development of cornary abnormalities. Sometimes an “RV-dependent coronary irculation (RVDCC)” where major portions of the myocarium are perfused directly from the RV will be present. Most nfants with RVDCC, however, will also have antegrade cornary blood supply from the aorta, and staged surgical palliaion with or without RV decompression can be accomplished ith good results.4,5 This report describes the authors experince with a neonate with absent aortocoronary connections and hus a total RVDCC.

Sternal wire removal in pediatric patients: Wire versus cable sternotomy closure

*Difference statistically significant by Fisher exact test (P 1⁄4 .008). Secure sternal closure after median sternotomy is important to facilitate sternal healing, optimize ventilatory mechanics, and minimize discomfort in the early postoperative period. Many techniques have been reported for sternal closure in adults, with the most widely used involving permanent stainless steel wires or cables. In the pediatric population, absorbable sutures may be used in smaller patients, but stainless steel wire or cable closure is generally preferred for larger children and teens. Although uncommon, persistent chest wall pain related to sternal wire closure is well described in the adult population and may necessitate reoperation for wire removal. This finding has not been described after cable closure in adults. Furthermore, the frequency of persistent pain after sternal closure with either wire or cable systems in children is unknown. Beginning in March 2005, a cable system was used for sternal closure in all patients larger than 30 kg at our institution. A seemingly disproportionate rate of reoperation for cable removal was subsequently observed. We therefore reviewed our institutional experience with wire and cable sternal closures to compare the performances of these sternal closure systems in the pediatric population.

Direct optical measurement of intraoperative myocardial oxygenation during congenital heart surgery

This study demonstrates use of novel technology to measure cellular oxygenation during corrective congenital heart surgery. Cellular oxygenation was measured using a custom-designed optical probe placed on the free wall of the right ventricle. Cellular oxygenation, determined from myoglobin saturation, was calculated using multiwavelength analysis. Timing of bypass, aortic cross-clamp, infusion of cardioplegic solution, and length of intensive care unit (ICU) stay were recorded. Baseline cellular oxygenation was approximately 50% just before aortic cross-clamp and decreased to approximately 20% during cardioplegia. Cellular oxygenation remained low throughout cardioplegia and returned toward baseline after bypass. In four cases, cellular oxygenation did not return as quickly to baseline as in the other three cases. Among the four patients demonstrating slow recovery, the average ICU length of stay was 2.25 days compared with an average stay of 1.33 days for those patients exhibiting rapid cellular oxygenation recovery (p = 0.06). The slow recovery group had an average cross-clamp time of 40.1 ± 28.4 minutes, compared with 26.0 ± 8.5 minutes for the fast recovery group (p = 0.34). This study demonstrates for the first time that myocyte cellular oxygenation can be measured intraoperatively during cardiac surgery. Measurement of cellular oxygenation may be useful for improving myocardial preservation techniques.

Impact of donor–recipient sex match on long‐term survival after heart transplantation in children: An analysis of 5797 pediatric heart transplants

The effect of donor–recipient sex matching on long‐term survival in pediatric heart transplantation is not well known. Adult data have shown worse survival when male recipients receive a sex‐mismatched heart, with conflicting results in female recipients. We analyzed 5795 heart transplant recipients ≤18 yr in the Scientific Registry of Transplant Recipients (1990–2012). Recipients were stratified based on donor and recipient sex, creating four groups: MM (N = 1888), FM (N = 1384), FF (N = 1082), and MF (N = 1441). Males receiving sex‐matched donor hearts had increased unadjusted allograft survival at five yr (73.2 vs. 71%, p = 0.01). However, this survival advantage disappeared with longer follow‐up and when adjusted for additional risk factors by multivariable Cox regression analysis. In contrast, for females, receiving a sex‐mismatched heart was associated with an 18% higher risk of allograft loss over time compared to receiving a sex‐matched heart (HR 1.18, 95% CI: 1.00–1.38) and a 26% higher risk compared to sex‐matched male recipients (HR 1.26, 95% CI: 1.10–1.45). Females who receive a heart from a male donor appear to have a distinct long‐term survival disadvantage compared to all other groups.

Hybrid stage 1 palliation as a bridge to cardiac transplantation in patients with high-risk single ventricle physiology

The hybrid stage 1 palliation for hypoplastic left heart syndrome (HLHS) was first described in 1993 as a bridge to heart transplant for HLHS. There are limited data on this strategy as primary heart transplantation for HLHS has become less common.

Long-Term Mechanical Cardiac Assist in Children: A Work in Progress

50 The article by Sachdeva et al. in this issue of the Journal of the American Society of Echocardiography describes the echocardiographic findings in pediatric patients with heart failure supported with the Berlin Heart EXCOR ventricular assist device (VAD) (Berlin Heart AG, Berlin, Germany). Chronic heart failure as a result of cardiomyopathy or congenital heart disease is diagnosed with increasing frequency in pediatric patients. As in the adult population, heart transplantation is the principal treatment for childrenwith end-stage heart failure. However, the limited availability of size-matched pediatric organ donors, particularly in neonates and infants, is associated with a prolonged median waiting time from listing to transplantation of 69 days. Currently, mortality for pediatric patients awaiting heart transplantation is 20%. Mechanical support of the severely failing heart may be used as a bridge to transplantation when pharmacologic therapy is no longer adequate. The resulting improvement in cardiac output stabilizes end-organ function, reduces mortality risk, and optimizes the patient’s overall condition before transplantation. A wide variety of devices are available for adult patients, but options for thepediatric population, particularly infants and small children, remain limited. Extracorporeal membrane oxygenation (ECMO) is the most frequently used form of mechanical assist in children. Advantages include widespread availability, ease of cannulation (via the right internal jugular vein and right common carotid artery), and applicability in neonates, infants, and older children. The primary disadvantage of ECMO is limited durability. Complications including infection, surgical site bleeding, and intracranial bleeding generally preclude support for longer than 3 to 4 weeks, severely reducing the utility of ECMO as a bridge to transplantation.