Christo I. Tchervenkov

A small post-operative rise in serum creatinine predicts acute kidney injury in children undergoing cardiac surgery

To predict development of acute kidney injury and its outcome we retrospectively studied children having cardiac surgery. Acute kidney injury (AKI) was defined using the serum creatinine criteria of the pediatric Risk Injury Failure Loss End-Stage (pRIFLE) kidney disease definition. We tested whether a small rise (less than 50%) in creatinine on post-operative days 1 or 2 could predict a greater than 50% increase in serum creatinine within 48 h in 390 children. AKI occurred in 36% of patients, mostly in the first 4 post-operative days. Using logistic regression, significant independent risk factors for AKI were bypass time, longer vasopressor use, and a tendency for younger age. Using Cox regression, AKI was independently associated with longer intensive care unit stay and duration of ventilation. Patients whose serum creatinine did not increase on post-operative days 1 or 2 were unlikely to develop AKI (negative predictive values of 87 and 98%, respectively). Percentage serum creatinine rise on post-operative day 1 predicted AKI within 48 h (area under the curve=0.65). Our study shows that AKI after pediatric heart surgery is common and is a risk factor for poorer outcome. Small post-operative increases in serum creatinine may assist in the early prediction of AKI.

The Challenge of Congenital Heart Disease Worldwide: Epidemiologic and Demographic Facts

Congenital heart disease (CHD) afflicts a large number of children every year. The incidence of CHD is generally considered to be 8 per 1,000 live births. However, this estimate is perhaps inaccurate and does not take into consideration regional differences. A large review of the literature was performed to establish the true incidence of CHD and geographical variations. Data on the incidence of specific lesions and their geographical variation, as well as on mortality from CHD, was also reviewed. Taking into consideration the available data on incidence, mortality, and access to care, the global challenge that CHD represents was analyzed. Insight into how to confront this challenge is given.

Contemporary Patterns of Management of Tetralogy of Fallot: Data From The Society of Thoracic Surgeons Database

BACKGROUND The Society of Thoracic Surgeons Database was queried to ascertain current trends in management of tetralogy of Fallot (TOF) and to determine the prevalence of various surgical techniques. METHODS The study population (n = 3059 operations) was all index operations in 2002-2007, age 0-18 years with Primary Diagnosis of TOF, and Primary Procedure TOF repair or palliation. Patients with Pulmonary Atresia, Absent Pulmonary Valve, and Atrioventricular Canal were excluded. RESULTS 294 patients had initial palliation, including 178 neonates. 2534 patients had repair of TOF as the initial operation (primary repair), including 154 neonates. 217 patients had repair of TOF after prior palliation. Of patients who had primary repair (n = 2534), 975 had repair at 3 to 6 months, 614 at 6 months to 1 year, 492 at 1 to 3 months, and 154 at 0 to 30 days. Of patients who had repair following prior palliation (n = 217), 65 had repair in the first 6 months of life, 111 at 6 months to 1 year, and only 41 (18.9%) at more than 1 year of age. Type of repair: Of 2534 primary repairs, 581 (23%) had no ventriculotomy, 571 (23%) had nontransanular patch, 1329 (52%) had transanular patch, and 53 (2%) had right ventricle to pulmonary artery conduits. Of repairs after prior palliation (n = 217), 20 (9%) had no ventriculotomy, 30 (14%) had nontransanular patch, 144 (66%) had transanular patch, and 24 (11%) had conduits. Discharge mortality (95% confidence interval; CI) was 22 of 294 (7.5%; CI: 4.7%-11.1%) for initial palliation, 33 of 2534 (1.3%; CI: 0.9%-1.8%) for primary repair, and 2 of 217 (0.9%; CI: 0.1%-3.3%) for secondary repair. For neonates, discharge mortality was 11 of 178 (6.2%; CI: 3.1%-10.8%) for palliation and 12 of 154 (7.8%; CI: 4.1%-13.2%) for primary repair. CONCLUSIONS Primary repair in the first year of life is the most prevalent strategy. Despite contemporary awareness of the late consequences of pulmonary insufficiency, ventriculotomy with transanular patch remains the most prevalent technique, both for primary repair and for repair following palliation.

A New Look at Outcomes of Infants With Congenital Heart Disease

This article provides an overview of a longitudinal study on a cohort of 131 newborns and young infants with congenital heart defects who required open heart surgery. The rationale for the study design is provided as well as a summary of the procedures used to evaluate these children prior to surgery, at discharge after surgery, 12-18 months later, and at 5 years of age. Results demonstrate that a substantial proportion of these infants had neurologic and developmental abnormalities prior to surgical repair. Developmental delays were common in children with both cyanotic and acyanotic heart defects, and these deficits persisted to school entry. A number of medical, surgical, demographic and environmental factors were significantly associated with developmental outcomes suggesting a multifactorial etiology to brain injury. Limited educational and rehabilitation resources for this cohort at early school age suggests that service needs may need to be more carefully planned for this high-risk population. Lessons learnt from this prospective study are highlighted as well as future directions for research and clinical practice.

The nomenclature, definition and classification of hypoplastic left heart syndrome

The hypoplastic left heart syndrome encompasses a spectrum of cardiac malformations that are characterized by significant underdevelopment of the components of the left heart and the aorta, including the left ventricular cavity and mass. At the severe end of the spectrum is found the combination of aortic and mitral atresia, when the left ventricle can be close to non-existent. At the mild end are the patients with hypoplasia of the aortic and mitral valves, but without intrinsic valvar stenosis or atresia, and milder degrees of left ventricular hypoplasia. Although the majority of the patients are suitable only for functionally univentricular repair, a small minority may be candidates for biventricular repair. The nature of the syndrome was a topic for discussion at the second meeting of the International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, the Nomenclature Working Group, held in Montreal, Canada, over the period January 17 through 19, 2003. Subsequent to these discussions, the Nomenclature Working Group was able to create a bidirectional crossmap between the nomenclature initially produced jointly on behalf of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and the alternative nomenclature developed on behalf of the Association for European Paediatric Cardiology. This process is a part of the overall efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system of nomenclature for paediatric and congenital cardiac disease, the International Paediatric and Congenital Cardiac Code. In this review, we discuss the evolution of nomenclature and surgical treatment for the spectrum of lesions making up the hypoplastic left heart syndrome and its related malformations. We also present the crossmap of the associated terms for diagnoses and procedures, as recently completed by the Nomenclature Working Group.

Congenital Heart Surgery Nomenclature and Database Project: double outlet right ventricle

Double outlet right ventricle (DORV) is a type of ventriculoarterial connection in which both great vessels arise entirely or predominantly from the right ventricle. Although the presence of aortic-mitral discontinuity and bilateral coni are important descriptors, they should not serve as absolute prerequisites for the diagnosis of DORV. The morphology of DORV is encompassed by a careful description of the ventricular septal defect (VSD) with its relationship to the semilunar valves, the great artery relationships to each other, the coronary artery anatomy, the presence or absence of pulmonary outflow tract obstruction (POTO) and aortic outflow tract obstruction (AOTO), the tricuspid-pulmonary annular distance, and the presence or absence of associated cardiac lesions. The preferred surgical treatment involves the connection of the left ventricle to the systemic circulation by an intraventricular tunnel repair connecting the VSD to the systemic semilunar valve. This ideal surgical therapy is not always possible due to the presence of confounding anatomical barriers. A multitude of alternative surgical procedures has been devised to accommodate these more complex situations. A framework for the development of the DORV module for a pediatric cardiac surgical database is proposed.

The Management of Chylothorax/Chylopericardium Following Pediatric Cardiac Surgery: A 10‐Year Experience

We reviewed the management of 25 cases of chylothorax/chylopericardium (CT/CP) in 24 patients (9 females, 15 male; 3 days to 11‐years‐old) following 1605 cardiothoracic procedures (incidence of 1.5%) between January 1984 and December 1993 at our institution. The surgical procedures preceding the occurrence of lymph leak included ligation of patent ductus arteriosus (6 patients), coarctation/double aortic arch repairs (3), complex intracardiac repairs (11), and systemic to pulmonary shunts (5). There were 3 CPs and 22 CTs. All of the patients were initially treated nonsurgically with diet modification using either total parenteral nutrition (TPN) or enteral low fat solid food or enteral elemental diet supplemented with intravenous lipid emulsion. Twenty‐one cases (84%) responded to conservative therapy. Of those, 15 had TPN as the initial treatment; the average duration of lymph leak was 13.7 (range 7 to 30) days and the average maximal lymph leak was 39.4 (range 15 to 130) mL/kg per day. The other six cases had low‐fat enteral diet as the initial treatment, four resolved completely. Two with high‐central venous pressure had to be switched to TPN prior to complete resolution. The average duration of lymph leak in this subgroup was 30 (range 12 to 56) days with the average maximal lymph leak was 30.1 (range 8.5 to 59) mL/kg per day. Excluding these two cases, the average lymph leak of the rest of the group was very compatible to the TPN group of 15 days. Lymphocytopenia and hyponatremia were frequently seen during CT/CP (47.6% and 43%, respectively). Two recurrent CTs in this group were easily treated with reinstitution of low fat diet in one and TPN the other. Four remaining patients required surgical interventions (rethoracotomy and ligation of lymph fistulae in 2, application of fibrin glue to the site of leakage in 1, 1 patient underwent four thoracotomies for persistent CT) for failed initial medical therapy. The mean peak daily lymph loss was 131.2 (range 68.4 to 216) mL/kg which was significantly higher than that of the conservative group (36.2 mL/kg, p < 0.001). Three (75%) had complete cessation of lymph drainage after surgery. We concluded that the majority of CT/CP following surgery for congenital heart diseases could safely be treated without surgical interventions by diet manipulations with acceptable inherent morbidity. Patients with high‐central venous pressure should be managed early with TPN and bowel rest. Enteral low‐fat diet used in appropriately selected patients appeared to be as effective in controlling lymph leak as TPN. Surgical ligation of severed lymphatics was indicated for few cases with excessive lymph loss.

Variation in Outcomes for Benchmark Operations: An Analysis of The Society of Thoracic Surgeons Congenital Heart Surgery Database

BACKGROUND We evaluated outcomes for common operations in The Society of Thoracic Surgeons Congenital Heart Surgery Database (STS-CHSDB) to provide contemporary benchmarks and examine variation between centers. METHODS Patients undergoing surgery from 2005 to 2009 were included. Centers with greater than 10% missing data were excluded. Discharge mortality and postoperative length of stay (PLOS) among patients discharged alive were calculated for 8 benchmark operations of varying complexity. Power for analyzing between-center variation in outcome was determined for each operation. Variation was evaluated using funnel plots and Bayesian hierarchical modeling. RESULTS Eighteen thousand three hundred seventy-five index operations at 74 centers were included in the analysis of 8 benchmark operations. Overall discharge mortality was: ventricular septal defect (VSD) repair = 0.6% (range, 0% to 5.1%), tetralogy of Fallot (TOF) repair = 1.1% (range, 0% to 16.7%), complete atrioventricular canal repair (AVC) = 2.2% (range, 0% to 20%), arterial switch operation (ASO) = 2.9% (range, 0% to 50%), ASO + VSD = 7.0% (range, 0% to 100%), Fontan operation = 1.3% (range, 0% to 9.1%), truncus arteriosus repair = 10.9% (0% to 100%), and Norwood procedure = 19.3% (range, 0% to 100%). Funnel plots revealed that the number of centers characterized as outliers were VSD = 0, TOF = 0, AVC = 1, ASO = 3, ASO + VSD = 1, Fontan operation = 0, truncus arteriosus repair = 4, and Norwood procedure = 11. Power calculations showed that statistically meaningful comparisons of mortality rates between centers could be made only for the Norwood procedure, for which the Bayesian-estimated range (95% probability interval) after risk-adjustment was 7.0% (3.7% to 10.3%) to 41.6% (30.6% to 57.2%). Between-center variation in PLOS was analyzed for all operations and was larger for more complex operations. CONCLUSIONS This analysis documents contemporary benchmarks for common pediatric cardiac surgical operations and the range of outcomes among centers. Variation was most prominent for the more complex operations. These data may aid in quality assessment and quality improvement initiatives.

Biventricular repair in neonates with hypoplastic left heart complex.

BACKGROUND Multiple obstructions in the left heart-aorta complex have been associated with poor survival. No consensus exists as to whether these patients will have a favorable outcome with biventricular repair where most advocate a univentricular approach. METHODS Since late 1988, all 11 neonates seen with hypoplastic left heart complex, which includes aortic arch obstruction, underwent biventricular repair. All patients had antegrade aortic flow and no intrinsic aortic or mitral stenosis. Elimination of the extracardiac afterload was achieved by extensive ascending aorta and aortic arch reconstruction with a pulmonary homograft patch. All intracardiac shunts were eliminated to fully preload the left heart. The median age at first operation was 7 days and the mean weight, 3.59+/-0.49 kg. The echocardiographic variables used to evaluate the left heart-aorta complex were reviewed, and the preoperative and postoperative measurements were compared. RESULTS There were two early deaths. Four patients had six reoperations for left ventricular outflow tract obstruction, 2 of whom have required prosthetic valve replacement (1, aortic and mitral; 1, aortic), and 2 patients had three reoperations for recurrent coarctation. There was one late death at 3 years from pulmonary hypertension. Mean follow-up was 44+/-35 months. The 8 current survivors are all in New York Heart Association class I or II. The actuarial survival rate at 8 years is 63%, and the freedom from reoperation at 3 years is 25%. CONCLUSIONS We have successfully achieved biventricular repair in most of the patients with hypoplastic left heart complex, a subset of patients with hypoplastic left heart syndrome. Some growth of the left ventricular structures was already observed at the time of hospital discharge. However, reoperation, particularly for left ventricular outflow tract obstruction, appears likely. Increasing experience will more accurately define predictive criteria for the feasibility of biventricular repair.

Developmental and Functional Outcomes at School Entry in Children with Congenital Heart Defects

OBJECTIVE To describe developmental and functional outcomes of children with congenital heart defects (CHDs) at school entry after open heart surgery. STUDY DESIGN Infants with CHDs who underwent surgical repair in infancy were recruited and assessed prospectively for developmental progress. At 5 years of age (64.2 +/- 11.3 months), 94 subjects were evaluated in a blind fashion by using a variety of standardized measures. RESULTS Mean IQ scores were in the low average range (90-94). Receptive language was in the average range (103.6 +/- 14.4). Behavioral difficulties were common (27.1%), with internalizing problems being more frequent. Functional limitations in socialization (93.0 +/- 17.1), daily living skills (94.6 +/- 16.4), communication (90.0 +/- 14.1), and adaptive behavior (92.1 +/- 15.8) were noted in 11% to 17% of children. With the Functional Independence Measure for Children, 20% to 22% of subjects were more dependent than their peers in self-care and social cognition, although few (4.5%) had mobility restrictions. Predictors of developmental and functional limitations included: abnormal postoperative neurologic examination, microcephaly, deep hypothermic circulatory arrest time, palliation, acyanotic heart lesion, age at surgery, and maternal education. CONCLUSIONS After infant open-heart surgery, children with CHDs may exhibit a range of developmental difficulties at school entry that enhances risk for learning challenges and decreased social participation.