Long-Term Quality of Life in Congenital Heart Disease Surgical Survivors: Multicenter Retrospective Study of Surgical and ICU Explanatory Factors.

OBJECTIVES: Greater congenital heart disease (CHD) complexity is associated with lower health-related quality of life (HRQOL). There are no data on the association between surgical and ICU factors and HRQOL in CHD survivors. This study assess the association between surgical and ICU factors and HRQOL in child and adolescent CHD survivors. DESIGN: This was a corollary study of the Pediatric Cardiac Quality of Life Inventory (PCQLI) Testing Study. SETTING: Eight pediatric hospitals participating in the PCQLI Study. PATIENTS: Patients in the study had the Fontan procedure, surgery for tetralogy of Fallot (TOF), and transposition of the great arteries (TGAs). MEASUREMENTS AND MAIN RESULTS: Surgical/ICU explanatory variables were collected by reviewing the medical records. Primary outcome variables (PCQLI Total patient and parent scores) and covariates were obtained from the Data Registry. General linear modeling was used to create the multivariable models. There were 572 patients included: mean ± sd of age 11.7 ± 2.9 years; CHD Fontan 45%, TOF/TGA 55%; number of cardiac surgeries 2 (1-9); and number of ICU admissions 3 (1-9). In multivariable models, lowest body temperature on cardiopulmonary bypass (CPB) was negatively associated with patient total score (p < 0.05). The total number of CPB runs was negatively associated with parent-reported PCQLI Total score (p < 0.02). Cumulative days on an inotropic/vasoactive drug in the ICU was negatively associated with all patient-/parent-reported PCQLI scores (p < 0.04). Neurological deficit at discharge was negatively associated with parent-reported PCQLI total score (p < 0.02). The variance explained by these factors ranged from 24% to 29%. CONCLUSIONS: Surgical/ICU factors, demographic, and medical care utilization variables explain a low-to-moderate amount of variation in HRQOL. Research is needed to determine whether modification of these surgical and ICU factors improves HRQOL, and to identify other factors that contribute to unexplained variability.

Targeting Glycemic Control After Pediatric Cardiac Surgery: The Influence of Age on Insulin Requirement.

OBJECTIVE: Factors influencing the development of hyperglycemia and pattern of insulin requirement in children undergoing cardiac surgery are poorly understood. This study investigated the impact of age on the pattern of hyperglycemia and insulin requirement in children after cardiac surgery. DESIGN: Cohort study, based on a prospectively collected dataset for patients enrolled into the Control of Hyperglycemia in Pediatric Intensive Care trial. SETTING: A 24-bedded multidisciplinary PICU. PATIENTS: Children randomized to the tight glycemic control arm (target blood glucose, 4-7 mmol/L [72-126 mg/dL]) of the Control of Hyperglycemia in Pediatric Intensive Care trial following cardiac surgery. Children were categorized into four age groups (neonate, 1-30 d; infant, 31-365 d; young child, 1-5 yr; older child, 5-16 yr) for analyses of patterns of hyperglycemia and insulin requirement over the 12-hour period following initiation of insulin. INTERVENTIONS: Insulin titration was performed based on blood glucose value and rate of change of blood glucose using an algorithm developed for the Control of Hyperglycemia in Pediatric Intensive Care trial. MEASUREMENTS AND MAIN RESULTS: Of 92 children, 72 children (78%) randomized to the tight glycemic control group developed hyperglycemia (blood glucose, > 7 mmol/L [126 mg/dL]) and received insulin. Older age was associated with higher blood glucose and a higher insulin dose per kilogram over the first 3 hours of the study period (p ≤ 0.02). Cumulative insulin dose was significantly higher in older children (median, 1.3 U/kg [range, 0.2-5.75]) compared with other age groups (neonate, 0.37 [0.05-2.2]; infant, 0.45 [0.05-2.2]; young child, 0.35 [0.05-0.81]) (p = 0.004). Age group, rather than body mass index, carbohydrate intake, or cardiac surgery variables, was the only variable (coefficient: 1.14 ± 0.3; p < 0.001) associated with cumulative insulin dose on multivariate analysis. CONCLUSIONS: When tight glycemic control is targeted in children who have undergone cardiac surgery, children in the older child age group (5-16 yr) require insulin at significantly higher doses. Further study is needed to understand the mechanisms involved.

Early change in blood glucose concentration is an indicator of mortality in critically ill children.

OBJECTIVE: Hyperglycaemia is associated with increased mortality in critically ill patients. A number of studies have highlighted an association between increased variability of blood glucose (BG) concentration and mortality, supporting a survival disadvantage if BG homeostasis is lost. By exploring the longitudinal BG profile of individual children over time, this study investigates the importance of intact homeostasis early after admission to the paediatric intensive care unit (PICU). DESIGN, SETTING, AND PATIENTS: Retrospective single-centre observational study in a large multi-specialty PICU in the UK. Children admitted between August 2003 and February 2006 were included unless they met exclusion criteria. Data were merged from the PICU clinical database and blood gas analyser database by means of a unique PICU identifier. BG was measured frequently on a blood gas analyser (Bayer Rapidlink). Primary outcome was 100-day mortality. BG parameters were investigated for possible associations with mortality. MEASUREMENTS AND MAIN RESULTS: A total of 1,763 patients were included (median age 1.1 years; IQR 0.1-5.8). Although admission BG was not associated with mortality, a survival advantage was found in children who showed a reduction in BG on day 1 relative to the admission BG value (p < 0.001). This remained statistically significant (p = 0.007) after adjusting for severity of illness. CONCLUSIONS: This study supports an association between early BG profile and mortality in children admitted to PICU, with increased survival in those who demonstrate a fall in BG on day 1 relative to PICU admission. These findings are consistent with a survival advantage of intact BG homeostasis.

Risk assessment and early outcome following the Norwood procedure for hypoplastic left heart syndrome.

BACKGROUND: This study was undertaken to identify risk factors for early mortality following the Norwood procedure for hypoplastic left heart syndrome (HLHS) and develop a predictive risk model to monitor clinical performance. METHODS AND RESULTS: Between December 1992 and June 2004, 333 patients with HLHS underwent a Norwood procedure at a single institution. The early mortality was 29% (n=95). Estimated early mortality improved progressively and was 10% at the end of the series. Multivariable analysis identified that body surface area at operation, size of the ascending aorta, preoperative right ventricular function and source of pulmonary blood flow established at operation were risk factors for early mortality (P<0.05). These variables were included in a preoperative risk model. The duration of cardiopulmonary support was an independent risk factor, which was included in a separate operative risk model. The performance of the risk models was evaluated by goodness-of-fit analyses, using the Hosmer-Lemeshow test and receiver operating characteristic (ROC) curve. Both models were well calibrated across all deciles (P=0.64, P=0.77) and discriminated moderately well. The area under the ROC curve was 0.71 for Model 1 and 0.75 for Model 2. Risk adjustment broadly accounted for the variation in early mortality observed during this series. CONCLUSIONS: Patient-related and predetermined operative variables have a major influence on the early outcome following the Norwood procedure for HLHS. The identification of these risk factors allows the risk of early mortality to be calculated. This information could be applied as part of a risk-adjusted performance-monitoring system to enable early identification of meaningful changes in practice.

Predicting the performance of mitral prostheses implanted in children under 5 years of age.

BACKGROUND: Mitral valve replacement (MVR) is occasionally indicated in infants and young children, necessitating the use of small prostheses. The performance of these small valves during somatic growth of the patient can lead to patient-prosthesis mismatch. This study examines performance of these valves over time to establish predicted performance and timing of replacement. METHODS: Records were reviewed of all patients under 5 years of who underwent small mechanical MVR between 1988 and 2004 (n=24). Valve sizes were between 17 and 23 mm (Bileaflet 91.6%, Tilting Disc 8.3%) with a median size of 19 mm. Mean age of patients was 1.4+/-1.3 years with a mean weight of 7.8+/-3.4 kg. RESULTS: Early deaths (n=5, 20.8%) were excluded. There were two late deaths and five patients required redo-MVR: four for outgrowth and one for acute thrombosis at 3 months. Age at redo for outgrowth was 8.6+/-6.6 years with mean body weight of 22.5+/-17.5 kg. Mean time between original operation and redo was 8.6+/-6.1 years in these four patients. Follow-up was a median of 7.5 years (range 0.1-15.7 years). Overall freedom from death or valve replacement was 82.6+/-9.1% at 5 years and 75.7+/-10.6% at 10 years. The performance of the original prostheses showed a peak blood flow velocity across the valves of 1.5+/-0.6 m/s at 5 years and 2.2+/-0.5 m/s at 10 years. Seventy-five percent of the survivors still have their original valve at a mean of 8.1+/-4.4 years postoperative with New York Heart Association status of I or II. Actuarial curves suggest that gradients across the valves reach a peak of >10 mmHg at a mean between 6.5 and 7 years postoperative. CONCLUSION: MVR in children under 5 years carries a high mortality. Nevertheless, small mechanical MVR perform remarkably well in young children with durable haemodynamics despite growth of the patients well beyond more than double the initial bodyweight. Valves can be expected to last over 8 years before requiring re-replacement.

The RV-PA conduit stimulates better growth of the pulmonary arteries in hypoplastic left heart syndrome.

OBJECTIVE: This retrospective study compared the size of the central pulmonary arteries in patients with hypoplastic left heart syndrome (HLHS) following either a classical Norwood or Norwood procedure with a right ventricle to pulmonary artery (RV-PA) conduit. METHODS: Between May 2001 and May 2003, 30 patients with HLHS underwent cardiac catheterization prior to stage II palliation. Patients were initially palliated with a classical Norwood (Classical group, n=18) or Norwood procedure with RV-PA conduit (RV-PA group; n=12). Indexed maximum and minimum diameters of the LPA and RPA were measured using the McGoon ratio. Cardiac catheterisation was performed at a median age of 4.0 months. There was no difference in the time interval to catheterisation (P=0.13), Qp:Qs (P=0.41) or median haemoglobin (P=0.42) between the groups. RESULTS: The combined PA diameter was larger in the RV-PA group (B) than the classical group (A) (1.99+/-0.38 versus 1.63+/-0.29, P<0.05). There were marked differences in the relative size of the pulmonary arteries between the two groups. In RV-PA patients, the LPA and RPA sizes were comparable (0.99+/-0.22 versus 1.00+/-0.31, P=1.00) whereas, in the classical group, the LPA was smaller than the RPA (0.75+/-0.15 versus 0.88+/-0.17, P<0.05). Both techniques were also associated with discrete PA stenoses at the site of shunt insertion. Stenoses were more severe in RV-PA group (RV-PA), causing a 42+/-16% reduction in the combined PA diameter compared with a 28+/-18% reduction in Classical group (classical) (P<0.05). CONCLUSIONS: The Norwood procedure with RV-PA conduit is associated with better and more evenly distributed central pulmonary artery growth. Nevertheless, it is also associated with central PA stenoses, which may require subsequent reconstruction.