A risk-prediction model for in-hospital mortality after heart transplantation in US children

We sought to develop and validate a quantitative risk-prediction model for predicting the risk of posttransplant in-hospital mortality in pediatric heart transplantation (HT). Children <18 years of age who underwent primary HT in the United States during 1999-2008 (n = 2707) were identified using Organ Procurement and Transplant Network data. A risk-prediction model was developed using two-thirds of the cohort (random sample), internally validated in the remaining one-third, and independently validated in a cohort of 338 children transplanted during 2009-2010. The best predictive model had four categorical variables: hemodynamic support (ECMO, ventilator support, VAD support vs. medical therapy), cardiac diagnosis (repaired congenital heart disease [CHD], unrepaired CHD vs. cardiomyopathy), renal dysfunction (severe, mild-moderate vs. normal) and total bilirubin (≥ 2.0, 0.6 to <2.0 vs. <0.6 mg/dL). The C-statistic (0.78) and the Hosmer-Lemeshow goodness-of-fit (p = 0.89) in the model-development cohort were replicated in the internal validation and independent validation cohorts (C-statistic 0.75, 0.81 and the Hosmer-Lemeshow goodness-of-fit p = 0.49, 0.53, respectively) suggesting acceptable prediction for posttransplant in-hospital mortality. We conclude that this risk-prediction model using four factors at the time of transplant has good prediction characteristics for posttransplant in-hospital mortality in children and may be useful to guide decision-making around patient listing for transplant and timing of mechanical support.

Effect of an acid mine drainage effluent on phytoplankton biomass and primary production at Britannia Beach, Howe Sound, British Columbia

We investigated the effect of acid mine drainage (AMD) from an abandoned copper mine at Britannia Beach (Howe Sound, BC, Canada) on primary productivity and chlorophyll a levels in the receiving waters of Howe Sound before, during, and after freshet from the Squamish River. Elevated concentrations of copper (integrated average through the water column >0.050 mgl(-1)) in nearshore waters indicated that under some conditions a small gyre near the mouth of Britannia Creek may have retained the AMD from Britannia Creek and from a 30-m deep water outfall close to shore. Regression and correlation analyses indicated that copper negatively affected primary productivity during April (pre-freshet) and November (post-freshet). Negative effects of copper on primary productivity were not supported statistically for July (freshet), possibly because of additional effects such as turbidity from the Squamish River. Depth-integrated average and surface chlorophyll a were correlated to copper concentrations in April. During this short study we demonstrated that copper concentrations from the AMD discharge can negatively affect both primary productivity and the standing stock of primary producers in Howe Sound.

Risk of death for Medicaid recipients undergoing congenital heart surgery

The objective of this study was to explore the effect of insurance type on mortality for congenital heart surgery. We performed a population-based retrospective cohort study using hospital discharge abstract data from five states in 1992 and 1996. The outcome measure was risk-adjusted in-hospital mortality. Cases of pediatric congenital heart surgery were identified and placed into six risk categories using the Risk Adjustment in Congenital Heart Surgery method. Multivariate analyses were used to determine the effect of insurance type on risk-adjusted mortality; regional effects were explored. Using standardized mortality ratios, institutions were grouped by outcome; within and between group differences were examined. Of 11,636 cases, 9656 (83%) were placed in a risk group for analysis. In 1996, children with Medicaid had a higher risk of death than those with commercial or managed care in both unadjusted (p = 0.002) and adjusted (p < 0.001) analyses. Overall mortality rates decreased between 1992 and 1996 (p = 0.001). However, improvement was not consistent among insurance groups. Differences were present within and between low, average, and high-mortality hospitals, suggesting that the adverse effect of Medicaid may be due to both differential referral and other differences in care among patients treated at similar institutions. Children with Medicaid insurance have a higher risk of dying after congenital heart surgery than those with commercial and some managed care insurance. Barriers to access go beyond differences in referral patterns.

Regional racial and ethnic differences in mortality for congenital heart surgery in children may reflect unequal access to care

The objective of this study was to explore racial differences in mortality for congenital heart surgery. We performed a population-based retrospective cohort study using hospital discharge abstract data from four states in 1996. The outcome measure was risk-adjusted in-hospital mortality. Cases of pediatric congenital heart surgery were classified into six risk categories using the Risk Adjustment in Congenital Heart Surgery method. Differences in risk-adjusted in-hospital mortality among racial groups were explored. Analyses stratified by state were used to identify regional differences. Of 5791 cases, 4822 (83%) were assigned to a risk group for analysis. Surgical mortality differed for whites compared to non-whites (3.7 vs 5.1%, p = 0.02). Among non-white groups, unadjusted mortality rates varied: Asian, 5.3%; black, 4.1%; Hispanic 4.9%; other, 7.3%; and missing, 7.6% (p = 0.008). Adjusted mortality also differed by race but was inconsistent across regions, making explanatory factors based solely on biology implausible. For example, compared to whites, blacks had a higher risk of dying in Massachusetts [odds ratio (OR) = 6.39, p = 0.08] but lower in Pennsylvania (OR = 0.41, p = 0.009). Adding insurance type to models did not eliminate racial differences. In risk-adjusted analyses, non-white groups had a higher risk of dying after congenital heart surgery than whites. Inconsistent effects among regions suggest that differential mortality is due to unequal access to care rather than biology.

Repeat balloon dilation of congenital valvar aortic stenosis: immediate results and midterm outcome

While balloon dilation (BD) has become the initial treatment for congenital valvar aortic stenosis (CVAS) at many institutions, repeat BD for recurrent obstruction has been reported only in a few. Between January 1985 and December 1996, 298 patients (70 neonates) underwent BD, 34 of whom underwent a repeat BD without mortality. A greater proportion of neonates had a repeat BD (26% vs. 8%, P < 0.001). At repeat BD (1 day-7.5 years post initial BD), the mean peak-to-peak gradient was reduced from 67+/-24 to 36+/-16 mm Hg (P < 0.0001). Aortic regurgitation (AR) increased immediately in 26%, being moderate or more in 24%. During a mean follow-up of 5.2 years, there was one surgically related death. Of the 33 survivors, 6 had surgery for residual stenosis and/or AR. Among the remaining 27 patients, 96% were asymptomatic, the peak instantaneous aortic valve Doppler gradient was 50+/-15 mm Hg with AR absent in 8%, mild in 62%, and moderate or more in 31%. In conclusion, repeat BD is effective and without mortality. AR was at least moderate in 24% of patients immediately after a second BD. Repeat BD was more common in patients who underwent the initial BD as neonates.