Risk Stratification and Transplant Benefit in Children Listed for Heart Transplant in the United States

Abstract

Background-The sickest children among those listed for heart transplant (HT) are also at higher risk of post-transplant mortality. We hypothesized that transplant benefit, defined as percentage reduction in risk of 1-year mortality on receiving HT, increases with higher risk of wait-list mortality. Methods and Results-We analyzed all children aged <18 years listed for first HT in the United States between July 2004 and December 2010. We developed a model for 90-day wait-list mortality (or removal because of deterioration) and stratified listed children into deciles based on their risk of wait-list mortality. Listed children were followed up for 1 year to assess cumulative 1-year wait-list mortality among the 10 risk groups. We developed a model for 1-year post-transplant mortality to estimate the risk of post-transplant mortality for children in each risk group. Of 2979 listed children, 15% reached the wait-list end point within 90 days and 18% within 1 year. Of 2034 HT recipients, 6.8% died within 90 days and 10.8% within 1 year. The risk of 90-day wait-list mortality increased progressively from 2.4% to 51.6% from the first to the tenth risk decile. Transplant benefit increased progressively across the wait-list risk groups (P<0.001 for trend). However, transplant benefit for children in the top 5% of risk (7.4%) was lower than that for children in the 91st to 95th percentile of risk (10.3%). Conclusions-Sicker children on the wait-list benefit more from HT unless the post-transplant mortality is predicted to be very high. Whether consideration of transplant benefit in allocation policy can improve overall survival among listed children requires further analysis. (Circ Heart Fail. 2013;6:800-808.)

Is Myocarditis an Independent Risk Factor for Post-Transplant Mortality in Pediatric Heart Transplant Recipients?

“…2 The process of HT evaluation encompasses a careful assessment of risk factors and estimating the risk of wait-list and post-transplant mortality in all candidates. 5 Our results do not support the notion of additional risk attributable to the diagnosis of myocarditis over and above that inherent in the severity of heart failure. Because our analysis is limited to children who were already listed for HT and it is unknown whether specific clinical, viral, and immunologic factors (such as duration between presentation and listing, specific viral agent identified, or active viremia) were considered before listing, how these factors contribute to post-transplant risk remains unknown.…”

“…[13][14][15][16] Indeed, several investigators have suggested using a combination of baseline risk factors-either using a score-based tool or a more sophisticated statistical model-to risk-stratify pediatric HT recipients for early posttransplant mortality. 5,15,17,18 The specific risk factors in these models may vary somewhat but, considered broadly, include younger age or congenital heart disease (markers of surgical complexity), level of hemodynamic support at transplant (a marker of heart failure severity), and presence of end-organ [18][19][20] A common analytic approach in clinical epidemiology when evaluating new risk factors (such as myocarditis) is to adjust for known risk factors even when they are not statistically significant in the cohort analyzed so that their confounding effect is accounted for. Our results suggest that the association of myocarditis with post-transplant survival is confounded by heart failure severity at the time of HT.…”

Changing Indications for Pediatric Heart Transplantation

“…14 More recently, Singh et al 77 reported an analysis of the United Network of Organ Sharing database that assessed the benefits of transplantation by evaluating the ability of heart transplantation to lower the risk of death. Their model compared mortality with and without transplantation in the first year after listing.…”

Association of Hemodynamic Profiles With Wait-List Mortality in Children Listed for Heart Transplantation With Idiopathic Dilated Cardiomyopathy

“…Therefore, once clinical fluid overload is relieved, the potential benefit of more aggressive diuresis aimed at attaining normal filling pressures should be weighed carefully against the potential risk of worsening renal function in children. 19 Third, the risk of death or deterioration associated with hemodynamic profiles should be carefully considered when evaluating a child for ventricular assist device implantation. 20,21 Finally, these findings raise important questions for future research such as whether clinical evaluation correlates with intracardiac hemodynamics in children with advanced heart failure and whether hemodynamic congestion and hypoperfusion can be diagnosed clinically.…”