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Waitlist mortality unchanged for sickest pediatric heart transplant patients

Overall waitlist mortality for children awaiting heart transplant improved from 25% in 2001 to 14% in 2011. However, the sickest children, including those on extracorporeal membrane oxygenation or a ventilator at listing, have not seen dramatic declines in waitlist mortality.

Using data from the Organ Procurement and Transplant Network, researchers examined 5,430 children aged younger than 18 years who were on a waiting list for a heart transplant from 2001 to 2011. Of those, 647 were on extracorporeal membrane oxygenation (ECMO) support. The results were presented at the International Society for Heart and Lung Transplantation Annual Meeting and Scientific Session.

According to results, waitlist mortality for pediatric patients not on invasive support declined 61%, from 18% in 2001 to 7% in 2011 (P<.01). Patients on ECMO support did not see a significant change in waitlist mortality during the study period (45% in 2001 vs. 41% in 2011; P=.89), whereas there was a larger decline, although nonsignificant, for mortality among patients on ventilator support (33% in 2001 vs. 26% in 2011; P=.15).

Baseline characteristics and number of patients (mean, 59 per year) on ECMO support at listing did not change appreciably from 2001 to 2011.

“The advances in ventricular assist device technology has contributed significantly to improving the overall pediatric heart transplant waitlist mortality in the United States; however, waitlist mortality for children listed from extracorporeal membrane oxygenation has not changed dramatically,” Christopher S. Almond, MD, assistant professor of pediatrics at Boston Children’s Hospital, said in a press release. “The biggest question is: Why are the sickest children not benefiting more obviously from recent technology advances? Do we simply need more time and patients to detect changes that are gradual and may become statistically significant in the future? This emphasizes the challenges of patient selection.”

For this study, waitlist mortality was defined as death while waiting or de-listing due to clinical deterioration, according to the abstract.

For more information:

Almond CS. Abstract #73. Presented at: International Society for Heart and Lung Transplantation Annual Meeting and Scientific Sessions; April 24-27, 2013; Montreal.

Disclosure: Almond reports no relevant financial disclosures.

Overall waitlist mortality for children awaiting heart transplant improved from 25% in 2001 to 14% in 2011. However, the sickest children, including those on extracorporeal membrane oxygenation or a ventilator at listing, have not seen dramatic declines in waitlist mortality.

Using data from the Organ Procurement and Transplant Network, researchers examined 5,430 children aged younger than 18 years who were on a waiting list for a heart transplant from 2001 to 2011. Of those, 647 were on extracorporeal membrane oxygenation (ECMO) support. The results were presented at the International Society for Heart and Lung Transplantation Annual Meeting and Scientific Session.

According to results, waitlist mortality for pediatric patients not on invasive support declined 61%, from 18% in 2001 to 7% in 2011 (P<.01). Patients on ECMO support did not see a significant change in waitlist mortality during the study period (45% in 2001 vs. 41% in 2011; P=.89), whereas there was a larger decline, although nonsignificant, for mortality among patients on ventilator support (33% in 2001 vs. 26% in 2011; P=.15).

Baseline characteristics and number of patients (mean, 59 per year) on ECMO support at listing did not change appreciably from 2001 to 2011.

“The advances in ventricular assist device technology has contributed significantly to improving the overall pediatric heart transplant waitlist mortality in the United States; however, waitlist mortality for children listed from extracorporeal membrane oxygenation has not changed dramatically,” Christopher S. Almond, MD, assistant professor of pediatrics at Boston Children’s Hospital, said in a press release. “The biggest question is: Why are the sickest children not benefiting more obviously from recent technology advances? Do we simply need more time and patients to detect changes that are gradual and may become statistically significant in the future? This emphasizes the challenges of patient selection.”

For this study, waitlist mortality was defined as death while waiting or de-listing due to clinical deterioration, according to the abstract.

For more information:

Almond CS. Abstract #73. Presented at: International Society for Heart and Lung Transplantation Annual Meeting and Scientific Sessions; April 24-27, 2013; Montreal.

Disclosure: Almond reports no relevant financial disclosures.

    Perspective
    Robert Stewart

    Robert Stewart

    I was surprised at the study results. The lead author recently published a study on the Berlin Heart VAD in Circulation (April 2013) which showed a 75% survival and that ECMO support prior to the Berlin Heart VAD was not a risk factor for early or late mortality. As the Berlin Heart VAD has been widely used since 2008 — and not uncommonly for 2 to 3 years before that — one would expect that increased survival to reflect in this study of decreased waitlist mortality for sicker patients (ie, those on ECMO or ventilators).

    One possible implication of the finding is that being ‘on ECMO at the time of listing’ is a population of patients selected late who have more risk factors for mortality prior to transplant. Those patients known to be in end-stage HF and being followed while awaiting a transplant, and then electively placed on a VAD — even if there is an intermediate step of temporary ECMO — are likely doing better. This suggests we should probably use mechanical support sooner, but there are risks of a VAD, and there is also a ‘too soon.’

    In the short term, HF centers are more experienced using pediatric VADs, and this will eventually change the curve. The waitlist mortality of the sickest patients will decrease. The long-term problem is with transplantation in general. The conflict is the organ shortage; while we certainly want to try and use every available organ (donor education, etc.), we don’t want more organ donors (pediatric deaths). Efforts at safety, including airbags, bicycle helmets and so on, are working. The adult solution has been destination therapy. This will be the next step for children, when we have an internally implantable VAD that children can live with for years while leading relatively normal lives.

    Finally, we look toward the future of gene-based and molecular-based medicine to correct and especially prevent pediatric heart disease.

    • Robert Stewart, MD
    • Cardiovascular Surgeon, Cleveland Clinic Children's Hospital

    Disclosures: Stewart reports no relevant financial disclosures.

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