Predicting Graft Loss by 1-Year in Pediatric Heart Transplant Candidates: An Analysis of the PHTS Database | Journal Scan

Study Questions:

What are the predictors of 1-year graft loss in pediatric heart transplant (HTx) candidates?

Methods:

This manuscript reports data from the Pediatric Heart Transplant Study (PHTS). Patients enrolled from 1996-2006 were stratified by pre-HTx diagnosis into separate cohorts for those with congenital heart disease (CHD) and cardiomyopathy (CMP). These data, as well as donor factors, were used to construct risk models for 1-year, post-HTx graft loss. Data for patients enrolled from 2007-2009 were used to validate the models.

Results:

Risk factors for graft loss were identified in 896 patients with CMP and 965 patients with CHD. Independent risk factors for patients with CMP included earlier year of transplant, nonwhite race, female gender, diagnosis other than dilated CMP, higher blood urea nitrogen (BUN), and panel reactive antibody (PRA) >10%. The recipient-characteristic model predicted graft survival of 97.5% as compared with actual graft survival of 95.3% (C-statistic 0.73). Independent risk factors for patients with CHD included nonwhite race, history of Fontan, ventilator dependence, higher BUN, PRA >10%, and lower body surface area. The model predicted graft survival of 86.6% as compared with actual survival of 92.4%.

Conclusions:

Risk factors for 1-year post-HTx graft loss differ based on pre-HTx cardiac diagnosis. Modeling effectively stratifies risk of graft loss in CMP patients, but is less accurate in those with CHD.

Perspective:

The study of outcomes in pediatric HTx is hampered by small patient numbers and significant patient heterogeneity. This multicenter study separated patients ‘up front’ by diagnosis into cohorts of patients with structural CHD and those with CMP. Data for the first 11 years of the study were used to construct risk models that were validated using data from the final 3 years of the study. The model was more accurate for patients with CMP than those with CHD, for which it underestimated survival. The authors speculate that this may be due to improved survival seen in the CHD cohort over the course of the study period. Additionally, the study importantly demonstrates that risk factors differ between underlying diagnosis (CHD vs. CMP). Overall, these data will be helpful in counseling families, developing allocation strategies, and benchmarking outcomes of individual centers.

Clinical Topics: Cardiac Surgery, Congenital Heart Disease and Pediatric Cardiology, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Cardiac Surgery and CHD & Pediatrics, Cardiac Surgery and Heart Failure, Congenital Heart Disease, CHD & Pediatrics and Interventions, CHD & Pediatrics and Quality Improvement, Heart Transplant, Interventions and Structural Heart Disease

Keywords: Cardiomyopathies, Cardiomyopathy, Dilated, Heart Defects, Congenital, Heart Transplantation, Graft Survival, Pediatrics, Risk Factors, Risk, Blood Urea Nitrogen


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