Introduction

The development of cardiac allograft vasculopathy (CAV) continues to limit long term survival following heart transplantation (HTx) in children.  Registry based data, demonstrates increasing prevalence with time post-HTx. Identified risk factors are multifactorial, diagnosis challenging, and interventions limited. We sought to review the risk factors for and outcomes of CAV in a single centre experience.

Materials & Methods

Retrospective review of 286 patients after primary HTx between 1989 and 2014. CAV screening is multimodal (angiography, stress testing and holter monitoring). Patients were censored at age 18, transfer to another centre or at re-HTx. Kaplan-Meier models were used to model freedom from CAV over time.

Results and Discussion

Freedom from CAV was 97.5±1.1% at 2 yrs, 90.4±2.3% at 5 yrs, 81.5±3.7% at 10 yrs and 76.4±5.0% at 12 yrs postHTx. Unexpectedly, a strong era effect was observed (Fig 1, p<0.001). Children transplanted before 2001 (n=109; f/u 5.6±4.9 years postHTx) had a rate of CAV of 6.4±0.3% at 2 yrs, 21.0±4.9% at 5 yrs, 34.6±6.0% at 10 yrs and 39.7±6.5% at 12 yrs. Children transplanted after 2001 (n=177, f/u 4.1±3.4 years postHTx) had a rate of freedom from CAV of 99.1±0.9% at 10 yrs postHTx, a rate precluding a meaningful risk factor analysis. Beyond the era effect, no other factors were identified as being associated with increased risk of CAV. The decrease in odds of CAV was temporally associated with the switch from locally produced RATS to Thymoglobulin for induction (HR for RATS: 29.8, p<0.001) and from cyclosporine to tacrolimus as primary immunosuppression (HR: 9.0, p=0.009). For the cohort transplanted before 2002, older donor age was associated with increased hazard of CAV (HR: 2.2/10 year, p=0.05).

Conclusion

We report a 10 year freedom from CAV of 99.1% following heart transplantation in the most recent era. Further study is ongoing to determine what factors may have influenced this dramatic change in this important post-transplant morbidity.