The Impact of Rejection Episodes after Heart Transplantation on Cardiac Growth in Children

Objective: This study evaluated the impact of rejection episodes on growth of transplanted hearts as well as somatic growth in children.

Methods: Extensive review of medical and echocardiographic records of 167 children (mean age: 8.65 ± 5.98, median: 9, range: 0–15 years) who underwent heart transplantation was performed. All patients had complete follow-up with echocardiographic series at different set time points. To demonstrate growth of the transplanted heart over time, only those ≤15 years old at the time of transplantation were included with at least 5-year follow-up. Noninvasive rejection monitoring techniques, particularly the intramyocardial echocardiogram were employed. Cardiac growth was measured by comparing donor cardiac dimensions (right and left ventricular end-diastolic dimensions, volumes and mass) at transplantation to the recipient cardiac dimensions over time. Normal growth was defined as a lack of z- score change between early and late follow-up.

Results: The mean duration of follow-up was 13 ± 0.8 (range: 5–22) years. One hundred fifty four episodes of rejections (< 1 year old = −18; 1–2 years old=33; < 2–5 years old = 28;< 5–10 years = 36; and >10–13 = 39) occurred in 49 children (mean age at transplantation 6.7 ± 5.1, range 4 months–13 years; mean weight 19.8 ± 12.9, range 4–52 kg; mean height 110 ± 35 cm, range 55–164 cm; mean age at follow-up 17.4 ± 7.6, range 3.8 months–38.7 years; mean weight 48.3 ± 23.8, range 13–135 kg; mean height 121.2 ± 25.9 cm, range 96–183 cm). Rejection episodes occurred less frequently in infants, and frequently in >5–10 and >10–15 years old. Severity of rejection was variable among the different age groups. Seventeen patients were three standard deviations below normal at early follow-up but were close to the normal range at late follow-up. These patients included 7 infants who have shown delayed linear growth while still receiving steroids and ten children on high-dose immunosuppressants because of rejection episodes. Over time, the mean range in BSA was 0.17 ± 0.03 m² (range: 0.12–0.50 m²). There was no significant difference (p = 0.078) in cardiac growth (Z score: 0.9–2.0) between those with rejection episodes regardless of severity and frequency and those who had not (p = 0.035).

Conclusion: This study indicates that despite frequency and severity of rejection episodes, transplanted heart undergoes normal growth in ventricular dimensions, volumes and myocardial mass over time appropriate for somatic growth in children.