Introduction: Left ventricular hypertrophy (LVH) affects about 40% of children one year after kidney transplantation (KTx) and strongly predicts cardiovascular mortality. Early after KTx, blood pressure (BP) is the main determinant of LV mass. Specific recommendations on BP goals in pediatric KTx recipients based on prospective data are currently not available. We aimed to assess the effect of BP control expressed by the cumulative exposure of systolic BP on the dynamics of left ventricular mass index (LVMI).
Methods: We included 96 children (64 males) ≥9 months post-KTx from the 4C study. BP and echocardiographic LVMI assessments were performed every 6 and 12 months, respectively. Only patients with two visits or more were included (median/maximum follow-up time of 2.5/7 years). The cumulative exposure of systolic BP z-scores was calculated for each visit as time-averaged area under the curve of BP z-scores (cAUC-SBP). cAUC-SBP was categorized into “<50^th percentile”, “50^th-75^th percentile”, “75^th-90^th percentile”, and “>90^th percentile”. Linear mixed regression model for LVMI (g/m^2.16) for cAUC-SBP adjusted for time since baseline, age, sex, estimated glomerular filtration rate (eGFR), body mass index (BMI) z-score, LVMI at baseline was performed.
Results: At baseline, LVMI was 49.7±12.7 g/m^2.16 and 64% (n=61) of patients showed LVH. Compared to patients with cAUC-SBP of >90^th percentile, those with cAUC-SBP of 50^th-75^th showed LVMI reduction of -5.24 g/m^2.16 (p=0.007) and those with <50^th showed a tendency of reduction (β=-3.70 g/m^2.16;p=0.067). Patients with cAUC-SBP of 75^th-90^th did not show a significant reduction (Fig. 1).
Conclusion: Continuous exposure to systolic BP values below the 75^th percentile lead to regression of LVH. Our data calls for stricter BP control in pediatric KTx recipients.