Objective: Arterial hypertension (AH) is the most common toxic effect of calcineurin inhibitor (CNI)-based immunosuppression in children after liver transplantation (LT). Activation of the renal sodium chloride cotransporter (NCC) by CNIs has been described as a major cause of CNI-induced AH. Thiazides, for example, hydrochlorothiazide (HCTZ), can selectively block the NCC and may ameliorate CNI-induced AH after pediatric LT.
Methods: From 2005 thru 2015 we conducted a retrospective, single-center analysis of blood pressure in 2 pediatric cohorts (each n = 33) with or without HCTZ in their first year after LT. All patients received CNI-based immunosuppression. According to AAP guidelines, AH was defined as stage 1 and stage 2. Cohort 1 received an HCTZ-containing regimen to target the CNI-induced effect on the NCC, leading to AH. Cohort 2 received standard antihypertensive therapy without HCTZ.
Results: In children who have undergone LT and been treated with CNI, AH overall was observed less frequently in cohort 1 vs cohort 2 (31% vs 44%; ns). Moreover, severe AH (stage 2) was significantly lower in cohort 1 vs 2 (1% vs 18%; p < 0.001). Multivariate analysis revealed HCTZ as the only significant factor with a protective effect on occurrence of severe stage 2 AH. While monitoring safety and tolerability, mild asymptomatic hypokalemia was the only adverse effect observed more frequently in cohort 1 vs 2 (27% vs 3%; p = 0.013).
Conclusions: Targeting NCC by HCTZ significantly improved control of severe CNI-induced AH and was well tolerated in children who underwent LT. This effect may reduce the risk of long-term end-organ damage and improve quality of life.
Keywords: arterial hypertension; calcineurin inhibitor; hydrochlorothiazide; pediatric liver transplantation; sodium chloride cotransporter.
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