Introduction: Hypertension (HTN) is an important cardiovascular risk factor influencing patient and allograft survival in renal transplantation. Ambulatory blood pressure monitoring (ABPM) has been found to be superior to casual-blood pressure (CBP) in diagnosing HTN in children, but is yet to be routinely performed after pediatric renal transplantation.

Aim: Compare CBP and 24h ABPM in diagnosing HTN in children with renal transplantation.

Material and Methods: A convenience sample of 40 pediatric renal transplant recipients had 24h ABPM. The values were compared with average CBP from 4 clinic visits around the day of ABPM. BP was considered to be high if it was more than the 95^thcentile for the patient’s height, age, and gender. Each patient had an echocardiogram to determine left ventricular mass index (LVMI) to determine the effect of HTN, serum creatinine (Cr), and allograft biopsy.

Results: All patients had adequate ABPM with a mean of 73 ± 20 successful readings. 8/40 (20%) patients were on >1 anti-hypertensive agent. 5/40 (12.5%) patients were hypertensive based on CBP at clinic visit. 1 patient (2.5%) had white coat HTN. However, on ABPM significantly higher number of patients were found hypertensive. 14/40 (35%) had high mean SBP at day (p=0.03), and 13/40 (32%) at night (p=0.03). 20/40 (50%) had SBP load >25% at day (p=0.0006) and 22/40 (55%) at night (p=0.0001). Elevated DBP load was found in 13/40 (32.5 %) at day (p=0.03) and 27/40 (67.5%) at night (p<0.0001). 14/40 (35%) had inadequate nocturnal dipping < 10% (p=0.03). Based on ABPM results antihypertensive therapy was initiated or modified in 16/40 (40%) patients, not based on CBP. 14/40 (35%) had left ventricular hypertrophy (LVH) (LVMI > 95^th centile for age). Patients with LVH had higher mean daytime SBP load (45.9 ± 29.9%) vs. those without LVH (23.3 ± 28.5%), p=0.03. Patients with elevated DBP load had a trend towards lower mean Cr clearance (118 vs. 98 ml/min/1.73m2, p=0.1). 4/5 (80%) patients with arteriosclerosis on biopsy had elevated SBP load at night.

Conclusion: Nearly 20% of the studied patients had hypertension identified by ABPM that would have been otherwise missed by routine CBP testing. ABPM led to change in management in 40% of the patients. ABPM improves the predictability of BP as a risk factor for target organ damage and allograft dysfunction. We recommend that ABPM should be routinely used for diagnosis and treatment of HTN to improve patient and graft longevity in pediatric renal transplantation.

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