Introduction: Our transplant cardiovascular service offers a systematic pathway to proactively screen post-renal transplant recipients for hypertension. We know that a significant number of patients have a degree of chronic kidney disease (CKD) predisposing them to hypertension, and many are hypertensive pre-transplant. Although blood pressures (BPs) are routinely measured in clinic, the pathway aims to identify those with masked hypertension as well as those with secondary echocardiogram changes. But what are the rates of masked hypertension, and how reliable are clinic BPs?
Methods: National and International guidelines for managing blood pressure in children, recommend performing 24-hour Ambulatory Blood Pressure Monitoring (ABPM) annually in kidney transplant recipients. ABPM is considered the gold standard and a tool to optimise cardiovascular outcomes.
Our transplant cardiovascular clinic takes place monthly and we aim to ensure that all transplant recipients get a clinic review within 4 months of transplant. The clinic review consists of a systematic measurement of blood pressure using the hypertension guidelines standardised protocol of 3 consecutives measurements on the right arm (unless fistula present) using stethoscope, sphygmomanometer and appropriate cuff. It also consists of ABPM and an echocardiogram.
Results: We reviewed the last 100 patients that have passed through our transplant hypertension clinic. 77 (77%) had normal clinic BPs (<90th centile), yet of these patients, 25 (32%) had masked hypertension.
23 (23%) had high clinic BPs (>90th centile) and of these 10 (43%) in fact had normal BPs on ABPM (and no echocardiographic changes), so-called white-coat hypertension.
Specifically looking at the cohort of patients who were already on anti-hypertensive medications (25 patients), 14 had normal clinic BP measurements (presumed controlled hypertension), but 3 (21%) of these in fact had uncontrolled hypertension on ABPM requiring escalation of treatment. A further 11 had high clinic BPs of which 3 (27%) had normal ABPMs.
Conclusion: This very clearly demonstrates that relying on clinic BPs is extremely inadequate at identifying a significant number of patients with masked hypertension, as well as for monitoring BPs in patients already on anti-hypertensive medications with high rates of white-coat hypertension. Performing ABPMs and echocardiograms in all patients ensures that we identify all patients with hypertension in order to treat appropriately. It also prevents the unnecessary treatment of approximately 10% of patients.