Concordance Between Central Blood PRessure dEvices In Nephrology Patients (CBP-REIN)

The most accurate way to determine intra-aortic BP is to obtain invasive measures by vascular catheterization, which is not possible to perform routinely during the regular follow-up of patients. However, in recent years, devices used to estimate central BP have been designed and approved for clinical use. These devices can determine aortic BP in a non-invasive way using various techniques and algorithms and offer a high degree of precision when compared to invasive measurements of intraaortic BP. On the other hand, certain characteristics specific to the different devices mean that the central BP values obtained may not be interchangeable. It is therefore important to determine the degree of agreement of central BP values obtained using commercially available devices. This study aims to determine the degree of agreement between central BP measurements obtained using 4 devices commonly used to measure central blood pressure, i.e. Mobil-o-Graph NG (IEM, Germany), WatchBP Office (Microlife, Taiwan), Oscar 2 with SphygmoCor inside (SunTech, USA) and BP+ (Uscom, Australia). These four devices record the shape of the pulsatile wave and then derive the central BP using an algorithm. The main differences between these devices lie in this algorithm, or "transfer function,", which is unique to each and the calibration used. All use a brachial cuff to capture the pulse waveform and can easily be used in clinical practice.

Patients with BP > 135/85 mmHg or taking any antihypertensive medication with normal kidney function (eGFR > 60 ml/min/1.73m2)

Brachial and Central BP measurements with Mobil-o-Graph NG device (IEM), WatchBP Office device (Microlife), BP+ device (Uscom) and Oscar 2 with SphygmoCor inside device (SunTech)

All participants will have three readings at 1-min interval after a 5-min seated rest with each device. The order in which each device will be tested is randomized.

Inclusion Criteria: - Age 18-80 years old Exclusion Criteria: Ongoing atrial fibrillation Arm circumference incompatible with the blood pressure cuffs for all devices (<18 cm or > 50 cm) Incapacity to give consent