International 24 hour aortic blood pressure consortium

The international 24 hour aortic blood pressure consortium (i24ABC) is an international collaborative launched in 2017 with the primary aim of deriving reference standards for 24 hour ambulatory central (aortic) blood pressure and pulsatile hemodynamics. Secondary aims include the study of central (aortic) blood pressure phenotypes and their association with hypertension mediated organ damage as well as with mortality-morbidity.

This is being achieved by pooling de-identified data from existing 24 hour aortic blood pressure databases around the world. Eligible contributing centres are those using the  validated monitor Mobil-O-Graph, IEM device for ambulatory blood pressure, monitoring. Currently, in the consortium participate  26 centers from 17 countries in 5 continents with more than 8,000 cases.

The first publication was released in November  2021;  providing reference values for 24-hour ambulatory aortic systolic blood pressure (cSBP) in  2423 eligible untreated adults (1275 women; age, 18-94 years) [data from  21 centers, from 14 countries in 5 continents] free from overt cardiovascular disease and identifying differences in the dipping behaviour between the  brachial and the aortic SBP . These data may serve for comparison in various diseases and have potential implications for refining hypertension diagnosis and management.

Hypertension. 2022 Jan;79(1):251-260. doi: 10.1161/HYPERTENSIONAHA.121.17765. Epub 2021 Nov 15.

We wish to congratulate and thank all centers and participants for the excellent co-operation!!! Recruitment of new centers willing to participate, as well as, sharing of new dataset  is now again open.

The executive committee

Thomas Weber, Athanase Protogerou, Jim Sharman, Sigi Wassertheurer

For over 100 years, blood pressure has conventionally been measured at the upper arm, but there are many limitations of this method that may result in sub optimal diagnosis of hypertension and individual patient care. New techniques have been developed to measure the blood pressure at the central (organ) level, by using an algorithm to generate a central (aortic) blood pressure waveform from the pulse wave recorded using an upper arm cuff device.

This has enabled measurement of aortic blood pressure over 24 hours using a methodology that is similar to conventional 24 hour ambulatory blood pressure monitoring (i.e. simple cuff inflation at regular times throughout the day and night, with data recorded by a small device worn on a belt).

Information from these new 24 hour ambulatory aortic blood pressure devices is expected to be clinically superior to conventional blood pressure measures and may be used to improve management of people with hypertension. However, to date there are no normative (or threshold) reference standards for 24 hour ambulatory aortic blood pressure as this type of analysis requires data from many thousands of participants. This data will be crucial for determining treatment thresholds and will be used to guide the design of future clinical trials.