BLOOD PRESSURE CLASSIFICATION USING BRACHIAL VERSUS CENTRAL HYPERTENSION PHENOTYPES AND ASSOCIATION WITH LEFT VENTRICULAR MASS – FINDINGS FROM THE I24ABC CONSORTIUM

Objective:
Brachial and central systolic blood pressure (BP) is different, which may have implications for BP classification and cardiovascular risk stratification. We investigated the association between BP phenotypes, based on brachial versus central SBP, and left ventricular mass, an important intermediate endpoint in hypertension.

Table

Design and method:
In all centers, 24-hour blood pressure (24hBP) was measured with the same validated oscillometric upper arm device (Mobil-O-Graph, I.E.M., Germany), using a transfer function and ARCSolver algorithms for determination of central pressures (using mean/diastolic BP calibration). Hypertension phenotypes were defined according to average 24h brachial BP as normotension (NTN), isolated systolic (ISH) and diastolic (IDH) hypertension, and systolic/diastolic hypertension (SDH), using brachial 130 and 80 mm Hg as systolic and diastolic threshold, respectively. Brachial BP phenotypes were further subdivided based on central 24h SBP (threshold for central hypertension was 135 mmHg). Left ventricular mass was determined by echocardiography, and indexed to body surface area (LVMi).

Results:
Overall, 2378 participants from 21 centers worldwide, connected in an academic research consortium, were included. Based on 24h brachial BP, 43.9%, 7.0%, 22.0% and 27.1% were classified as NTN, ISH, IDH, and SDH, respectively. The fraction of discordantly elevated central SBP in brachial NTN and IDH was 10.4% and 5.2%, respectively, and the fraction of discordantly normal central SBP in brachial ISH and SDH was 15.1% and 28.1%, respectively. Sex-differences were most striking in brachial NTN with elevated central SBP (male predominance), and brachial SDH with normal central SBP (female predominance). LVMi was higher in all brachial BP phenotypes, if central SBP was elevated (as compared to normal; see Table).

Conclusions:
Discordant BP classification based on central systolic BP is not uncommon and to some degree sex-specific. Measurement of central SBP likely adds to risk stratification in all brachial-BP based phenotypes, due to the stronger relationship with LVMi.