ISOLATED SYSTOLIC HYPERTENSION IN YOUNG, MIDDLE-AGED AND OLDER PEOPLE – FINDINGS FROM THE INTERNATIONAL ACADEMIC 24HOUR ACADEMIC BLOOD PRESSURE CONSORTIUM (I24ABC)

Objective:
Comprehensive hemodynamic data, obtained with 24hour ambulatory blood pressure monitoring (24hABPM), comparing isolated systolic hypertension (ISH) with normotension (NTN) and the other hypertension phenotypes (systolic-diastolic hypertension - SDH, isolated diastolic hypertension - IDH) are sparse.

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Design and method:
We compared steady-state (cardiac output – CO, total peripheral resistance – TPR) and pulsatile (brachial and central Pulse Pressure - bPP, cPP, Augmentation Index – AIx, Augmentation Pressure – AP, amplitude of forward – Pf and backward – Pb wave, estimated aortic pulse wave velocity - ePWV) hemodynamics, obtained with identical validated oscillometric cuff-based devices in a large academic research consortium, between ISH, NTN, IDH, and SDH across a wide age range. Hemodynamics were derived from brachial waveforms, calibrated with mean/diastolic BP, and processed with validated ARCSolver algorithms. Participants were divided into a younger (9-35 years), middle (36-65 years) and older (66-104 years) age group.

Results:
Overall, 8837 participants (47.9% women, 9-104 years old, 37.9% with treated hypertension) were included. Based on 24hABPM, 46.0%, 16.2%, 10.2% and 27.6% had NTN, IDH, ISH and SDH, respectively. ISH was rare in the youngest group (9-35years) – 6.8%, very rare in middle age – 4.7%, and more common in the oldest age group (66-104 years) – 17.4%. There were striking sex-related differences: the percentage of women with ISH was 10.9%, 68.4% and 65.6% in the youngest, middle and oldest group, respectively. Independent of age, ISH participants were characterized by the highest values for bPP, cPP, antegrade and reflected waves (AP, Pf, Pb), and ePWV, and the lowest heart rate (Table). In addition, young ISH participants had the highest CO among all BP phenotypes. Of note, middle-aged and elderly ISH participants had the highest LVMi among all BP phenotypes.

Conclusions:
ISH phenotype, based on brachial 24hABPM, is not unfrequently observed in a large multinational convenience sample, with striking sex-differences among young and middle-aged/elderly participants. ISH has unique hemodynamic features across all age groups, namely unfavourable pulsatile hemodynamics. In addition, LVMi as a common metric of cardiac organ damage is highest among all BP phenotyps in middle-aged and elderly ISH participants.