P2.07 MASKED HYPERTENSION IS “UNMASKED” BY LOW INTENSITY EXERCISE BLOOD PRESSURE

Abstract

Background: Masked hypertension (MH) independently predicts mortality but cannot be diagnosed from clinic blood pressure (BP). We sought to determine if MH could be identified from BP or pressure waveform analysis (PWA) at rest or during low intensity exercise. Methodology: Brachial and estimated central BP (by PWA; SphygmoCor) were recorded at rest and during ≈10minutes of cycling exercise (60–70% of age-predicted maximal heart rate) in 77 untreated subjects with a hypertensive response to exercise (HRE) (aged 54±8years) and 61 patients with hypertension (HT) receiving therapy (aged 62±8years). All subjects underwent 24hour ambulatory BP monitoring (24hrABPM) and MH was defined as clinic systolic BP (SBP) <140mmHg and 24ABPM SBP ≥130mmHg. Results: There were 44 (57%) HRE and 32 (52%) HT patients with MH. For the HRE group at rest, there were no significant differences between MH and normotensive subjects in any haemodynamic variable except brachial systolic BP, which was higher in MH subjects (127±9 vs. 120±9mmHg; p<0.05). After correction for resting SBP, MH subjects had significantly higher brachial (187±22 vs. 168±15mmHg; p<0.05) and central SBP (154±17 vs. 141±12mmHg; p<0.05) during exercise, with greater changes in both from baseline (p<0.05). No differences were observed in the HT group. Exercise brachial SBP predicted the presence of MH independent from all resting hemodynamic variables (β=0.35; p<0.001), and if >190mmHg, identified MH with 97% specificity (p<0.001). Conclusions: MH can be identified in untreated individuals from low intensity exercise brachial SBP. Exercise BP testing may be indicated in patients with borderline raised clinic brachial SBP.