Background: Clinic brachial BP averaged over 10 minutes correlates more strongly with out-of-office BP compared with BP recorded after the recommended 5 minutes rest. Central BP is a stronger predictor of mortality than brachial BP. However, the clinical value of measuring central BP after 5 compared with 10 minutes rest has never been assessed and was the aim of this study.

Methods: Clinic brachial and central BP, 7 day home BP and left ventricular mass index (LVMI) were measured in 250 patients with treated hypertension (aged 64±8 years). Clinic seated BP was measured at two time points; time 1) after 5 minutes, as per recommendations, and time 2) after 10 minutes.

Results: Brachial and central BP’s were significantly lower at time 2 compared to time 1 (p<0.001 for all). Time 1 brachial SBP was significantly higher than 7 day SBP (131.3±14.9 vs. 127.6±12.3 mmHg; p<0.001). However, time 2 brachial SBP was almost identical to 7 day SBP (127.1±13.5 mmHg; mean difference 0.6±13.7 mmHg; p=0.511). Moreover, time 2 brachial and central pulse pressures significantly correlated with LVMI (r=0.171, p=0.006 and r=0.139, p=0.027, respectively), whereas there were no significant correlations with time 1 brachial or central pulse pressures (r=0.115, p=0.068 and r=0.084, p=0.185, respectively).

Conclusion: Clinic brachial BP recorded after 10 minutes is closely representative of out-of-office BP, and the corresponding central BP values are more clinically relevant than those acquired after the conventional 5 minutes rest. These findings have relevance to appropriate diagnosis of hypertension and design of clinical trials.