P1.29 One Clinic Measure of Light Exercise Central Blood Pressure is a Stronger Correlate of Left Ventricular Mass than 24 Hour Ambulatory Blood Pressure Monitoring

Abstract

Background

Twenty four hour ambulatory blood pressure (24ABPM) is the gold standard for assessing blood pressure (BP) control. However, central BP during daily activity may be a stronger determinant of cardiovascular risk. This study aimed to compare 24ABPM with light exercise central BP (mimicking daily activity) for predicting left ventricular (LV) mass.

Methods

Study population comprised 54 patients (aged 58±7 years; 20 men) including those with treated hypertension (n = 16), untreated masked hypertension (n = 23) and normotensive controls (n = 15). Subjects underwent 2D echocardiography for determination of LV mass (indexed; g/m^2.7), resting brachial BP, 24ABPM and estimated central BP by radial tonometry during graded cycle ergometry. Central systolic BP (SBP) was estimated from the radial second systolic peak (P2) as well as the derived central waveform.

Results

The range of LV mass index and 24ABPM SBP were 17.8-55.1 g/m².⁷ and 107–153 mmHg respectively. As expected, 24ABPM SBP was significantly associated with LV mass index (r = 0.30, p = 0.02), but not with clinic resting brachial (r = 0.21; p = 0.14) or central SBP (r = 0.20; p = 0.14). However, the strongest correlates of LV mass index were light exercise (50% heart rate reserve) radial P2 (r = 0.54, p<0.001) and central SBP (r = 0.47; p<0.001). On multiple regression analysis, radial P2, but not 24ABPM SBP, was independently associated (β = 0.45; p<0.01)with LV mass index after accounting for other confounding variables.

Conclusion

A one-off clinic estimate of light activity central SBP outweighs 24ABPM for predicting LV mass. This rapid, noninvasive technique may provide a superior measure of BP control compared with the current gold standard.