Stress-Induced Laboratory Blood Pressure in Relation to Ambulatory Blood Pressure and Left Ventricular Mass Among Borderline Hypertensive and Normotensive Individuals

Abstract

Our primary aim in the present study was to investigate the association between blood pressure measured in the laboratory and in the ambulatory state in a group of middle-aged borderline hypertensive men and age-matched normotensive control subjects. In addition, we examined the relation between stress-induced blood pressure measurements and left ventricular mass. Blood pressure and heart rate were measured noninvasively during a standardized laboratory stress protocol and four times per hour throughout 24 hours. Borderline hypertensive subjects had significantly higher systolic and diastolic pressures than normotensive subjects during both the daytime (systolic pressure, 141.1 +/- 9.7 versus 130.9 +/- 8.6 mm Hg; diastolic pressure, 88.8 +/- 7.0 versus 79.4 +/- 6.2 mm Hg, P < .001) and nighttime (systolic pressure, 114.0 +/- 9.9 versus 107.1 +/- 8.3 mm Hg; diastolic pressure, 71.5 +/- 7.5 versus 64.6 +/- 7.2 mm Hg, P < .001). The borderline hypertensive group also displayed increased systolic pressure reactivity in the laboratory compared with the normotensive group. The groups did not differ significantly in left ventricular mass (index). In both borderline hypertensive and normotensive individuals, blood pressure levels during stress testing were closely related to ambulatory blood pressure levels (r = .51 to .82). Furthermore, stress-induced blood pressure levels were significantly correlated to left ventricular mass in borderline hypertensive (r = .33 to .40) but not normotensive subjects. Since stress-induced blood pressure levels were significantly associated with both ambulatory blood pressure levels and left ventricular mass in borderline hypertensive subjects, the addition of standardized stress testing to casual blood pressure measurements may improve risk estimation.