OFFICE AND LABORATORY BLOOD PRESSURES AS PREDICTORS OF DAILY BLOOD-PRESSURE LEVEL IN NORMOTENSIVE SUBJECTS AND BORDERLINE AND MILD HYPERTENSIVE SUBJECTS

A series of standardized laboratory tests [10 min sitting and supine, 9 min standing, dynamic; cycle ergometer (ERG) and isometric exercise; handgrip (HG)] were performed during intra-arterial blood pressure (B P) recording in 97 healthy unmedicated men, initially classified as no rmotensive (NT, n = 34), borderline hypertensive (BHT, n = 29) or mild ly hypertensive (HT, n = 34) by repeated office blood pressure (OBP) m easurements. After testing, a 24-h intra-arterial ambulatory BP (IABP) recording was obtained while subjects performed their normal activiti es. Day and night periods were analysed as well as 24-h averages for s ystolic BP (SBP) and diastolic BP (DBP) using Pearson correlations and multiple linear regressions. In normotensive subjects, the supine SEP predicted IABP measurements best (r range 0.39-0.69, P<0.05-0.001). I n multiple regression, supine SEP explained 49% of 24-h SEP variance ( F = 12.4, P = 0.001). For BHT, supine SEP was also the best predictor (r range 0.09-0.64, P NS to P<0.001), and it explained 37% of 24-h SEP variance (F = 15.6, P = 0.0005). In HT, ERG DBP correlated best with IABP (r range 0.52-0.75, P<0.01-0.001). ERG SEP explained 49% of 24-h SEP (F = 31.0, P = 0.0000) and ERG DBP explained 56% of 24-h DBP (F = 35.4, P = 0.0000) variance. Laboratory BP correlations were generally better with day than with night measurements. OSBP correlated moderate ly well with IABP in NT, and weakly in BHT and HT; ODBP instead correl ated with IABP in NT and HT but not significantly in BHT. In conclusio n, OBP is less closely related to IABP than laboratory BP, but even la boratory BP generally explains less than 50% of IABP variance. Stresso rs such as exercise are useful only in HT. For BHT, the prediction of IABP with laboratory measures was even weaker than in other groups, an d thus ambulatory measurements cannot be replaced by short-duration la boratory measurements and stress tests.