Difference between office and ambulatory blood pressure or real white coateffect: does it matter in terms of prognosis?

Objective The blood pressure (BP) response to the doctor's visit, generally referred as the white coat (WC) response, is usually estimated by the diff erence between office BP (OBP) and ambulatory BP (ABP). The purpose of this study was to determine the validity of this estimation. To that end, we co mpared the real WC effect and the estimated WC effect (OBP-ABP) in terms of magnitude and consequences on target organs. Design The study comprised 88 patients referred for hypertension. The real WC effect was measured using a Finapres device and expressed as the maximal WC effect (Max WC) or the average WC effect (Aver WC), For the estimation of target organ damages, the whole hypertensive group was separated into tw o groups according to the medians of the Aver WC, the Max WC, and the estim ated WC effects, successively Left ventricular mass index, E to A mitral wa ve ratio and pulse wave velocity were compared between groups as were serum creatinine, cholesterol and glucose levels. Results The estimated WC effect proved to be a bad index of the real respon se to the doctor's visit as assessed by their difference of magnitude betwe en the two (20 +/- 17, 12 +/- 12 and 30 +/- 14 mmHg as estimated WC, Aver W C and Max WC effects, respectively), their loose correlations (r = 0.31, P = 0.004 between estimated WC and Aver WC effects; r = 0.27, P = 0.01 betwee n estimated WC and Max WC effects), and finally by the fact that they were in agreement in less than two-thirds of the patients for the categorization of the WC response, Concerning target organ damages, no difference in term s of cardiac mass, diastolic function, arterial distensibility, renal funct ion and cardiovascular risk profile could be discerned between the groups w ith a high and a low WC effect, either real or estimated, when age and ABP were taken into account. Conclusion The present work supports the view that the true WC effect and i ts estimation are not equivalent, However, the way in which the WC response is defined does not alter its effect on target organs or cardiovascular ri sk profile. J Hypertens 2000, 18:383-389 (C) Lippincott Williams & Wilkins.