Is there any real target organ damage associated with white-coat normotension?

Abstract

Subjects with white-coat normotension (WCNT) or masked hypertension, i. e. a normal office blood pressure (BP) reading but elevated ambulatory blood pressure monitoring (ABPM) results, have not been extensively studied. The aim of this work was to compare true normotensive subjects (NT), WCNT and nevertreated hypertensive subjects (HT, with elevated BP according to both office and ABPM readings). One hundred and fifty subjects were recruited to analyze cardiovascular characteristics. Office BP readings coupled with ABPM results were used to break this population down into 51 NT, 18 WCNT and 81 HT. Office BP readings were higher in WCNT than in NT. In WCNT, carotid-femoral pulse wave velocity (PWV) was higher than in NT (with a borderline significance p = 0.05) and the standing baroreflex sensitivity (BRS) was lower (p = 0.04). Left ventricular mass index (LVMI) and carotid intima-media thickness (IMT) tended to increase and BRS measurements tended to decrease from NT through WCNT to HT. However, the difference across the board is only significant (p < 0.05) between NT and HT. If only the subset of NT subjects with SBP readings comparable to those of the WCNT subjects (i. e. SBP > 120 mmHg) is considered, no significant difference is detected in PWV and the only difference is detected in BRS (respectively for standing [PS+/RR+]: 5.7 +/- 1.4 ms/mmHg vs 4.9 +/- 1.2 ms/mmHg, p = 0.04). In conclusion, the principal cardiovascular differences measured between the NT and the WCNT can probably be explained by their difference in clinical level of pressure at rest. Only the BRS remains different between NT and WCNT when the real level of clinical pressure is taken into account.