Identification of subjects with white-coat hypertension and persistently normal ambulatory blood pressure.

: OBJECTIVE: To assess the spontaneous changes in clinic blood pressure, ambulatory blood pressure (ABP) and left ventricular structure in untreated subjects with white-coat hypertension (WCH). DESIGN: A prospective observational study. PATIENTS AND METHODS: In 83 untreated subjects with WCH, 24 h non-invasive ABP monitoring and echocardiographic studies of the left ventricle were repeated after 0.5-6.5 years (mean 2.5) in the absence of antihypertensive drug treatment. WCH was defined by an average daytime ABP < 131/86 mmHg in women and < 136/87 mmHg in men. Ambulatory hypertension was defined by higher ABP values. RESULTS: In the whole population, the clinic blood pressure, ABP and left ventricular mass did not change from baseline to the follow-up visit, whereas the peak A: peak E ratio (where A is the velocity of transmitral blood flow after atrial contraction and E is the velocity during passive left ventricle filling) increased from 0.86 to 0.93. Sixty-three per cent of subjects remained in the WCH category at follow-up study; the remaining 37% shifted to the ambulatory hypertension category. The former group showed no changes in clinic blood pressure, ABP, left ventricular mass and peak A: peak E ratio. The clinic blood pressure of those who developed ambulatory hypertension did not change, whereas their ABP and peak A: peak E ratio increased and their left ventricular mass increased slightly but not significantly. The left ventricular mass increased from baseline to follow-up study by 6.2% in those who developed ambulatory hypertension and decreased by 1.6% in those who remained in the WCH category. The changes in left ventricular mass were associated with the changes in average 24 h systolic blood pressure, but not with the changes in clinic blood pressure. In a stepwise logistic regression analysis, average daytime diastolic blood pressure was the sole variable to enter the model and the probability of ambulatory hypertension at follow-up study was 20.0%percnt; in those with basal daytime ABP <130/80 mmHg, versus 81% in those with higher basal daytime blood pressure levels. CONCLUSION: After 0.5-6.5 years, WCH spontaneously evolved into ambulatory hypertension in 37% of subjects, with an accompanying rise in left ventricular mass. The probability of ambulatory hypertension increased with the baseline values of ABP, rather than with those of clinic blood pressure. WCH might be a prehypertensive state (particularly in subjects with higher baseline ABP levels) and should be defined by low levels of daytime ABP, possibly lower than 130/80 mmHg.