[Should nocturnal arterial pressure be monitored in treated hypertensive patients?]

Ambulatory blood pressure monitorings for diagnosis purpose in non treated hypertensive patients are often performed only during day time for two reasons. First, target organ responses to hypertension, and mainly left ventricular hypertrophy, are more closely related to activity than to rest BP. Second, these automatic devices are frequently not well tolerated during sleep because of their noise during inflation of the cuff. However, 24 h BP monitoring seems of greater interest in treated hypertensive patients to control the efficiency of the treatment. As suggested by our work, incomplete lowering of BP during night may not be harmless. In a prospective study, we evaluated the relationship between BP recorded during 24 h (Spacelabs 5200) and M mode echocardiographic measurements of left ventricular mass index (LVMI) (Devereux's formula) both in non treated hypertensive patients (group A, n = 40) who had discontinued therapy at least 8 days prior to the study and in hypertensive patients treated with the same drugs for more than 3 months (group B, n = 24). More than half of these patients were receiving beta blocking agents. As previously stated day (8 h-22 h), systolic BP is better related with LVMI than clinical (C) and night (23 h-7 h) SBP in group A. In contrast, a higher correlation was found between night BP and LVMI in group B, which was significantly different from the correlation found in group A (Z test, p less than 0.05). (Table: see text). In conclusion, 24 h BP monitoring is useful in treated hypertensive patients. Inadequate lowering of BP during night time may partially account for persistent left ventricular hypertrophy in treated hypertensive patients.