Target organ damage and non-dipping pattern defined by two sessions of ambulatory blood pressure monitoring in recently diagnosed essential hypertensive patients.

OBJECTIVE: To evaluate in a selected population of patients with a recent diagnosis of hypertension whether a reduced nocturnal fall in blood pressure, confirmed by two 24 h ambulatory blood pressure monitoring (ABPM) sessions is associated with more prominent target organ damage (TOD).

METHODS: The study was structured in two phases: in the first, 141 consecutive, recently diagnosed, never-treated essential hypertensives underwent 24 h ABPM twice within 3 weeks; in the second phase, 118 of these patients showing reproducible dipping or non-dipping patterns underwent the following procedures: (1) routine blood chemistry, (2) 24 h urinary collection for microalbuminuria, (3) amydriatic photography of ocular fundi, (4) echocardiography and (5) carotid ultrasonography.

RESULTS: The 92 patients with (>10%) night-time fall in systolic blood pressure (SBP) and diastolic blood pressure (DBP) (dippers) in both monitoring sessions were similar for age, gender, body surface area, smoking habit, clinic BP, 24 h and 48 h BP to the 26 patients with a < or = 10% nocturnal fall (non-dippers) in both sessions. The prevalence of left ventricular hypertrophy (LVH) (defined by two criteria: (1) LV mass index > or = 125 g/m2 in both genders; (2) LV mass index > or = 120 and 100 g/m2 in men and women, respectively) and that of carotid intima-media (IM) thickening (IM thickness > or = 0.8 mm) were significantly higher in non-dippers than in dippers (23 versus 5%, P < 0.01; 50 versus 22%, P < 0.05; and 38 versus 18%, P < 0.05, respectively). There were no differences among the two groups in the prevalence of retinal changes and microalbuminuria. The strength of the association of LV mass index with night-time BP was slightly but significantly greater than that with daytime BP.

CONCLUSIONS: This study suggests that a blunted reduction in nocturnal BP, persisting over time, may play a pivotal role in the development of some expressions of TOD, such as LVH and IM thickening, during the early phase of essential hypertension, despite similar clinic BP, 24 h and 48 h BP levels observed in non-dippers and dippers.