Cardiovascular target organ damage in essential hypertensives with or without reproducible nocturnal fall in blood pressure

Objective The clinical significance of classifying patients as dippers and non-dippers on the basis of a single period of ambulatory blood pressure monitoring (ABPM ) has been questioned. The aim of this study was to evaluate the relationship between nocturnal dipping status, defined on the basis of two periods of ABPM , and cardiac and extracardiac target organ damage in essential hypertension. Methods A total of 375 never-treated essential hypertensive patients [mean 24-h blood pressure (BP ) greater than or equal to 125/80 mmHg; mean +/- SD age 45.9 +/- 11.9 years] referred for the first time to our outpatient clinic underwent the following procedures: (i) repeated clinic BP measurements; (ii) blood sampling for routine chemistry examinations; (iii) 24-h urine collection for microalbuminuria; (iv) ABPM over two 24-h periods within 4 weeks; (v) echocardiography; and (vi) carotid ultrasonography. Results A reproducible nocturnal dipping (decrease in BP > 10% from mean daytime BP in both ABPM periods) and non-dipping profile (decrease in BP less than or equal to 10% in both ABPM periods) was found in 199 (group I) and 79 patients (group II), respectively; 97 patients (group III) had a variable dipping profile. The three groups did not differ with regard to age, gender, body mass index, clinic BP, 48-h BP and heart rate. Left ventricular mass index, interventricular septum thickness, left atrium and aortic root diameters were significantly higher in group II compared with group I (mean +/- SD 108.5 +/- 19.5 versus 99.7 +/- 19.6 g/M-2, P< 0.05; 9.3 +/- 0.9 versus 9.1 +/- 0.9 mm, P < 0.05; 33.6 +/- 3.6 versus 32.2 +/- 3.7 mm, P < 0.01; 36.9 +/- 4.6 mm versus 35.5 +/- 4.6, P < 0.05, respectively). The smaller differences seen between groups II and III and between groups I and III were not statistically significant. The prevalence of left ventricular hypertrophy (defined as a left ventricular mass index > 134 g/m(2) in men and > 110 g/M-2 in women) was greater in group II (119%) than in group I (6%) (P< 0.05), whereas the differences between groups II and III and between groups I and III did not reach statistical significance. Differences among the three groups in the prevalence of carotid structural alterations (such as carotid plaques or intima-media thickening) were not statistically significant, and microalbuminuria had a similar prevalence in all three groups. Conclusions Despite similar clinic and 48-h BP values, never-treated hypertensive patients with a persistent non-dipper pattern showed a significantly greater extent of cardiac structural alterations compared with subjects with a reproducible dipping pattern, but not those with a variable BP nocturnal profile. A non-dipping pattern diagnosed on two concordant ABPM periods instead of a single monitoring therefore represents a clinical trait associated with more pronounced cardiac abnormalities. Finally, in non-dipping middle-aged hypertensives, echocardiography appears to provide a more accurate risk stratification than carotid ultrasonography or microalbuminuria . (c) 2004 Lippincott Williams & Wilkins.