N-terminal probrain natriuretic peptide predicts altered circadian variation in essential hypertension

Diminished nocturnal blood pressure fall in nondipper hypertensive patients are closely associated with poor prognosis. N-terminal probrain natriuretic peptide can also identify poor prognosis in miscellaneous heart diseases. In this study, we aimed to clarify the association between probrain natriuretic peptide levels and diminished nocturnal blood pressure fall in patients with essential hypertension. Twenty-six consecutive nondipper (age: 53+/-8 years, 14 men) (group 1), and 26 dipper hypertensive patients (age: 52+/-9 years, 16 men) (group 2), based on ambulatory blood pressure monitoring, and age and sex-matched 28 normotensive participants (age: 50+/-11 years, 16 men) (group 3) were compared with each other. Although systolic and diastolic ambulatory blood pressure values were similar in hypertensives during the day, those at night were higher in group 1 (P<0.0001). Echocardiographic findings revealed that the left ventricular mass index was higher in both group 1 (184+/-47) and group 2 (142+/-39) compared with control participants (102+/-19) (P<0.0001), but ejection fraction and relative wall thickness were similar in all groups. The transmitral E-wave velocity decreased in group 1 (0.62+/-0.15 m/s) and group 2 (0.7+/-0.14 m/sec) compared with group 3 (0.95+/-0.22 m/s) (P<0.01). The transmitral E/A ratio decreased (0.71+/-0.12, 0.81+/-0.2 and 0.79+/-0.57, respectively P<0.05), and the transmitral E-wave deceleration time increased in group 1 (208+/-46, 203+/-38 and 169+/-42 ms, respectively, P<0.05). The isovolumic relaxation time increased (112+/-23, 110+/-18 and 86+/-11 m/s, respectively, P<0.01). Although group 1 and 2 have a similar number of patients with diastolic dysfunction (23/26 and 22/26, respectively, P>0.05), there were great differences between plasma probrain natriuretic peptide levels (88+/-20, 58+/-22 and 47+/-20 pg/ml, respectively, P<0.0001). In addition, serum uric acid (6.5+/-1.4, 5.3+/-1.5 and 5.0+/-1.9, respectively P<0.001), and creatinine levels (0.88+/-0.2 and 0.78+/-0.2 vs. 0.72+/-0.3, respectively P<0.05) were higher in group 1. These observations suggest that nondipper state may be related to the increase in left ventricular mass index and probrain natriuretic peptide levels and elevation in both plasma uric acid and creatinine levels. Serum probrain natriuretic peptide levels are found to be correlated with left ventricular mass index (Pearson's correlation 469 P<0.0001); but not creatinine (Pearson's correlation 188 P>0.05).