Background: Few studies have reported the effect of angiotensin-converting enzyme inhibitors on 24-h blood pressure (BP) and regulation of sympathetic nervous activity in hypertensive patients with diabetic nephropathy. Using ambulatory BP monitoring (ABPM) devices equipped with spectral analysis of heart rate variability, we assessed the effects of perindopril on 24-h BP and autonomic nervous activity in these patients.
Methods: Thirty-four hypertensive patients with non-insulin-dependent diabetic nephropathy underwent ABPM before and after treatment with perindopril (final dose: 4.9 +/- 1.8 mg/d). Simultaneously, spectral analysis was performed to calculate the high frequency components (HF) as a marker of parasympathetic nervous activity, and the low frequency components (LF)/HF ratios as an index of the sympathovagal balance.
Results: Perindopril significantly and equally decreased the waking and sleeping BP in the diabetic patients. During the sleeping period, the magnitude of change of mean BP induced by perindopril correlated inversely with the sleeping/waking ratio of mean BP before treatment. However, there was no correlation between these parameters during the waking period. Perindopril decreased both waking and sleeping LF/HF ratios, although no differences in HF components were observed between before and after treatment.
Conclusions: In patients with diabetic nephropathy, perindopril decreased 24-h BP. Spectral analysis suggested that this finding was partially related to inhibited sympathetic nervous activity. During sleeping periods, the BP-lowering effect of perindopril was more pronounced in patients showing no nocturnal decrease in BP. Perindopril may be a potent antihypertensive agent to reduce increased nocturnal BP, a risk factor of target organ damage in these patients.