Blood pressure (BP) is believed to be a major determinant of vascular disease, and BP lowering is the most important goal in hypertension treatment. Thus, clinical guidelines for hypertension are mainly focused on lowering mean BP. However, despite an increasing incidence of stroke with age, the association between systolic BP (SBP) and the risk of stroke decreases with age. This disparity highlights a gap in the link between BP and vascular-related diseases (i.e., stroke). In clinical practice, visit-to-visit fluctuations in BP have been largely ignored and are thought to be an unreliable finding, even though this phenomenon is frequently observed. Rothwell et al. demonstrated that the visit-to-visit variability in SBP was a more powerful independent predictor of stroke than mean SBP, and that an increased residual variability in SBP in treated hypertensive patients was also a strong predictor of stroke and coronary events. Recently updated (2011) hypertension guidelines from the National Institute for Health and Clinical Excellence (NICE) recommend an angiotensin converting enzyme inhibitor (ACEi) \[or angiotensin II receptor blocker (ARB)\] and calcium-channel blocker (CCB) as a first line drug. Although the significance of BP variability (BPV) has been illustrated, the main focus of the current guidelines is to reduce systolic and diastolic BP, not BPV. In the X-CELLENT study, a CCB (amlodipine) and thiazide-like diuretic drug (indapamide sustained-release) led to a significant reduction in BPV, compared to an ARB (candesartan). In addition, the CCB showed the most effective reduction in systolic BPV among the antihypertensive drug class in a meta-analysis. However, there are no direct comparison studies of a CCB and ARB on BPV. Thus, we aim to compare the systolic BPV effects of a CCB versus an ARB in essential hypertensive patients. The primary hypothesis is that an ARB is not inferior to a CCB in the reduction of the systolic BPV standard deviation (SD) in essential hypertensive patients.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
144
Eligible subjects will be randomized 1:1 to either an amlodipine or a losartan group by a computer-generated random number table. For patients who fail to respond to 5 mg amlodipine, the dose will be titrated up to 10 mg amlodipine. At subsequent visits, additional antihypertensive therapy (hydrochlorothiazide) will be added if systolic (\>140 mmHg) or diastolic (\>90 mmHg) BP is inadequate. Study drugs are administered once a day for 24 weeks. The dose will be titrated up if SBP is over 90 mmHg or there are no symptoms of hypotension (syncope, loss of consciousness, or orthostatic hypotension). If up-titration is not tolerable, because of side effects or hypotension, the previous dose will be administered as the final tolerable dose.
Eligible subjects will be randomized 1:1 to either an amlodipine or a losartan group by a computer-generated random number table. For patients who fail to respond to 50 mg losartan, the dose will be titrated up to 100 mg losartan. At subsequent visits, additional antihypertensive therapy (hydrochlorothiazide) will be added if systolic (\>140 mmHg) or diastolic (\>90 mmHg) BP is inadequate. Study drugs are administered once a day for 24 weeks. The dose will be titrated up if SBP is over 90 mmHg or there are no symptoms of hypotension (syncope, loss of consciousness, or orthostatic hypotension). If up-titration is not tolerable, because of side effects or hypotension, the previous dose will be administered as the final tolerable dose.
Wonju Severance Christian Hospital
Wŏnju, Gangwon-do, South Korea
SD of visit-to-visit systolic blood pressure variability
Consecutive measured blood pressure values from each visit will be averaged, and the standard deviation (SD) is calculated using the mean systolic blood pressure of each visit.
Time frame: 6 months
Central systolic blood pressure
Measurement of central blood pressure will be performed at randomization and 6 months.
Time frame: 6 months
Augmentation index of central blood pressure
Augmentation index of central blood pressure will be measured at randomization and 6 months.
Time frame: 6 months
Standard deviation of within-visit systolic blood pressure variability
Time frame: 6 months
Coefficient of variation of visit-to-visit systolic blood pressure variability
The coefficient of variation (CV) is defined as the standard deviation/mean systolic blood pressure.
Time frame: 6 months
Variation independent of the mean of visit-to-visit systolic blood pressure variability
To eliminate the correlation of coefficient variation with mean SBP, we will calculate a further transformed variable, the variation independent of the mean (VIM). The VIM is defined as the standard deviation/mean\^x, with x estimated from curve fitting of the data.
Time frame: 6 months
24-h ambulatory blood pressure monitoring
Time frame: 6 months
Home systolic blood pressure
Home systolic blood pressure will be measured at each scheduled visit.
Time frame: 6 months
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