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Effects of ACE inhibitor therapy on derived central arterial waveforms in hypertension
A M Dart1, C M Reid, B McGrath
1Baker Medical Research Institute, Monash Medical Centre, Melbourne, Australia. a.dart@alfred.org.au
Insights
Perindopril therapy showed a trend towards greater reduction in large artery stiffness (augmentation index) compared to usual care in hypertensive patients. However, these changes were largely attributed to hemodynamic factors, not direct arterial effects.
Area of Science:
- Cardiovascular Medicine
- Pharmacology
- Hypertension Research
Background:
- Large artery properties significantly influence left ventricular afterload in hypertension.
- Understanding the impact of antihypertensive therapies on arterial properties is crucial.
Purpose of the Study:
- To investigate the responsiveness of large artery properties to angiotensin converting enzyme inhibitor (ACE inhibitor) therapy, specifically perindopril.
- To compare the effects of perindopril versus usual care on arterial stiffness in hypertensive individuals.
Main Methods:
- A 12-week prospective, randomized study involving 138 hypertensive patients.
- Assessed large artery properties using applanation tonometry and transfer function to determine augmentation index (AI) and augmentation pressure (AP).
- Compared perindopril therapy against usual care (UC) in a subset of patients.
Main Results:
- Perindopril treatment showed a significant decrease in augmentation index (AI), while usual care did not.
- Both groups experienced a decrease in augmentation pressure (AP), with a trend for greater reduction in the perindopril group.
- Changes in AI were influenced by baseline heart rate, systolic blood pressure, weight, and sex, but not significantly by the treatment group.
Conclusions:
- Perindopril therapy may lead to greater improvements in large artery stiffness compared to usual care, though differences were not statistically significant.
- The observed arterial changes with perindopril are likely mediated by hemodynamic alterations rather than direct effects on arterial tissue.
- Further research is needed to elucidate the direct vascular effects of ACE inhibitors.
Abstract:
Large artery properties constitute an important component of left ventricular afterload in hypertension. The present study examined whether such properties were particularly responsive to angiotensin converting enzyme inhibitor therapy. A prospective, randomized, 12-week study in 138 previously treated hypertensive subjects, in 67 of whom usual treatment (UC) was replaced with perindopril (P) therapy. Large artery properties were assessed as central arterial pressure augmentation determined by applanation tonometry of the radial artery and a transfer function. At baseline both augmentation index (AI, %) and pressure (AP, mm Hg) were related to body size, heart rate, and gender. In addition AP was related to age and systolic blood pressure (BP). After 12 weeks of treatment AP decreased significantly in both perindopril and UC groups, whereas AI only decreased significantly (151.7%+/-2.3% to 144.9%+/-2.6%) in those treated with perindopril. Decreases in AP (-4.2+/-0.9 mm Hg v -1.9+/-0.7 mm Hg) and AI (-6.8%+/-2.2% v -2.2%+/-2.5%) from week 0 to week 12 were greater in the perindopril-treated group, but differences between groups failed to reach statistical significance (P = .05 and .09, respectively). The change in AI during the 12-week treatment period was dependent on the initial heart rate (P < .001), systolic BP (P < .05), weight (P < .001), and sex (P < .001), but not on treatment group (P > .5). Al at 12 weeks was negatively correlated with heart rate but regression slopes for the association were virtually identical for perindopril and UC groups. Perindopril treatment produces a greater decrease in AI than continuation with previous therapy, but this can be largely explained by hemodynamic changes rather than direct arterial effects.