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Arterial stiffness and wave reflections following acute calcium blockade in essential hypertension
B M Pannier1, A B Lafleche, X J Girerd
1Department of Internal Medicine, Broussais Hospital, Paris, France.
Insights
Lacidipine, a calcium channel blocker, reduced mean arterial pressure but did not alter pulse pressure in hypertensive patients. It did, however, change wave reflection patterns and increase the incident pressure wave ratio.
Area of Science:
- Cardiovascular Physiology
- Pharmacology
Background:
- Antihypertensive agents are typically assessed by their effects on systolic, diastolic, and mean arterial pressure.
- Pulse pressure can be independently influenced by arterial mechanical properties and wave reflection timing.
Purpose of the Study:
- To evaluate the impact of lacidipine, a dihydropyridine calcium blocker, on pulse pressure in patients with mild to moderate hypertension.
- To assess changes in arterial wave reflection and timing following acute lacidipine administration.
Main Methods:
- A double-blind, placebo-controlled study involving 18 hypertensive subjects.
- Noninvasive applanation tonometry to record carotid and femoral pressure waveforms.
- Echo-tracking techniques to analyze pulsatile arterial diameter changes.
Main Results:
- Lacidipine significantly decreased mean arterial pressure but did not change pulse pressure at brachial, carotid, or femoral sites.
- No significant alterations were observed in carotid-femoral pulse wave velocity, arterial stiffness, or wave travel time (delta tp).
- Lacidipine significantly reduced the ratio of wave reflections ((Ppk-Pi)/PP) and left ventricular ejection time, while increasing the incident pressure wave ratio (Pi/PP).
Conclusions:
- Acute lacidipine administration affects arterial wave dynamics, specifically reducing wave reflections and enhancing the incident wave component, despite not altering overall pulse pressure.
- These findings suggest that lacidipine's antihypertensive effect may involve modulation of arterial wave propagation independent of changes in mean arterial pressure or pulse pressure magnitude.
Abstract:
Antihypertensive agents are routinely studied in terms of changes in the level of systolic, diastolic, and mean arterial pressure. Pulse pressure may be independently modified from these parameters as a consequence of specific changes in the mechanical properties of the large arteries and in the timing of incident and reflected pressure waves. The aim of this study was to evaluate the changes in pulse pressure produced by acute calcium blockade by the dihydropiridine derivative, lacidipine, in a double-blind design versus placebo in 18 subjects with mild to moderate hypertension. Carotid and femoral pressure waveforms were recorded noninvasively by applanation tonometry using a Millar micromanometer-tipped probe. Early (Pi) and mid-to-late (Ppk) systolic peaks of carotid pressure waveform were evaluated, enabling the effect of incident pressure wave to be quantified as the ratio of Pi to the total height of carotid pulse wave (PP) (Pi/PP) and the effect of wave reflections as the ratio (Ppk-Pi)/PP. Travel time of the reflected wave (delta tp) was timed from the foot of the pressure wave to the foot of the late systolic peak. Pulsatile changes in diameter were studied using noninvasive echo-tracking techniques. Whereas mean arterial pressure significantly decreased following lacidipine, pulse pressure measured at three different sites (brachial, carotid, and femoral arteries) was unchanged. Carotid-femoral pulse wave velocity, carotid and femoral arterial stiffness, and delta tp were not modified, whereas the (Ppk-Pi)/PP ratio and left ventricular ejection time was significantly reduced and the Pi/PP ratio was significantly increased.(ABSTRACT TRUNCATED AT 250 WORDS)