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[Arterial compliance is not diminished in hypertensive patients when compared at the same level of blood pressure]
S Laurent1, P Lacolley, X Girerd
1Service de pharmacologie, hôpital Broussais, Paris.
Insights
Hypertension (HT) does not intrinsically alter large artery compliance. However, age-related decreases in carotid artery compliance were observed in hypertensive patients compared to normotensive individuals.
Area of Science:
- Cardiovascular Physiology
- Vascular Mechanics
- Hypertension Research
Background:
- Decreased large artery compliance is a hallmark of hypertension (HT), but its cause—elevated pressure versus intrinsic vascular changes—is debated.
- Understanding arterial wall alterations in HT is crucial for managing cardiovascular risk.
Purpose of the Study:
- To compare arterial compliance between normotensive (NT) and never-treated essential hypertensive (HT) subjects at a standardized distending pressure (100 mmHg).
- To investigate the relationship between age, blood pressure, and common carotid artery compliance.
Main Methods:
- Non-invasive assessment of common carotid artery diameter and pressure waveforms using high-resolution echotracking and applanation tonometry.
- Derivation of pressure-diameter and compliance-pressure curves to calculate isobaric compliance (C100) and mean arterial pressure compliance (CMAP).
- Inclusion of 14 NT and 15 never-treated essential HT subjects.
Main Results:
- Despite significant blood pressure differences, the overall compliance-pressure curves of HT and NT subjects were similar.
- Mean arterial pressure compliance (CMAP) decreased with age and elevated mean arterial pressure, and was lower in HT compared to NT subjects, adjusted for age.
- Isobaric compliance (C100) decreased with age but was not significantly reduced in hypertensive individuals compared to normotensive individuals, adjusted for age.
Conclusions:
- Intrinsic alterations in large artery wall properties do not appear to explain the decreased compliance observed in essential hypertension.
- Age is a significant factor in reduced arterial compliance, and this effect is more pronounced in hypertensive individuals.
- Isobaric compliance at 100 mmHg is preserved in never-treated essential hypertension, suggesting pressure-induced remodeling is not the primary driver of reduced compliance in this group.
Abstract:
Whether the decrease in large artery compliance, observed in hypertensive patients (HT), is due to an increase in distending pressure or to intrinsic alterations of the vascular wall remains much debated. We determined the diameter-pressure curve of the common carotid artery over the systolic-diastolic range, then derived the compliance-pressure curve, in order to compare arterial compliance in normotensive subject (NT) and in HT, for a common level of distending blood pressure: 100 mmHg (isobaric compliance). Fourteen NT and 15 never treated essential HT were included in the study. The diameter-pressure curve of the common carotid artery was determined non-invasively by simultaneously and continuously recording the systolic-diastolic changes in internal diameter (using a high resolution echotracking system) and pressure waveform (using high fidelity applanation tonometry on the contralateral artery) over 4-6 cardiac cycles. The level of MAP of the carotid pressure waveform was determined electronically and set equal to mean brachial pressure. Compliance-pressure curve was then derived from the pressure-diameter curve in order to determine compliance (C) for any given level of blood pressure, particularly MAP (CMAP) and 100 mmHg (C100). Despite the considerable differences in blood pressure, the compliance-pressure curve of HT was not different from that of NT. CMAP decreased with aging (p < 0.001) and MAP (p < 0.001). According to age, CMAP was reduced in HT as compared to NT (84 +/- 49 vs 116 +/- 52 mm2.mmHg.10(-3) p < 0.01). C100 decreased with aging (p < 0.05) but not with MAP. According to age, C100 was not reduced in hypertensives.(ABSTRACT TRUNCATED AT 250 WORDS)