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Relationship between small-artery structure and systolic, diastolic and pulse pressure in essential hypertension
1MRC Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, Québec, Canada. schiffe@ircm.qc.ca
Insights
Pulse pressure does not significantly alter small artery structure in human essential hypertension. Diastolic blood pressure is a key factor in hypertensive patients, not pulse pressure.
Area of Science:
- Cardiovascular Physiology
- Hypertension Research
- Vascular Biology
Background:
- Previous studies in rats suggested pulse pressure is a key determinant of small artery structure.
- Contradictory findings exist for human essential hypertension.
- This study investigates hemodynamic determinants in human small arteries.
Purpose of the Study:
- To determine if pulse pressure contributes to structural alterations in human essential hypertension.
- To investigate the relationship between hemodynamic factors and small artery structure in hypertensive patients.
Main Methods:
- Small arteries (<300 microns) were obtained from gluteal subcutaneous biopsies.
- 40 normotensive and 45 untreated essential hypertensive subjects were analyzed.
- Media:lumen ratio was correlated with systolic, diastolic, mean, and pulse pressures.
Main Results:
- Hypertensive patients showed significantly higher media:lumen ratio and smaller lumen diameter than normotensive subjects.
- Media:lumen ratio correlated with systolic, diastolic, and mean arterial pressure in both groups combined.
- In hypertensive patients, media:lumen ratio correlated with diastolic blood pressure only.
- No correlation was found between media:lumen ratio and pulse pressure.
Conclusions:
- Pulse pressure is not a significant determinant of small artery structure in humans with essential hypertension.
- Diastolic blood pressure is more closely related to small artery structural changes in hypertensive individuals.
- Findings contrast with previous animal studies, highlighting species-specific differences.
Objective:
Studies of cerebral arterioles have suggested that pulse pressure may be a more important determinant of small-artery structure than systolic, diastolic or mean blood pressure in stroke-prone spontaneously hypertensive rats and in rats with an arterio-venous shunt. A study of small arteries has suggested that this is not the case in human essential hypertension. We therefore investigated the role of hemodynamic determinants on small-artery structure in hypertensive patients.
Design And Methods:
To determine whether pulse pressure contributes to structural alterations in human essential hypertension, small arteries (lumen < 300 microns) were obtained from gluteal subcutaneous biopsies of 40 normotensive subjects aged 40.7 +/- 1.2 years and 45 untreated essential hypertensive humans aged 46.5 +/- 1.3 years. The relationship between the media: lumen ratio of the small arteries and levels of systolic, diastolic and mean blood pressure and pulse pressure was investigated.
Results:
The media: lumen ratio (5.33 +/- 0.001%) of small gluteal subcutaneous arteries of normotensive subjects was significantly smaller and the lumen diameter (306 +/- 13 microns) significantly larger than in untreated hypertensive patients (7.42 +/- 0.001% and 244 +/- 9.7 microns respectively, P < 0.001). The media: lumen ratio of both groups examined together correlated with systolic blood pressure (r = 0.45, P < 0.001), diastolic blood pressure (r = 0.56, P < 0.001) and mean arterial pressure (r = 0.55, P < 0.001). The media: lumen ratio of vessels from hypertensive patients correlated with diastolic blood pressure (r = 0.22, P < 0.01) but not with systolic or mean blood pressure. There was no correlation between the media: lumen ratio of small gluteal subcutaneous arteries and pulse pressure in this population of normotensive and hypertensive subjects, examined together or separately.
Conclusion:
These results suggest that in 30- to 65-year-old humans with systolodiastolic essential hypertension, pulse pressure does not appear to be an important determinant of small-artery structure.