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The relation between peripheral vascular structure, left ventricular hypertrophy, and ambulatory blood pressure in
I Sihm1, A P Schroeder, C Aalkjaer
1Department of Medicine and Cardiology, Aarhus University Hospital, Denmark.
Insights
Essential hypertension leads to parallel structural changes in the heart and peripheral arteries. Left ventricular hypertrophy and increased arterial media:lumen ratio are linked to elevated blood pressure.
Area of Science:
- Cardiovascular Medicine
- Hypertension Research
- Vascular Biology
Background:
- Essential hypertension is a major risk factor for cardiovascular disease.
- Left ventricular hypertrophy (LVH) and structural changes in peripheral arteries are common in hypertensive patients.
- The relationship between cardiac and arteriolar remodeling in hypertension requires further elucidation.
Purpose of the Study:
- To investigate the relationship between left ventricular mass (LVM), peripheral resistance artery structure, and ambulatory blood pressure (BP) in patients with essential hypertension.
- To determine if structural changes in resistance arteries correlate with LVM and BP.
- To identify independent predictors of LVM in hypertensive individuals.
Main Methods:
- Echocardiography was used to assess LVM in 83 hypertensive patients and 20 controls.
- Peripheral resistance arteries were isolated from skin biopsies and analyzed using a myograph to determine media:lumen ratio, media thickness, and media cross-sectional area.
- Ambulatory BP was measured, and statistical analyses, including multiple regression, were performed.
Main Results:
- 81% of hypertensive patients exhibited signs of LVH.
- Hypertensive patients had significantly higher ambulatory BP, LVM, media thickness, and media:lumen ratio compared to controls.
- Both LVM index (LVMI) and media:lumen ratio correlated significantly with BP.
- Media:lumen ratio and BP were independent predictors of LVMI.
- Correlation between media:lumen ratio and LVMI was significant only in patients with LVH.
Conclusions:
- Cardiac and arteriolar tissues undergo parallel structural remodeling in essential hypertension.
- Increased media:lumen ratio of resistance arteries is associated with LVH and elevated BP.
- These findings highlight the systemic nature of vascular and cardiac adaptations in hypertension.
Abstract:
The relations between left ventricular mass (LVM), peripheral resistance artery structure, and ambulatory BP were studied in 83 patients with previously untreated or poorly regulated essential hypertension and 20 healthy controls of similar age and sex. LVM was assessed by echocardiography. Signs of left ventricular hypertrophy (LVH) were present in 67 (81%) of the patients and in none of the controls. Peripheral resistance arteries were isolated from surgical gluteal skin biopsies and mounted in a Mulvany-Halpern isometric small vessel myograph, and their media:lumen ratio, media thickness, and media cross-sectional area were determined under standardized conditions. Mean (+/- SD) ambulatory BP was 122 +/- 9 mm Hg among patients and 96 +/- 8 mm Hg among controls (P < .001). LVM was 327 +/- 99 g among patients and 197 +/- 37 g among controls (P < .001). Media thickness of resistance arteries was 21.0 +/- 4.2 microns among hypertensives and 16.2 +/- 2.6 microns among controls (P < .001). The media:lumen ratio of arteries from patients was 10.2 +/- 2.6% v 7.9 +/- 2.0% in arteries of similar internal diameter from controls (P < .01). Both LVM index (LVMI) and media/lumen ratio correlated significantly with BP. There was significant correlation between media:lumen ratio and LVMI among hypertensive patients (r = 0.45, P < .001), but if patients were subdivided according to the presence of LVH this correlation was found only among patients with LVH (r = 0.60 P< .001) and not among patient without LVH nor controls. Multiple regression analyses of age, body surface area, media/lumen ratio, and BP on LVM or LVMI revealed independent contributions of media/lumen ratio and BP. Age had no influence in the models. Similar results were obtained when casual BP was replaced with ambulatory BP in these analyses. No correlation was found between LVMI and media cross-sectional area. A minor subset of patients with complete absence of nocturnal BP drop had particularly great LVM and media:lumen ratio. The study suggests that cardiac and arteriolar tissue undergo parallel structural remodeling in essential hypertension.