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Relations between cardiac and vascular structure in patients with primary and secondary hypertension
D Rizzoni1, M L Muiesan, E Porteri
1Semeiotica and Metodologia Medica, University of Brescia, Italy. Damiano.Rizzoni@schering-plough.it
Insights
In hypertensive patients with activated renin-angiotensin-aldosterone system, small artery structure relates to cardiac and carotid artery changes. This connection was not seen in normotensive individuals or those with essential hypertension or pheochromocytoma.
Area of Science:
- Cardiovascular research
- Hypertension studies
- Vascular biology
Background:
- Limited data exists on cardiac and vascular structure in secondary hypertension.
- Interrelations between cardiac mass and vessel wall characteristics in large and small arteries are not well understood.
Purpose of the Study:
- To investigate the relationship between structural changes in small arteries, left ventricular mass, and carotid artery wall thickness in hypertensive patients.
- To compare these relationships across different types of hypertension, including primary and secondary forms.
Main Methods:
- A study involving 74 subjects: 11 with pheochromocytoma, 14 with primary aldosteronism (PA), 19 with renovascular hypertension (RVH), 18 with essential hypertension (EH), and 12 normotensive (NT) controls.
- Evaluation of subcutaneous small resistance arteries using micromyography and assessment of left ventricular mass index (LVMI) and common carotid artery intima-media thickness (CCIMT) via ultrasound.
Main Results:
- A stronger correlation between small artery media-to-lumen ratio (M/L) and LVMI or CCIMT was found in RVH compared to pheochromocytoma, EH, or NT groups.
- Primary aldosteronism (PA) showed slightly weaker correlations than RVH, and an increased prevalence of carotid plaques was noted in RVH.
Conclusions:
- A significant relationship between small resistance artery morphology and cardiac/carotid artery structure exists in hypertensive patients with activated renin-angiotensin-aldosterone system.
- No significant correlation was observed between M/L and LVMI or CCIMT in normotensive individuals, those with essential hypertension, or pheochromocytoma.
Background:
Data on cardiac and vascular structure in secondary hypertension are generally scarce, and no data on the interrelations between cardiac mass and structural characteristics of the vessel wall, both in large and in small resistance arteries, are presently available.
Objectives:
The aim of this study was to investigate the relation between structural changes in subcutaneous small arteries, left ventricular mass and wall thickness of the common carotid artery in patients with primary and secondary hypertension.
Methods:
Seventy-four subjects were included in the study: 11 patients with pheochromocytoma, 14 with primary aldosteronism (PA), 19 with renovascular hypertension (RVH), 18 with essential hypertension (EH) and 12 normotensive (NT) control subjects. All subjects were submitted to a biopsy of subcutaneous fat. Morphologic characteristics of subcutaneous small resistance arteries (relaxed diameter <300 microm) were directly evaluated using a micromyographic technique. All subjects were submitted to calculation of left ventricular mass index (LVMI) and common carotid artery intima-media thickness (CCIMT), using ultrasound technique.
Results:
The correlation coefficients between the media to lumen ratio in subcutaneous small arteries (M/L) and LVMI or between M/L and CCIMT were closer in RVH than in pheochromocytoma, EH or NT; in PA the correlation coefficients were slightly less close than those in RVH. An excess prevalence of carotid plaques in RVH was observed.
Conclusions:
A close relation between small resistance artery morphology and cardiac or carotid artery structure may be observed in those hypertensive patients in whom the renin-angiotensin-aldosterone system is activated. In constrast, in NT, EH and pheochromocytoma no significant correlation between M/L and LVMI or CCIMT was observed.