The Microcirculation and Hypertension
The role of the microcirculation is increasingly being recognized in the pathophysiology of cardiovascular disease. It is the major site of control of vascular resistance. In addition, the microcirculation is a major site of damage in most target organs o
- PDF / 225,048 Bytes
- 12 Pages / 439.37 x 666.142 pts Page_size
- 80 Downloads / 172 Views
17
H. A. J. Struijker-Boudier and Bart F. J. Heijnen
17.1
Introduction
The hemodynamic characteristic of essential and most forms of secondary hypertension consists of elevated blood pressure (BP) and peripheral vascular resistance. BP comprises two components: a pulsatile (pulse pressure) and a steady [mean arterial pressure (MAP)] component. Pulse pressure is predominantly influenced by the elastic properties of the larger conduit arteries, whereas MAP is determined by the resistance to flow in smaller arteries and arterioles, ranging in diameter from 10 to 300 lm. The small arteries and arterioles are a continuous segment of the vascular system associated with a gradual drop in pressure. Instead of referring to specific components as resistance vessels, the entire arterial microcirculation vessels of between 10 and 300 lm should be regarded as a site of resistance, and thus MAP, control. The exact location of the pressure drop may differ in relation to tissue. In cardiac tissue, for example, the pressure drop occurs distally in the arterial tree, whereas in the mesentery it is located more proximally. The role of the microcirculation is increasingly being recognized in the pathophysiology of cardiovascular disease [1, 2]. The microcirculation is a major site of damage in most target organs of cardiovascular disease, such as the heart, brain, and kidney. Both functional and structural alterations in the small arteries, arterioles, and capillaries are the basis of target organ damage (Table 17.1). Detailed mechanistic studies in both human and animal models of cardiovascular disease have revealed the nature of microcirculatory dysfunction. Largescale epidemiological studies in the last two decades have identified the associations between deranged microvascular perfusion and structure, target organ
H. A. J. Struijker-Boudier (&) B. F. J. Heijnen Department of Pharmacology, Maastricht University, Maastricht, The Netherlands e-mail: [email protected] A. E. Berbari and G. Mancia (eds.), Special Issues in Hypertension, DOI: 10.1007/978-88-470-2601-8_17, Ó Springer-Verlag Italia 2012
213
214
H. A. J. Struijker-Boudier and B. F. J. Heijnen
Table 17.1 Microvascular involvement in target organ damage in cardiovascular disease Target organ
Morbid events
Mortality
Eye
Retinopathy
Brain
Ischemia, Dementia
CVA
Kidney
Albuminuria, Glomerulopathy
ESRD
Heart
Ischemia
Heart failure
Periphery
Arteriosclerosis, Ischemia
CVA cerebrovascular accident; ESRD end-stage renal disease
Table 17.2 Major methods to assess the microcirculation
Intravital microscopy Capillaroscopy Retinal imaging Isolated small arteries Contrast angiography Magnetic resonance imaging Positron emission tomography Laser Doppler flowmetry
damage, and subsequent cardiovascular disease [3]. Major technological developments now allow the study of the microcirculation both in mechanistic and epidemiological studies. The purpose of this brief review is to provide a critical appraisal of these developments and thei
Data Loading...
