Hysteresis of the venous pressure-volume relationship in the forearm of borderline hypertensive subjects

H, Journo; Chanudet, X.; Pannier, Bruno; Laroque, Philippe; London, Gérard M.; Safar, M

doi:10.1042/cs0820329

Cited by 11 publications

(11 citation statements)

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“…1,2 In particular, it has been proposed that attenuated venous elasticity and capacity affect blood volume redistribution in such a manner that blood volume moves from peripheral veins into small arteries 3 or centrally, 2,4 contributing to chronic increases in arterial blood pressure (BP). Supporting this conceptual scheme, previous studies found reduced venous distensibility and blood holding capacity in animals 5,6 and humans [7][8][9] with hypertension. These changes in venous circulation are potentially due to chronic increases in sympathetic autonomic regulation of venous tone.…”

Section: Introductionsupporting

confidence: 49%

Limb venous compliance responses to lower body negative pressure in humans with high blood pressure

et al. 2011

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This study tested the hypothesis that limb venous responses to baroreceptor unloading are altered in individuals with high blood pressure (HBP) compared with normotensive (NT) controls. Calf venous compliance was assessed in 20 subjects with prehypertension and stage-1 hypertension (mean arterial pressure, MAP: 104 ± 1 mm Hg) and 13 NT controls (MAP: 86 ± 2 mm Hg) at baseline and during lower body negative pressure (LBNP), using venous occlusion plethysmography. Baroreflex sensitivity (BRS) was measured using the sequence technique and total peripheral resistance (TPR) was estimated from finger plethysmography. Baseline venous compliance was not different between groups, but the HBP group had lower baseline lnBRS (2.22±0.14 vs 2.7±0.18 ms mm Hg À1) and greater baseline TPR (3828 ± 138 vs 3250 ± 111 dyn sec À1 cm À5 m 2 , Po0.05). Calf venous compliance was reduced in response to LBNP only in the NT group (Po0.05). The HBP group had a greater increase in TPR (DTPR) compared with the NT group ( þ 1649 ± 335 vs þ 718 ± 196 dyn sec À1 cm À5 m 2 , Po0.05). In conclusion, the early stages of hypertension are characterized by an attenuated venoconstrictor response to baroreceptor unloading, which may compensate for an exaggerated vasoconstrictor response and protect against further increases in blood pressure.

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Section: Introductionsupporting

confidence: 49%

Limb venous compliance responses to lower body negative pressure in humans with high blood pressure

et al. 2011

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“…Stress-relaxation refers to the intrinsic ability of the vascular walls to stretch slowly when the pressure rises and to contract slowly when the pressure falls (17). In humans, the effect of stress-relaxation on the vascular pressure-volume relation has been shown (11,25), but the results of these studies are not suitable for quantification. We therefore use the results of experiments conducted in dogs (41).…”

Section: Description Of the Modelmentioning

confidence: 99%

“…The venous pressurevolume relation is affected by three major mechanisms: the baroreflex (16), viscoelastic vessel properties referred to as stress relaxation (also named "creep" or "delayed compliance") (11,25,42), and transcapillary fluid transfer (37). The combined effect of these mechanisms defines the pressure-volume relation in time, making it difficult to experimentally distinguish the individual contribution of each.…”

Section: Factors Affecting Preload During Hutmentioning

confidence: 99%

Mathematical modeling of gravitational effects on the circulation: importance of the time course of venous pooling and blood volume changes in the lungs

Heusden

Gisolf

Stok

et al. 2006

American Journal of Physiology-Heart and Circulatory Physiology

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A dip in blood pressure (BP) in response to head-up tilt (HUT) or active standing might be due to rapid pooling in the veins below the heart (preload) or muscle activation-induced drop in systemic vascular resistance (afterload). We hypothesized that, in the cardiovascular response to passive HUT, where, in contrast to active standing, little BP dip is observed, features affecting the preload play a key role. We developed a baroreflex model combined with a lumped-parameter model of the circulation, including viscoelastic stress-relaxation of the systemic veins. Cardiac contraction is modeled using the varying-elastance concept. Gravity affects not only the systemic, but also the pulmonary, circulation. In accordance with the experimental results, model simulations do not show a BP dip on HUT; the tilt-back response is also realistic. If it is assumed that venous capacities are steady-state values, the introduction of stress-relaxation initially reduces venous pooling. The resulting time course of venous pooling is comparable to measured impedance changes. When venous pressure-volume dynamics are neglected, rapid (completed within 30 s) venous pooling leads to a drop in BP. The direct effect of gravity on the pulmonary circulation influences the BP response in the first ϳ5 s after HUT and tilt back. In conclusion, the initial BP response to HUT is mainly determined by the response of the venous system. The time course of lower body pooling is essential in understanding the response to passive HUT. baroreflex; cardiovascular system; modeling; tilt table A MODELING APPROACH to the study of the blood circulation and its response to postural changes can provide insight into the underlying physiology. Existing models approximate certain aspects of the circulation and its response to orthostatic stress, but the transients seen on passive head-up tilt (HUT) have proven difficult to capture.Transient response of the cardiovascular system to active standing and passive HUT has been the focus of various studies (3,34,45,47,51,59). The steady-state response to active standing and HUT is usually comparable, but there is a difference in the blood pressure (BP) and heart rate (HR) responses in the first 30 s (Fig. 1). On passive HUT, Rossberg and Martinez (34) found initial increases in HR comparable to the response to active standing. In later studies, however, a BP dip on active standing was reduced (3, 47) or absent (45,51,59) in passive HUT responses. The initial BP dip on standing is thought to be due to a decrease in peripheral resistance resulting from the active part of the maneuver (45). Sprangers et al. (45) point out two mechanisms: 1) the central (autonomic) command that accompanies active muscle contraction and 2) the displacement of large amounts of venous blood to the right atrium by the massive muscle action induced by active standing, eliciting a cardiopulmonary (CP) reflex effect on the systemic circulation. In passive tilt, if abrupt muscle contraction in response to sudden tilt maneuvers is avoided, perip...

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“…6,7 Forearm blood flow was measured by venous occlusion plethysmography using a mercury-in-silastic strain gauge. [8][9][10] The left upper limb was supported 5-10 cm above the level of the heart with cushions at the arm, elbow, and palm to facilitate venous outflow.…”

Section: Methodsmentioning

confidence: 99%

Cold-induced elevation of forearm vascular resistance is inversely related to birth weight

et al. 2005

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Fetal growth retardation has been linked to elevated blood pressure in adult life. This association between birth weight and blood pressure is present in childhood and is amplified with age. However, the mechanisms that underlie this association are largely unknown. We examined the relationship between birth weight and forearm vascular resistance and forearm blood flow in children aged 9-12.7 years. A total of 58 children were randomly selected from a cohort of 1610 born at the University Hospital of the West Indies in Jamaica where adequate antenatal and delivery records were available. Blood pressure, heart rate and forearm blood flow (by venous occlusion plethysmography) were measured at rest and after cold pressor and mental arithmetic tests.There was a significant inverse correlation between birth weight and the change in the vascular resistance for the cold pressor test (r ¼ À0.47; Po0.001) and the mental arithmetic stress test (r ¼ À0.26; P ¼ 0.05). The log ratio of vascular resistance under stress to resting decreased by 0.289 units per kg of birth weight (95% CI: 0.145-0.434; P ¼ 0.0002). Lower birth weight is associated with increased vascular responsiveness. Increased vascular resistance might be one mechanism linking fetal growth to subsequent elevated blood pressure.

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Hysteresis of the venous pressure-volume relationship in the forearm of borderline hypertensive subjects

Cited by 11 publications

References 0 publications

Limb venous compliance responses to lower body negative pressure in humans with high blood pressure

Limb venous compliance responses to lower body negative pressure in humans with high blood pressure

Mathematical modeling of gravitational effects on the circulation: importance of the time course of venous pooling and blood volume changes in the lungs

Cold-induced elevation of forearm vascular resistance is inversely related to birth weight

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