Haemodynamic response to peripheral venous congestion in patients with unexplained recurrent syncope

Bellard, Elisabeth; Fortrat, Jacques‐Olivier; Dupuis, Jean‐Marc; Victor, Jacques; Lefthériotis, Georges

doi:10.1042/cs20030061

Cited by 9 publications

(9 citation statements)

References 31 publications

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“…We speculate that the venous vascular atrophy, as reported in P (Hopman et al 1994(Hopman et al , 1996, is beneficial for their orthostatic tolerance, although the relationship between venous blood pooling and orthostatic tolerance is controversial (Bellard et al 2003). Individuals with low thoracic lesions may be able to induce splanchnic vasoconstriction, which will contribute to their orthostatic tolerance, although Halliwil et al (1998) demonstrated that the splanchnic area may not be important in blood redistribution during head-up tilt.…”

Section: Discussionmentioning

confidence: 95%

Leg vascular resistance increases during head-up tilt in paraplegics

et al. 2005

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Despite loss of centrally mediated sympathetic vasoconstriction to the legs, spinal cord-injured individuals cope surprisingly well with an orthostatic challenge. This study assessed changes in leg vascular resistance following head-up tilt in healthy (C) and in paraplegic (P) individuals. After 10 min of supine rest, subjects were tilted 30 degrees head-up. Mean arterial pressure (MAP) and total peripheral resistance (TPR) increased in C (MAP from 76.7 +/ -6.6 mmHg to 80.6 +/- 8.2 mmHg; TPR from 1.12 +/- 0.26 AU to 1.19 +/ -0.31 AU) while both remained unchanged in P. Echo Doppler ultrasound determined red blood cell velocity in the femoral artery, which decreased (P from 18.9+/-6.2 cm/s to 12.5 +/- 4.5 cm/s, P = 0.001; C from 16.3 +/- 6.2 cm/s to 10.8 +/- 5.0 cm/s, P = 0.001) and leg vascular resistance, which increased (P from 402 +/- 137 AU to 643 +/- 274 AU, P = 0.001; C from 238 +/- 68 AU to 400 +/- 122 AU, P = 0.003) from supine to upright. The present study shows that independent of supraspinal sympathetic control, humans are able to increase leg vascular resistance and maintain blood pressure during head-up tilt.

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Section: Discussionmentioning

confidence: 95%

Leg vascular resistance increases during head-up tilt in paraplegics

et al. 2005

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“…Upright positioning produces thoracic hypovolemia by a caudal shift of blood volume 10 that is affected by splanchnic vasoconstriction 11 and potentiated by hypovolemia of any pathogenesis. 12 Increased fainting risk has been attributed to excessive orthostatic redistribution of blood to the lower extremities, but data from our laboratory 13 and others 14 suggest that lower-limb pooling is not different between fainters and control subjects.…”

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confidence: 93%

Relation of Postural Vasovagal Syncope to Splanchnic Hypervolemia in Adolescents

Stewart

McLeod²,

Sanyal³

et al. 2004

Circulation

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Background-The mechanisms of simple faint remain elusive. We propose that postural fainting is related to excessive thoracic hypovolemia and splanchnic hypervolemia during orthostasis compared with healthy subjects. Methods and Results-We studied 34 patients 12 to 22 years old referred for multiple episodes of postural faint and 11 healthy subjects. Subjects were studied in the supine position and during upright tilt to 70°for 30 minutes and subgrouped into Sϩ, historical fainters who fainted during testing (nϭ24); SϪ, historical fainters who did not faint during testing (nϭ10); and control subjects. Supine venous occlusion plethysmography showed no differences between blood flows of the forearm and calf in Sϩ, SϪ, or control. Cardiac index, total peripheral resistance, and blood volume were not different. Using impedance plethysmography, we assessed blood redistribution during upright tilt. This demonstrated decreased thoracic blood volume and increased splanchnic, pelvic, and leg blood volumes for all subjects. However, thoracic blood volume was decreased in Sϩ compared with control volume, correlating well with the maximum upright heart rate. Splanchnic volume was decreased in the Sϩ and SϪ groups, correlating with the change in thoracic blood volume. Pelvic and leg volume changes were similar for all groups and uncorrelated to thoracic blood volume. Conclusions-Enhanced

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“…As a logical follow‐on from this, blood pooling in the calf has been proposed as a factor that precipitates the development of syncope (Hargreaves & Muir, 1992). Nevertheless, in some patients the increase in calf volume after moving to the standing position did not correlate with the onset of a vasovagal syncope (Bellard et al 2003). This may be due to the fact that direct measurement of vein compliance in humans is still difficult.…”

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confidence: 99%

Calf venous volume during stand‐test after a 90‐day bed‐rest study with or without exercise countermeasure

Chantemèle

Pascaud

Custaud

et al. 2004

The Journal of Physiology

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The objectives to determine both the contribution to orthostatic intolerance (OI) of calf venous volume during a stand-test, and the effects of a combined eccentric-concentric resistance exercise countermeasure on both vein response to orthostatic test and OI, after 90-day head-down tilt bed-rest (HDT). The subjects consisted of a control group (Co-gr, n = 9) and an exercise countermeasure group (CM-gr, n = 9). Calf volume and vein cross-sectional area (CSA) were assessed by plethysmography and echography during pre-and post-HDT stand-tests. From supine to standing (post-HDT), the tibial and gastronemius vein CSA increased significantly in intolerant subjects (tibial vein, +122% from pre-HDT; gastronemius veins, +145%; P < 0.05) whereas it did not in tolerant subjects. Intolerant subjects tended to have a higher increase in calf filling volume than tolerant subjects, in both sitting and standing positions. The countermeasure did not reduce OI. Absolute calf volume decreased similarly in both groups. Tibial and gastrocnemius vein CSA at rest did not change during HDT in either group. During the post-HDT stand-test, the calf filling volume increased more in the CM-gr than in the Co-gr both in the sitting (+1.3 ± 5.1%, vs. -7.3 ± 4.3%; P < 0.05) and the standing positions (+56.1 ± 23.7% vs. +1.6 ± 9.6%; P < 0.05). The volume ejected by the muscle venous pump increased only in the CM-gr (+38.3 ± 21.8%). This study showed that intolerant subjects had a higher increase in vein CSA in the standing position and a tendency to present a higher calf filling volume in the sitting and standing positions. It also showed that a combined eccentric-concentric resistance exercise countermeasure had no effects on either post-HDT OI or on the venous parameters related to it.

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Haemodynamic response to peripheral venous congestion in patients with unexplained recurrent syncope

Cited by 9 publications

References 31 publications

Leg vascular resistance increases during head-up tilt in paraplegics

Leg vascular resistance increases during head-up tilt in paraplegics

Relation of Postural Vasovagal Syncope to Splanchnic Hypervolemia in Adolescents

Calf venous volume during stand‐test after a 90‐day bed‐rest study with or without exercise countermeasure

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