Limb venous tone and responsiveness in hypertensive humans

Delaney, Erin P.; Young, Colin N.; DiSabatino, Angela; Stillabower, Michael; Farquhar, William B.

doi:10.1152/japplphysiol.90574.2008

Cited by 19 publications

(27 citation statements)

References 40 publications

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“…Mean age and interval from delivery to test were comparable between groups (32±4 versus 32±4 years, P=0.62 and 7±2 versus 7±1 months, P=0.88, respectively). Formerly PE women had delivered at an earlier gestational age compared with controls (32 [29][30][31][32][33][34][35][36][37] , P=0.32) as were body mass index, stroke volume, cardiac output, and serum creatinine concentration. All subjects were normotensive (by inclusion).…”

Section: Resultsmentioning

confidence: 99%

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Aerobic Exercise Training in Formerly Preeclamptic Women

et al. 2015

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Women with a history of preeclampsia are at increased risk of recurrent gestational hypertensive disease and cardiovascular disease later in life.1,2 Fifty percent of formerly preeclamptic women (formerly PE women) have low plasma volume (PV) 3 and the recurrence risk of preeclampsia varies inversely with PV. 4 In pregnancy, a marked PV expansion (+30% to 60%) is required to meet the physiological demands of advanced pregnancy. 5,6 Formerly PE women with low PV show reduced PV expansion in pregnancy, which suggests that the adaptive capacity of the venous system in these women is limited.7 When PV expansion cannot meet the physiological demands, the circulation may compensate for it by an increase in sympathetic activity. 7 The resulting lowvolume high-output circulation will exert extra shear stress on the endothelium. 3,7 This may set the stage for endothelial dysfunction, vascular damage, and hypertensive disease in pregnancy and later in life.The venous compartment is the most prominent blood volume reservoir of the body. Although at rest two-thirds of PV is localized in the venous system, it can be rapidly mobilized by sympathetic-mediated venoconstriction in times of increased arterial demands, including pregnancy and exercise. 8,9 Venous capacity is largely determined by venous compliance (VeC) and varies dynamically with sympathetic tone predominantly controlled by the baroreflex system. 8 Dynamic changes in VeC can be tested through orthostatic stress testing. Previous studies demonstrated that formerly PE women at rest have low venous reserve, characterized by low PV, low VeC, and high sympathetic tone. 10Aerobic exercise is perhaps the best intervention to improve venous reserve. It increases PV and reduces sympathetic tone in healthy individuals. 11,12 In formerly PE women with low PV, aerobic exercise training could help to normalize venous reserve and thereby reduce the risk of hypertensive disease in future pregnancy and later in life. The extent to which formerly PE women are able to improve their venous reserve by exercise training is unknown. Our study addresses the question to what extent an aerobic exercise training program Abstract-In women with a history of preeclampsia, low plasma volume (≤1373 mL/m 2 ) is associated with recurrent preeclampsia and chronic hypertension. Interventions that improve volume reserve may reduce these risks in formerly preeclamptic women. In this study, we examined the effects of aerobic exercise training on venous reserves in 24 normotensive formerly preeclamptic women and 20 controls. Before and after 12-week aerobic exercise training, we measured plasma volume with albumin indicator dilution technique and venous compliance with venous occlusion plethysmography. Venous compliance and hemodynamic responses were assessed dynamically during graded head-up tilt (HUT). Formerly preeclamptic women had lower pretraining plasma volume and venous compliance than controls (1348±78 versus 1529±112 mL/m ; P<0.01, respectively). Blood pressure decreased comparably between...

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Section: Resultsmentioning

confidence: 99%

“…[31][32][33] The VeC at rest was lower in formerly PE women than in controls before training and improved markedly by exercise training. VeC modulation during HUT was initially blunted in formerly PE women compared with controls, but training shifted the curve upward and increased the slope.…”

Section: Discussionmentioning

confidence: 99%

Aerobic Exercise Training in Formerly Preeclamptic Women

et al. 2015

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“…It has been postulated that as resting sympathetic outflow is high in individuals with HBP, acute increases in sympathetic activity cannot further reduce venous capacitance. 11 Calf venous vessels can be influenced by sympathetic stimulation either through direct neural innervation or indirectly through circulating norepinephrine actions. 12 In this study, analysis of BP variability was used to estimate sympathetic modulation of vasomotor tone.…”

Section: Discussionmentioning

confidence: 99%

“…Calf volume across pressures from 60 to 10 mm Hg was used as an index of calf venous capacitance, assuming that cuff pressure is an index of transmural distending pressure. 11 As the pressure-volume relationship is nonlinear, a single number cannot be used to define the slope of the pressure-volume curve. Therefore, the group-average regression parameters b 1 and b 2 were used to estimate venous compliance as follows: Compliance ¼ b 1 þ 2* b 2 *(cuff pressure).…”

Section: Data Analysesmentioning

confidence: 99%

“…19 Previous studies have determined the relationship between collecting cuff pressure and intravenous pressure in young (r ¼ 0.998) and older NT adults (r ¼ 0.999), 20 as well as in hypertensive subjects (r ¼ 0.998). 11 In our laboratory, the coefficient of variation of this method is o10% (measurements obtained on two separate days in a sample of 14 subjects). Data were collected at a rate of 200 Hz via a data acquisition system (BIOPAC, Santa Barbara, CA, USA).…”

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confidence: 98%

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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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Greater forearm venous compliance in resistance-trained men

et al. 2010

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Greater venous compliance is associated with attenuation of the tolerance response to orthostatic stress and reduced incidence of venous diseases. Resistance training induces tolerance to orthostatic challenge and the growth of capillaries, which may lead to negative and positive effects on venous compliance, respectively. It has not been confirmed, however, whether habitual resistance training positively or negatively affects venous compliance. We compared the forearm venous compliance in resistance-trained men with age-matched controls. Eleven resistance-trained middle-aged men (37.7 ± 1.5 years) and 12 age-matched sedentary controls (36.7 ± 1.6 years) were studied. Forearm venous compliance was measured in subjects in the supine position by inflating a venous collecting cuff placed around the upper arm to 60 mmHg for 8 min and then decreasing cuff pressure to 0 mmHg at a rate of 1 mmHg/s. Forearm venous compliance was determined using the first derivative of the pressure-volume relation during cuff pressure reduction (compliance = β(1) + 2β(2) × cuff pressure). Forearm venous compliance at 20 mmHg cuff pressure was 16% greater in the resistance-trained group than in the age-matched sedentary controls (0.097 ± 0.005 vs. 0.083 ± 0.004 ml/dl/mmHg, P < 0.05). Forearm venous compliance was positively related to forearm venous volume (r = 0.643, P = 0.0009), but not forearm muscle mass (r = 0.391, P = 0.0648). In conclusion, the present study suggests that (1) the resistance-trained men have greater forearm venous compliance than age-matched controls, and (2) the higher forearm venous compliance in the resistance-trained men may be explained by greater forearm venous capacitance.

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Limb venous tone and responsiveness in hypertensive humans

Cited by 19 publications

References 40 publications

Aerobic Exercise Training in Formerly Preeclamptic Women

Aerobic Exercise Training in Formerly Preeclamptic Women

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

Greater forearm venous compliance in resistance-trained men

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