Association between ankle blood pressure and central arterial wave reflection

Contralateral differences in ankle SBP and pulse wave velocity: associations with incident heart failure and mortality

BACKGROUND

Contralateral differences in brachial SBP are indicative of underlaying cardiovascular issues.

OBJECTIVES

To examine the association of contralateral differences in ankle SBP, brachial-ankle pulse wave velocity (baPWV), and heart-ankle pulse wave velocity (haPWV) with incident heart failure and all-cause and cardiovascular mortality.

METHODS

Cox proportional-hazards models were used to calculate hazard ratios and 95% confidence intervals (95% CIs) in 5077 participants (75 ± 5 years) of the Atherosclerosis Risk in Communities study.

RESULTS

Over a mean follow-up of 7.5 ± 2.2 years, there were 457 heart failure events, 1275 all-cause and 363 cardiovascular deaths. Interankle SBP difference of at least 10 mmHg [hazard ratio = 1.12; confidence interval (CI) 1.00-1.28], at least 15 mmHg (hazard ratio = 1.21; CI 1.03-1.43), contralateral difference in baPWV more than 240 cm/s (hazard ratio = 1.22; CI 1.02-1.46), and haPWV more than 80 cm/s (hazard ratio = 1.24; CI 1.04-1.48) were each independently associated with all-cause mortality after adjustment for confounders. Contralateral differences in ankle SBP of at least 15 mmHg (hazard ratio = 1.56; CI 1.17-2.09), and haPWV more than 80 cm/s (hazard ratio = 1.42; CI 1.03-1.96) were both independently associated with cardiovascular mortality. Unadjusted analysis revealed that those with contralateral differences in ankle SBP of at least 10 and at least 15 mmHg, baPWV more than 240, and haPWV more than 80 cm/s had higher risks of heart failure (all P  < 0.05).

CONCLUSION

These results underscore the significance of evaluating contralateral differences in ankle SBP and PWV as potential markers of increased mortality risk among older adults.

Arterial stiffness and contralateral differences in blood pressure: The Atherosclerosis Risk in Communities (ARIC) study

A large interarm difference in brachial systolic blood pressure (SBP) (≥10 or ≥15 mmHg) is strongly associated with elevated cardiovascular events and mortality. Evidence demonstrating whether such contralateral differences in SBP occur in ankle blood pressure and its association with arterial stiffness is scarce. The aims of this study were to characterize arm and ankle contralateral SBP differences in a sample of community‐dwelling older adults (5077), and to determine whether this difference is associated with arterial stiffness assessed by pulse wave velocity (PWV) between the heart and ankle (haPWV), femoral artery and ankle (faPWV), and brachial artery and ankle (baPWV) in the right and left sides. Prevalence of interarm SBP differences ≥10 and ≥15 mmHg was 5.1% and .7%, respectively; the corresponding prevalence for interankle SBP was 24.9% and 12.0%. Higher BMI and lower ankle‐brachial index (ABI) were significantly correlated with greater interarm SBP differences. Increased age, higher BMI, lower ABI, and greater contralateral differences in haPWV, faPWV, and baPWV were significantly correlated to greater interankle SBP differences. Interankle SBP difference ≥15 mmHg was significantly associated with contralateral differences of >80 cm/s in haPWV (OR = 1.94 [95% CI = 1.52–2.49]), >165 cm/s in faPWV (OR = 1.64 [95% CI = 1.27–2.12]), and >240 cm/s in baPWV (OR = 2.43 [95% CI = 1.94–3.05]). The associations remained significant after adjustment for age, sex, race, BMI, smoking status, and ABI. Compared with interarm differences, interankle differences in SBP are common in older adults. The magnitude of interankle, but not interarm, differences in SBP is associated with various measures of arterial stiffness.

Ankle pulse pressure to diastole ratio as a novel non-invasive costless screening tool for subclinical atherosclerosis

Atherosclerosis develops gradually as a subclinical condition and eventually becomes clinically apparent as heart disease or stroke. The degree of decreased arterial compliance affects both pulse pressure (PP) and diastolic blood pressure (DBP). These relations would be clear in the distal periphery. We propose that the ankle PP/ankle DBP ratio (APPD) can uncover the ongoing subclinical vascular risk. Based on the elastic chamber theory, APPD = (Cs-Cd)/(Cd-C0) in which Cs, Cd, and C0 represent arterial compliance at systolic pressure, diastolic pressure, and zero-pressure. For a given ventricular ejection, the value of Cs-Cd (i.e. PP) positively differs in the same person from brachium to ankle based on the distance from the heart, degree of arterial stiffness, and the local arterial function. On the other hand, the decreased arterial compliance increases the speed of reflected pulse waves to the heart resulting in earlier ventricular ejection by which the value of Cd-C0 (i.e. DBP) decreases over the arterial tree. In the same person, studies of ankle-brachial blood pressure (BP) differences revealed that PP greatly differed from brachium to ankle while DBPs were of minimal change or almost equivalent. However, DBP would be lower in those with arterial stiffness compared to others of the same age. Accordingly, APPD increases as arterial compliance decreases. Moreover, decreased APPD after a certain limit would reflect either local arterial stenosis or a compromised left ventricular function. When we divided ankle PP by ankle DBP, we could control the diversity of ankle PP as being not related to the BP level and possibly fluctuates in the same person. Additionally, APPD will indicate the extra rapid reflected pulse wave given in decreased DBP. Since increased common carotid artery intima-media thickness (CIMT) is a well-established marker of atherosclerosis, we initially studied 115 subjects apparently free form vascular diseases and had not taken a drug that can affect BP on the day of the study, aged 40-60 years, without a history of stroke, coronary heart disease or peripheral vascular disease to evaluate the relation between APPD and CIMT. The association was statistically significant even after adjusting for age, sex and important covariates and the area under the receiver operating characteristic curve was 0.902 ± 0.031. Therefore, the potential applicability of APPD as a tool for subclinical atherosclerosis was greatly proven.

Four-Limb Blood Pressure Measurement with an Oscillometric Device: a Tool for Diagnosing Peripheral Vascular Disease

PURPOSE OF REVIEW

Traditionally, the term peripheral vascular disease (PAD) is restricted to the occlusive arterial disease in the leg, but now, the connotation of PAD is more widespread as it encompasses all extracoronary and extracerebral vascular disease. The incidence of PAD is increasing worldwide; therefore, it is necessary to diagnose PAD at an early stage.

RECENT FINDINGS

Oscillometric BP device is widely used for four-limb measurement in clinical practice and provides several parameters for evaluating inter-limb BP difference, such as ankle-brachial index (OS-ABI), inter-arm BP differences (IAD), and inter-ankle BP difference (IAND). Using angiographic results as reference, the ABI, IAD, and IAND from an oscillometric BP device have been demonstrated having high accuracy for diagnosis of PAD. Meanwhile, combination of these parameters could further improve the accuracy of PAD, including the occlusive artery disease in the arm, leg, and aorta. For example, some patients with severe PAD in the leg have normal ABI; in this situation, an increased sIAND could confirm the diagnosis of PAD in the leg. Because ABI, IAD, and IAND from inter-limb oscillometric BP measurement can also predict adverse prognosis, we encourage the use of an oscillometric device to measure four-limb BP and to evaluate the inter-limb BP difference.

Investigation of Viscoelasticity in the Relationship Between Carotid Artery Blood Pressure and Distal Pulse Volume Waveforms

We investigated the relationship between carotid artery blood pressure (BP) and distal pulse volume waveforms (PVRs) via subject-specific mathematical modeling. We conceived three physical models to define the relationship: a tube-load model augmented with a gain (TLG), Voigt (TLV), and standard linear solid (TLS) models. We compared these models using PVRs measured via BP cuffs at an upper arm and an ankle as well as carotid artery tonometry waveform collected from 133 subjects. At both upper arm and ankle, PVR was related to carotid artery tonometry by TLV and TLS models better than by TLG model; when root-mean-squared over all the subjects, the systolic and diastolic BP errors between measured carotid artery tonometry waveform and the one estimated from distal PVR reduced from 4.3 mmHg and 4.6 mmHg (TLG) to 1.1 mmHg and 1.0 mmHg (TLS) for the upper arm (p < 0.0167), and from 2.1 mmHg and 1.7 mmHg (TLG) to 2.1 mmHg and 1.5 mmHg (TLV) for the ankle. Further, TLV and TLS models exhibited superior Akaike's Information Criterion (AIC) in both locations than TLG model. However, the difference between TLG versus TLV and TLS models associated with the ankle was not large. Therefore, the relationship of central arterial BP to arm PVR arises from both wave reflection and viscoelasticity while the relationship to ankle PVR mainly arises from wave reflection. These findings may imply that an effective subject-specific transfer function for estimating accurate central arterial BP from an arm PVR should account for the impact of viscoelasticity.

Valuation of Normal Range of Ankle Systolic Blood Pressure in Subjects with Normal Arm Systolic Blood Pressure

Subject

This study aimed to establish a normal range for ankle systolic blood pressure (SBP).

Methods

A total of 948 subjects who had normal brachial SBP (90-139 mmHg) at investigation were enrolled. Supine BP of four limbs was simultaneously measured using four automatic BP measurement devices. The ankle-arm difference (An-a) on SBP of both sides was calculated. Two methods were used for establishing normal range of ankle SBP: the 99% method was decided on the 99% reference range of actual ankle BP, and the An-a method was the sum of An-a and the low or up limits of normal arm SBP (90–139mmHg).

Results

Whether in the right or left side, the ankle SBP was significantly higher than the arm SBP (right: 137.1±16.9 vs 119.7±11.4 mmHg, P<0.05). Based on the 99% method, the normal range of ankle SBP was 94~181 mmHg for the total population, 84~166 mmHg for the young (18–44 y), 107~176 mmHg for the middle-aged(45–59 y) and 113~179 mmHg for the elderly (≥60y) group. As the An-a on SBP was 13mmHg in the young group and 20mmHg in both middle-aged and elderly groups, the normal range of ankle SBP on the An-a method was 103–153 mmHg for young and 110–160 mmHg for middle-elderly subjects.

Conclusion

A primary reference for normal ankle SBP was suggested as 100-165 mmHg in the young and 110-170 mmHg in the middle-elderly subjects.

The variability of ankle-arm blood pressure difference and ankle-brachial index in treated hypertensive patients

The purpose of this study was to investigate whether ankle-arm blood pressure (BP) difference (An-a) and ankle-brachial index (ABI) are consistent in treated hypertensive patients with obvious BP variation. This study enrolled 414 hypertensive patients (200 males; mean age, 61.3 ± 13.3 years) admitted to our hospital. BP of four limbs was simultaneously measured using four automatic BP measurement devices on the day of admission, and three and six day after admission. The An-a differences on systolic BP (SBP), diastolic BP (DBP), mean artery pressure (MAP), and pulse pressure (PP) in both sides were calculated, respectively. The relative decrease amplitude (RDA) of BP was calculated using the formula: RDA = (BP1 - BPn)/BP1. The ABI of the right side was calculated. From the first to the third measurement, arm SBP and DBP levels of both arms significantly decreased (right arm: SBP: 163.7 ± 18.4, 147.7 ± 15.3 vs. 135.4 ± 11.7 mm Hg; P < .05; DBP: 86.6 ± 13.4, 79.9 ± 11.6 vs. 74.5 ± 9.6 mm Hg; P < .05); at the same time, the ankle SBP (right ankle: 182.1 ± 22.1, 147.7 ± 15.3 vs. 153.4 ± 16.6 mm Hg; P < .05) and DBP (84.8 ± 13.4, 79.9 ± 11.6 vs. 75.8 ± 9.8 mm Hg; P < .05) of both sides also significantly decreased. The mean An-a of three measurements of both sides was consistent at the levels of about 20 mm Hg on SBP and PP, 7 mm Hg on MAP, and 0 mm Hg on DBP. However, sABI gradually increased from the first to the third measurement.In treated hypertensive patients, the An-a differences on SBP, DBP, PP, and MAP are generally consistent, but sABI is associated with underlying SBP levels.

High-density lipoproteins and cerebrovascular integrity in Alzheimer's disease

Cerebrovascular dysfunction significantly contributes to the clinical presentation and pathoetiology of Alzheimer's disease (AD). Deposition and aggregation of β-amyloid (Aβ) within vascular smooth muscle cells leads to inflammation, oxidative stress, impaired vasorelaxation, and disruption of blood-brain barrier integrity. Midlife vascular risk factors, such as hypertension, cardiovascular disease, diabetes, and dyslipidemia, increase the relative risk for AD. These comorbidities are all characterized by low and/or dysfunctional high-density lipoproteins (HDL), which itself is a risk factor for AD. HDL performs a wide variety of critical functions in the periphery and CNS. In addition to lipid transport, HDL regulates vascular health via mediating vasorelaxation, inflammation, and oxidative stress and promotes endothelial cell survival and integrity. Here, we summarize clinical and preclinical data examining the involvement of HDL, originating from the circulation and from within the CNS, on AD and hypothesize potential synergistic actions between the two lipoprotein pools.

Effect of systemic α1-adrenergic receptor blockade on central blood pressure response during exercise

The aortic pulse pressure (PP), which consists mainly of the incident wave and the reflected wave, has emerged as an important property of systemic blood vessels underlying the pathophysiology of cardiovascular disease. To determine the role of sympathetic nerve activity on the aortic PP response during dynamic exercise, we evaluated aortic hemodynamics during the right-leg knee-extension (40 and 60 % of maximal voluntary contraction) in six young adults with and without the systemic α1-adrenergic receptor blockade using prazosin (1 mg/20 kg body weight). The use of prazosin attenuated the exercise-induced increase in aortic PP (P < 0.05) but not in radial arterial PP. The amplitude of the reflected waves (via augmentation index) significantly decreased with the exercise and decreased more with the use of prazosin. These results suggest that during dynamic exercise the α1-adrenergic-mediated vasoconstrictor tone of the peripheral resistance vessels is manifestly involved in the magnitude of the reflected wave and the modulation of the aortic PP responses.

The prevalence and influence factors of inter-ankle systolic blood pressure difference in community population

Aim

The aim of this study was to investigate the prevalence of interankle systolic blood pressure difference (sIAND) and its influencing factors in community population.

Methods

This study included 2849 (65.1±9.4 y) subjects. Blood pressure (BPs) of four limbs was simultaneously measured with 4 electronic sphygmomanometers after 10 min rest in supine position. The difference of systolic BP (SBP) between two ankles was calculated as DETASBP. The criterion for abnormal sIAND was ≥10 mmHg of absolute DeltaSBP, in which the criterion for 1o sIAND was 10–19 mmHg and for 2o sIAND was ≥20 mmHg. Age, gender, smoking, hypertension, family histories of hypertension and diabetes were recorded. Fasting blood glucose and lipids, circumference of hip and waist, and body mass index (BMI) were measured.

Results

The SBP was higher in the right ankle than in the left ankle (158.9±21.8 vs 157.3±21.6 mmHg, P<0.05) and mean DeltaSBP was 6.08±6.26 mmHg. Similar difference was found in both genders. The prevalence of abnormal was 18.5%, in which, the prevalence 1o sIAND was 15.3% and that of 2o sIAND was 3.1%. Multivariate regression analysis showed that age, waist circumference and blood glucose level were the positive factors for DeltaSBP. The normal upper limit for DeltaSBP was 16.7 mmHg in this population, the prevalence of sIAND by≥16 mmHg was 5.8%.

Conclusion

Aging, hypertension, obesity and abnormal glucose metabolism are positive factors for inter-ankle SBP difference.

Watermelon extract supplementation reduces ankle blood pressure and carotid augmentation index in obese adults with prehypertension or hypertension

BACKGROUND

Ankle-brachial index (ABI) and ankle blood pressure (BP) are associated with increased carotid wave reflection (augmentation index, AIx). Oral L-citrulline and L-arginine from synthetic or watermelon sources have reduced brachial BP, aortic BP, and aortic AIx. A directly measured carotid AIx (cAIx) rather than aortic AIx has been proposed as a better measurement of central AIx. We evaluated the effects of watermelon extract on ankle BP and cAIx in individuals with normal ABI and prehypertension or stage 1 hypertension.

METHODS

Ankle and brachial systolic BP (SBP), diastolic BP (DBP), mean arterial pressure (MAP), cAIx, ABI, and heart rate (HR) were evaluated in the supine position in 14 adults (11 women/3 men, age 58 ± 1 years) with prehypertension or stage 1 hypertension (153 ± 4 mm Hg). Subjects were randomly assigned to 6 weeks of watermelon extract supplementation (L-citrulline/L-arginine, 6 g daily) or placebo followed by a 2-week washout period and then crossover.

RESULTS

Ankle and brachial SBP (-11.5 ± 3.8 and -15.1 ± 2.8 mm Hg), DBP (-7.8 ± 2.3 and -7.6 ± 1.8 mm Hg), and MAP (-9.8 ± 2.6 and -7.3 ± 1.8 mm Hg), and cAIx (-8.8 ± 2.6 %) decreased significantly (P < 0.05) after watermelon supplementation compared to placebo. Watermelon supplementation had no significant effect (P > 0.05) on ABI and HR.

CONCLUSIONS

This study shows that watermelon extract supplementation reduces ankle BP, brachial BP, and carotid wave reflection in obese middle-aged adults with prehypertension or stage 1 hypertension and normal ABI, which may reflect improved arterial function.

Non-steroidal anti-inflammatory drug (NSAID) related inhibition of aldosterone glucuronidation and arterial dysfunction in patients with rheumatoid arthritis: a cross-sectional clinical study

OBJECTIVE

Patients with rheumatoid arthritis (RA) are at increased risk of cardiovascular (CV) disease and are also commonly prescribed non-selective non-steroidal anti-inflammatory drugs (ns-NSAIDs). New in vitro evidence suggests that this increased CV risk may be mediated through aldosterone glucuronidation inhibition (AGI), which differs between NSAIDs (diclofenac>naproxen>indomethacin>ibuprofen). Our aim was to explore the association between ns-NSAID-related AGI and arterial dysfunction.

METHODS

The extent (augmentation index, AIX%) and timing (reflected wave transit time, RWT, ms) of aortic wave reflection (measured using radial applanation pulse wave analysis, PWA, SphygmoCor device) were assessed on a single occasion in 114 consecutive RA patients without overt CV disease aged 40-65 years. A higher AIX% and lower RWT indicate arterial dysfunction. Assessment included a fasting blood sample, patient questionnaire and medical record review. Multivariate analysis was used to adjust for age, sex, mean blood pressure, smoking, cumulative erythrocyte sedimentation rate (ESR-years) and Stanford disability score.

RESULTS

We identified 60 patients taking ns-NSAIDs and 25 non-users. Using a ns-NSAID with the highest AGI was associated with a higher AIX% (and lower RWT) versus treatment with a ns-NSAID with the lowest AGI (diclofenac AIX% 32.3, RWT 132.7 ms vs ibuprofen AIX% 23.8, RWT 150.9 ms): adjusted mean differences AIX% 6.5 (95% CI 1.0 to 11.9; p=0.02); RWT -14.2 ms (95% CI -22.2 to -6.3; p=0.001). Indomethacin demonstrated an intermediate level of arterial dysfunction. In relation to arterial dysfunction, both indomethacin and naproxen were more similar to diclofenac than to ibuprofen.

CONCLUSIONS

ns-NSAID-related AGI is associated with arterial dysfunction in patients with RA. These findings provide a potentially novel insight into the CV toxicity of commonly used ns-NSAIDs. However, the findings are limited by the small number of patients involved and require further replication in a much larger study.