Uric acid is an independent predictor of arterial stiffness in hypertensive patients

High Prevalence of Hyperuricemia and Associated Factors among Zhuang Adults: A Cross-Sectional Study Based on the Ethnic Minority Population Cohort in the Southwestern China

The highest prevalence of hyperuricemia was found in Zhuang minority adults in two national surveys in China, with only 1% Zhuang study subjects. However, the prevalence of hyperuricemia and the associated factors in Zhuang adults have not been well-addressed. A cross-sectional study was conducted to explore the prevalence of hyperuricemia and the common comorbidities, and the associated factors in Zhuang adults based on the Guangxi Ethnic Minority Population Cohort. Among 11,175 Zhuang adults aged 35-74 years, the age- and sex-standardized prevalence rate was 18.1% for hyperuricemia and 1.1% for gout. The standardized prevalence rate and awareness rate were 31.6% and 32.3%, respectively, for hypertension, and were 5.1% and 48.2%, respectively, for diabetes. High education level, history of coronary heart disease (CHD), hypertension, being a current drinker, high body mass index (BMI), central obesity, hyper-triglyceride (hyper-TG), hyper-total cholesterol (hyper-TC), hypo-high density lipoprotein cholesterol (hypo-HDL-C), and abnormal aspartate aminotransferase (AST) were risk factors, while smoking and diabetes were protective factors of hyperuricemia in males. Older age, being single/divorced, having a high education level, hypertension, drinking tea, high BMI, central obesity, hyper-TG, hyper-TC, hypo-HDL-C, and abnormal alanine aminotransferase (ALT) were risk factors in females. The high prevalence of hyperuricemia but low prevalence of gout and common comorbidities in Zhuang adults may be due to a lag effect of lifestyle changes. Health education and health management should be strengthened to prevent the progression of comorbidities, considering the lag effect and low awareness rate.

Inflammaging and Vascular Function in Metabolic Syndrome: The Role of Hyperuricemia

Background and Objectives: Early vascular aging determines a more rapid course of age-related arterial changes. It may be induced by a proinflammatory state, caused by hyperuricemia and metabolic syndrome and their interrelationship. However, the impact of serum uric acid (SUA) on early arterial stiffening and vascular function remains uncertain. Materials and Methods: A total of 696 participants (439 women aged 50–65 and 257 men aged 40–55) from the Lithuanian High Cardiovascular Risk (LitHiR) primary prevention program were enrolled in the study. They underwent anthropometric measurements and laboratory testing along with arterial parameters’ evaluation. Quality carotid stiffness (QCS), carotid-radial pulse wave velocity (crPWV), carotid-femoral pulse wave velocity (cfPWV), flow-mediated dilatation (FMD), and carotid intima-media thickness (CIMT) were registered. Results: We found that hyperuricemia was significantly associated with inflammation, registered by high-sensitivity C-reactive protein in both sexes. A very weak but significant association was observed between cfPWV and SUA in men and in women, while, after adjusting for risk factors, it remained significant only in women. A positive, weak, but significant association was also observed for QCS, both right and left in women. No relationship was observed between crPWV, FMD, CIMT, and SUA.

Carotid vascular strain predicts cardiovascular events in patients with hypertension

BACKGROUND

We aim to investigate prognostic effects of carotid strain (CS) and strain rate (CSR) in hypertension.

METHODS

We prospectively recruited 120 patients being treated for hypertension (65.8 ± 11.8 years, 58% male) in this observational study. Peak circumferential CS and peak CSR after ejection were identified using two-dimensional speckle tracking ultrasound. Major cardiovascular events were any admission for stroke, acute coronary syndrome, and heart failure.

RESULTS

After a mean follow-up period of 63.6 ± 14.5 months, 14 (12%) patients had cardiovascular events. Age (75.3 ± 9.2 vs 64.6 ± 11.6 years; p = 0.001), systolic blood pressure (131.8 ± 15.5 vs 143.1 ± 16.6 mm Hg; p = 0.021), diastolic blood pressure (74.6 ±11.4 vs 82.1 ± 12.2 mm Hg; p = 0.039), use of diuretics (71 vs 92%; p = 0.014), carotid CS (2.17 ± 1.02 vs 3.28 ± 1.14 %; p = 0.001), and CSR (.28 ± .17 vs .51 ± .18 1/s; p < 0.001) were significantly different between the patients who did and did not reach the end-points. Multivariate Cox regression analysis controlling for age, systolic blood pressure, diastolic blood pressure, and use of diuretics showed that CS (HR .425, 95%CI .223-.811, p = 0.009) and CSR (HR .001, 95%CI .000-.072, p = 0.001) were independent predictors for cardiovascular events.

CONCLUSION

In conclusions, decreased CS and CSR were associated with cardiovascular events in hypertension.

Carotid Plaques From Symptomatic Patients Are Characterized by Local Increase in Xanthine Oxidase Expression

[Figure: see text].

Effects of intensive urate lowering therapy with febuxostat in comparison with allopurinol on pulse wave velocity in patients with gout and increased cardiovascular risk: the FORWARD study

AIMS

Hyperuricaemia and gout are strongly related with traditional cardiovascular risk factors and vascular damage. This study aimed to assess whether febuxostat and allopurinol could differently influence carotid-femoral pulse wave velocity (cfPWV) in patients with gout and elevated serum uric acid (SUA) levels.

METHODS AND RESULTS

A multi-centre, multinational, phase IV, randomized, parallel-group, active-controlled, open label trial with blind end-points evaluation. One hundred and ninetyseven adults with gout and SUA levels ≥8 mg/dL were randomised to febuxostat or allopurinol in a 1:1 ratio for 36 weeks. The primary outcome was the comparison of the effects of febuxostat and allopurinol on changes in cfPWV. The mean cfPWV values at randomisation and week 36 were respectively 8.69 m/s and 9.00 m/s for subjects randomised to febuxostat and 9.02 m/s and 9.05 m/s for subjects randomised to allopurinol. No statistically significant changes in cfPWV by treatment assignment were observed at any time point for any of the assessed parameters. More subjects who received febuxostat had serum urate concentrations ≤6 mg/dL following treatment (78.3% vs 61.1% at week 36, p = 0.0137). Treatment-emergent adverse events were reported by 51 (52.0%) patients randomised to febuxostat and 63 (62.5%) patients randomised to allopurinol. The majority of events were mild in both treatment groups and included gout flares and arthralgia.

CONCLUSIONS

In patients with gout and elevated SUA levels the arterial stiffness remained stable both with febuxostat and allopurinol. Febuxostat was more effective and faster than allopurinol in achieving the SUA target. Both treatments were safe and well tolerated.

Uric Acid and Arterial Stiffness

Hyperuricemia is usually associated with hypertension, diabetes mellitus, metabolic syndrome and chronic kidney disease. Accumulating data from epidemiological studies indicate an association of increased uric acid (UA) with cardiovascular diseases. Possible pathogenic mechanisms include enhancement of oxidative stress and systemic inflammation caused by hyperuricemia. Arterial stiffness may be one of the possible pathways between hyperuricemia and cardiovascular disease, but a clear relationship between increased UA and vascular alterations has not been confirmed. The review summarizes the epidemiological studies investigating the relationship between UA and arterial stiffness and highlights the results of interventional studies evaluating arterial stiffness parameters in patients treated with UA-lowering drugs.

Presence of tophi is a predictive factor of arterial stiffness in patients with gout

The objective of this study is to determine whether the presence of tophi could predict an increase in arterial stiffness. Between June 2017 and June 2018, the augmentation index (AI) was measured using SphygmoCor^® for patients with gout who visited the Jeju National University Hospital in South Korea. Patients were divided into the following groups: group with tophi and group without tophi. Medical records, laboratory data, and AI were retrospectively analyzed. One hundred and twenty patients with gout or participated in the study, with most (96.7%) of the patients being male. The mean duration of the disease was 7.0 years. At the time of the examination, 99 patients (82.5%) were treated with a uric acid-lowering agent. Of the total patients, 24 (19.7%) had tophi. Patients with tophi were significantly older (60.2 ± 11.6 years vs. 53.8 ± 13.0 years, p = 0.031), had longer disease duration (13.0 ± 6.5 years vs 5.5 ± 5.4 years, p < 0.001), and higher AI@75 (28.7 ± 7.8 vs 20.9 ± 10.0, p = 0.001) than those without tophi. In the multiple linear regression analysis, tophi was shown to be a significant predictor of high AI (p = 0.040). The presence of tophi is a predictor of increased arterial stiffness in patients with gout. Therefore, more strict control of cardiovascular disease risk factors is needed in the treatment of patients with tophi.

Uric acid and the cardio-renal effects of SGLT2 inhibitors

Sodium/glucose co-transporter-2 (SGLT2) inhibitors, which lower blood glucose by increasing renal glucose elimination, have been shown to reduce the risk of adverse cardiovascular (CV) and renal events in type 2 diabetes. This has been ascribed, in part, to haemodynamic changes, body weight reduction and several possible effects on myocardial, endothelial and tubulo-glomerular functions, as well as to reduced glucotoxicity. This review evaluates evidence that an effect of SGLT2 inhibitors to lower uric acid may also contribute to reduced cardio-renal risk. Chronically elevated circulating uric acid concentrations are associated with increased risk of hypertension, CV disease and chronic kidney disease (CKD). The extent to which uric acid contributes to these conditions, either as a cause or an aggravating factor, remains unclear, but interventions that reduce urate production or increase urate excretion in hyperuricaemic patients have consistently improved cardio-renal prognoses. Uric acid concentrations are often elevated in type 2 diabetes, contributing to the "metabolic syndrome" of CV risk. Treating type 2 diabetes with an SGLT2 inhibitor increases uric acid excretion, reduces circulating uric acid and improves parameters of CV and renal function. This raises the possibility that the lowering of uric acid by SGLT2 inhibition may assist in reducing adverse CV events and slowing progression of CKD in type 2 diabetes. SGLT2 inhibition might also be useful in the treatment of gout and gouty arthritis, especially when co-existent with diabetes.

Uric acid: from a biological advantage to a potential danger. A focus on cardiovascular effects

Non-communicable diseases represent nowadays the most common cause of death worldwide, having largely overcome infectious diseases. Among them, cardiovascular diseases constitute the majority. Given these premise, great efforts have been made by scientific societies to emphasize the fundamental role of cardiovascular prevention and risk factors control. In addition to classical cardiovascular risk factors such as smoking, arterial hypertension, hypercholesterolemia and male gender, new risk factors are emerging from international literature. Among them, uric acid is the protagonist. Several evidences show a direct role of hyperuricemia in the determinism of metabolic and vascular disorders. From the other hand, some researchers have demonstrated that uric acid is only a marker of cardiovascular damage and not a risk factor for its development. Aim of this review is to evaluate the scientific evidences on the role of uric acid in cardiovascular diseases in order to shed light on this confusing topic.

Pegloticase Treatment Significantly Decreases Blood Pressure in Patients With Chronic Gout

Serum urate is correlated with blood pressure (BP), and lowering urate may decrease BP, but a consistent effect has not been observed. Here, we evaluated whether pegloticase, a recombinant uricase conjugated to polyethylene glycol, which can lead to persistently low serum urate levels (<1 mg/dL), can modulate BP in subjects with chronic refractory gout. This post hoc analysis used results from two 6-month randomized clinical trials in which subjects were treated with 8 mg pegloticase every 2 or 4 weeks (q2w or q4w) or placebo. Responders in this study were defined as those individuals in whom a persistently low urate level (<6 mg/dL and usually <1 mg/dL) was maintained. Serial sitting BP was measured in 173 subjects, and estimated glomerular filtration rate was determined at baseline and after 3 and 6 months. Significant reductions in mean arterial pressure (MAP) from baseline to 6 months were noted in q2w responders ( P=0.0028), whereas reductions in MAP in other groups were not significant. Significant decreases in both systolic and diastolic BP paralleled the change in MAP. Of the 62% of q2w responders exhibiting persistent decreases in MAP, there were no significant differences in baseline age, sex, race, weight, body mass index, history of hypertension, hyperlipidemia, history of coronary artery disease, gout duration, MAP, serum urate, estimated glomerular filtration rate or urinary uric acid/creatinine ratio compared with those who did not lower MAP. No significant changes in estimated glomerular filtration rate occurred in any of the groups during the study. Responders to biweekly pegloticase who maintained a persistently lower serum urate level throughout the trial experienced significant reductions in both systolic and diastolic BP that were independent of changes in renal function. Clinical Trial Registration- URL: http://www.clinicaltrials.gov . Unique identifier: NCT00325195.

Uric acid association with pulsatile and steady components of central and peripheral blood pressures

OBJECTIVE

Whether the cardiovascular risk attributed to elevated uric acid levels may be explained by changes in central and peripheral pulsatile and/or steady blood pressure (BP) components remains controversial.

METHODS

In a cross-sectional analysis of normotensive and untreated hypertensive participants of the CARTaGENE populational cohort, we examined the relationship between uric acid, and both pulsatile and steady components of peripheral and central BP, using sex-stratified linear regressions.

RESULTS

Of the 20 004 participants, 10 161 individuals without antihypertensive or uric acid-lowering drugs had valid pulse wave analysis and serum uric acid levels. In multivariate analysis, pulsatile components of BP were not associated with uric acid levels, whereas steady components [mean BP (MBP), peripheral and central DBP] were all associated with higher levels of uric acid levels in women and men (all P < 0.001). Furthermore, there was a gradual increase of central SBP (cSBP), DBP and MBP from the lowest to the highest quintiles of uric acid levels but not for MBP-adjusted cSBP. Peripheral and cSBP, which are aggregate measures of pulsatile and steady BP, were also associated with uric acid levels in women (β = 0.063 and 0.072, respectively, both P < 0.001) and men (β = 0.043 and 0.051, both P ≤ 0.003). After further adjustments for MBP to account for the concomitant increase in steady component of BP, SBPs were no longer associated with uric acid levels.

CONCLUSION

Serum uric acid levels appear to be associated with both central and peripheral steady but not pulsatile BP, regardless of sex.

Association between previous schistosome infection and incident hyperuricemia: A prospective cohort study in China

Background

More than 11 million people were estimated to be infected by Schistosoma japonicum in China before the 1950s. However, seldom studies have been conducted to evaluate the longitudinal effects of previous schistosome infection (PSI). We aimed to investigate the association between PSI and hyperuricemia in China.

Methods

From February 2013 to October 2013, 3,517 Chinese subjects (908 persons with PSI and 2,609 persons without PSI) were recruited from a prospective cohort study of “135”. After two years, 113 and 462 participants had developed hyperuricemia in the persons with and without PSI, respectively. Multivariable logistic models were used to estimate Relative Ratios (RR) and 95% confidence intervals (CIs) for hyperuricemia.

Results

The PSI participants had a decreased risk of hyperuricemia compared with those without PSI [adjusted RR (95%CI): 0.73 (0.55, 0.97)]. Within the PSI group, higher level of fasting plasma glucose was significantly associated with the reduced incidence of hyperuricemia in PSI population (RR: 0.40, 95% CI: 0.26–0.63). For females, hypertension, increased levels of serum creatinine and triglycerides were the risk factors for incident hyperuricemia in the PSI group.

Conclusions

Our results suggest that PSI is significantly associated with the lower incidence of hyperuricemia. Moreover, elevated fasting plasma glucose might prevent the onset of hyperuricemia in PSI population.

The baseline levels and risk factors for high-sensitive C-reactive protein in Chinese healthy population

BACKGROUND

Recent studies show that C-reactive protein (CRP) is not only a biomarker but also a pathogenic mediator contributing to the development of inflammation and ageing-related diseases. However, serum levels of CRP in the healthy ageing population remained unclear, which was investigated in the present study.

METHODS

Serum levels of high sensitive C-reactive protein (hs-CRP), glucose (Glu), triglyceride (TG), cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-c), low-density lipoprotein cholesterol (LDL-c), superoxide dismutase (SOD), serum creatinine (SCr), serum uric acid (SUA) were measured in 6060healthy subjects (3672 male and 2388 female, mean age:45.9 years) who received routine physical examination at Sun Yat-sen Memorial Hospital, Guangzhou, China.

RESULTS

In total of 6060 healthy people, serum levels of hs-CRP were significantly increased with ageing (P < 0.05), particularly in those with age over 45-year-old (1.31[0.69-2.75] vs 1.05[0.53-2.16]mg/L, P < 0.001). Interestingly, levels of serum hs-CRP were significantly higher in male than female population (1.24[0.65-2.57] vs 1.07[0.53-2.29]mg/L, P < 0.001). Correlation analysis also revealed that serum levels of hs-CRP positively correlated with age and SUA, but inversely correlated with serum levels of HDL-c and SOD (all P < 0.05).

CONCLUSIONS

Baseline levels of serum hs-CRP are increased with ageing and are significantly higher in male than female healthy population. In addition, elevated serum levels of hs-CRP are also associated with increased SUA but decreased HDL-c and SOD. Thus, serum levels of hs-CRP may be an indicator associated with ageing in healthy Chinese population.

Assessment of Arterial Stiffness in Stable Heart Transplant Recipients

INTRODUCTION

Arterial stiffness depends on both genetic and environmental factors. The aim of this study was to assess arterial stiffness in patients after heart transplant.

METHODS

The study was conducted between May and June 2017. Fifty patients from the Transplantology Clinic of the Institute of Cardiology in Anin, Warsaw, Poland, were enrolled in the study. Pulse wave velocity (PWV), central systolic blood pressure (CSBP), and central diastolic blood pressure (CDBP) were measured and patients' medical records were also analyzed.

RESULTS

In the study, 50 patients aged 57.9 years on average were evaluated, of whom 88% were male patients, with average PWV of 8.94 m/s and an average time after transplant of 9.7 years. The study has shown that age (R = 0.77), total cholesterol concentration (R = 0.22, P = .017) and creatinine concentration (R = 0.34; P = .15) show positive correlation with PWV.

CONCLUSIONS

Our data indicates that age has significant impact on arterial stiffness and the type of immunosuppressive drugs and transplant rejection episodes do not impact an increase in arterial stiffness.

Association between serum uric acid and arterial stiffness in a low-risk, middle-aged, large Korean population: A cross-sectional study

We investigated the association between serum uric acid (SUA) and brachial ankle pulse wave velocity (baPWV) in an apparently healthy population. We performed a cross-sectional study on middle-aged Koreans who completed a yearly health-screening program between January and December 2014. Subjects with coronary artery disease, diabetes, or hypertension were excluded. Linear regression analyses were used to study the relationship between SUA and baPWV. Multiple adjustments were made for variables based on clinical or statistical significance. Of 66,917 study participants (38,170 men and 28,747 women), the mean age was 39.4 ± 6.7 years and the average SUA level was 5.23 ± 1.4 mg/dL. SUA values were higher in men than in women (6.1 ± 1.2 mg/dL vs. 4.1 ± 0.8 mg/dL). SUA was linearly associated with baPWV in women and in men (P < .001, respectively). Multiple regression analyses remained significant for women with a positive association with baPWV across SUA quintiles in a dose-response manner (P < .001) while no longer for men with a J-shaped association between SUA quintiles and baPWV. When SUA modeled continuously, baPWV rose by 12.413 cm/s in women (P < .001) and by 6.588 cm/s in men (P < .001) for each 1 mg/dL increase of SUA. In a low-risk, middle-aged, large Korean population, higher SUA levels could have an unfavorable impact on arterial stiffness as measured by baPWV, and this association was stronger in women than in men.

Assessment of Metabolic Syndrome and Clinical Significance of Brachial-Ankle Pulse Wave Velocity in Type 2 Diabetes Mellitus Patients

Background and Aims: Metabolic syndrome (MS) is a constellation of various CVD risk factors comprised of abdominal obesity, glucose intolerance, hyperinsulinemia, hypertension and dyslipidemia. The present study was aimed to assess the prevalence of MS in type 2 diabetes mellitus (T2DM) patients, and to evaluate the clinical significance of brachial-ankle pulse wave velocity in these patients.

Methods: The sample comprised of 251 T2DM patients. MS was evaluated in all the studied subjects according to NCEP-ATP III, IDF and JIS criteria. The subjects were screened for demographic as well as clinical characteristics.

Results: Prevalence of MS was estimated to be 65%, 69% and 75% according NCEP-ATP-III, IDF and JIS criteria respectively. JIS criteria was only preceded for further analysis as it explained the highest prevalence and also showed the better level of agreement (0.862) with IDF criteria. Abdominal obesity was the most frequent component of MS in the studied subjects. Moreover, 20.21% of MS subjects were found to have very high risk of cardiovascular disease (CVD) / future mortality according to different combinations of brachial-ankle pulse wave velocity (baPWV) and ankle brachial index (ABI).

Conclusions: The study revealed an increased prevalence of MS in the studied subjects. Risk of CVD may be better explained when these subjects were segregated according to different combinations of baPWV and ABI.

A higher baseline plasma uric acid level is an independent predictor of arterial stiffness: A community-based prospective study

Hyperuricemia has been demonstrated to be a risk factor for cardiovascular diseases. Though the association between uric acid (UA) and arterial stiffness has been investigated previously in patients with basic diseases, the predictive value of baseline UA level for arterial stiffness has not been conducted. We aimed at identifying the predictive role of UA for arterial stiffness prospectively.A longitudinal follow-up study in a routine health check-up population was performed with an average follow-up of 4.8 years. The demographic information, baseline and follow-up anthropometric parameters, arterial stiffness (pulse-wave velocity, PWV), and biomarker variables including UA have been measured and analyzed.A total of 1447 valid follow-ups were available for the final analysis. Both of the baseline and follow-up UA levels were significantly higher in the arterial stiffness groups than that in the nonarterial stiffness groups (all P values <0.001). The follow-up carotid-femoral PWV [(cf-PWV), r = 0.161, P < 0.001] was strongly correlated with baseline UA. At the follow-up cross-section, cf-PWV was also closely associated with UA (r = 0.101, P < 0.001). Logistic regressions revealed that a higher baseline UA level was an independent predictor of follow-up arterial stiffness assessed by cf-PWV [odds ratio (OR): 1.824; P = 0.046].A higher baseline level of UA is closely related to arterial stiffness and is an independent predictor of arterial stiffening.

Longitudinal Association Between Serum Uric Acid and Arterial Stiffness: Results From the Baltimore Longitudinal Study of Aging

Serum uric acid (SUA) has long been associated with increased cardiovascular risk, with arterial stiffness proposed as a mediator. However, evidence on the association between SUA and arterial stiffness is limited to contradicting cross-sectional studies. In this analysis, we examined the longitudinal relationship between SUA and pulse wave velocity, a measure of arterial stiffness, in a community-dwelling population. We studied 446 women and 427 men participating in the BLSA (Baltimore Longitudinal Study of Aging), with 1409 and 1434 observations, respectively, over an average period of 6 years. At baseline, mean ages of women and men were 65±13 and 68±13 years; mean SUA, 4.6±1.1 and 5.7±1.3 mg/dL; mean pulse wave velocity, 8.1±1.7 and 8.6±1.9 m/s, respectively (P<0.0001). In gender-stratified models accounting for age, blood pressure, renal function, metabolic measures, and medications, there was a significant interaction between SUA and follow-up time in men (β=0.69; P=0.0002) but not in women. Men, but not women, in the highest gender-specific SUA tertile at baseline (SUA≥6.2 mg/dL in men and SUA≥4.9 mg/dL in women) had a greater rate of pulse wave velocity increase over time than those in the lowest tertiles (β=0.997; P=0.012). This gender difference was lost when the distribution of SUA in men and women was made comparable by excluding hyperuricemic men (SUA≥6.2 mg/dL). In conclusion, higher SUA was associated with greater increase in pulse wave velocity in men but not women; this association was lost when men with SUA≥6.2 mg/dL were not included, suggesting a threshold for SUA association with arterial stiffness, which is more frequently reached in men.

Serum Bilirubin Is Inversely Associated with Increased Arterial Stiffness in Men with Pre-Hypertension but Not Normotension

OBJECTIVE

Serum bilirubin level has shown to be inversely associated with coronary atherosclerosis, and may serve as a protective biomarker of coronary artery disease. Serum bilirubin has also been shown to be negatively associated with brachial-ankle pulse wave velocity (baPWV) in men without a history of hypertension, and in men with hypertension. It is unknown whether such associations can be observed in the pre-hypertensive or normotensive population. This study thus aimed to investigate the relationship between serum bilirubin level and increased arterial stiffness in subjects with pre-hypertension and normotension for both genders.

METHODS

A cross-sectional sample of 3,399 apparently healthy subjects undergoing a medical check-up at National Cheng Kung University Hospital was enrolled between October 2006 and August 2009, after excluding subjects with serum total bilirubin level greater than 20.52 μmol/L. Increased arterial stiffness was defined as baPWV of 1,400 cm/s or higher as the dichotomous variable and bilirubin as the continuous variable.

RESULTS

Based on multiple linear regression analysis, serum bilirubin level was inversely associated with baPWV in non-hypertensive men (β = -0.066, p < 0.001) but not in non-hypertensive women. In addition, the inverse relationship between bilirubin level and baPWV was found statistically significant only in pre-hypertensive men (β = -0.110, p < 0.001). Multiple logistic regression analysis showed that serum bilirubin was inversely associated with increased arterial stiffness in men with pre-hypertension (odds ratio = 0.955, 95% confidence interval = 0.916-0.996, p < 0.05) but not normotension after adjustment for other confounding factors. However, the relationship between total bilirubin level and increased arterial stiffness did not reach statistical significance for female subjects with pre-hypertension and normotension.

CONCLUSION

Serum bilirubin is inversely associated with increased arterial stiffness in men with pre-hypertension but not normotension. The association between bilirubin level and arterial stiffness was not found significant in women.

Association of Uric Acid With Vascular Stiffness in the Framingham Heart Study

BACKGROUND

Uric acid is associated with increased risk of cardiovascular disease and arterial stiffness in patients with hypertension or stroke. It remains unknown if uric acid is associated with arterial stiffness in the general population.

METHODS

We analyzed the association between serum uric acid levels and measures of arterial stiffness such as carotid-femoral pulse wave velocity (CF PWV), carotid-radial pulse wave velocity (CR PWV) and augmentation index (AI) in 4,140 participants from the Generation 3 Framingham cohort using linear regression.

RESULTS

Mean (SD) age was 40.0 (8.8) years and mean (SD) serum uric acid levels were 5.3 (1.5) mg/dl. Mean (SD) CF PWV was 7.0 (1.4) m/s. Individuals in the highest quartile of uric acid were more likely to be male, have a higher prevalence of hypertension, higher BMI, fasting glucose and insulin, and lower estimated glomerular filtration rate (eGFR). Multivariate adjusted means of CF PWV were 6.90, 6.94, 7.06, and 7.15 m/s for uric acid quartile 1, 2, 3, and 4 respectively. In unadjusted analysis each 1mg/dl increase in uric acid was associated with higher CF-PWV (β = 0.27; 95% CI = 0.25, 0.29; P < 0.0001). This was attenuated but remained significant after adjusting for age, sex, smoking, hypertension, BMI, fasting glucose, insulin, animal protein intake, and eGFR (β= 0.06; 95% CI = 0.02, 0.09; P < 0.0007). There was no association between serum uric acid levels and AI upon adjustment for cardiovascular risk factors.

CONCLUSIONS

Serum uric acid levels are significantly associated with CF PWV and CR PWV in a younger Caucasian population.

Uric acid as a biomarker and a therapeutic target in diabetes

Diabetic nephropathy is a long-standing microvascular complication of diabetes mellitus and is the leading cause of end stage renal disease in developed countries. Current therapeutic strategies used to prevent or delay diabetic nephropathy exert limited clinical protective effects and can have serious adverse effects. Thus, identification of new pharmacologic agents that protect against the initiation and progression of complications of diabetes is of the utmost importance. Uric acid (UA) recently emerged as an inflammatory factor that increases oxidative stress and promotes activation of the renin angiotensin aldosterone system. As a consequence, higher UA levels are associated with various stages of the onset and progression of diabetic nephropathy, including metabolic, cardiovascular and kidney function abnormalities. If UA-lowering drugs, such as the xanthine oxidase inhibitors, block the mechanisms responsible for micro- and macrovascular injury in diabetes, these agents could represent a critical step toward preventing the progression of diabetes. This review focuses on the evidence that supports serum UA levels as a biomarker of renal and cardiovascular risk and as a potential additional therapeutic target in diabetes.

Associations of non-high density lipoprotein cholesterol and traditional blood lipid profiles with hyperuricemia among middle-aged and elderly Chinese people: a community-based cross-sectional study

Background

Increased serum uric acid (SUA) is associated with dyslipidemia. However, there are conflicting data about the role of single lipid species including non-high density lipoprotein cholesterol (non-HDL-C) in promoting SUA accumulation. Here, we aimed to compare non-HDL-C with other traditional blood lipid profiles in relation to hyperuricemia in a middle-aged and elderly Chinese population.

Methods

Data was collected from 9580 participants undergoing routine physical examinations in Xiangcheng district of Suzhou. SUA, total cholesterol (TC), triglyceride (TG), low density lipoprotein cholesterol (LDL-C), and high density lipoprotein cholesterol (HDL-C) were examined for all participants. Non-HDL-C was calculated by subtracting HDL-C from TC. The associations of blood lipid profiles with hyperuricemia were examined in men and women, respectively. The areas under Receiver Operating Characteristic (ROC) curves (AUCs) were compared to assess the discriminatory value of blood lipid parameters for predicting hyperuricemia.

Results

All blood lipid parameters significantly correlated with SUA (all P values <0.001). The correlation coefficient between SUA and TG was the highest in both genders. The correlation coefficient of non-HDL-C was higher than HDL-C in males and was higher than TC and LDL-C but followed HDL-C in females. In male group, AUC of TG (0.659) was greater than that of non-HDL-C (0.595) (P values <0.001). The AUC values of HDL-C, TC and LDL-C were lower; respectively 0.581, 0.559 and 0.552. In female group, AUC was highest for TG (0.678) followed by HDL-C (0.616), non-HDL-C (0.610), LDL-C (0.559) and TC (0.557) (all P values < 0.001).

Conclusions

In both genders, serum TG has the strongest association with hyperuricemia among blood lipid parameters. Non-HDL-C is also significantly associated with hyperuricemia.

Relationships between mild hyperuricaemia and aortic stiffness in untreated hypertensive patients

BACKGROUND AND AIMS

Clinical studies exploring the relationship between serum uric acid (SUA) and arterial stiffness yielded conflicting results. Only in a few of these studies, arterial distensibility was examined by measuring aortic pulse wave velocity (PWV), which is considered the gold standard for evaluating arterial stiffness. In none of the previous investigations was the influence of SUA on aortic distensibility assessed, taking into account the effect of albuminuria. The purpose of our study was to comprehensively analyse the relationships between SUA and aortic PWV in a group of essential hypertensive patients.

METHODS AND RESULTS

We enrolled 222 untreated and uncomplicated hypertensive subjects (mean age: 44 ± 10 years; 60% males), without gout. In all patients, SUA and urinary albumin excretion rate (AER) were determined. Moreover, carotid-femoral (c-f) PWV was measured. C-f PWV was significantly higher in hypertensive patients belonging to the uppermost tertile of SUA distribution, compared to subjects of the lowest tertiles (10.9 ± 2.2 vs. 10 ± 1.8 vs. 9.9 ± 1.7 m s(-1); p = 0.001). In univariate analysis, SUA correlated with c-f PWV (r = 0.24; p < 0.001). This association disappeared when AER was added in a multiple regression model, including SUA, age, mean arterial pressure, gender, metabolic syndrome components and glomerular filtration rate.

CONCLUSION

The results of our study showed that, in essential hypertensive subjects, there is a positive relationship between mild hyperuricaemia and aortic stiffness. This association weakened after adjustment for covariates and lost statistical significance after further correction for albuminuria.

Interaction of inflammation, hyperuricemia, and the prevalence of hypertension among adults free of metabolic syndrome: NHANES 2009-2010

Background

Hyperuricemia and markers of inflammation are correlated with the risk for hypertension. Whether hyperuricemia has any impact on the association between C‐reactive protein (CRP) and hypertension is not known.

Methods and Results

We analyzed cross‐sectional data from the National Health and Nutrition Examination Survey, 2009–2010, using ordinary least squares and logistic regression models. Those who met the criteria for metabolic syndrome, had self‐reported gout, or were <20 years old were excluded. For each 1‐SD increase in serum urate, the serum CRP concentration was 20% higher in unadjusted linear regression models and 13% higher in multivariable linear regression models, after accounting for the effects of age, sex, race, socioeconomic and educational strata, renal function, lipids, smoking, and body mass index. In multivariable models adjusting for the same covariates, hyperuricemia was associated with hypertension with an odds ratio of 2.21 (1.71 to 2.85). When analyzed separately, this was observed in men and women. In multivariable analyses of the overall sample, elevated CRP levels were not associated with hypertension.

Conclusions

Among adults free of metabolic syndrome, elevated uric acid, but not elevated CRP, is independently associated with prevalent hypertension.

Serum uric acid concentration and asymptomatic hyperuricemia with subclinical organ damage in general population

We assessed the effect of increased serum uric acid (SUA) concentration and hyperuricemia on subclinical organ damage. A cross-sectional examination of 1243 asymptomatic patients aged 55 to 84 years was conducted from September to October 2012. All participants underwent the measurements of SUA and other established cardiovascular (CV) risk factors. A morning spot urine sample was collected to detect microalbuminuria, and carotid plaque was scanned by B-mode ultrasound; the cardioankle vascular index and ankle-brachial index were obtained to evaluate arterial stiffness and peripheral artery disease (PAD), respectively. After adjustment for established CV risk factors, multiple logistic regression analyses showed that the highest quartile of SUA concentration and hyperuricemia had an independent association with PAD (respective odds ratios: 3.86 [1.26-11.83] and 2.33 [1.14-4.77]); this association maintained significantly in males but disappeared in females. Serum uric acid concentration and hyperuricemia are significantly associated with PAD in males.

Relationship between uric acid and vascular structure and function in hypertensive patients and sex-related differences

BACKGROUND

We sought to analyze the relationship between uric acid (UA) and vascular structure and function based on the carotid intima-media thickness, the pulse-wave velocity (PWV), the central arterial pressure, and the augmentation index in hypertensive patients and to evaluate the sex-related differences.

METHODS

A cross-sectional study was performed with 366 hypertensive individuals aged 34-75 years (men = 61.74%). The vascular structure was assessed based on the carotid intima-media thickness, the arterial stiffness was assessed by PWV, and the vascular function was assessed using hemodynamic parameters such as the central and peripheral augmentation index and the ambulatory arterial stiffness index (AASI).

RESULTS

In the bivariable analysis, the PWV (r = 0.28; P < 0.01) and AASI (r = 0.25; P < 0.01) were positively correlated with UA in women. The central augmentation index (r = -0.16; P < 0.05) and peripheral augmentation index (r = -0.18; P < 0.05) were negatively correlated with UA, whereas the maximum carotid intima-media thickness (r = 0.11; P < 0.05) was positively correlated with UA in the global analysis. In the multiple linear regression analysis, a positive association between PWV and UA was observed after adjusting for classical risk factors (β = 0.27; P = 0.01) in women only. In turn, a negative association was observed between the AASI and UA after adjusting for confounders in men (β = -0.06; P = 0.04), with a positive association in women (β = 0.11; P = 0.03).

CONCLUSIONS

Serum UA showed a positive correlation with the mean maximum intima-media thickness and PWV, and this parameter showed a negative correlation with the central and peripheral augmentation indices, although this relationship was lost after adjusting for confounding factors. AASI showed a positive association in women and a negative association in men after adjusting for confounding factors.

CLINICAL TRIALS REGISTRATION

Clinical Trials.gov Identifier: NCT01325064.

Associations of serum uric acid levels with arterial wave reflections and central systolic blood pressure

BACKGROUND

Uric acid may be involved in the pathogenesis of hypertension. We investigated the roles of four major hemodynamic parameters of blood pressure, including arterial stiffness, wave reflections, cardiac output (CO), and total peripheral resistance (TPR), in the association between uric acid and central systolic blood pressure (SBP-c).

METHODS

A sample of 1303 normotensive and untreated hypertensive Taiwanese participants (595 women, aged 30-79 years) was drawn from a community-based survey. Study subjects' baseline characteristics, biochemical parameters, carotid-femoral pulse wave velocity (cf-PWV), amplitude of the backward pressure wave decomposed from a calibrated tonometry-derived carotid pressure waveform (Pb), CO, TPR, and SBP-c were analyzed.

RESULTS

In multi-variate analyses adjusted for age, waist circumference, body mass index, creatinine, total cholesterol, smoking, and heart rate, uric acid significantly correlated with Pb and cf-PWV in men, and Pb and TPR in women. The correlation between uric acid and Pb remained significant in men and women when cf-PWV was further adjusted. In the final multi-variate prediction model (model r(2)=0.839) for SBP-c, the significant independent variables included uric acid (partial r(2)=0.005), Pb (partial r(2)=0.651), cf-PWV (partial r(2)=0.005), CO (partial r(2)=0.062), TPR (partial r(2)=0.021), with adjustment for age, sex, waist circumference, body mass index, creatinine, total cholesterol, smoking, and heart rate.

CONCLUSIONS

Uric acid was significantly independently associated with wave reflections, which is the dominant determinant of SBP-c. Uric acid was also significantly associated with SBP-c independently of the major hemodynamic parameters.

Relationships between serum uric acid, adiponectin and arterial stiffness in postmenopausal women

OBJECTIVES

Cardiovascular disease (CVD) is a leading cause of death in postmenopausal women. Elevated serum uric acid levels, hypoadiponectinemia and arterial stiffness are strongly associated with cardiovascular diseases. We investigated the relationships among uric acid, adiponectin and arterial stiffness in postmenopausal women.

STUDY DESIGN

9555 subjects who had the routine health check-ups, 841 postmenopausal women aged 50 years or older who had not had a menstrual period for more than 12 consecutive months were included in this study.

MAIN OUTCOME MEASURES

BMI, WC, and serum concentrations of uric acid, adiponectin, glucose, lipids (total cholesterol, triglycerides, LDL cholesterol, and HDL cholesterol) were measured. Insulin resistance was estimated by the insulin resistance index of homeostasis model assessment (HOMA-IR). Pulse wave velocity (PWV) was evaluated to assess arterial stiffness.

RESULTS

The subjects were stratified into three groups according to uric acid values. PWV values gradually increased and adiponectin level decreased with uric acid tertiles. Serum uric acid levels in postmenopausal women correlated significantly with age, BMI, WC, TG, HDL-C, insulin, HOMA-IR, adiponectin and PWV. Multiple regression analysis showed that WC (β=0.141, P<0.01), HOMA (β=0.137, P<0.01), adiponectin (β=-0.104, P<0.01), and PWV (β=0.129, P<0.01) were independently correlated with uric acid levels. In multiple logistic regression analysis after adjusting for risk factors, uric acid was a significant contributor to increased PWV.

CONCLUSIONS

These findings indicate that serum uric acid is independently associated with adiponectin and arterial stiffness in postmenopausal women.

Association between Serum Uric Acid Levels and Sleep Variables: Results from the National Health and Nutrition Survey 2005-2008

Sleep disordered breathing as well as high serum uric acid levels are independent risk factors for cardiovascular disease. However, studies evaluating the relationship between sleep-disordered breathing and hyperuricemia are limited. We examined the 2005-2008 National Health and Nutrition Examination survey's sleep variables and high serum uric acid among 6491 participants aged ≥20 years. The sleep variables included sleep duration, snoring, snorting, and daytime sleepiness. The main outcome was high serum uric acid level, defined as levels of serum uric acid >6.8 mg/dL in males and >6.0 mg/dL in females. We found that snoring more than 5 nights per week, daytime sleepiness, and an additive composite score of sleep variables were associated with high serum uric acid in the age- , sex-adjusted model and in a multivariable model adjusting for demographic and lifestyle/behavioral risk factors. The association was attenuated with the addition of variables related to clinical outcomes such as depression, diabetes, hypertension, and high-cholesterol levels. Our results indicate a positive relationship between sleep variables, including the presence of snoring, snorting, and daytime sleepiness, and high serum uric acid levels.

Decreased estimated glomerular filtration rate (eGFR) is not an independent risk factor of arterial stiffness in Chinese women

Recent studies suggest that decreased estimated glomerular filtration rate (eGFR) and uric acid (UA) may be independent risk factors for arterial stiffness (AS). As serum UA level is linked to renal function, we hypothesize that decreased eGFR may be not an independent risk factor of AS, but may be related to UA level. In this study, we aimed to validate this hypothesis in a large community-based Chinese population. A total of 13,899 people were selected from the Cardiovascular Risk Survey (CRS) from October 2007 to March 2010. Pulse wave velocity (PWV) was calculated using the established methods. The relationships between eGFR, fasting blood glucose (FBG), UA and PWV were analyzed with multivariate linear regression. We found that PWV was significantly correlated to FBG (r = 0.173, p < 0.001) and UA (r = 0.177, p < 0.001), and inversely correlated to eGFR (r = - 0.161, p < 0.001). A multivariable regression analysis revealed that FBG (β = 0.056, p < 0.001) and UA (β = 0.039, p < 0.001), but not eGFR (β = - 0.011, p = 0.062) were significantly related to elevation of PWV. In women, eGFR was not an independent risk factor of AS with progressively decreasing renal function (all p > 0.05). However, in men, eGFR was associated with PWV in subjects with eGFR < 60 ml/min/1.73 m(2). Our results suggest that decreased eGFR is not independently associated with AS in Chinese women.

Relationship between serum uric acid and internal carotid resistive index in hypertensive women: a cross-sectional study

Background

The impact of serum uric acid (SUA) on arteries of hypertensive subjects remains to be fully established. This study investigated the relationship between SUA and carotid structural and hemodynamic parameters in hypertensive men and women.

Methods

Three hundred and thirty eight patients (207 women and 131 men) were cross-sectionally evaluated by clinical, laboratory, hemodynamic and carotid ultrasound analysis. Common carotid diameters, circumferential wall tensions, Young’s Elastic Modulus, Stiffness Index, Arterial Compliance and intima-media thickness (IMT) were determined. Internal carotid artery resistive index (ICRI), a hemodynamic measure that reflects local vascular impedance and microangiopathy, was also assessed.

Results

Univariate analysis showed no significant correlation of SUA with carotid diameters, elasticity/stiffness indexes, IMT and circumferential wall tensions in both genders. Conversely, SUA correlated with ICRI (r = 0.34; p < 0.001) in women, but not in men, and hyperuricemic women presented higher ICRI than normouricemic ones (0.684 ± 0.007 vs. 0.649 ± 0.004; p < 0.001). Stepwise and logistic regression analyses adjusted for potential confounding factors showed that ICRI was independently associated with SUA and hyperuricemia in women.

Conclusions

This study demonstrated that SUA was associated with ICRI in hypertensive women, suggesting that there might gender-related differences in the relationship between SUA and vascular damage in subjects with systemic hypertension.

Significance of high-normal serum uric acid level as a risk factor for arterial stiffness in healthy Korean men

A high serum uric acid (SUA) level is a known risk factor for cardiovascular disease. However, little is known about the relationship between arterial stiffness and uric acid in healthy subjects with a normal SUA level. We assessed whether a high-normal uric acid level increased arterial stiffness by measuring brachial-ankle pulse wave velocity (ba-PWV) in healthy subjects. Among 779 subjects who visited the health promotion center, 393 men and 234 women with normal SUA levels (male: 3.5-8.0 mg/dl, female: 2.5-5.4 mg/dl) were divided into quartiles: in men, Q1 (n = 90, 3.5-4.3 mg/dl), Q2 (n = 94, 4.4-5.1 mg/dl), Q3 (n = 106, 5.2-5.9 mg/dl) and Q4 (n = 103, 6.0-8.0 mg/dl); in women, Q1 (n = 57, 2.5-3.6 mg/dl), Q2 (n = 49, 3.7-4.1 mg/dl), Q3 (n = 61, 4.2-4.6 mg/dl) and Q4 (n = 67, 4.7-5.4 mg/dl). The mean values of ba-PWV increased gradually by SUA quartile. The men's SUA had an independent, positive association with ba-PWV after correcting for age, glucose, body mass index, blood pressure, resting heart rate, high-sensitivity C-reactive protein (hs-CRP), high-density lipoprotein (HDL)-cholesterol and triglyceride (R (2) = 0.39, adjusted R (2) = 0.37, p < 0.001). The odds ratios (95% CI) for high ba-PWVs (> 75th percentile, 1473 cm/s) in men were 1.89 (0.69-5.20, Q2), 2.36 (1.10-5.08, Q3), and 2.91 (1.39-6.11, Q4), after adjusting for confounding factors (p < 0.001). In women, SUA showed no independent association with ba-PWV (p = 0.186). After adjusting for confounding factors, the mean ba-PWV values of Q3 (1418 cm/s) and Q4 (1421 cm/s) in men were higher than those of Q1 (1355 cm/s) (p < 0.05). Above the SUA level of 5.2 mg/dl, arterial stiffness was increased in healthy Korean men.

Hyperuricemia induces endothelial dysfunction via mitochondrial Na+/Ca2+ exchanger-mediated mitochondrial calcium overload

BACKGROUND

Uric acid (UA) has proven to be a causal agent in endothelial dysfunction in which ROS production plays an important role. Calcium overload in mitochondria can promote the mitochondrial production of ROS. We hypothesize that calcium transduction in mitochondria contributes to UA-induced endothelial dysfunction.

METHODS AND RESULTS

We first demonstrated that high concentrations of UA cause endothelial dysfunction, marked by a reduction in eNOS protein expression and NO release in vitro. We further found that a high concentration of UA increased levels of [Ca2+]mito, total intracellular ROS, H2O2, and mitochondrial O2·-, and Δψmito but not the [Ca2+]cyt level. When the mitochondrial calcium channels NCXmito and MCU were blocked by CGP-37157 and Ru360, respectively, the UA-induced increases in the levels of [Ca2+]mito and total intracellular ROS were significantly reduced. Mitochondrial levels of O2·- and Δψmito were reduced by inhibition of NCXmito but not of MCU. Moreover, inhibition of NCXmito, but not of MCU, blocked the UA-induced reductions in eNOS protein expression and NO release.

CONCLUSIONS

The increased generation of mitochondrial O2·- induced by a high concentration of UA is triggered by mitochondrial calcium overload and ultimately leads to endothelial dysfunction. In this process, the activation of NCXmito is the major cause of the influx of calcium into mitochondria. Our results provide a new pathophysiological mechanism for UA-induced endothelial dysfunction and may offer a new therapeutic target for clinicians.

Serum uric acid level and its association with metabolic syndrome and carotid atherosclerosis in patients with type 2 diabetes

Objective

We aimed to investigate whether elevated serum uric acid concentrations are associated with higher risk of metabolic syndrome (MetS) and carotid atherosclerosis in patients with type 2 diabetes.

Methods

We conducted a population-based cross-sectional survey in Shanghai, with a total of 395 men and 631 women age 41 to 92 years. The carotid artery intima-media thickness (IMT) and carotid atherosclerotic plaques (PLQ) were measured by B-mode ultrasound. MetS was defined according to the updated National Cholesterol Education Program Adult Treatment Panel III criteria for Asian Americans.

Results

Uric acid levels were negatively associated with duration of diabetes, fasting plasma glucose, glycohemoglobin, eGFR, HDL-cholesterol (all P < 0.001) and positively with BMI, CRP, waist circumference, triglycerides, systolic blood pressure, ACR, HOMA-IR and IMT (all P < 0.05). In the highest quartile of uric acid levels, the risks were substantially higher for MetS [odds ratio 3.97, (95% confidence interval 2.58-6.13)] (P < 0.001 for trend) and PLQ [odds ratio 2.71 (95% confidence interval 1.62-4.47)] (p = 0.013 for trend) compared with that in the lowest quartile of uric acid levels after multiple adjustment. These associations remained significant after further adjustment for potential confounders.

Conclusions

Serum uric acid level is associated with MetS and is an independent risk factor for carotid atherosclerosis in patients with type 2 diabetes.

Sleep apnea is a stronger predictor for coronary heart disease than traditional risk factors

BACKGROUND

Sleep apnea (SA) may be linked to coronary artery disease (CAD). Both conditions have similar risk factors, confounding the analyses. Investigation of the lipid profile is routine in the adult population, even without symptoms or suspected cardiac ailment. SA, however, remains underdiagnosed even in the presence of unambiguous clinical manifestations.

PURPOSE

The aim of this study was to verify the association between SA and CAD, adjusting for usual CAD risk factors.

METHODS

Patients who underwent diagnostic or therapeutic coronariography and portable type III polysomnography were studied. The severity of SA was determined by the apnea-hypopnea index (AHI). We measured classic CAD risk factors: fasting glucose; total, HDL, and LDL cholesterols; triglycerides; uric acid, and high-sensitivity C-reactive protein. We excluded patients older than 65 years, with body mass index higher than 40 kg/m(2), with diabetes, and with history of smoking in the last year.

RESULTS

Of 55 included patients, 28 had AHI > 14, showing an odds ratio of 8.7 for CAD. Patients without (n = 29) and with CAD (n = 26), showed AHI of, respectively, 11 ± 11 and 23 ± 14 per hour (P = 0.001). In a binary logistic regression to predict CAD, controlling for all the above risk factors, the only variables entered in the stepwise model were AHI (either as continuous or categorical variable) and uric acid.

CONCLUSION

In a sample without smokers, morbidly obese, or diabetic patients, AHI is the main predictor of CAD. SA should integrate the set of risk factors routinely assessed in clinical investigation for coronary disease risk stratification.

Clinical analysis of the risk factors of slow coronary flow

Slow coronary flow (SCF) phenomenon is a coronary microvascular disorder characterized by the delayed passage of contrast in the absence of obstructive epicardial coronary disease, and is an important clinical entity because it may be the cause of precordial pain when the body is at rest and/or during exercise. Although clinical and pathological features of SCF have been previously described, its etiopathogenesis remains unclear. The present study aims to investigate the risk factors of slow coronary flow, in order to provide the foundation for further exploration of potential mechanisms of SCF. A total of 47 consecutive patients with documented slow coronary flow, and 33 patients with normal coronary flow--as defined by TIMI frame count (TFC)--were recruited for this study. Clinical information was collected, and biochemical indicators including high-sensitivity C-reactive protein (hs-CRP), and a marker of systemic inflammation were detected. Logistic regression analysis was performed for statistical analysis. SCF patients had a higher level of serum uric acid (323.2 ± 79.3 vs. 282.8 ± 82.4 μmol/l, p = 0.03), 2-h postprandial blood glucose (8.6 ± 2.7 vs. 7.5 ± 1.8 mmol/l, p = 0.04), platelet count (165.9 ± 51.6 × 10(3) vs. 127.0 ± 32.0 × 10(3) cells/μl, p = 0.0003) and hs-CRP (3.4 ± 0.8 vs. 2.0 ± 0.9 mg/l, p < 0.0001) than those of patients in the control group. No marked differences in other variables were observed between the two groups. Logistic regression showed serum uric acid level (χ(2) = 3.84, β = 0.007, p = 0.049), 2-h postprandial blood glucose (χ(2) = 5.02, β = 0.277, p = 0.025) and blood platelet count (χ(2) = 12.16, β = 0.026, p = 0.001) were independent predictors of SCF. When hs-CRP was included in the multivariate model, hs-CRP (χ(2) = 21.19, β = 1.90, p < 0.0001) was the only independent predictor of SCF. These findings suggested that an elevation of serum uric acid level, 2-h postprandial blood glucose, and blood platelet count might be the causes of SCF, and inflammation was likely to be implicated in the causal pathway leading to SCF.

Effects of cold pressor-induced sympathetic stimulation on the mechanical properties of common carotid and femoral arteries in healthy males

Our aim was to evaluate the effects of sympathetic excitation and elevation of blood pressure on mechanical properties of common carotid and femoral arteries by wave intensity analysis (WIA). The diameters and arterial stiffness parameters of right common carotid artery (RCCA) and right common femoral artery (RCFA) in healthy young men were measured by WIA at baseline and during cold pressor test (CPT). In addition, the blood pressure and heart rate were recorded simultaneously. The heart rates and blood pressures increased during CPT compared with baseline, while the pulse pressures remained unchanged. The diameters of RCCA increased slightly, while those of RCFA did not change. The Peterson's pressure modulus (Ep), augment index (AI), and pulse wave velocity from β (PWVβ) increased obviously, while arterial compliance (AC) decreased with no change in stiffness index (β) of both arteries during CPT when compared with baseline. There was an obvious increase in pulse wave velocity from wave intensity (PWV_WI) of RCCA, while the PWV_WI of RCFA showed no significant change during CPT. The sympathetic nervous system exerts a more marked tonic restraint on RCFA than on RCCA. The Ep, AC, AI, PWVβ of RCCA, and RCFA are much affected by variations in blood pressure and sympathetic status, while the β of both arteries are less vulnerable to these factors and are more reliable in reflecting the actual arterial stiffness; The PWV_WI appears to be suitable only for evaluating the stiffness of RCCA instead of RCFA.

Hypertension in children: new trends and challenges

Childhood HTN (hypertension) has become a widely investigated topic within the last decade due to its increasing prevalence. In the present review, we examine new developments and trends that have significantly contributed to aetiology, diagnosis, evaluation and management of childhood HTN. Many recent reports document an increasing prevalence of HTN, mainly essential HTN, in children worldwide. This is probably related to the increase of childhood obesity, although obesity is not the only factor. Evidence has been accumulating to suggest a rather complex interplay between obesity, uric acid level, dietary sodium intake, inflammation, inheritance and other factors, which lead to increased risk of developing HTN in childhood and adulthood. The detection and monitoring of HTN has significantly improved with the use of ABPM (ambulatory blood pressure monitoring), which allows not only for a more accurate classification and staging of HTN, but also for the calculation of more sophisticated parameters such as the AASI (ambulatory arterial stiffness index). Measurement of arterial stiffness enables assessment of arterial dysfunction, which may precede structural vascular changes evaluated by carotid intima media thickness. Sustained HTN eventually leads to end-organ damage [LVH (left ventricular hypertrophy), central nervous system], which in turn increases the risk of cardiovascular morbidity and mortality. New developments in childhood HTN, as outlined in the present review, will hopefully contribute to better screening and management of HTN in children.