Association between blood viscosity and common carotid artery elasticity

Whole blood viscosity is associated with reduced myocardial mechano-energetic efficiency in nondiabetic individuals

INTRODUCTION

This cross-sectional study aimed to investigate the association between myocardial mechano-energetic efficiency (MEE) and whole blood viscosity (WBV) in nondiabetic adults participating in the CATAnzaro MEtabolic RIsk factors (CATAMERI) study.

METHODS

1143 participants underwent an oral glucose tolerance test and an echocardiogram for myocardial MEE per gram of left ventricular mass (MEEi) measurement. WBV was measured as: [0.12 × h] + [0.17 × (p-2.07)], where h is haematocrit and p is plasma protein levels.

RESULTS

Study population includes 595 males and 548 females with a mean age of 46 ± 12 years and a mean BMI of 30.0 ± 6.2 kg/m2 . Individuals with normal glucose tolerance were 63%, while those with impaired fasting glucose, impaired glucose tolerance and or the combination of both were 14.3%, 13% and 9.7%, respectively. A univariate analysis showed that MEEi was significantly associated with sex, age, smoking, BMI, waist circumference, total cholesterol, HDL, triglycerides, fasting glucose, fasting insulin, HOMA-IR index, glucose tolerance, C-reactive protein, haematocrit, haemoglobin, plasma protein and WBV. In a multivariable regression model including variables that were significantly associated with MEEi in univariate analysis, MEEi was associated with HOMA-IR (β = -0.144, p < .001), age (β = -0.140, p < .001), WBV (β = -0.129, p < .001) and glucose tolerance (β = -0.064, p = .04). The independent association between WBV and MEEi remained statistically significant (β = -0.122, p < .001) when antihypertensive therapy and lipid-lowering therapy were included in the model.

CONCLUSION

WBV is associated with decreased myocardial MEE independently of other cardiovascular risk factors.

Relationship between blood viscosity and existence and severity of carotid artery plaque

BACKGROUND

Accumulating evidence shows that the increase in blood viscosity (BV) is an independent risk factor for atherosclerosis and its related diseases, but as far as we know, there are few studies on the relationship between blood viscosity and carotid plaque severity. Therefore, we aimed to investigate the relationship between blood viscosity and the presence of carotid plaques, and further explore its relationship with the severity of carotid plaques.

METHODS

We retrospectively analyzed the data of consecutive subjects in the physical examination center of the Affiliated Hospital of Ningbo University Medical College from January 2022 to May 2022.The parameters of blood viscosity include the whole blood viscosity (WBV) at high, middle, and low shear rate, plasma viscosity (PV), hematocrit (HCT), rigidity "k", rigidity index (RI), aggregation index (AI) and electrophoresis rate (ER), and standardized BV calculated by Quemada's equation were included in the study. Carotid plaque score (CPS) was used to measure the severity of carotid artery disease, and participants were divided into mild, moderate, and severe groups according to the quartile of the score. Independent samples t-test and one-way ANOVA were used to compare normally distributed continuous variables between two or more independent groups, respectively. Binary logistic regression was used to evaluate the risk factors of carotid plaque.

RESULTS

314 men were enrolled in the study, of which 165 participants were diagnosed with Carotid artery plaque (CAP) (66.9%). Compared with the CAP- group, the WBV and PV of the CAP+group decreased, but the difference only existed in the PV (p = 0.001). However, standardized BV values (HCT set at 0.45) were higher in the CAP+group than in the CAP- group (3.8643±0.35431vs 3.9542±0.64871, p = 0.188). Regarding the rigidity and aggregation of RBC, the parameters including rigidity "k", RI, AI and ER increased in the CAP+group compared with the CAP- group. The difference was statistically significant in k and ER (p = 0.04, p = 0.009). To assess the severity of carotid plaque, we divided the participants into mild, moderate, and severe groups by using the tertile of CPS value. The mild group was defined as CPS≤0.5 (n = 108), the moderate group as 0.5 <  CPS≤1.7 (n = 105), and the severe group as CPS >  1.7 (n = 101). It was found that WBV and PV decreased with the increase of plaque severity, but the difference among the three groups was significant in PV (F = 8.073, p <  0.0001). In addition, with the severity of plaque from mild to severe, standardized BV gradually increased, which were 3.8611±0.34845, 3.8757±0.36637, 3.9007±0.38353 respectively. The difference between the groups was close to statistically significant (F = 2.438, p = 0.089). The values of parameters describing erythrocyte aggregation and rigidity increased among the mild, moderate, and severe groups. The difference was statistically significant in RBC rigidity "k" and ER of RBC (F = 3.863, p = 0.022; F = 5.897, p = 0.003, respectively).

CONCLUSION

Increased blood viscosity is a risk factor for carotid plaque, but its increase may be hidden by decreased hematocrit. Therefore, it is necessary to comprehensively analyze various parameters of blood viscosity, such as the standardized BV calculated by Quemada's equation, which may provide more useful reference value.

[Peripheral blood albumin level in significantly correlated with the severity of atherosclerosis in hypertensive patients]

OBJECTIVE

To investigate the relationship between peripheral blood albumin (Hb) level and the severity of arteriosclerosis in hypertensive patients.

METHODS

This retrospective analysis was conducted among 419 randomly selected patients with hypertension. The pulse wave velocity (ba-PWV) of the bilateral limbs was measured using an arteriosclerosis tester. According to the ba-PWV value (the higher value of the two sides), the hypertensive patients were divided into 4 groups, namely normal arterial group [S0 group, ba-PWV < 1400 cm/s; 49 cases (11.7%)], mild arteriosclerosis group [S1 group, ba-PWV of 1400-1800 cm/s; 190 cases (45.3%)], moderate arteriosclerosis group [S2 group, ba-PWV of 1800-2000 cm/s); 69 cases (16.5%)], and severe arteriosclerosis group [S3 group, ba-PWV > 2 000 cm/s; 111 cases (26.5 %)]. The clinical data of the patients were collected and multivariate logistic regression was used to analyze the risk factors of arteriosclerosis.

RESULTS

The patients' age, obesity, albumin, alanine aminotransferase (ALT), total bile acid, adenosine deaminase, urea nitrogen, serum creatinine, cystatin C, low-density lipoprotein, red blood cells, hemoglobin (Hb), fibrinogen, and FT3 all differed significantly between S0 group and the 3 arteriosclerosis groups (P < 0.05). Multivariate logistic regression analysis revealed that in hypertensive patients, age was an independent risk factor for severe arteriosclerosis (OR=1.094, 95% CI: 1.052-1.137, P < 0.05) and moderate arteriosclerosis (OR= 1.081, 95% CI: 1.039-1.125, P < 0.05); Hb was an independent risk factor for new-onset severe arteriosclerosis (OR= 1.025, 95% CI: 1.003-1.045, P < 0.05) and moderate arteriosclerosis (OR=1.035, 95% CI: 1.008-1.056, P < 0.05), and an increase of Hb levels by 1 standard deviation was associated with a doubled risk in hypertensive patients.

CONCLUSIONS

Peripheral Hb level is significantly correlated with the severity of arteriosclerosis and may serve as a new predictor for arteriosclerosis in hypertensive patients.

Living Arrangement: a Contributor to Vascular Disease in Asymptomatic African American Women

BACKGROUND

Diminished social support lias shown to lead to worse cardiovascular outcomes and since cardiovascular disease (CVD) is the leading cause of death in the United States (U.S.), it is critical to non-invasively study its precursor- vascular disease (VD). Assessing the impact social support lias on vascular outcomes can unveil potential CVD susceptibilities in at-risk populations. African American women exhibit the greatest burden of CVD morbidity and mortality; therefore, the purpose of tins study is to examine the association between living arrangement/social support and impaired vascular function in asymptomatic African American women.

METHODS

Vascular function was assessed by a non-invasive screening tool, HDI/PulseWave CR-2000, during screenings at community outreach events on participants clinically free of CVD. Vascular disease was defined as abnormal/impaired vascular function. Living arrangement, a binary variable (living with someone/living alone), was determined by survey responses (N=67) and represented social support. Multivariable analyses were used to estimate adjusted odds ratios (AORs) and 95% confidence intervals (95% CIs) to determine the association between living arrangement and vascular disease after controlling for confounders. Analyses were conducted using SAS 9.2.

RESULTS

Of those who lived alone, 82% had vascular disease (p=0.03). After adjusting for family CVD, and other CVD risk factors, those who lived with a spouse/partner or relative were 78% (p=0.04) less likely to develop vascular disease (AOR=0.22; 95% 0=0.05, 0.98).

CONCLUSIONS

Our study provides preliminary evidence to suggest that among African American women, clinically free of CVD, living arrangement is associated with vascular disease. While living alone may place individuals at an increased risk of CVD because of the association, living with a spouse/partner or relative may act as a protective factor against vascular disease and reduce the risk of CVD. Public health practitioners may use individuals' living arrangement as preventive measure for CVD risk.

Pulse wave velocity is lower in trained than in untrained sickle cell trait carriers

BACKGROUND

Sickle cell trait (SCT) is a benign condition of sickle cell disease. Nevertheless, previous reports showed that SCT carriers have increased blood viscosity and decreased vascular reactivity compared to non-SCT carrier. The benefit of regular exercise on vascular function has been well documented in the general population but no study focused on the SCT population.

PURPOSE

The aim of our study was to compare arterial stiffness and blood viscosity between trained and untrained SCT carriers, as well as a group of untrained non-SCT.

METHODS

Arterial stiffness (finger-toe pulse wave velocity) and blood viscosity were evaluated in untrained non-SCT carriers (n = 10), untrained SCT carriers (n = 23) and trained SCT carriers (n = 17) who reported at least 10 hours of physical exercise per week.

RESULTS

Untrained SCT carriers had higher pulse wave velocity (p = 0.032) and blood viscosity (p < 0.001) than their trained counterparts. In addition, untrained SCT carriers had higher blood viscosity (p < 0.001) than the untrained non-SCT group. A positive association was noted between blood viscosity and pulse wave velocity in the whole study population.

CONCLUSION

Our study suggests that regular exercise may be beneficial for the vascular function of SCT carriers.

Elevated 1-h post-challenge plasma glucose levels in subjects with normal glucose tolerance or impaired glucose tolerance are associated with whole blood viscosity

AIM

It has been suggested that glucose levels ≥155 mg/dl at 1-h during an oral glucose tolerance test (OGTT) may predict development of type 2 diabetes and cardiovascular events among adults with normal glucose tolerance (NGT 1 h-high). Studies showed a link between increased blood viscosity and type 2 diabetes. However, whether blood viscosity is associated with dysglycemic conditions such as NGT 1 h-high, impaired glucose tolerance (IGT) or impaired fasting glucose (IFG) is unsettled.

METHODS

1723 non-diabetic adults underwent biochemical evaluation and OGTT. A validated formula based on hematocrit and total plasma proteins was employed to estimate whole blood viscosity. Subjects were categorized into NGT with 1 h glucose <155 mg/dL (NGT-1 h-low), NGT-1 h-high, IFG and/or IGT.

RESULTS

Hematocrit and blood viscosity values appeared significantly higher in individuals with NGT 1 h-high, IFG and/or IGT as compared to NGT 1 h-low subjects. Blood viscosity was significantly correlated with age, waist circumference, blood pressure, HbA1c, fasting, 1- and 2-h post-challenge insulin levels, total cholesterol and low-density lipoprotein, triglycerides, fibrinogen, white blood cell, and inversely correlated with high-density lipoprotein and insulin sensitivity. Of the four glycemic parameters, 1-h post-challenge glucose showed the strongest correlation with blood viscosity (β = 0.158, P < 0.0001) in a multivariate regression analysis model including several atherosclerosis risk factors.

CONCLUSIONS

Our results demonstrate a positive relationship between blood viscosity and 1-h post-challenge plasma glucose. They also suggest that a subgroup of NGT individuals with 1-h post-challenge plasma >155 mg/dl have increased blood viscosity comparable to that observed in subjects with IFG and/or IGT.

Association of hemoglobin with ankle-brachial index in general population

OBJECTIVES

Previous studies have demonstrated that both low and high hemoglobin concentrations are predictive of adverse cardiovascular outcomes in various populations. However, an association of hemoglobin with the ankle-brachial index, which is widely used as a screening test for peripheral arterial disease, has not yet been identified.

METHODS

We examined 786 subjects (236 women and 550 men) who received routine physical check-ups. The ankle-brachial index and several hematological parameters, including the hemoglobin level, hematocrit and red blood cell count and other demographic and biochemical characteristics were collected. Univariate and multivariate linear regression analyses were performed to assess the relationships between the ankle-brachial index and the independent determinants. Receiver operating characteristic curve analysis was conducted to calculate the cut-off level of hemoglobin for detecting a relatively low ankle-brachial index (less than 20% of all subjects, which was 1.02).

RESULTS

The hemoglobin level, hematocrit and red blood cell count were correlated with the ankle-brachial index in the males (r=-0.274, r=-0.224 and r=-0.273, respectively, p<0.001 for all), but these associations were not significant in the females. Multivariate linear regression analysis revealed that the independent determinants of the ankle-brachial index included age, total cholesterol, high-density lipoprotein cholesterol and the white blood cell count for the females and age, hypertension, total cholesterol and hemoglobin (β=-0.001, p<0.001) for the males after adjusting for confounding factors. Receiver operating characteristic curve analysis revealed that the cut-off level of hemoglobin for predicting a low ankle-brachial index was 156.5 g/L in the males.

CONCLUSIONS

A high hemoglobin concentration was independently correlated with a low ankle-brachial index in the healthy males, indicating that an elevation in this level may be associated with an increased atherosclerosis risk.

Prognostic significance of whole blood viscosity estimated by de Simone’s formula in ST-elevation myocardial infarction

Background: We assessed the predictive value of estimated whole blood viscosity (WBV) in-hospital and long-term cardiovascular outcomes in patients with ST-elevation myocardial infarction (STEMI). Materials & methods: One thousand eight hundred and thirty-five STEMI patients were followed up for median 34.6 months. WBV was calculated consistent with the de Simone’s formula. Results: In-hospital and long-term major adverse cardiovascular events (MACE) demonstrated an incremental trend in ascending order of WBV tertiles at low and high shear rate. Kaplan–Meier analysis showed a higher occurrence of long-term MACE in third WBV tertiles compared with other tertiles. Conclusion: WBV seems to be a feasible prognostic indicator of short- and long-term cardiovascular adverse events in patients with STEMI. As an easily available parameter, WBV may be utilized in identifying high-risk patients for subsequent MACE.