Common carotid and brachial artery hemodynamic alterations in periodontal disease.

AIM: In patients affected by periodontal disease, hypertension and systemic inflammation might cause an arterial hemodynamic derangement; this, in turn, can act as a mediator of the atherogenic process often seen in these patients. This study aimed at a comprehensive hemodynamic evaluation in periodontal patients. METHODS: Fourty-eight subjects participating to a cardiovascular prevention programme were enrolled. Periodontitis, classical risk factors for atherosclerosis, and shear and tensile forces in both carotid and brachial arteries were evaluated. Calculated periodontal indexes were plaque, gingival and pocket deep (PD) indexes. Simple and multiple regression analyses were performed. Afterwards, 30 of them with normal PD index were compared with 30 carefully - matched patients with periodontitis. RESULTS: Brachial and carotid parietal tension were significantly associated with periodontal indexes, especially PD-Sum, in both simple (r = 0.42, p < 0.001 for carotid artery and r = 0.36, p < 0.02 for brachial artery) and multiple regression analyses. Shear stress gave similar results. In case-control analysis, shear stress was lower by 15% and 30%, respectively, in carotid and brachial artery in patients with high PD; common carotid parietal tension was higher. Arterial stiffness resulted not associated with periodontitis. CONCLUSIONS: Periodontal disease is associated to a complex atherosclerotic prone hemodynamic derangement, particularly in large elastic arteries.

Wall shear stress is lower in the carotid artery responsible for a unilateral ischemic stroke.

According to the focal nature of atherosclerosis, ischemic stroke is frequently unilateral. Atherosclerotic plaques are favoured by local hemodynamic factors as low wall shear stress and/or elevated circumferential wall tension. Aim of the present study was to investigate the possible association between hemodynamic forces and cerebrovascular disease. Common carotid mean wall shear stress and circumferential wall tension, Peterson's elastic modulus, and blood flow were measured in 25 patients with a recent unilateral large-artery stroke presenting non-stenotic plaques of the carotid arteries (large-artery group), and in 10 patients affected by a recent unilateral cardioembolic stroke without carotid plaques (cardioembolic group). In the large-artery group, atherosclerosis was slightly more evident in the side of cerebral ischemia. All hemodynamic factors were more unfavourable at the affected side in this group (shear stress: 6.2+/-3.0 versus 8.6+/-4.0 dynes/cm2, p<0.0001; wall tension: (7.3+/-1.3)x10(4) versus (6.6+/-1.3)x10(4) dynes/cm, p<0.00001; Peterson's modulus: (16.8+/-11.9)x10(5) versus (12.4+/-5.7)x10(5) dynes/cm2, p=0.06). No difference was detectable in blood flow and in cardioembolic group. The present data demonstrate an unfavourable hemodynamic profile in the common carotid artery supplying the area of a single large-artery stroke and might help to explain the frequent one-sidedness of this disease.

Association between blood viscosity and common carotid artery elasticity.

OBJECTIVE: Elastic properties of the vessel wall are associated with atherosclerosis and major cardiovascular events. Several physiological and pathological conditions can affect arterial elasticity, but few studies have considered the role of hemorheological parameters. The present study aimed to investigate the relationship between hemorheological parameters and vascular stiffness in the carotid artery district. METHODS: One hundred and two individuals were enrolled. Blood and plasma viscosity were measured by a cone-plate viscometer (Wells-Brookfield DV-III, Stoughton, U.S.A.). Echo-Doppler evaluation of carotid arteries was performed in order to calculate elastic indexes (strain, ß-stiffness index and distensibility). The association between hemorheological parameters and carotid elasticity indexes was assessed by simple and multiple regression analyses. RESULTS: In simple correlation analysis, only blood viscosity was directly associated with ß-stiffness index (r = 0.20, p = 0.05) and inversely with strain (r =-0.26, p = 0.01) and distensibility (r =-0.34, p = 0.001). After adjusting for cardiovascular risk factors, blood viscosity, but not plasma viscosity or hematocrit, was independently associated carotid arterial measures, together with age, obesity, hypertension, and dyslipidemia. CONCLUSIONS: The results of the present study demonstrate a strong association between blood viscosity and common carotid elasticity indexes.

Red blood cell distribution width predicts two-hours plasma glucose levels during OGTT.

OBJECTIVE: Red blood cell distribution width (RDW) is a numerical measure, reported as part of a standard complete blood count, usually employed for differential diagnosis of anemic state. Some lines of evidence demonstrate that RDW associates with type 2 diabetes incidence and its complications. To further explore the role of RDW as predictor of abnormal glucose metabolism, we have analyzed the relationship between RDW and 2-hours plasma glucose concentration during an oral glucose tolerance test (OGTT). METHODS: Forty-five outpatients were enrolled for the present study. Participants underwent 75 g OGTT and measurements of hematological parameters. Cardiovascular disease risk factors (blood pressure, blood lipids, cigarette smoking, obesity) were evaluated by routine methods. RESULTS: In simple regression analysis 2-hours post-load glucose was directly associated with age (r = 0.36, p = 0.01), fasting glucose levels (r = 0.40, p = 0.002) and RDW (r = 0.31, p = 0.037). In multiple regression analysis fasting glucose, RDW, triglycerides and age significantly and independently predicted 2-hours plasma glucose (p <  0.01 for all coefficients). CONCLUSION: The present findings demonstrate that RDW associates with plasma glucose concentration after a 75-g oral glucose tolerance test. Our results highlight the role of RDW as predictor of glucose metabolism disturbance.

Carotid endothelial shear stress reduction with aging is associated with plaque development in twelve years.

BACKGROUND AND AIMS: Atherosclerosis is associated with clinical, biochemical and haemodynamic risk factors. In a group of subjects studied twelve years apart, we evaluated carotid plaque development in relation to baseline and to changes at follow-up in common carotid haemodynamic profile. METHODS: Forty-eight participants were recruited to a cardiovascular disease prevention programme. Atherosclerotic plaques were evaluated and scored by echography. Endothelial shear stress, circumferential wall tension, and Peterson's elastic modulus as an index of arterial stiffness, were computed by echo-Doppler, along with blood viscosity data. Binary logistic regression analyses were used to test the association among the development of atherosclerosis, cardiovascular risk factors and haemodynamic variations. Analyses were also performed on participants who presented at the follow-up with carotid haemodynamic variations in the left or right common carotid only. RESULTS: Participants (69% male) were aged 64.5 ± 9.7 years at follow-up. Peak and mean endothelial shear stress was significantly lower at follow-up as previously reported; circumferential wall tension and arterial stiffness were significantly higher. Carotid plaque scores increased after 12 years (0.39 ± 0.72 vs. 0.67 ± 0.86, p < 0.01). Of the 96 common carotids analysed, shear stress reduction with aging was an independent predictor of carotid atherosclerosis (B = -0.063; odds ratio = 0.94; p = 0.01). Out of 48 participants, 21 (44%) showed shear stress reduction with aging in only one side of the body and, on this side, the plaque score increased (0.52 ± 0.98 vs. 0.90 ± 0.94, p < 0.05), remaining unchanged in the contralateral carotid tree. CONCLUSIONS: Aging-related shear stress reduction is an independent predictor of atherosclerosis development.

Plasma viscosity is increased in subjects with elevated ankle brachial index.

OBJECTIVE: Peripheral artery occlusive disease (PAOD) is associated with increased cardiovascular risk (CVR). Recently it has been reported that also the increased stiffness of lower limb arteries is associated with increased CVR. In particular, subjects with poorly compressible arteries (PCA) appear to have a CVR even higher than that of subjects with PAOD. Limited data are available on the role of hemorheological factors in determining increase in arterial stiffness. Our study aimed to investigate possible association between blood and plasma viscosity and elevated ankle brachial index (ABI). METHODS: Subjects were free-living participants to a cardiovascular disease screening campaign. Sixty-two subjects with ABI ranging 1.3-1.4, and 20 with ABI >1.4 were matched with 124 and 40 control subjects, respectively. Cardiovascular disease risk factors (blood pressure, blood lipids, glucose, cigarette smoking, obesity) were evaluated by routine methods. Blood and plasma viscosities were measured by a cone-plate viscometer. Ankle-brachial index was computed as measure of arterial stiffness. RESULTS: Compared with controls, who were carefully matched for age, sex and all cardiovascular risk factors, subjects with elevated ABI values had increased levels of plasma viscosity (1.42 ± 0.11 vs. 1.35 ± 0.10 cP, p <  0.001, for subjects with ABI ranging 1.3-1.4, and 1.41 ± 0.10 vs. 1.33 ± 0.10 cP, p <  0.01, for subjects with ABI >1.4). No difference in blood viscosity was observed. CONCLUSION: The present investigation provides evidence that plasma viscosity is increased in subjects with elevated ABI values, independently of other cardiovascular risk factors. This finding contributes to explain the high CVR of patients with PCA.

Biphasic hemodynamic effects of LDL-apheresis in common carotid artery.

OBJECTIVE: Heparin-induced Extracorporeal Low Density Lipoprotein Precipitation (HELP) Apheresis gives beneficial reductions in Low Density Lipoprotein (LDL) cholesterol levels; otherwise, extracorporeal circulation settings might elicit inflammation and platelet aggregation. The net effect of these variations on carotid hemodynamic has not been established. Aim of the present study was to investigate periprocedural variations of common carotid artery wall shear stress, circumferential wall tension, and Peterson's elastic modulus. METHODS: Measurements were sequentially performed on 22 procedures: immediately before apheresis (T1), within one hour after (T2), after 24 (T3) and 48 hours (T4). In order to confirm acute effects, in additional 30 procedures measurements were performed at T1 and T2. RESULTS: Mean shear stress was decreased at T2, with an improvement at T4. Mean circumferential wall tension showed an improvement at T4; arterial stiffness showed the same trend, but only close to statistical significance. The following 30 procedures, where measurements were performed at T1 and T2 only, confirmed previous results, showing a deep wall shear stress decrease at T2 (-21%). CONCLUSION: LDL apheresis seems to have a biphasic effect on common carotid hemodynamics: the acute worsening of shear stress, probably mediated by extracorporeal circulation, was followed by its improvement, possibly driven by LDL cholesterol reduction.

Influence of blood lipids on plasma and blood viscosity.

BACKGROUND AND AIM: The relationship between hyperlipidemia and blood and plasma viscosity is not completely clear. While increasing viscosity is often reported with increasing blood lipids, lipid-lowering treatments are often unable to normalize the viscosity values. Aim of this study is to try to clarify the relationship between blood lipids and viscosity. METHODS AND RESULTS: Apparently healthy subjects were enrolled (n = 410). Smokers, diabetics, obese, and hypertriglyceridemic (above 400 mg/dl) were excluded. Blood (at shear rate 225/s) and plasma viscosity were measured at 37°C. Erythrocyte rigidity (Tk) was calculated according to Dintenfass. Blood lipids and glucose were measured by routine methods. Hyperlipidemic subjects (n = 315) had higher values of plasma viscosity (1.44 ± 0.13 vs. 1.40 ± 0.12 cP, p = 0.007), and blood viscosity (4.51 ± 0.54 vs. 4.35 ± 0.55 cP, p = 0.013), compared to normolipidemic subjects (n = 95). In simple correlation analysis, plasma viscosity was directly associated with LDL cholesterol, and inversely with Tk and HDL cholesterol. In multiple regression analysis the association with LDL and HDL was strengthened, though these two variables as a whole accounted for only 5% (adjusted R2) of the variability of plasma viscosity. Blood viscosity was significantly associated with haematocrit, plasma viscosity, Tk and all considered variables but age in simple correlation analysis, but only with haematocrit, plasma viscosity and Tk in multiple regression analysis. CONCLUSIONS: LDL cholesterol and HDL cholesterol influence plasma viscosity, but not blood viscosity. Triglycerides up to values of 400 mg/dl do not seem to have important effects, at least in apparently healthy subjects and at the shear rates used in the present study. The contribution of LDL and HDL cholesterol to plasma viscosity seems however quite limited.

Blood viscosity in subjects with normoglycemia and prediabetes.

OBJECTIVE: Blood viscosity (BV) is higher in diabetic patients and might represent a risk factor for the development of insulin resistance and type 2 diabetes. However, data in subjects with normal glucose or prediabetes are missing. In the current study, we evaluated the relationship between BV and blood glucose in subjects with normal glucose or prediabetes. RESEARCH DESIGN AND METHODS: Enrolled subjects were divided into three groups according to blood glucose: group A (n = 74), blood glucose <90 mg/dL; group B (n = 96), blood glucose ranging from 90 to 99 mg/dL; and group C (n = 94), blood glucose ranging from 100 to 125 mg/dL. BV was measured at 37°C with a cone-plate viscometer at shear rates ranging from 225 to 22.5 s(-1). RESULTS: Blood pressure, blood lipids, fibrinogen, and plasma viscosity were similar in the three groups. BMI and waist circumference were significantly increased in group C. Hematocrit (P < 0.05) and BV (P between 0.01 and 0.001) were significantly higher in groups B and C compared with group A. Blood glucose was significantly and inversely correlated with HDL cholesterol and directly with BMI, waist, hematocrit (r = 0.134), and BV (from 225 s(-1) to 22.5 s(-1); r ranging from 0.162 to 0.131). BV at shear rate 225 s(-1) was independently associated with blood glucose. CONCLUSIONS: The current study shows a direct relationship between BV and blood glucose in nondiabetic subjects. It also suggests that, even within glucose values considered completely normal, individuals with higher blood glucose levels have increased BV comparable with that observed in subjects with prediabetes.

Human common carotid wall shear stress as a function of age and gender: a 12-year follow-up study.

Hemodynamic forces play a role in the development of atherosclerosis. Their variations with age have been assessed in cross-sectional, but not longitudinal, studies. The aim of the present study was to investigate in both sexes the age-dependent change in wall shear stress and arterial stiffness in subjects studied twice 12 years apart. Forty-eight subjects (15 women and 33 men) were studied twice 12 years apart. Subjects underwent blood viscosity measurement and echo-Doppler of carotid arteries, from which the intima-media thickness (IMT) was measured and the wall shear stress and Peterson's elastic modulus were calculated. Blood viscosity increased in both sexes, more markedly in women (+13.2%) than men (+7.2%). Common carotid diameter increased in both sexes, but in men (+7.4%) more than in women (+5.5%). Peak and mean velocity decreased at follow-up by 10.7% and 18.9% in women and by 14.2% and 18.1% in men. Peak and mean shear stress significantly decreased in men by 13.0% and 17.5%, respectively, while in women only the mean shear stress was reduced (-11.8%). The IMT of the common carotid artery increased by 29% in women and 20% in men. Arterial stiffness significantly increased (+74.5% in women and +28.0% in men). The percent change in mean shear stress was significantly and inversely associated with the percent change in IMT. The data of this study show that, in a middle-aged population observed for almost 12 years, the mean shear stress decreases significantly in both sexes, while peak shear stress decreases significantly only in men. The change in mean shear stress is inversely associated with changes in IMT. Arterial stiffness, on the other hand, increases with aging.

Periodontal disease and carotid atherosclerosis: are hemodynamic forces a link?

OBJECTIVE: The link between periodontal disease and atherosclerosis has not yet been clarified, though systemic inflammation seems to be the common soil for both conditions. Inflammation influences also hemodynamic forces, that act as local risk factors for carotid plaques. It is not known if the link between periodontitis and carotid atherosclerosis is mediated, at least in part, by physical forces. Therefore, aim of the present study was to evaluate the association between carotid shear stress force and periodontal disease. METHODS: Thirty-three subjects underwent complete cardiovascular screening, carotid hemodynamic evaluation and dental inspection. Presence of classical risk factors for atherosclerosis, common carotid peak and mean wall shear stress values and periodontal indices of disease (plaque index, gingival index and pocket deep) have been evaluated. RESULTS: Worse periodontal health was associated to the presence of carotid atherosclerosis. Patients with carotid plaques (n=19) had higher periodontal indices compared with subjects without plaques (n=14) (gingival index: 1.40 ± 0.71 vs. 0.69 ± 0.64, p=0.006). These relations were independent of the presence of cardiovascular risk factors in multiple logistic regression analysis. In the 66 examined common carotids, wall shear stress was inversely related to all periodontal indices (r=0.54, p<0.00001 for peak wall shear stress and gingival index). These relations remained significant also in multiple regression analysis, after correction for cardiovascular risk factors, gender and age. CONCLUSIONS: The present study identifies for the first time a link between periodontal indices and wall shear stress, suggesting that an alteration of hemodynamic profile might contribute to atherosclerosis in subjects with periodontal disease.