Femoral artery wall thickness and stiffness in evaluation of peripheral vascular disease in type 2 diabetes mellitus

Vascular strain of the aorta and peripheral arteries in patients with type 1 diabetes mellitus in comparison with healthy controls

BACKGROUND AND AIMS

Local variations of vascular strain may be related to the development of atherosclerotic lesions. Whether vascular strain of peripheral arteries without manifest atherosclerosis is affected by diabetes mellitus is not known. This study aimed to assess vascular strain of peripheral arteries and the abdominal aorta of young patients with type 1 diabetes mellitus (T1DM) in comparison with healthy controls.

METHODS

Vascular strain was determined by sonographic speckle tracking of the common carotid arteries (CCA), the abdominal aorta (AA), the common femoral arteries (CFA), and the popliteal arteries (PA) of patients with type 1 diabetes mellitus but without atherosclerosis and in controls.

RESULTS

Thirty-three patients with T1DM (mean age 33 years, SD 11.6) and 34 controls (mean age 24 years, SD 5.4) underwent sonographic determination of vascular strain in the CCA, AA, CFA, and PA. In total 4221 clips were processed for the analysis of vascular strain. To account for a potential impact of age on vascular strain, an age-matched model containing 18 patients with T1DM and 33 controls was used for the final analysis. In this age-matched model T1DM was independently related to vascular strain in the CFA (r = -0.48; p = 0.04), while no association was observed at other sites of the vascular tree. Intima media thickness was negatively correlated with vascular strain in the AA (r = -15.11) and the PA (r = -12.76, both p < 0.05).

CONCLUSION

T1DM appears to have an early impact on vascular strain of the CFA. Longitudinal observational studies are needed to further asses the course of these changes over time and to determine the impact of these early findings on patients' cardiovascular risk.

Effect of Anagliptin on Vascular Injury in the Femoral Artery of Type 2 Diabetic Rats

Patients with diabetes mellitus (DM) often experience complications such as peripheral arterial disease (PAD), which is thought to be caused by vascular damage resulting from increased oxidative stress. Dipeptidyl peptidase-4 inhibitors have been reported to reduce oxidative stress, although the exact mechanism remains unclear. This study aimed to investigate the impact of long-term (6 weeks) anagliptin treatment at a dose of 200 mg/kg/d against oxidative stress in the femoral artery of Otsuka Long-Evans Tokushima Fatty (OLETF) rats using a well-established animal model for type 2 DM. Serum toxic advanced glycation end-products concentrations and blood glucose levels after glucose loading were significantly elevated in OLETF rats compared to Long-Evans Tokushima Otsuka (LETO) rats but were significantly suppressed by anagliptin administration. Plasma glucagon-like peptide-1 concentrations after glucose loading were significantly increased in anagliptin-treated rats. Superoxide production and reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity in femoral arteries were significantly increased in OLETF rats compared to LETO rats but were significantly decreased by anagliptin administration. The expressions of NADPH oxidase components (p22phox in the intima region and p22phox and gp91phox in the media region) in the femoral artery were significantly increased in OLETF rats compared to LETO rats but were significantly suppressed by anagliptin administration. Furthermore, the femoral artery showed increased wall thickness in OLETF rats compared to LETO rats, but anagliptin administration reduced the thickening. This study suggests that long-term anagliptin administration can reduce oxidative stress in femoral arteries and improve vascular injury.

Longitudinal Magnetic Resonance Imaging-Based Superficial Femoral Artery Velocity Measurements in Diabetic and Nondiabetic Patients With Peripheral Artery Disease

BACKGROUND

Longitudinal associations of noninvasive 2-dimensional phase-contrast magnetic resonance imaging (2D-PC-MRI) velocity markers of the superficial femoral artery (SFA) were analyzed along with the characteristics of peripheral artery disease (PAD). We hypothesized that the 2-year differences in MRI-based measures of SFA velocity were associated with longitudinal changes in markers of PAD.

METHODS

A total of 33 (11 diabetic, 22 nondiabetic) patients with PAD with baseline and 2-year follow-up MRI scans were included in this secondary analysis of the Effect of Lipid Modification on Peripheral Artery Disease after Endovascular Intervention Trial (ELIMIT). Electrocardiographically gated 2D-PC-MRI was performed at a proximal and a distal location of the distal SFA territory. SFA lumen, wall, and total vessel volumes and the normalized wall index (NWI) were analyzed.

RESULTS

Baseline characteristics did not differ between diabetic and nondiabetic PAD patients. Maximum proximal and distal SFA velocity measures did not differ between baseline and 2 years (41.98 interquartile range (IQR) (23.58-72.6) cm/s vs. 40.31 IQR (26.69-61.29) cm/s; P = 0.30). Pooled analysis (N = 33) showed that the 24-month change in the NWI was inversely associated with the 24-month change in the proximal maximal SFA velocity (beta = -168.36, R2 = 0.150, P value = 0.03). The 24-month change of the maximum velocity differences between the proximal and distal SFA locations was inversely associated with the 24-month changes in peak walking distance (beta = -0.003, R2 = 0.360, P value = 0.011).

CONCLUSION

The 2-year change of SFA plaque burden is inversely associated with the 2-year change of proximal peak SFA blood flow velocity. 2D-PC-MRI measured SFA velocity may be of interest in assessing PAD longitudinally.

Advances for the treatment of lower extremity arterial disease associated with diabetes mellitus

Lower extremity arterial disease (LEAD) is a major vascular complication of diabetes. Vascular endothelial cells dysfunction can exacerbate local ischemia, leading to a significant increase in amputation, disability, and even mortality in patients with diabetes combined with LEAD. Therefore, it is of great clinical importance to explore proper and effective treatments. Conventional treatments of diabetic LEAD include lifestyle management, medication, open surgery, endovascular treatment, and amputation. As interdisciplinary research emerges, regenerative medicine strategies have provided new insights to treat chronic limb threatening ischemia (CLTI). Therapeutic angiogenesis strategies, such as delivering growth factors, stem cells, drugs to ischemic tissues, have also been proposed to treat LEAD by fundamentally stimulating multidimensional vascular regeneration. Recent years have seen the rapid growth of tissue engineering technology; tissue-engineered biomaterials have been used to study the treatment of LEAD, such as encapsulation of growth factors and drugs in hydrogel to facilitate the restoration of blood perfusion in ischemic tissues of animals. The primary purpose of this review is to introduce treatments and novel biomaterials development in LEAD. Firstly, the pathogenesis of LEAD is briefly described. Secondly, conventional therapies and therapeutic angiogenesis strategies of LEAD are discussed. Finally, recent research advances and future perspectives on biomaterials in LEAD are proposed.

Electrical Impedance Plethysmography Versus Tonometry To Measure the Pulse Wave Velocity in Peripheral Arteries in Young Healthy Volunteers: a Pilot Study

The leading cause of health loss and deaths worldwide are cardiovascular diseases. A predictor of cardiovascular diseases and events is the arterial stiffness. The pulse wave velocity (PWV) can be used to estimate arterial stiffness non-invasively. The tonometer is considered as the gold standard for measuring PWV. This approach requires manual probe fixation above the artery and depends on the skills of the operator. Electrical impedance plethysmography (IPG) is an interesting alternative using skin surface sensing electrodes, that is miniaturizable, cost-effective and allows measurement of deeper arteries. The aim of this pilot study was to explore if IPG can be a suitable technique to measure pulse wave velocity in legs as an alternative for the tonometer technique. The PWV was estimated by differences in the ECG-gated pulse arrival times (PAT) at the a. femoralis, a. popliteal, a. tibialis dorsalis and a. dorsalis pedis in nine healthy young adults using IPG and the SphygmoCor tonometer as a reference. The estimated PWV results from bioimpedance and the tonometer were fairly in agreement, and the beat-to-beat variability in PAT was similar. This pilot study indicates that the use of IPG may be a good alternative for estimating PWV in the legs.

Relationship Between Diabetic Retinopathy Stages and Risk of Major Lower-Extremity Arterial Disease in Patients With Type 2 Diabetes

OBJECTIVE

We evaluated the association between diabetic retinopathy stages and lower-extremity arterial disease (LEAD), its prognostic value, and the influence of potential contributors to this relationship in a prospective cohort of patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

Diabetic retinopathy was staged at baseline as absent, nonproliferative, or proliferative. A Cox regression model was fitted in order to compute the hazard ratio (HR) (95% CI) for major LEAD (lower-limb amputation or revascularization) during follow-up by baseline retinopathy stages. The retinopathy-LEAD association was assessed in subgroups by age, sex, diabetes duration, HbA_1c, systolic blood pressure, diabetic kidney disease, smoking, and macrovascular disease at baseline. The performance of retinopathy in stratifying LEAD risk was assessed by using the C statistic, integrated discrimination improvement (IDI), and net reclassification improvement (NRI).

RESULTS

Among 1,320 participants without a history of LEAD at baseline, 94 (7.1%) developed a major LEAD during a 7.1-year median follow-up (incidence rate 9.6 per 1,000 person-years [95% CI 7.8-11.7]). The LEAD incidence rate (per 1,000 person-years) increased as retinopathy worsened: it was 5.5 (95% CI 3.9-7.8) in participants in whom retinopathy was absent, 14.6 (11.1-19.3) in those with nonproliferative retinopathy, and 20.1 (11.1-36.3) in those with proliferative retinopathy. Nonproliferative retinopathy (adjusted HR 2.31 [95% CI 1.43-3.81], P = 0.0006) and proliferative retinopathy (3.14 [1.40-6.15], P = 0.007) remained associated with major LEAD. No heterogeneity was observed across subgroups. Retinopathy enhanced the C statistic (+0.023 [95% CI 0.003-0.044], P = 0.02), IDI (0.209 [0.130-0.321], P < 0.001), and NRI (0.562 [0.382-0.799], P < 0.001) values for risk of LEAD, beyond traditional risk factors.

CONCLUSIONS

An independent dose-response relationship was identified between diabetic retinopathy stages and major LEAD. Retinopathy yielded incremental prognostic information for stratifying risk of LEAD, suggesting its usefulness as a predictor of LEAD.

Acute mitochondrial antioxidant intake improves endothelial function, antioxidant enzyme activity, and exercise tolerance in patients with peripheral artery disease

The results of this study reveal for the first time that acute oral intake of mitochondrial-targeted antioxidant (MitoQ, 80 mg) is effective for improving vascular endothelial function and superoxide dismutase in patients with peripheral artery disease (PAD). Acute MitoQ intake is also effective for improving maximal walking capacity and delaying the onset of claudication in patients with PAD. These findings suggest that the acute oral intake of MitoQ-mediated improvements in vascular mitochondria play a pivotal role for improving endothelial function, the redox environment, and skeletal muscle performance in PAD.

Effects of heated water-based versus land-based exercise training on vascular function in individuals with peripheral artery disease

Peripheral artery disease (PAD) is an atherosclerotic disease that is associated with poor vascular function, walking impairment, and reduced quality of life. Land-based exercise therapy (LBET) is frequently recommended to improve walking and reduce symptoms. Recently, evidence has suggested that heated-water exercise therapy (HWET) is an effective intervention for PAD. However, the efficacy of LBET versus HWET in PAD patients had not been elucidated. Therefore, we sought to compare effects of LBET with HWET on cardiovascular function, exercise tolerance, physical function, and body composition in PAD patients. PAD patients (n = 53) were recruited and randomly assigned to a LBET group (n = 25) or HWET group (n = 28). The LBET group performed treadmill walking, whereas the HWET group performed walking in heated water for 12 wk. Leg (legPWV) and brachial-to-ankle arterial stiffness (baPWV), blood pressure (BP), ankle-brachial index (ABI), 6-min walking distance (6MWD), claudication onset time (COT), physical function, and body composition were assessed before and after 12 wk. There were significant group-by-time interactions (P < 0.05) for legPWV, BP, 6MWD, COT, body composition, and resting metabolic rate (RMR). Both groups significantly reduced (P < 0.05) legPWV, BP, and body fat percentage, and HWET measures were significantly lower than LBET measures. Both groups significantly increased 6MWD, COT, and RMR, and HWET group measures were significantly greater than LBET measures. A time effect was noted for baPWV reduction in both groups (P < 0.05). These results suggest that both LBET and HWET improve cardiovascular function, exercise tolerance, and body composition, and HWET showed considerably greater improvements compared with LBET in patients with PAD.NEW & NOTEWORTHY The results of this study reveal for the first time that although land-based exercise therapy is effective for reducing arterial stiffness and blood pressure in patients with peripheral artery disease (PAD), heated-water exercise therapy demonstrates greater benefits on vascular function. The greater improvements in muscular strength, time to onset of claudication, and exercise tolerance after heated-water exercise therapy may have clinical implications for improving quality of life in patients with PAD. The heated-water exercise therapy intervention demonstrated relatively higher exercise training adherence (∼88%) compared with the land-based exercise intervention (∼81%).

Lower extremity arterial disease in patients with diabetes: a contemporary narrative review

Lower-extremity arterial disease (LEAD) is a major endemic disease with an alarming increased prevalence worldwide. It is a common and severe condition with excess risk of major cardiovascular events and death. It also leads to a high rate of lower-limb adverse events and non-traumatic amputation. The American Diabetes Association recommends a widespread medical history and clinical examination to screen for LEAD. The ankle brachial index (ABI) is the first non-invasive tool recommended to diagnose LEAD although its variable performance in patients with diabetes. The performance of ABI is particularly affected by the presence of peripheral neuropathy, medial arterial calcification, and incompressible arteries. There is no strong evidence today to support an alternative test for LEAD diagnosis in these conditions. The management of LEAD requires a strict control of cardiovascular risk factors including diabetes, hypertension, and dyslipidaemia. The benefit of intensive versus standard glucose control on the risk of LEAD has not been clearly established. Antihypertensive, lipid-lowering, and antiplatelet agents are obviously worthfull to reduce major cardiovascular adverse events, but few randomised controlled trials (RCTs) have evaluated the benefits of these treatments in terms of LEAD and its related adverse events. Smoking cessation, physical activity, supervised walking rehabilitation and healthy diet are also crucial in LEAD management. Several advances have been achieved in endovascular and surgical revascularization procedures, with obvious improvement in LEAD management. The revascularization strategy should take into account several factors including anatomical localizations of lesions, medical history of each patients and operator experience. Further studies, especially RCTs, are needed to evaluate the interest of different therapeutic strategies on the occurrence and progression of LEAD and its related adverse events in patients with diabetes.

Association of arterial calcification with chronic limb ischemia in patients with peripheral artery disease

OBJECTIVE

Arterial calcification is associated with an increased risk of limb events, including amputation. The association between calcification in lower extremity arteries and the severity of ischemia, however, has not been assessed. We thus sought to determine whether the extent of peripheral artery calcification (PAC) was correlated with Rutherford chronic ischemia categories and hypothesized that it could independently contribute to worsening limb status.

METHODS

We retrospectively reviewed all patients presenting with symptomatic peripheral artery disease who underwent evaluation by contrast and noncontrast computed tomography scan of the lower extremities as part of their assessment. Demographic and cardiovascular risk factors were recorded. Rutherford ischemia categories were determined based on history, physical examination, and noninvasive testing. PAC scores and the extent of occlusive disease were measured on noncontrast and contrast computed tomography scans, respectively. Spearman's correlation testing was used to assess the relationship between occlusive disease and calcification scores. Multivariable logistic regression was used to identify factors associated with increasing Rutherford ischemia categories.

RESULTS

There were 116 patients identified, including 75 with claudication and 41 with critical limb ischemia. In univariate regression, there was a significant association between increasing Rutherford ischemia category and age, diabetes duration, hypertension, the occlusion score, and PAC. There was a moderate correlation between the extent of occlusive disease and PAC scores (Spearman's R = 0.6). In multivariable analysis, only tobacco use (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.2-8.3), diabetes duration (OR, 1.04; 95% CI, 1.01-1.08), and the calcification score (OR, 2.1; 95% CI, 1.4-3.2) maintained an association with increasing ischemia categories after adjusting for relevant cardiovascular risk factors and the extent of occlusive disease.

CONCLUSIONS

PAC is independently associated with increased ischemia categories in patients with peripheral artery disease. Further research aimed at understanding the relationship between arterial calcification and worsening limb ischemia is warranted.

Vasoactive actions of nitroxyl (HNO) are preserved in resistance arteries in diabetes

Endothelial dysfunction is a major risk factor for the vascular complications of diabetes. Increased reactive oxygen species (ROS) generation, a hallmark of diabetes, reduces the bioavailability of endothelial vasodilators, including nitric oxide (NO·). The vascular endothelium also produces the one electron reduced and protonated form of NO·, nitroxyl (HNO). Unlike NO·, HNO is resistant to scavenging by superoxide anions (·O₂^─). The fate of HNO in resistance arteries in diabetes is unknown. We tested the hypothesis that the vasodilator actions of endogenous and exogenous HNO are preserved in resistance arteries in diabetes. We investigated the actions of HNO in small arteries from the mesenteric and femoral beds as they exhibit marked differences in endothelial vasodilator function following 8 weeks of streptozotocin (STZ)-induced diabetes mellitus. Vascular reactivity was assessed using wire myography and ·O₂^─ generation using lucigenin-enhanced chemiluminescence. The HNO donor, Angeli's salt, and the NO· donor, DEA/NO, evoked relaxations in both arteries of control rats, and these responses were unaffected by diabetes. Nox2 oxidase expression and ·O₂^─ generation were upregulated in mesenteric, but unchanged, in femoral arteries of diabetic rats. Acetylcholine-induced endothelium-dependent relaxation was impaired in mesenteric but not femoral arteries in diabetes. The HNO scavenger, L-cysteine, reduced this endothelium-dependent relaxation to a similar extent in femoral and mesenteric arteries from control and diabetic animals. In conclusion, HNO and NO· contribute to the NO synthase (NOS)-sensitive component of endothelium-dependent relaxation in mesenteric and femoral arteries. The role of HNO is sustained in diabetes, serving to maintain endothelium-dependent relaxation.

Microvascular and Macrovascular Disease and Risk for Major Peripheral Arterial Disease in Patients With Type 2 Diabetes

OBJECTIVE

Peripheral arterial disease (PAD) is a common manifestation of atherosclerosis in type 2 diabetes, but the relationship between other vascular diseases and PAD has been poorly investigated. We examined the impact of previous microvascular and macrovascular disease on the risk of major PAD in patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS

We analyzed 10,624 patients with type 2 diabetes free from baseline major PAD in the Action in Diabetes and Vascular Disease: Preterax and Diamicron MR Controlled Evaluation (ADVANCE) clinical trial. The primary composite outcome was major PAD defined as PAD-induced death, peripheral revascularization, lower-limb amputation, or chronic ulceration. The secondary end points were the PAD components considered separately.

RESULTS

Major PAD occurred in 620 (5.8%) participants during 5 years of follow-up. Baseline microvascular and macrovascular disease were both associated with subsequent risk of major PAD after adjustment for age, sex, region of origin, and randomized treatments. However, only microvascular disease remained significantly associated with PAD after further adjustment for established risk factors. The highest risk was observed in participants with a history of macroalbuminuria (hazard ratio 1.91 [95% CI 1.38-2.64], P < 0.0001) and retinal photocoagulation therapy (1.60 [1.11-2.32], P = 0.01). Baseline microvascular disease was also associated with a higher risk of chronic lower-limb ulceration (2.07 [1.56-2.75], P < 0.0001) and amputation (1.59 [1.15-2.22], P = 0.006), whereas baseline macrovascular disease was associated with a higher rate of angioplasty procedures (1.75 [1.13-2.73], P = 0.01).

CONCLUSIONS

Microvascular disease, particularly macroalbuminuria and retinal photocoagulation therapy, strongly predicts major PAD in patients with type 2 diabetes, but macrovascular disease does not.

Reference values for local arterial stiffness. Part B: femoral artery

OBJECTIVE

Carotid-femoral pulse wave velocity (PWV) is considered the gold standard measure of arterial stiffness, representing mainly aortic stiffness. As compared with the elastic carotid and aorta, the more muscular femoral artery may be differently associated with cardiovascular risk factors (CV-RFs), or, as shown in a recent study, provide additional predictive information beyond carotid-femoral PWV. Still, clinical application is hampered by the absence of reference values. Therefore, our aim was to establish age and sex-specific reference values for femoral stiffness in healthy individuals and to investigate the associations with CV-RFs.

METHODS

Femoral artery distensibility coefficient, the inverse of stiffness, was calculated as the ratio of relative diastolic-systolic distension (obtained from ultrasound echo-tracking) and pulse pressure among 5069 individuals (49.5% men, age range: 15-87 years). Individuals without cardiovascular disease (CVD), CV-RFs and medication use (n = 1489; 43% men) constituted a healthy subpopulation used to establish sex-specific equations for percentiles of femoral artery distensibility coefficient across age.

RESULTS

In the total population, femoral artery distensibility coefficient Z-scores were independently associated with BMI, mean arterial pressure (MAP) and total to high-density lipoprotein (HDL) cholesterol ratio. Standardized βs, in men and women, respectively, were -0.18 [95% confidence interval (95% CI) -0.23 to -0.13] and -0.19 (-0.23 to -0.14) for BMI; -0.13 (-0.18 to -0.08) and -0.05 (-0.10 to -0.01) for MAP; and -0.07 (-0.11 to -0.02) and -0.16 (-0.20 to -0.11) for total-to-HDL cholesterol ratio.

CONCLUSION

In young and middle-aged men and women, normal femoral artery stiffness does not change substantially with age up to the sixth decade. CV-RFs related to metabolic disease are associated with femoral artery stiffness.

Innovative Thoughts on Treating Diabetes from the Perspective of Traditional Chinese Medicine

The rapidly increasing incidence of diabetes mellitus (DM) is becoming a major public health issue. As one of the important parts in complementary and alternative therapies, traditional Chinese medicine (TCM) is promising in treating DM. In this review, we summarize new thoughts on treating DM that aim to improve the clinical efficacy of TCM from the perspectives of principle, methods, formula, herbs, and doses. Our approach is as follows: principle: we use a combination of symptoms, syndromes, and diseases as a new mode for treating diabetes; methods: emphasizing heat-clearing in the early and middle stage of T2DM and invigorating blood circulation throughout the whole process of T2DM are two innovative methods to treat T2DM; formulas and herbs: choosing formulas and herbs based on the combination of TCM theory and current medicine. We will emphasize four strategies to help doctors choose formulas and herbs, including treatment based on syndrome differentiation, choosing herbs of bitter and sour flavors to counteract sweet flavor, choosing formulas and herbs aimed at main symptoms, and using modern pharmacological achievements in clinical practice; dose: reasonable drug dose plays an important role in the treatment of DM and a close relationship exists between dose and clinical efficacy.

A near infrared spectroscopy-based test of calf muscle function in patients with peripheral arterial disease

Background The study aims to test a new, simple, and reliable apparatus and procedure for the diagnostics and treatment evaluation of peripheral arterial disease (PAD). The test apparatus involves near infrared spectroscopy (NIRS) of a main part of the lower leg muscles during isometric flexion and extension of the ankle joint performed with the foot strapped in a specially designed pedal ergometer. Design To evaluate the reproducibility of the new test compared with an existing testing method of treadmill walking. Methods Eleven patients participated in the study: nine patients with claudication and two age-matched patients without claudication. Each patient was tested with an isometric ergometer pedal test and a treadmill test applying NIRS measurements of the anterior tibial and the gastrocnemius muscles (GAS). Tests were repeated three times with randomly selected intervals between individual test runs. Intraclass correlation constant (ICC) was used to describe reproducibility. The ICC was calculated using the area under the NIRS oxygenated hemoglobin (Hbox) curve, the initial velocity of the Hbox recovery curve, force measurements, and walking time. Results The ICC of the GAS was between 0.92-0.95 (foot-pedal) and 0.70-0.98 (tread mill) and of the anterior tibial muscle was between 0.87-0.96 (foot-pedal) and 0.67-0.79 (tread mill). Conclusion In this study, we contribute a new apparatus and test protocol for peripheral arterial disease (PAD) applying NIRS technique and controlled physical activity to evaluate the degree of muscle oxygenation under specific functionally relevant conditions. Thus, we have developed a clinically applicable "easy-to-do" exercise test of patients with chronic PAD which show high reproducibility.

Site-specific association between distal aortic pulse wave velocity and peripheral arterial stenosis severity: a prospective cardiovascular magnetic resonance study

BACKGROUND

Vascular disease expression in one location may not be representative for disease severity in other vascular territories, however, strong correlation between disease expression and severity within the same vascular segment may be expected. Therefore, we hypothesized that aortic stiffening is more strongly associated with disease expression in a vascular territory directly linked to that aortic segment rather than in a more remote segment. We prospectively compared the association between aortic wall stiffness, expressed by pulse wave velocity (PWV), sampled in the distal aorta, with the severity of peripheral arterial occlusive disease (PAOD) as compared to atherosclerotic markers sampled in remote vascular territories such as PWV in the proximal aorta and the normalized wall index (NWI), representing the vessel wall thickness, of the left common carotid artery.

METHODS

Forty-two patients (23 men; mean age 64±10 years) underwent velocity-encoded cardiovascular magnetic resonance (CMR) in the proximal and distal aorta, whole-body contrast-enhanced MR angiography (CE-MRA) and carotid vessel wall imaging with black-blood CMR in the work-up for PAOD. Strength of associations between aortic stiffness, carotid NWI and peripheral vascular stenosis grade were assessed and evaluated with multiple linear regression.

RESULTS

Stenosis severity correlated well with PWV in the distal aorta (Pearson rP=0.64, p<0.001, Spearman rS=0.65, p<0.001) but to a lesser extent with PWV in the proximal aorta (rP=0.48, p=0.002, rS=0.22, p=0.18). Carotid NWI was not associated with peripheral stenosis severity (rP=0.17, p=0.28, rS=0.14, p=0.37) nor with PWV in the proximal aorta (rP=0.22, p=0.17) nor in the distal aorta (rP=0.21, p=0.18). Correlation between stenosis severity and distal aortic PWV remained statistically significant after correction for age and gender.

CONCLUSIONS

Distal aortic wall stiffness is more directly related to peripheral arterial stenosis severity than markers from more remote vascular territories such as proximal aortic wall stiffness or carotid arterial wall thickness. Site-specific evaluation of vascular disease may be required for full vascular risk estimation.

Effect of Danzhijiangtang capsule on monocyte chemoattractant protein-1 mRNA expression in newly diagnosed diabetes subclinical vascular lesions

AIM: To investigate the effect of Danzhijiangtang capsule (DJC) on monocyte chemoattractant protein-1 (MCP-1) mRNA expression in newly diagnosed type 2 diabetes mellitus (T2DM) subclinical vascular lesions.

METHODS: Sixty-two patients with newly diagnosed T2DM subclinical vascular lesions were randomly divided into a control group and treatment group of 31 cases each. Oral antidiabetic therapy with routine western medicine was conducted in both groups, and the treatment group was additionally treated with DJCs. The treatment course for both groups was 12 wk. Before and after treatment, the total efficiency and traditional Chinese medicine (TCM) syndrome score were calculated. The fasting plasma glucose (FPG), 2-h plasma glucose (2hPG), fasting insulin (FINS), insulin resistance index (IRI), hemoglobin (Hb)A1c, blood lipids, and hemorheology indices were determined. In addition, the levels of vascular endothelial growth factors including thrombomodulin (TM), von Willebrand factor (vWF), P-selectin and MCP-1 mRNA were determined.

RESULTS: After 12 wk of treatment, the TCM syndrome score was significantly decreased compared to before treatment in both groups. After treatment, FPG, 2hPG, HbA1c, FINS, IRI, total cholesterol, triglycerides, low-density lipoprotein, high-density lipoprotein, whole blood low shear specific viscosity, plasma specific viscosity, TM, vWF, P-selectin and MCP-1 mRNA were significantly improved compared to before treatment in both groups. After treatment, the total efficiency and TCM syndrome score in the treatment group were better than in the control group. FINS, IRI, whole blood high shear specific viscosity, plasma specific viscosity, TM, vWF, P-selectin and MCP-1 mRNA level in the treatment group were significantly reduced after treatment compared with control group.

CONCLUSION: DJCs are efficacious in supplementing qi, nourishing yin and invigorating blood circulation, and upregulate MCP-1 mRNA expression in patients with T2DM subclinical vascular lesions.

Lower-extremity arterial stiffness vs. aortic stiffness in the general population

While determinants of aortic pulse wave velocity (aPWV) are well known, much less is known about factors affecting lower-extremity pulse wave velocity (lePWV). Unlike aPWV, increased lePWV does not predict cardiovascular risk, but limits lower-extremity blood flow and is associated with increased left ventricular mass. The aim of this study was to compare the effect of cardiovascular risk factors on aPWV and lePWV. A total of 911 individuals from the Czech post-MONICA study (a randomly selected 1% representative population sample, mean age 54±13.5 years, 47% men) were examined. Pulse wave velocity was measured using the SphygmoCor device. Aging had a large effect on aPWV, but only a small effect on lePWV. After adjustment for covariates, we observed that hypertension, diabetes, chronic kidney disease and dyslipidemia were positively and significantly associated with aPWV. However, only hypertension had a significant effect on lePWV. Increased ankle systolic blood pressure was associated with increased aPWV independently of brachial blood pressure. Ankle systolic blood pressure was more closely related to aPWV than lePWV. Subjects with an ankle-brachial index <1.0 had higher aPWV and lower lePWV compared with individuals with a normal ankle-brachial index. Lower-extremity arterial stiffness is affected by age and cardiovascular risk factors to a lesser extent than aortic stiffness. Increased ankle systolic blood pressure is linked not only to increased lower-extremity arterial stiffness, but also increased aortic stiffness. In subjects with a low ankle-brachial index, lower-extremity arterial stiffness is spuriously decreased.

Association of endothelial and vascular smooth muscle dysfunction with cardiovascular risk factors, vascular complications, and subclinical carotid atherosclerosis in type 2 diabetic patients

AIM

Atherosclerosis and arteriosclerosis are mainly caused by the dysfunction of arterial components, namely, vascular endothelial cells, smooth muscle cells, and the extracellular matrix. Endothelial dysfunction is well established as a predictive surrogate marker of cardiovascular events; however, little is known regarding the clinical implications of vascular smooth muscle dysfunction for cardiovascular disease and microangiopathy. In the present study, we aimed to clarify the association of arterial dysfunction with micro-/macroangiopathy and conventional cardiovascular risk factors in 181 type 2 diabetic patients (T2DM; age ± SD, 64 ± 10 years; duration of diabetes, 12 ± 10 years).

METHODS

Flow-mediated dilatation (FMD) and nitroglycerin-mediated dilatation (NMD) were assessed to evaluate endothelial dysfunction and vascular smooth muscle dysfunction, respectively, by using a novel ultrasound device, UNEXEF18G (Unex Co. Ltd., Japan).

RESULTS

The FMD and NMD were 6.4 ± 3.9% and 13.4 ± 6.6%, respectively. No significant differences in FMD were noted between T2DM with and without micro- or macroangiopathy; however, NMD in T2DM patients with micro- and macroangiopathy was significantly lower than that in T2DM patients without angiopathy. NMD decreased with the progression of chronic kidney disease (CKD) stage (p = 0.005), but not FMD (p = 0.071). On multiple regression analysis, significant independent contributors to FMD were age, smoking, systolic blood pressure, glycosylated hemoglobin, and serum total cholesterol, while those for NMD were age, systolic blood pressure, and waist circumference.

CONCLUSION

The relationship of vascular complications and cardiovascular risk factors with NMD is different from that with FMD in type 2 diabetic patients.

Association between γ-glutamyltransferase, adiponectin and arterial stiffness

AIM

Serum γ-glutamyltransferase (GGT) is used as a marker of hepatic dysfunction. Recently, several studies reported that GGT is significantly associated with cardiovascular mortality and atherosclerosis. Adiponectin is known to play an important role in the development of atherosclerosis, but its physiologic role has yet to be fully determined. In this study, we investigated the relationships among serum GGT, adiponectin and arterial stiffness.

METHODS

Of 4236 subjects recruited from 17 different medical centers in Seoul, Korea, 2846 subjects were enrolled in our study. The parameters of metabolic syndrome (MetS) were assessed in these subjects, and their plasma adiponectin levels and pulse wave velocity (PWV) were measured along with anthropometric and biochemical profiles, including GGT.

RESULTS

The subjects were stratified into 3 groups according to GGT values. PWV values gradually increased and the adiponectin level decreased with GGT tertiles. Aortic PWV showed a significant correlation with age, SBP, FPG, but there was no correlation among aortic PWV, GGT and adiponectin. Peripheral PWV demonstrated a significant correlation with age, SBP, DBP, BMI, WC, FPG and GGT, but there was no correlation between peripheral PWV and adiponectin. In multiple logistic regression analysis after adjusting for risk factors, GGT was a significant contributor to increased peripheral PWV.

CONCLUSIONS

These findings indicate that serum GGT is independently associated with increased arterial stiffness, but there was no correlation between adiponectin and arterial stiffness in both males and females.

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.

Arterial elasticity imaging: comparison of finite-element analysis models with high-resolution ultrasound speckle tracking

BACKGROUND

The nonlinear mechanical properties of internal organs and tissues may be measured with unparalleled precision using ultrasound imaging with phase-sensitive speckle tracking. The many potential applications of this important noninvasive diagnostic approach include measurement of arterial stiffness, which is associated with numerous major disease processes. The accuracy of previous ultrasound measurements of arterial stiffness and vascular elasticity has been limited by the relatively low strain of nonlinear structures under normal physiologic pressure and the measurement assumption that the effect of the surrounding tissue modulus might be ignored in both physiologic and pressure equalized conditions.

METHODS

This study performed high-resolution ultrasound imaging of the brachial artery in a healthy adult subject under normal physiologic pressure and the use of external pressure (pressure equalization) to increase strain. These ultrasound results were compared to measurements of arterial strain as determined by finite-element analysis models with and without a surrounding tissue, which was represented by homogenous material with fixed elastic modulus.

RESULTS

Use of the pressure equalization technique during imaging resulted in average strain values of 26% and 18% at the top and sides, respectively, compared to 5% and 2%, at the top and sides, respectively, under physiologic pressure. In the artery model that included surrounding tissue, strain was 19% and 16% under pressure equalization versus 9% and 13% at the top and sides, respectively, under physiologic pressure. The model without surrounding tissue had slightly higher levels of strain under physiologic pressure compared to the other model, but the resulting strain values under pressure equalization were > 60% and did not correspond to experimental values.

CONCLUSIONS

Since pressure equalization may increase the dynamic range of strain imaging, the effect of the surrounding tissue on strain should be incorporated into models of arterial strain, particularly when the pressure equalization technique is used.

Low bone mineral density is related to atherosclerosis in postmenopausal Moroccan women

BACKGROUND

Some studies have implicated several possible metabolic linkages between osteoporosis and vascular calcification, including estrogen deficiency, vitamin D excess, vitamin K deficiency and lipid oxidation products. Nevertheless, it remains unclear whether osteoporosis and atherosclerosis are related to each other or are independent processes, both related to aging. The aim of this cross-sectional study was to evaluate the correlation between arterial thickening and bone status in a sample of apparently healthy Moroccan women.

METHODS

Seventy-two postmenopausal women were studied. All patients were without secondary causes that might affect bone density. Bone status was assessed by bone mineral density (BMD) in lumbar spine and all femoral sites. Arterial wall thickening was assessed by intima-media thickness (IMT) in carotid artery (CA) and femoral artery (FA). Prevalent plaques were categorized into four groups ranging from low echogenicity to high echogenicity.

RESULTS

The mean age was 59.2 +/- 8.3 years. 84.7% had at least one plaque. By Spearman Rank correlation, CA IMT was negatively correlated to Femoral total BMD (r = -0.33), Femoral neck BMD (r = -0.23), Ward triangle BMD (r = -0.30) and Trochanter BMD (r = -0.28) while there was no association with lumbar BMD. In multiple regression analysis, CA IMT emerged as an independent factor significantly associated with all femoral sites BMD after adjusting of confounding factors. FA IMT failed to be significantly associated with both Femoral and Lumbar BMD. No significant differences between echogenic, predominantly echogenic, predominantly echolucent and echolucent plaques groups were found concerning lumbar BMD and all femoral sites BMD CONCLUSION: Our results demonstrate a negative correlation between bone mineral density (BMD) qnd carotid intima-media thickness (IMT) in postmenopausal women, independently of confounding factors. We suggest that bone status should be evaluated in patients with vascular disease to assess whether preventive or therapeutic intervention is necessarry.

The combination of IMT and stiffness parameter beta is highly associated with concurrent coronary artery disease in type 2 diabetes

AIMS

The clinical implications of stiffness of the carotid artery (CA) have not been fully clarified in the prediction of coronary artery disease (CAD), although intima-media thickness (IMT) has been established as a surrogate marker. We examined the associations of stiffness parameter beta (ST) and IMT with concurrent CAD.

METHODS

IMT and ST were measured by ultrasound in 439 nondiabetic subjects as a control and 1528 type 2 diabetic subjects (T2DM) with or without CAD in a cross-sectional study.

RESULTS

Both IMT and ST significantly increased with age and group category, in the order of control, T2DM without CAD, and T2DM with CAD (p<0.001). The area under the curve on ROC analysis of ST for concurrent CAD was comparable to that for IMT. On multivariate logistic regression analysis, High IMT (>or=1.30 mm) and High stiffness (>or=20.0) had significant odds ratios for concurrent CAD (2.205, p<0.001 and 1.548, p<0.05, respectively). The group with High IMT and High Stiffness exhibited a stronger multivariate odds ratio (3.115, p=0.0001).

CONCLUSIONS

ST and IMT are associated with CAD and exhibited significant odds ratios for CAD. Our findings suggest that the combination of IMT and ST is a useful marker of atherosclerosis.

Glycemic control and survival of diabetic hemodialysis patients--importance of lower hemoglobin A1C levels

AIMS

The significance of hemoglobin A1C (HbA1C) on the survival of diabetic hemodialysis patients still remains controversial. We investigated the impact of HbA1C on the survival.

METHODS

A total of 122 diabetic patients on maintenance hemodialysis (age, 59.9+/-11.9 years [mean+/-SD]; hemodialysis duration: 53+/-38 months) were surveyed (survey period: 46+/-19 months).

RESULTS

The cumulative survival of the poor glycemic control group (mean HbA1C of 3-month period > or =6.3%, n=62) was significantly lower than that of the good group (HbA1C<6.3%, n=60), as determined by Kaplan-Meier estimation (P=0.0084, log-rank test). Kaplan-Meier analysis also demonstrated that both cardiovascular and non-cardiovascular mortalities were higher in the poor group than in the good group (P=0.0545 and P=0.0453, respectively). In a multivariate Cox proportional hazard model, the mean HbA1C was a significant predictor of survival (OR 1.260 per 1.0%, 95% CI 1.020-0.579, P=0.0325).

CONCLUSIONS

Poor glycemic control is an independent predictor of poor prognosis in diabetic hemodialysis patients. HbA1C is a clinically useful parameter for identifying the risk for mortality, both for cardiovascular and non-cardiovascular mortality, and that careful management of glycemic control by use of HbA1C is important.

The Association Between Ankle Brachial Pressure Index and Pulse Wave Velocity: Clinical Implication of Pulse Wave Velocity

Objective: The aim of this study was to assess the relationship between ankle brachial pressure index and pulse wave velocity in patients with peripheral arterial disease.

Methods: Brachial-knee and brachial-ankle pulse wave velocity were measured by pneumoplethysmography using cuffs in a standard technique. Correlation between pulse wave velocity and Doppler-ankle brachial pressure index was assessed by Spearman correlation and receiver operating curves.

Results: A total of 133 claudicants were assessed. Analysis by developing receiver operating curves for ankle brachial pressure index and pulse wave velocity showed that patients with ankle brachial pressure index over 0.6 were more likely to have a bk-pulse wave velocity over 9.2 m/s and ba-pulse wave velocity over 9.5 m/s.

Conclusion: These results show for the first time that nondiabetic vascular patients may have measurable significant arterial stiffness independent of an impaired ankle brachial pressure index. These data suggest that pulse wave velocity may be valuable in screening and evaluating the severity of peripheral arterial disease.

High-resolution ultrasound speckle tracking may detect vascular mechanical wall changes in peripheral artery bypass vein grafts

We report the use of high-resolution, phase-sensitive ultrasound speckle tracking to measure the local vessel-wall strain in two subjects with artery-vein bypass grafts. In addition, we combined this technique with a free-hand pressure equalization procedure to elucidate the nonlinear effects of blood pressure on vessel wall compliance. While conventional ultrasound imaging can be used to elucidate the mechanical properties of tissues within the body, it is constrained by comparatively lower resolution and inferential, rather than direct, measurements of strain and by the small strain normally produced under physiological pressure in highly nonlinear structures such as arteries. One of our subjects was examined both before and after developing stenosis 3 months postsurgery. The strain values for this individual were found to be significantly lower, indicating a stiffer vessel wall at the stenotic region than at a nonstenotic region under both physiological and equalized pressure. These results suggest the possibility of noninvasive detection of neointimal hyperplasia preceding anastomotic stenosis.

High-resolution ultrasound elasticity imaging to evaluate dialysis fistula stenosis

Accurate, noninvasive characterization of arterial wall mechanics and detection of fibrotic vascular lesions could vastly improve the ability to predict patient response to local treatments such as angioplasty. Current imaging and other techniques for determining wall compliance rely on imprecise or indirect estimates of wall motion. This study used high-resolution ultrasound imaging with phase-sensitive speckle tracking to obtain detailed and direct measurements of arterial stiffness in two subjects with dialysis fistula dysfunction. In both subjects, the absolute values of strain were much higher in normal regions of fistula than in regions of stenosis. The lower values of strain in stenotic fistula indicate greater stiffness of the vessel wall. The ultrasound speckle tracking technique used here may have potential to determine vascular mechanical properties noninvasively with a level of precision and accuracy not currently available.

Early manifestation of macrovasculopathy in newly diagnosed never treated type II diabetic patients with no traditional CVD risk factors

Type II diabetes patients have increased risk of macrovascular complications compared with the general population. Arterial stiffness is considered as an independent predictor of macrovascular events. This study investigated arterial stiffness in newly diagnosed never treated diabetes and impaired glucose tolerance (IGT) patients without any traditional cardiovascular diseases (CVD) risk factors. After preliminary screening of 1620 individuals, 30 diabetic and 30 IGT patients were recruited and compared with age- and sex-matched 30 normoglycaemic subjects. The subjects were newly diagnosed, never treated, normotensive, non-obese, non-hyperlipidaemic and non-smoker. Haemodynamic variables, pulse wave velocity (PWV) and augmentation index (AI) were measured. The PWV was significantly higher in diabetic patients (10.37+/-2.64m/s vs. 8.70+/-1.29m/s; p=0.035) and was of borderline significant in IGT subjects (9.54+/-1.56m/s vs.8.70+/-1.29m/s, p=0.078) compared to normoglycaemic individuals. Augmentation index was higher of borderline significant in diabetic (134.53+/-17.32% vs. 129.17+/-11.18%, p=0.055) and IGT patients (132.02+/-16.11% vs. 129.17+/-11.18%, p=0.059) compared to normoglycaemic individuals. The study demonstrated that newly diagnosed never treated diabetic patients without any CV complications had early manifestation of macrovascular diseases as evident by increased arterial stiffness. The findings also revealed early manifestations of preclinical vasculopathy and potentially increased risk for development of macrovascular diseases at an early age in diabetic patients.

Arterial stiffness in diabetes and the metabolic syndrome: a pathway to cardiovascular disease

Increased arterial stiffness associated with diabetes and the metabolic syndrome may in part explain the increased cardiovascular disease risk observed in these conditions. Arterial stiffness can be estimated by quantifying pulse pressure but is better described by distensibility and compliance coefficients, pulse wave velocity and wave reflection. The most common non-invasive methodologies used to quantify these estimates of arterial stiffness (e.g. ultrasonography and applanation tonometry) are also described. We then review and summarise the current data on the associations between diabetes, the metabolic syndrome and insulin resistance on the one hand and greater arterial stiffness on the other, and identify and discuss some unresolved issues such as differential stiffening of central vs peripheral arterial segments, the impact of sex, and the pathobiology of increased arterial stiffness in diabetes and the metabolic syndrome. Finally, some considerations with regard to treatment options are presented. At present the most powerful therapy available for reducing arterial stiffness is to vigorously treat hypertension using pharmacological agents. New pharmacological strategies to reduce arterial stiffness are likely to be especially relevant to individuals with diabetes.

Clustering of metabolic syndrome risk factors and arterial stiffness in young adults: the Northern Ireland Young Hearts Project

OBJECTIVES

This study aimed to investigate whether the clustering of the risk factors of the metabolic syndrome (MetS) is associated with stiffness of central and peripheral arterial segments; whether these associations are similar in men and women; and whether insulin resistance and low-grade inflammation mediate any such associations.

BACKGROUND

Increased arterial stiffness may explain, at least in part, the increased cardiovascular and diabetes risk associated with the MetS. However, the mechanisms linking the MetS to an increased arterial stiffness are incompletely understood, and gender differences may exist.

METHODS

Cross-sectional analyses of data on 313 young men and women (mean age 23 years) from the Northern Ireland Young Hearts Project. Subjects were categorized according to the number of traits of the MetS; in addition a continuous MetS score was calculated. Arterial stiffness was assessed by measuring pulse wave velocity (PWV) in three arterial segments using a non-invasive optical method.

RESULTS

The prevalence of the MetS was similar for men (10.6%) and women (10.5%). After adjustment for potential confounders and other cardiovascular risk factors, PWV of the three arterial segments investigated increased with increasing traits of the MetS in women only. Women with the MetS, as compared to those without risk factors of the syndrome, had greater PWV of the aorto-iliac (+14.0%, P = 0.016), the aorto-radial (+13.2%, P = 0.010) and aorto-dorsalis pedis (+11.8%, P = 0.011) segments. A great deal (up to 75%) of the association between the MetS and aortic-iliac PWV was mediated by heart rate, inflammation markers [C-reactive protein (CRP) and fibrinogen] and insulin resistance [homeostatic model assessment-insulin resistance (HOMA-IR)], whereas these variables did not explain much of the association between the MetS and PWV of the peripheral segments.

CONCLUSIONS

Young women with the MetS show increased stiffness of peripheral and central arteries, a mechanism that may explain their increased cardiovascular risk. Low-grade inflammation, insulin resistance and sympathetic activation explain much of the adverse impact of the MetS on central, but not peripheral, arterial stiffness.

Estimated Glomerular Filtration Rate and Urinary Albumin Excretion Are Independently Associated with Greater Arterial Stiffness: The Hoorn Study

Mild renal insufficiency is a risk factor for cardiovascular disease (CVD). Both a decline in GFR and (micro)albuminuria are associated with greater cardiovascular mortality. In ESRD, arterial stiffness, an important cause of CVD, is known to be greater, but few data exist in individuals with mild renal insufficiency or microalbuminuria. This study investigated the association of impaired renal function expressed as lower GFR or greater urinary albumin excretion with arterial stiffness. In a population-based study in 806 individuals (402 men), mean age 68 yr (range 50 to 87), peripheral arterial stiffness (by compliance and distensibility of the carotid, brachial, and femoral arteries and by the carotid elastic modulus [E(inc)]) and central arterial stiffness (by total systemic arterial compliance, carotid-femoral transit time, and aortic augmentation index) were measured ultrasonically. GFR was estimated (eGFR) by the Modification of Diet in Renal Disease (MDRD) formula. Urinary albumin excretion was expressed as urinary albumin/creatinine ratio (UACR). eGFR was 60.6 +/- 11.1 ml/min per 1.73 m(2). Median UACR was 0.57 mg/mmol (range 0.1 to 26.6). After adjustment for age, mean arterial pressure (MAP), gender, and glucose tolerance status (GTS), each 5-ml/min per 1.73 m(2) lower eGFR was associated with a lower distensibility coefficient of the carotid (regression coefficient beta -0.20 10(-3)/kPa; 95% confidence interval [CI] -0.34 to -0.07 10(-3)/kPa) and brachial artery (-0.15 10(-3)/kPa; 95% CI -0.28 to -0.03 10(-3)/kPa) and a greater carotid E(inc) (0.02 kPa; 95% CI 0.0004 to 0.04 kPa). No statistically significant association was found of eGFR with other arterial stiffness indices. After adjustment for age, MAP, gender, and GTS, a greater UACR (per quartile) was associated with a greater E(inc) (0.03 kPa; 95% CI 0.001 to 0.07 kPa) and a trend to a lower distensibility coefficient (-0.24 10(-3)/kPa; 95% CI -0.49 to 0.02 10(-3)/kPa) of the carotid artery. After adjustment for age, MAP, gender, and GTS, a greater UACR (per quartile) was in addition associated with a shorter carotid-femoral transit time (-1.67 ms; 95% CI -3.24 to -0.10 ms). These associations were not substantially changed by mutual adjustment for eGFR and UACR. In individuals with mild renal insufficiency, both a lower eGFR and a greater albumin excretion, even below levels that are considered to reflect microalbuminuria, are independently associated with greater arterial stiffness. Moreover, these associations were mutually independent. These findings may explain, in part, why eGFR and microalbuminuria are associated with greater risk for CVD and suggest that amelioration of arterial stiffness could be a target of intervention.

Relationship of smoking and smoking cessation with ankle-to-arm blood pressure index in elderly Japanese men

BACKGROUND

Cigarette smoking is associated with an increased risk of peripheral arterial disease, but the relationship between smoking cessation and preclinical peripheral atherosclerosis is uncertain.

DESIGN AND METHODS

A cross-sectional, population-based study to examine the effect of smoking and smoking cessation on the prevalence of peripheral arterial disease among 1215 men aged 60-79 years in two Japanese communities in 1999-2000. The ankle-to-arm systolic blood pressure index (AAI) was used as an estimate of the presence of peripheral atherosclerosis.

RESULTS

The mean AAI correlated inversely and linearly with smoking status and pack-years of smoking. The multivariate prevalence odds ratio [95% confidence interval (CI)] of low AAI (< 0.90) compared with never-smokers was 3.7 (95% CI 1.1-12.7) for current smokers and 4.2 (95% CI 1.2-14.6) for men with 45 or more pack-years of smoking. In men who have quit smoking for 20 years or more, the mean AAI was higher and the prevalence of low AAI (< 0.90) was lower than those of current smokers, but similar to those of never-smokers.

CONCLUSIONS

Our results confirm that current smoking and pack-years of smoking correlate with the presence of peripheral artery disease. The results suggest that smoking cessation for 20 years or more is associated with the regression of atherosclerosis in peripheral arteries. This finding needs to be confirmed by a prospective study.

Effect of adiponectin on carotid arterial stiffness in type 2 diabetic patients treated with pioglitazone and metformin

Adiponectin, an adipocyte-specific plasma protein, has been reported to exhibit protective effects against atherosclerosis as well as an insulin-sensitizing effect. This study was designed to investigate the effect of adiponectin on carotid arterial stiffness in type 2 diabetic patients treated with pioglitazone and metformin. Twenty type 2 diabetic patients were enrolled and divided into 2 groups, a pioglitazone-treated group (n = 10) and a metformin-treated group (n = 10). Before and after intervention, plasma adiponectin levels were measured by enzyme-linked immunosorbent assay and carotid arterial stiffness was evaluated by the stiffness parameter beta, measured by ultrasound equipped with a phase-locked echo-tracking system. In the pioglitazone group, plasma adiponectin level significantly increased and stiffness parameter beta significantly decreased, whereas in the metformin group neither of these parameters changed significantly. The changes in stiffness parameter beta were significantly and inversely correlated with change in plasma adiponectin level after treatment with pioglitazone or metformin in the group of all subjects (r = -0.472, P = .036). In conclusion, the present study is the first to demonstrate that increase in adiponectin level after treatment with the insulin sensitizers pioglitazone and metformin may improve arterial stiffness in patients with type 2 diabetes mellitus.

Regional arterial stiffness associated with ischemic heart disease in type 2 diabetes mellitus

Arterial stiffness is increased in type 2 diabetes mellitus, and diabetes preferentially affects arterial stiffness of the central (elastic, capacitive) over peripheral (muscular, conduit) arteries. We hypothesized that arterial stiffness of the central artery may be more closely associated with ischemic heart disease (IHD) than stiffness of peripheral arteries in type 2 diabetes mellitus. The subjects were 595 type 2 diabetes patients including 70 with IHD. Arterial stiffness was measured as pulse wave velocity (PWV) in the heart-carotid, heart-femoral, heart-brachial, and femoral-ankle regions. The PWV values of the four segments correlated with each other in patients without IHD. However, the correlations were less impressive in those with IHD, suggesting unequal stiffening of regional arteries in IHD. As compared with patients without IHD, the IHD group showed significantly higher PWV values of the four arterial segments, particularly of the heart-femoral region. The presence of IHD was significantly associated with higher heart-femoral PWV, and this association remained significant and independent of other factors in a multiple logistic regression analysis. Pulse pressure was more strongly correlated with PWV of the heart-femoral than other arterial regions. Thus, diabetic patients with IHD have increased stiffness of arteries, particularly of the aorta, supporting the concept that central arterial stiffness plays an important role in the development of IHD.

The association of plasma adiponectin level with carotid arterial stiffness

Adiponectin plays important roles in protecting against both insulin resistance and the development of atherosclerosis. The aim of the present study was to investigate the clinical impact of plasma adiponectin on arterial stiffness, a functional property of atherosclerosis, in type 2 diabetic and nondiabetic subjects. We evaluated plasma adiponectin levels and stiffness index beta for the common carotid artery assessed by ultrasound using a phase-locked echo-tracking system for 98 type 2 diabetic subjects and 116 nondiabetic subjects as controls. Plasma adiponectin levels were significantly lower in the diabetic than in the nondiabetic group. The stiffness index beta was significantly higher in the diabetic than in the nondiabetic group. Plasma adiponectin level was significantly correlated with stiffness index beta in the group of all subjects (r=-0.189, P=.006) and the nondiabetic group (r=-0.187, P=.045), but not in the diabetic group (r=0.045, P=.665). On multiple regression analysis, plasma adiponectin level was found to be a significant independent contributor to stiffness index beta in the group of all subjects (beta=-0.232, P=.020) and the nondiabetic group (beta=-0.337, P=.016), but not in the diabetic group. In conclusion, adiponectin is significantly but weakly associated with carotid arterial stiffness independently of known atherogenic factors in the nondiabetic group and that of all subjects, although no significant association between these variables was found in the group of diabetic subjects.

Effect of atorvastatin on regional arterial stiffness in patients with type 2 diabetes mellitus

OBJECTIVE

A statin, a potent lipid-lowering drug, improves pain-free walking distance in patients with peripheral arterial disease (PAD) without increasing the ankle-brachial pressure index (ABI). Arterial stiffness affects the blood flow of peripheral arteries. The purpose of this study was to evaluate the effect of cholesterol-lowering with atorvastatin on regional arterial stiffness in patients with type 2 diabetes mellitus.

METHODS

The subjects were 22 type 2 diabetic patients with hypercholesterolemia, who received atorvastatin at a daily dose of 10 mg for 6 months. Before and after the treatment with atorvastatin, we measured pulse wave velocity (PWV) in the heart-brachial, heart-carotid, heart-femoral and femoral-ankle segments.

RESULTS

Following treatment with atorvastatin, femoral-ankle PWV showed a significant reduction. The PWV of other arterial segments tended to decrease, although the changes were not statistically significant. We found no significant changes in blood pressure, heart rate, ABI, or plasma concentrations of glucose, L-arginine and asymmetric dimethylarginine (ADMA), an endogenous inhibitor of endothelial function.

CONCLUSIONS

Atorvastatin treatment was associated with an improvement in the stiffness of leg arteries in type 2 diabetes mellitus. This may partly explain the statin-mediated improvement of walking performance in those with PAD.