Microvascular degenerative complications are associated with increased aortic stiffness in type 2 diabetic patients

Intradermal Advanced Glycation End-products Relate to Reduced Sciatic Nerve Structural Integrity in Type 2 Diabetes

BACKGROUND

Cardiovascular risk management is beneficial, but stringent glycemic control does not prevent the progression of distal sensorimotor polyneuropathy (DSPN). Persistent hyperglycemia-induced alterations and cardiovascular factors may contribute to diabetes-associated nerve damage. This study aimed to evaluate the correlation between skin auto-fluorescence (sAF), an indicator of dermal advanced glycation end-product (AGE) accumulations, cardiovascular risk, and changes in peripheral nerve integrity.

METHODS

Sixty-two individuals with type 2 diabetes (T2D) (20 women and 42 men), including 29 diagnosed with DSPN (7 women and 22 men), and 10 healthy controls (HC) underwent diffusion tensor MR imaging of the sciatic nerve to assess fractional anisotropy (FA), an indicator of nerve structural integrity. sAF measurements were combined with clinical, serological, and electrophysiological evaluations. Arterial stiffness was assessed via pulse wave velocity (PWV).

RESULTS

sAF (HC 2.1 ± 0.25 AU, nDSPN 2.3 ± 0.47, DSPN 2.6 ± 0.43; p = 0.005) was higher in individuals with DSPN compared to HC (p = 0.010) and individuals without DSPN (p = 0.035). Within the group of T2D FA correlated negatively with sAF (r = -0.49, p < 0.001), PWV (r = -0.40, p = 0.009) and high-sensitivity troponin T (hsTNT), a marker of microvascular damage (r = -0.39, p < 0.001). In DSPN, sAF correlated positively with hsTNT (r = 0.58, p = 0.005) and with PWV (r = 0.52, p = 0.007), the sciatic nerve's FA correlated negatively with PWV (r = -0.47, p = 0.010).

CONCLUSIONS

This study is the first to show close correlations between reduced peripheral nerve integrity and both intradermal AGE deposition and arterial stiffness in individuals with T2D. These findings highlight a mechanistic link between glycation-related vascular injury and neuronal damage emphasizing the importance of cardiovascular risk management in preventing DSPN.

Association of arterial stiffness and eye disease: a systematic review and meta-analysis

BACKGROUND

This systematic review and meta-analysis assesses the association of arterial stiffness with age-related macular degeneration (AMD), glaucoma, retinal vein occlusion (RVO) and retinopathy (diabetic and hypertensive).

METHODS

Medline and Embase were systematically searched for observational studies of arterial stiffness and eye disease. Cohort studies were included if they estimated arterial stiffness using any measures based on the arterial waveform, with cross-sectional and case-control studies limited to measures of pulse wave velocity. We assessed the certainty of evidence using Grading of Recommendations, Assessment, Development and Evaluation.

RESULTS

The systematic review of 61 studies (six for AMD, ten for glaucoma, six for RVO and 39 for retinopathy) showed that arterial stiffness overall was higher in people with eye disease than people without eye disease. Forty-four cross-sectional and case-control studies were included in the meta-analysis. Arterial stiffness estimated by way of pulse wave velocity was associated with AMD (mean difference: 0.92 m/s, 95% CI 0.37 to 1.46; 2 studies; n=381; low certainty evidence), glaucoma (mean difference: 0.97 m/s, 95% CI 0.31 to 1.64; 7 studies; n=3418; low certainty evidence), RVO (mean difference: 2.79 m/s, 95% CI 2.02 to 3.55; 5 studies; n=414; very low certainty evidence) and retinopathy (1.48 m/s, 95% CI 0.1.16 to 1.81; 22 studies; n=10 074; low certainty evidence). The 19 cohort studies identified (five for AMD, three for glaucoma, one for RVO and 10 for retinopathy) indicated overall that increased arterial stiffness was associated with the future development of eye disease.

CONCLUSIONS

Higher arterial stiffness is associated with AMD, glaucoma, RVO and retinopathy PROSPERO REGISTRATION NUMBER: CRD42019129563.

AST/ALT ratio is an independent risk factor for diabetic retinopathy: A cross-sectional study

The aspartate to alanine transaminase (AST/ALT) ratio indicates oxidative stress and inflammatory reactions related to the occurrence of diabetic retinopathy (DR). Currently, there are no reports on the correlation between AST/ALT ratio and DR. Hence, this study aimed to explore the relationship between AST/ALT ratio and DR. This cross-sectional study utilized data from the Metabolic Management Center of the First People's Hospital in City. In total, 1365 patients with type 2 diabetes mellitus (T2DM) participated in the study, including 244 patients with DR and 1121 patients without DR. We collected the results of fundus photography, liver function, and other research data and grouped them according to tertiles of AST/ALT ratios. DR prevalence was the highest in the group with the highest AST/ALT ratio (22.12%, P = .004). Both univariate (OR = 2.25, 95% CI: 1.51-3.34, P < .001) and multivariable logistic regression analyses (adjusted for confounding factors) showed that the risk of DR increased by 36% when the AST/ALT ratio increased by 1 standard deviation (SD) (OR = 1.36, 95% CI: 1.16-1.59, P < .001), and 29.3% was mediated by the duration of diabetes. A sensitivity analysis confirmed the stability of the results. This study showed that an increase in AST/ALT ratio is an independent risk factor for DR.

Mechanical Regulation of Retinal Vascular Inflammation and Degeneration in Diabetes

Vascular inflammation is known to cause degeneration of retinal capillaries in early diabetic retinopathy (DR), a major microvascular complication of diabetes. Past studies investigating these diabetes-induced retinal vascular abnormalities have focused primarily on the role of molecular or biochemical cues. Here we show that retinal vascular inflammation and degeneration in diabetes are also mechanically regulated by the increase in retinal vascular stiffness caused by overexpression of the collagen-cross-linking enzyme lysyl oxidase (LOX). Treatment of diabetic mice with LOX inhibitor β-aminopropionitrile (BAPN) prevented the increase in retinal capillary stiffness, vascular intracellular adhesion molecule-1 overexpression, and leukostasis. Consistent with these anti-inflammatory effects, BAPN treatment of diabetic mice blocked the upregulation of proapoptotic caspase-3 in retinal vessels, which concomitantly reduced retinal capillary degeneration, pericyte ghost formation, and the diabetes-induced loss of contrast sensitivity in these mice. Finally, our in vitro studies indicate that retinal capillary stiffening is sufficient to increase the adhesiveness and neutrophil elastase-induced death of retinal endothelial cells. By uncovering a link between LOX-dependent capillary stiffening and the development of retinal vascular and functional defects in diabetes, these findings offer a new insight into DR pathogenesis that has important translational potential.

ARTICLE HIGHLIGHTS

Atomic Force Microscopy-Based Measurements of Retinal Microvessel Stiffness in Mice with Endothelial-Specific Deletion of CCN1

Vascular stiffness is an independent predictor of human vascular diseases and is linked to ischemia, diabetes, high blood pressure, hyperlipidemia, and/or aging. Blood vessel stiffening increases owing to changes in the microscale architecture and/or content of extracellular, cytoskeletal, and nuclear matrix proteins. These alterations, while best appreciated in large blood vessels, also gradually occur in the microvasculature and play an important role in the initiation and progression of numerous microangiopathies including diabetic retinopathy. Although macroscopic measurements of arterial stiffness by pulse wave velocity are often used for clinical diagnosis, stiffness changes of intact microvessels and their causative factors have not been characterized. Herein, we describe the use of atomic force microscopy (AFM) to determine stiffness of mouse retinal capillaries and assess its regulation by the cellular communication network (CCN) 1, a stiffness-sensitive gene-encoded matricellular protein. AFM yields reproducible measurements of retinal capillary stiffness in lightly fixed freshly isolated retinal flat mounts. AFM measurements also show significant changes in compliance properties of the retinal microvasculature of mice with endothelial-specific deletion of CCN1, indicating that CCN1 expression, or lack thereof, affects the mechanical properties of microvascular cells in vivo. Thus, AFM has the force sensitivity and the spatial resolution necessary to measure the local modulus of retinal capillaries in situ and eventually to investigate microvascular compliance heterogeneities as key components of disease pathogenesis.

Brachial-ankle pulse wave velocity as a predictor of long-term cardiovascular events in 2174 subjects with type 2 diabetes mellitus: A retrospective cohort study

The prognostic value of arterial stiffness in patients with diabetes mellitus (DM) remains unclear. The aim of this study was to investigate the association between brachial-ankle pulse wave velocity (baPWV) and the occurrence of cardiovascular events in people with DM. A total of 2714 subjects (mean age, 63.6 years; males, 59.3%) with type 2 DM and without documented cardiovascular disease and stroke were analyzed. The primary end-point of this study was composite cardiovascular events of cardiac death, non-fatal myocardial infarction, coronary revascularization and stroke. There were 118 composite events (4.3%) during a median follow-up period of 3.84 years (interquartile range, 1.60-5.52 years). In multivariable Cox regression analysis, higher baPWV (≥1672 cm/s) was associated with composite events even after controlling for potential confounders (hazard ratio [HR], 2.00; 95% confidence interval [CI], 1.31-3.07; P = .001). Compared to the lowest baPWV tertile, both middle (HR, 1.84; 95% CI, 1.03-3.27; P = .037) and the highest (HR, 2.97; 95% CI, 1.69-5.22; P < .001) tertile of baPWV were associated with increased risk of cardiovascular events in the same multivariable model. In conclusion, the baPWV was associated with cardiovascular events in people with type 2 DM. Considering the simplicity and convenience of baPWV measurement, baPWV may be useful for risk stratification of people with type 2 DM.

Prognostic impact of changes in aortic stiffness for cardiovascular and mortality outcomes in individuals with type 2 diabetes: the Rio de Janeiro cohort study

BACKGROUND

The prognostic importance of changes in aortic stiffness for the occurrence of adverse cardiovascular outcomes and mortality has never been investigated in patients with type 2 diabetes. We aimed to evaluate it in a cohort of 417 patients.

METHODS

Changes in aortic stiffness were assessed by 2 carotid-femoral pulse wave velocity (CF-PWV) measurements performed over a 4-year period. Multivariable Cox analysis examined the associations between changes in CF-PWV, evaluated as a continuous variable with splines and as categorical ones (quartiles and stable/reduction/increase subgroups), and the occurrence of total cardiovascular events (CVEs), major adverse CVEs (MACEs), and all-cause and cardiovascular mortality.

RESULTS

Over a median follow-up of 8.2 years after the 2nd CF-PWV measurement, there were 101 total CVEs (85 MACEs) and 135 all-cause deaths (64 cardiovascular). As a continuous variable, the lowest risk nadir was at -2.5%/year of CF-PWV change, with significantly higher risks of mortality associated with CF-PWV increases, but no excess risks at extremes of CF-PWV reduction. Otherwise, in categorical analyses, patients in the 1st quartile (greatest CF-PWV reductions) had excess risks of all-cause and cardiovascular mortality (hazard ratios [HRs]: 2.0-2.7), whereas patients in 3rd quartile had higher risks of all outcomes (HRs: 2.0-3.2), in relation to the lowest risk 2nd quartile subgroup. Patients in the 4th quartile had higher risks of all-cause mortality. Categorization as stable/reduction/increase subgroups was confirmatory, with higher risks at greater reductions (HRs: 1.7-3.3) and at greater increases in CF-PWV (HRs: 1.9-3.4), in relation to those with stable CF-PWV.

CONCLUSIONS

Changes in aortic stiffness, mainly increases and possibly also extreme reductions, are predictors of adverse cardiovascular outcomes and mortality in individuals with type 2 diabetes.

Increased Arterial Stiffness as a Predictor for Onset and Progression of Diabetic Retinopathy in Type 2 Diabetes Mellitus

INTRODUCTION

Brachial-ankle pulse wave velocity (baPWV), an indicator of arterial stiffness, has been demonstrated to be associated with type 2 diabetes mellitus (T2DM) and its vascular complications. This study was aimed at investigating the correlations of baPWV with both the presence and severity of diabetic retinopathy (DR) at baseline and at exploring the predictive role of baPWV in the new onset/progression of DR in the follow-up analysis.

METHODS

The prospective cohort study recruited 2,473 Chinese patients with T2DM, of whom 663 participants were finally included in the follow-up analysis. The presence and grading of DR were performed by the modified Early Treatment Diabetic Retinopathy Study. Uni- or multivariate linear and logistic regression models and Cox proportional-hazards regression analysis were conducted.

RESULTS

Of 2,473 patients with T2DM at baseline, 734 individuals were assessed to have DR and further categorized into 630 with non-sight-threatening DR (NSTDR) and 104 with STDR. In addition to the positive relationship between increased baPWV and the presence of DR, multinominal logistic regression analysis revealed that higher tertiles of baPWV were significantly related to the NSTDR (T2: OR = 1.62 (1.22, 2.15), p < 0.001, and T3: OR = 2.58 (1.86, 3.58), p < 0.001) and STDR group (T3: OR = 3.87 (1.87, 8.02), p < 0.001). During a follow-up (mean period of 16.4 months), 111 participants had new onset/progression of DR. The cox regressions showed that high baseline baPWV was correlated with increased risk of development/progression of DR (HR = 2.24, 95% CI (1.24, 4.03), p = 0.007, for T2 baPWV and HR = 2.90, 95% CI (1.49, 5.64), p = 0.002, for T3 baPWV) after adjustments for multiple factors.

CONCLUSIONS

Our results demonstrated that baseline baPWV might be an independent predictor in new onset/worsening of DR, suggesting that increased arterial stiffness might be involved in the development of DR. Follow-up studies with a longer duration are needed.

Effect of insulin treatment on pulsatility ratio and resistance index of the retinal artery in patients with type 2 diabetes

This study aimed to evaluate whether long-term insulin treatment is associated with abnormalities in retinal circulation in type 2 diabetic patients. We evaluated 19 eyes of nondiabetic individuals and 68 eyes of type 2 diabetic patients. The eyes of diabetic patients were classified into two groups according to the presence or absence of long-term insulin therapy. We used a Doppler optical coherence tomography flowmeter to measure diameter, velocity, and blood flow in the major temporal retinal artery. The pulsatility ratio (PR) and resistance index (RI), indices of vascular rigidity, were calculated from the blood velocity profile. PR and RI were significantly elevated in type 2 diabetic patients compared with nondiabetic subjects (P < 0.05). In type 2 diabetes patients, PR and RI were significantly higher in patients receiving long-term insulin treatment than in those without (P < 0.01). There was a significant difference in velocity (P < 0.05), but not diameter and blood flow, between nondiabetic subjects and type 2 diabetes patients. No significant difference in diameter, velocity, or blood flow was observed between the groups with and without long-term insulin treatment. Long-term insulin treatment can affect PR and RI, which might be associated with vascular rigidity of the retinal artery in patients with type 2 diabetes.

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.

High pulse wave velocity is associated with the severity of diabetic retinopathy in patients with type 2 diabetes

Pulse wave velocity (PWV) is a non-invasive test for assessing arterial stiffness, and brachial-ankle PWV has been used as an index of peripheral arterial stiffness. This study aimed to investigate the association between the PWV value and severity of diabetic retinopathy (DR). 846 patients with type 2 diabetes (T2DM) consecutively underwent brachial-ankle PWV, and the degree of PWV was defined by tertile. The severity of DR was categorized as no diabetic retinopathy (NDR), non-proliferative diabetic retinopathy (NPDR) or proliferative diabetic retinopathy (PDR) based on the Early Treatment Diabetic Retinopathy Study Scale. Multinomial logistic regression analyses were utilized not only to explore the association between the degree of PWV and severity of DR but also to examine the association of a high-tertile PWV with PDR. PWV levels, diabetes duration and blood pressure were all significantly higher in subjects with NPDR or PDR as compared with individuals with NDR. In the univariate analysis, the highest tertile of PWV (>19.6 m/s) was significantly associated with both NPDR (p<0.001) and PDR (p<0.001) as compared with NDR. After adjusting for confounding factors, the highest tertile of PWV remained significantly associated with PDR (p=0.005), but not with NPDR (p=0.107). Furthermore, the highest tertile of PWV was more significantly associated with PDR (OR=6.15, 95%CI 1.38 to 27.38) as compared with the lowest tertile. In our study, an increasing degree of PWV was positively associated with the severity of DR. High PWV was strongly associated with the risk of severe DR, especially PDR.

Total White Blood Cell Count Mediated the Association Between Increased Arterial Stiffness and Risk of Type 2 Diabetes Mellitus in Chinese Adults

OBJECTIVE

Type 2 diabetes mellitus (T2DM) is known to be related to increased arterial stiffness. However, little is known about the risk of T2DM due to accelerated arterial stiffness and the underlying mechanism involved. We aimed to examine arterial stiffness, as determined by brachial-ankle pulse wave velocity (baPWV), in relation to T2DM among a community-based population and whether the association was mediated by white blood cell (WBC) counts. Approach and results: A total of 1036 Chinese adults aged 64.3 years with complete data were qualified in the present study. The dose-response association between baPWV levels, WBC counts, and risk of T2DM were explored using generalized linear models or multivariate logistic regression models. A mediation analysis was conducted to investigate the role of WBC counts on the association between baPWV and T2DM. After multivariate adjustments, we observed a dose-responsive relationship between increased baPWV and elevated risk of T2DM: comparing extreme tertiles of baPWV, the adjusted odds ratio for T2DM risk was 2.29 (95% CI, 1.32-3.98; P for trend =0.005). In addition, significant dose-dependent relationships were found across baPWV tertiles with increasing total or differential WBC counts, which in turn, were positively related to higher risk of T2DM (all P for trend <0.05). Mediation analyses indicated that total WBC count mediated 4.5% of the association between increased baPWV and elevated T2DM risk.

CONCLUSIONS

Increased arterial stiffness might increase T2DM risk among middle-aged and older Chinese adults, which was partially mediated by total WBC count.

Central arterial stiffness and retinal vessel calibers: the Atherosclerosis Risk in Communities Study-Neurocognitive Study

BACKGROUND

The retinal microvasculature provides a window to the cerebral vasculature and enables examination of changes in retinal caliber that may mimic those occurring in cerebrovascular disease. The association of central arterial stiffness and retinal vessel caliber in a population sample is not fully understood.

METHODS

In 1706 older adults (mean age 76.3, 58.1% women) from the population-based Atherosclerosis Risk in Communities Study, we examined the cross-sectional association of central arterial stiffness [carotid-femoral pulse wave velocity (cfPWV)] with retinal vessel calibers [central retinal arteriolar equivalent (CRAE) and central retinal vein equivalent (CRVE)]. We estimated the association of cfPWV with CRAE narrowing (<25th percentile) and CRVE widening (>75th percentile) after adjustment for age, sex, race-field center, BMI, smoking, and type 2 diabetes. We tested for effect modification by sex, hypertension, and type 2 diabetes.

RESULTS

Carotid-femoral PWV (m/s) was not associated with the odds of CRAE narrowing [odds ratio (OR): 0.99; 95% CI: 0.95-1.03]. The association of cfPWV with CRVE widening was stronger in those without hypertension (OR: 1.10; 95% CI: 1.01-1.20) versus those with hypertension (OR: 1.01 95% CI: 0.96-1.05) and slightly stronger in those with type 2 diabetes (OR: 1.07; 95% CI: 1.00-1.14) versus without type 2 diabetes (OR: 1.01; 95% CI: 0.96-1.06).

CONCLUSIONS

In older adults, cfPWV was associated with wider retinal venular caliber, particularly in individuals without hypertension. Central arterial stiffening may be associated with cerebral microvascular changes, as exhibited in its retinal vasculature component.

Association Between Atherosclerosis and Diabetic Retinopathy in Chinese Patients with Type 2 Diabetes Mellitus

AIM

To explore the association between the atherosclerosis and diabetic retinopathy (DR) in Chinese patients with type 2 diabetes mellitus (T2DM).

METHODS

This hospital-based cross-sectional study included 949 patients (700 males and 249 females) with T2DM. The atherosclerotic parameters were assessed using the cardio-ankle vascular index (CAVI), ankle-brachial index (ABI), and carotid plaque. DR was assessed and graded using digital retinal photography and fundus fluorescein angiography as either nonproliferative DR (NPDR) or proliferative DR (PDR). Multiple logistic regression analysis was performed to identify the associations between the atherosclerotic parameters and DR status.

RESULTS

The prevalence of DR was 23.6% in total patients, including 167 (17.6%) patients with NPDR and 57 (6.0%) patients with PDR. Patients with NPDR and PDR were more likely to have higher prevalence of increased CAVI, increased ABI, and carotid plaque than those without DR. In multivariable adjusted logistic regression analysis, patients with NPDR showed an odds ratio (OR) of 2.59 [95% confidence interval (CI), 1.61-4.19] for increased CAVI, 1.99 (0.62-6.34) for increased ABI, and 1.75 (1.13-2.71) for carotid plaque. Patients with PDR showed an OR of 7.83 (3.52-17.41) for increased CAVI, 10.65 (3.33-34.04) for increased ABI, and 11.40 (2.67-48.63) for carotid plaque.

CONCLUSION

Both NPDR and PDR were independently associated with increased CAVI and presence of carotid plaque in Chinese patients with T2DM.

Association of central arterial stiffness with the presence and severity of diabetic retinopathy in Asians with type 2 diabetes

OBJECTIVE

Arterial stiffness has been associated with diabetic retinopathy; however, the information is limited in Asians. We aim to examine the association of central arterial stiffness with the presence and severity of diabetic retinopathy in type 2 diabetes mellitus patients in Singapore.

METHODS

Arterial stiffness was estimated by carotid-femoral pulse wave velocity and augmentation index using applanation tonometry method. Digital colour fundus photographs from 1,203 patients were assessed for diabetic retinopathy. Diabetic retinopathy severity was categorized into non-proliferative diabetic retinopathy and proliferative diabetic retinopathy. Logistic regression model was used to evaluate the associations of diabetic retinopathy with pulse wave velocity and augmentation index.

RESULTS

Diabetic retinopathy was diagnosed in 391 (32.5%) patients, including 271 non-proliferative diabetic retinopathy and 108 proliferative diabetic retinopathy. Diabetic retinopathy have higher pulse wave velocity (11.2 ± 3.3 vs 9.5 ± 2.6 m/s, p < 0.001) and augmentation index (28.4 ± 9.4 vs 26.1 ± 10.6%, p < 0.001) than non-diabetic retinopathy. After multivariable adjustment, pulse wave velocity [odds ratio = 1.11 (95% confidence interval = 1.05-1.17), p < 0.001] and augmentation index [odds ratio = 1.03 (95% confidence interval = 1.01-1.04), p = 0.009] was associated with diabetic retinopathy. In severity analyses, pulse wave velocity was associated with non-proliferative diabetic retinopathy [odds ratio = 1.10 (95% confidence interval = 1.03-1.17), p = 0.002] and proliferative diabetic retinopathy [odds ratio = 1.15 (95% confidence interval = 1.06-1.25), p = 0.001] (p-trend < 0.001). Augmentation index showed significant associations with non-proliferative diabetic retinopathy [odds ratio = 1.02 (95% confidence interval = 1.01-1.04), p = 0.008], but not with proliferative diabetic retinopathy [odds ratio = 1.01 (95% confidence interval = 0.98-1.04), p = 0.36] (p-trend = 0.03).

CONCLUSION

Central arterial stiffness was associated with the presence and severity of diabetic retinopathy in type 2 diabetes mellitus patients, suggesting its etiologic implication in diabetic retinopathy.

Cardio-ankle vascular index is associated with diabetic retinopathy in younger than 70 years patients with type 2 diabetes mellitus

AIMS

This study aimed to investigate the relationship between cardio-ankle vascular index (CAVI) and diabetic retinopathy (DR) in Caucasian patients with type 2 Diabetes Mellitus (T2DM).

METHODS

This was a cross-sectional study of 299 T2DM patients admitted to Endocrine Unit of Foggia. DR was diagnosed using the International Clinical Disease Severity Scale of American Academy of Ophthalmology. The VaSera VS-1500N was used to measure CAVI. Because age is the most powerful determinant of arterial stiffness and affects the progression of DR, we divided the whole sample into two subgroups: above (older) and below (younger) 70 years.

RESULTS

The mean age of patients was 60.4 ± 12.6 years and the mean CAVI value was 8.6 ± 1.7. In the whole population DR was diagnosed in 74 (24.7%) patients. CAVI value was clearly higher in patients with DR (9.5 ± 1.6) than in those without (8.7 ± 1.7) (P = 0.001) although this difference was not any more significant when adjusted by age and gender (P = 0.067). In the multivariate model taking into account several possible confounders, the correlation between DR and CAVI remained significant only in younger subjects. In the same subgroup we found a significant association between the stages of DR and CAVI (p = 0.019 adjusted by age and gender).

CONCLUSIONS

This study shows that CAVI is significantly higher in younger patients with DR than in those without, with a relationship between the stages of DR and CAVI in the same subgroup. Physicians should pay attention to sub-clinical macroangiopathy in younger T2DM patients who have DR.

Retinal vessel reactivity is not attenuated in patients with type 2 diabetes compared with matched controls and is associated with peripheral endothelial function in controls

BACKGROUND AND AIMS

Attenuated retinal vasoreactivity in patients with type 2 diabetes preceding diabetic retinopathy development has been proposed to reflect local endothelial dysfunction. Whether retinal vessel reactivity is associated with peripheral endothelial dysfunction and large artery stiffness in patients with type 2 diabetes remains to be elucidated.

METHODS

Twenty patients with type 2 diabetes without retinopathy and 20 sex- and age matched controls (diabetes duration: 9.9 years (range 6.0;12.4), 40% male, age: 66.5 ± 7.3 (diabetes) and 65.2 ± 7.6 years (controls)) were included. Endothelial function was assessed using EndoPAT. Arterial stiffness was assessed by carotid-femoral pulse wave velocity using the SphygmoCor. Retinal blood supply regulation was examined by retinal arteriolar diameter change during 1) isometric exercise (hand-weight lifting), 2) exposure to flickering lights, and 3) a combined stimulus of 1) + 2) using the Dynamic Vessel Analyzer.

RESULTS

No significant differences were observed in retinal vessel reactivity in T2DM patients compared to controls. Endothelial function was associated with mean arteriolar diameter change during only the combination intervention, (Beta = 0.033 [0.0013;0.064], p = 0.042) in the overall population of patients and controls. When groups were analyzed separately, the associations was statistically significant only in controls. However, formal test for interaction was not statistically significant, p = 0.40. No association was observed between pulse wave velocity and retinal arteriolar %-diameter change in patients or controls.

CONCLUSION

Peripheral endothelial function was associated with retinal arteriolar diameter change in the combined sample. The association seemed to be driven primarily by the controls. Our findings indicate that peripheral endothelial function is reflective of endothelial function in the retina mainly in subjects without T2DM, whereas an association in T2DM without retinopathy was not observed. Further studies are needed in T2DM patients with more advanced retinopathy.

Arterial Stiffness Assessed by Cardio-Ankle Vascular Index

Arterial stiffness is an age-related disorder. In the medial layer of arteries, mechanical fracture due to fatigue failure for the pulsatile wall strain causes medial degeneration vascular remodeling. The alteration of extracellular matrix composition and arterial geometry result in structural arterial stiffness. Calcium deposition and other factors such as advanced glycation end product-mediated collagen cross-linking aggravate the structural arterial stiffness. On the other hand, endothelial dysfunction is a cause of arterial stiffness. The biological molecular mechanisms relating to aging are known to involve the progression of arterial stiffness. Arterial stiffness further applies stress on large arteries and also microcirculation. Therefore, it is closely related to adverse outcomes in cardiovascular and cerebrovascular system. Cardio-ankle vascular index (CAVI) is a promising diagnostic tool for evaluating arterial stiffness. The principle is based on stiffness parameter β, which is an index intended to assess the distensibility of carotid artery. Stiffness parameter β is a two-dimensional technique obtained from changes of arterial diameter by pulse in one section. CAVI applied the stiffness parameter β to all of the arterial segments between heart and ankle using pulse wave velocity. CAVI has been commercially available for a decade and the clinical data of its effectiveness has accumulated. The characteristics of CAVI differ from other physiological tests of arterial stiffness due to the independency from blood pressure at the time of examination. This review describes the pathophysiology of arterial stiffness and CAVI. Molecular mechanisms will also be covered.

Impact of Diabetes Mellitus on Ventricular Structure, Arterial Stiffness, and Pulsatile Hemodynamics in Heart Failure With Preserved Ejection Fraction

Background Heterogeneity in the underlying processes that contribute to heart failure with preserved ejection fraction ( HF p EF ) is increasingly recognized. Diabetes mellitus is a frequent comorbidity in HF p EF , but its impact on left ventricular and arterial structure and function in HF p EF is unknown. Methods and Results We assessed the impact of diabetes mellitus on left ventricular cellular and interstitial hypertrophy (assessed with cardiac magnetic resonance imaging, including T1 mapping pregadolinium and postgadolinium administration), arterial stiffness (assessed with arterial tonometry), and pulsatile arterial hemodynamics (assessed with in-office pressure-flow analyses and 24-hour ambulatory monitoring) among 53 subjects with HF p EF (32 diabetic and 21 nondiabetic subjects). Despite few differences in clinical characteristics, diabetic subjects with HFpEF exhibited a markedly greater left ventricular mass index (78.1 [95% CI , 70.4-85.9] g versus 63.6 [95% CI , 55.8-71.3] g; P=0.0093) and indexed extracellular volume (23.6 [95% CI , 21.2-26.1] mL/m2 versus 16.2 [95% CI , 13.1-19.4] mL/m2; P=0.0008). Pronounced aortic stiffening was also observed in the diabetic group (carotid-femoral pulse wave velocity, 11.86 [95% CI , 10.4-13.1] m/s versus 8.8 [95% CI , 7.5-10.1] m/s; P=0.0027), with an adverse pulsatile hemodynamic profile characterized by increased oscillatory power (315 [95% CI , 258-373] mW versus 190 [95% CI , 144-236] mW; P=0.0007), aortic characteristic impedance (0.154 [95% CI , 0.124-0.183] mm Hg/mL per second versus 0.096 [95% CI , 0.072-0.121] mm Hg/mL per second; P=0.0024), and forward (59.5 [95% CI , 52.8-66.1] mm Hg versus 40.1 [95% CI , 31.6-48.6] mm Hg; P=0.0010) and backward (19.6 [95% CI , 16.2-22.9] mm Hg versus 14.1 [95% CI , 10.9-17.3] mm Hg; P=0.0169) wave amplitude. Abnormal pulsatile hemodynamics were also evident in 24-hour ambulatory monitoring, despite the absence of significant differences in 24-hour systolic blood pressure between the groups. Conclusions Diabetes mellitus is a key determinant of left ventricular remodeling, arterial stiffness, adverse pulsatile hemodynamics, and ventricular-arterial interactions in HF p EF . Clinical Trial Registration URL : https://www.clinicaltrials.gov . Unique identifier: NCT 01516346.

Usefulness of the vibration perception thresholds measurement as a diagnostic method for diabetic peripheral neuropathy: Results from the Rio de Janeiro type 2 diabetes cohort study

AIMS

To investigate the associated factors with the vibration threshold perception (VPT) in patients with type 2 diabetes and to assess whether it is useful for detection of diabetic peripheral neuropathy (DPN).

METHODS

VPTs were measured with Vibration Sensory Analyzer (VSA-3000) in 426 diabetic patients. The diagnosis of DPN was based on Neuropathy Symptom Score and Neuropathy Disability Score (NDS). ROC curve analysis and multiple linear and logistic regressions were performed to investigate the associations between VPT and DPN.

RESULTS

Values of VPT were progressively higher according to NDS stages. Age, height, diabetes duration, and mean cumulative HbA_1c exposure (partial correlation coefficients: 0.34; 0.27; 0.10; and 0.13; respectively) were the variables independently associated with VPT. Area under ROC curve of VPT for detection of DPN was 0.71 (95% CI: 0.66-0.75) and >8.9 μm was its best cut-off value. VPT, age, female sex, height, diabetes duration and mean HbA_1c levels were the independent correlates of the presence of DPN. An increased VPT triplicate the likelihood of having DPN (OR: 3.24; 95% CI: 2.05-5.11).

CONCLUSIONS

VPT, measured by an automatic device, shares common correlates with DPN and is strongly associated with its presence. VPT testing may be useful as a screening tool for DPN assessment.

The effects of metformin on maternal haemodynamics in gestational diabetes mellitus: A pilot study

BACKGROUND

Gestational diabetes mellitus (GDM) is a major clinical challenge and is likely to remain so as the incidence of GDM continues to increase.

AIM

To assess longitudinal changes in maternal haemodynamics amongst women diagnosed with GDM requiring either metformin or dietary intervention in comparison to low-risk healthy controls.

METHODOLOGY

Fifty-six pregnant women attending their first appointment at the GDM clinic and 60 low-risk healthy pregnant controls attending their routine antenatal clinics were recruited and assigned to three groups: GDM Metformin (GDM-M), GDM Diet (GDM-D) and Control. Non-invasive assessment of maternal haemodynamics, using recognised measures of arterial stiffness and central blood pressure (Arteriograph®), were undertaken under controlled conditions within four gestational windows: antenatal; AN1 (26-28 weeks), AN2 (32-34 weeks) and AN3 (37-40 weeks), and postnatal (PN) (6-8 weeks after delivery). Data were analysed using a linear mixed model incorporating gestational age and other relevant predictors, including age, blood pressure (BP), baseline bodyweight and pulse as fixed effects, and patient as a random effect.

RESULTS

Fitted linear mixed models showed evidence of a two-way interaction effect between groups (GDM-D, GDM-M and Control) and stages of gestation (AN1, AN2, AN3 and PN) for maternal haemodynamic parameters: brachial artery augmentation index (AIx) (p = 0.004), aortic AIx (p = 0.008), and central systolic BP (p = 0.001). However, differences in respect of aortic pulse wave velocity (p = 0.001) and heart rate (p < 0.001) were only significant for gestational stage. At AN2, we did not observe any evidence that the mean brachial Aix in the GDM-M was different from the control group (p = 0.158).

CONCLUSION

AIx and central systolic BP measures of arterial stiffness are adversely affected by GDM in comparison to controls during pregnancy. The possible beneficial effects of metformin therapy seen at 32 to 34 weeks of gestation require further exploration.

Aortic stiffness and ambulatory blood pressure as predictors of diabetic kidney disease: a competing risks analysis from the Rio de Janeiro Type 2 Diabetes Cohort Study

AIMS/HYPOTHESIS

Diabetic kidney disease (DKD) is a microvascular complication associated with poor control of blood glucose and BP. We aimed to evaluate the predictors of development and progression of DKD in a cohort of high-risk individuals with type 2 diabetes, placing emphasis on ambulatory BP and arterial stiffness.

METHODS

In a prospective study, 629 individuals without advanced renal failure had their renal function evaluated annually over a median follow-up period of 7.8 years. Ambulatory BP was monitored and aortic stiffness was assessed by carotid-femoral pulse wave velocity at baseline. Multivariate competing risks analysis with all-cause mortality, using the Fine and Gray approach, was used to examine the independent predictors of development and progression of DKD, a composite of development or progression of abnormal albuminuria and worsening of renal function (doubling of serum creatinine or progression to end-stage renal disease).

RESULTS

At baseline, 197 individuals had DKD. During follow-up, DKD developed or progressed in 195 individuals, abnormal albuminuria developed or progressed in 125 individuals and renal function deteriorated in 91. After adjustments for baseline albuminuria and renal function, age, sex, diabetes duration and use of renin-angiotensin antagonists, poorer control of blood glucose (HR 1.17; 95% CI 0.98, 1.40; p = 0.09 for each 1 SD increment in mean first-year HbA_1c), higher ambulatory systolic BP (HR 1.28; 95% CI 1.09, 1.50; p = 0.003, for each 1 SD increase in daytime systolic BP [SBP]) and increased aortic stiffness (HR 1.16; 95% CI 1.00, 1.34; p = 0.05) were independent predictors of development or progression of DKD. At baseline, ambulatory BP was a stronger predictor than BP measured in the clinic. Aortic stiffness predicted abnormal albuminuria development or progression (HR 1.26; 95% CI 1.02, 1.56; p = 0.036) whereas ambulatory BP was a stronger predictor of renal function deterioration (HR 1.32; 95% CI 1.09, 1.60; p = 0.005 for daytime SBP).

CONCLUSIONS/INTERPRETATION

Poor blood glucose and BP control and increased aortic stiffness were the main predictors of development or progression of DKD; ambulatory SBP was a better predictor than BP measured in the clinic. Ambulatory BP monitoring and assessment of aortic stiffness should be more widely used in clinical type 2 diabetes management.

Predictors of Development and Progression of Retinopathy in Patients with Type 2 Diabetes: Importance of Blood Pressure Parameters

Diabetic retinopathy (DR) is a chronic microvascular complication associated a worse prognosis. We aimed to evaluate the predictors of development/progression of DR in a cohort of 544 high-risk patients with type 2 diabetes who had annual ophthalmologic examinations over a median follow-up of 6 years. Ambulatory blood pressure (BP) monitoring and aortic stiffness by carotid-femoral pulse wave velocity were performed. Multivariate Cox survival analysis examined the independent predictors of development or progression of DR. During follow-up, 156 patients either newly-developed or worsened DR. Patients who developed/progressed DR had longer diabetes duration, higher ambulatory and clinic BP levels, higher aortic stiffness, and poorer glycemic control than patients who did not developed/progressed DR. After adjustments for baseline retinopathy prevalence, age and sex, a longer diabetes duration (p < 0.001), higher baseline ambulatory BPs (p = 0.013, for 24-hour diastolic BP), and higher mean cumulative exposure of HbA_1c (p < 0.001), clinic diastolic BP (p < 0.001) and LDL-cholesterol (p = 0.05) during follow-up were the independent predictors of development/progression of DR. BP parameters were only predictors of DR development. In conclusion, a longer diabetes duration, poorer glycemic and lipid control, and higher BPs were the main predictors of development/progression of DR. Mean cumulative clinic diastolic BP was the strongest BP-related predictor.

Inactive Matrix Gla-Protein and Arterial Stiffness in Type 2 Diabetes Mellitus

BACKGROUND

Large artery stiffness is increased in diabetes mellitus and causes an excessive pulsatile load to the heart and to the microvasculature. The identification of pathways related to arterial stiffness may provide novel therapeutic targets to ameliorate arterial stiffness in diabetes. Matrix Gla-Protein (MGP) is an inhibitor of vascular calcification. Activation of MGP is vitamin K dependent. We hypothesized that levels of inactive MGP (dephospho-uncarboxylated MGP; dp-ucMGP) are related to arterial stiffness in type 2 diabetes.

METHODS

We enrolled a multiethnic cohort of 66 participants with type 2 diabetes. Carotid-femoral pulse wave velocity (CF-PWV) was measured with high-fidelity arterial tonometry (Sphygmocor Device). Dp-ucMGP was measured with ELISA (VitaK; The Netherlands).

RESULTS

The majority of the participants were middle-aged (62 ± 12 years), male (91%), and had a history of hypertension (82%). Average hemoglobin A1C was 7.2% (55 mmol/mol). Mean dp-ucMGP was 624 ± 638 pmol/l and mean CF-PWV was 11 ± 4 m/sec. In multivariable analyses, dp-ucMGP was independently related to African American ethnicity (β = -0.24, P = 0.005), warfarin use (β = 0.56, P < 0.001), and estimated glomerular filtration rate (eGFR, β = -0.32, P < 0.001). Dp-ucMGP predicted CF-PWV (β = 0.40, P = 0.011), even after adjustment for age, gender, ethnicity, mean arterial pressure, eGFR, and warfarin use.

CONCLUSIONS

In our cross-sectional analysis, circulating dp-ucMGP was independently associated with CF-PWV in type 2 diabetes. This suggests that deficient vitamin K-dependent activation of MGP may lead to large artery stiffening and could be targeted with vitamin K supplementation in the patients with diabetes.

Aortic Stiffness as a Surrogate Endpoint to Micro- and Macrovascular Complications in Patients with Type 2 Diabetes

Increased aortic stiffness has been recognized as a predictor of adverse cardiovascular outcomes in some clinical conditions, such as in patients with arterial hypertension and end-stage renal disease, in population-based samples and, more recently, in type 2 diabetic patients. Patients with type 2 diabetes have higher aortic stiffness than non-diabetic individuals, and increased aortic stiffness has been correlated to the presence of micro- and macrovascular chronic diabetic complications. We aimed to review the current knowledge on the relationships between aortic stiffness and diabetic complications, their possible underlying physiopathological mechanisms, and their potential applications to clinical type 2 diabetes management.

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.

Clinical interaction between diabetes duration and aortic stiffness in type 2 diabetes mellitus

Diabetes complications increase with disease duration. No study was performed on the relationship between aortic stiffness and diabetes duration, taking into account the respective influence of such factors on macro- and microcirculation. In total, 618 subjects with type 2 diabetes (259 men) attending the Department of Internal Medicine of Tizi Ouzou Hospital (Algeria) were studied in collaboration with Hotel-Dieu Hospital (Paris, France). Brachial blood pressure (BP), anthropometric, clinical and biological data were evaluated. Aortic stiffness was estimated by carotid-femoral pulse wave velocity (PWV). From lower to higher tertile of diabetes duration, age, BP and PWV (10.1±2.7 to 12.3±2.8 m s^-1) increased, while diabetes control and renal function worsened (all P<0.01). Diabetes duration was independently associated with PWV (R²=0.035, P<0.0001), even after adjustment for age, BP, heart rate, cardiovascular events and metabolic syndrome. Diabetes duration was significantly correlated to the prevalence of microalbuminuria (OR (95% CL) 1.3 (1.06-1.63), P=0.01), independently of age, sex, BP and renal function. Increased aortic stiffness was independently associated with the prevalence of cardiovascular events (P<0.001), reaching its maximal value above the first 2 years of diabetes duration. In conclusion, diabetes duration is an independent determinant of aortic stiffness in subjects with type 2 diabetes, representing about 4% of PWV variability. Diabetes duration is associated with microvascular complications independently of renal function, and with macrovascular complications through the presence of increased aortic stiffness.

Increasing aortic stiffness is predictive of advanced liver fibrosis in patients with type 2 diabetes: the Rio-T2DM cohort study

BACKGROUND & AIMS

Type 2 diabetes mellitus (T2DM) is a risk factor for cardiovascular disease (CVD) and advanced stages of non-alcoholic fatty liver disease (NAFLD). The aim was to evaluate the association between aortic stiffness, a preclinical CVD marker, with advanced liver fibrosis identified by transient elastography (TE) in T2DM outpatients with NAFLD.

METHODS

This longitudinal study included 291 T2DM patients with NAFLD detected by ultrasonography, who had two carotid-femoral pulse wave velocity (cf-PWV) measurements and a TE examination (Fibroscan(®) ) performed over a median follow-up of 7 years. Advanced liver fibrosis (corresponding to ≥ F3 stage) was considered as median values >7.9 kPa (M probe) or >7.2 kPa (XL probe). Increased aortic stiffness was defined as cf-PWV >10 m/s.

RESULTS

Eighty patients (27.5%) had advanced liver fibrosis. Overall, there was an increase in cf-PWV of 0.1 m/s/year (1% per year). Both a high aortic stiffness at the 2nd cf-PWV examination [odds ratios (OR): 3.0; 95% CI: 1.3-7.2; P = 0.011] and a serial increase in aortic stiffness (OR: 2.1; 95% CI: 1.0-4.3; P = 0.046) were associated with increased odds of having advanced liver fibrosis. Patients who presented either an increase in aortic stiffness or persisted with high values had significantly higher mean liver stiffness than those who either decreased aortic stiffness or persisted with normal cf-PWV values (mean difference: 2.1 kPa, 95% CI: 0.5-3.7 kPa, P = 0.012), after adjustments for anthropometric-demographic and clinical laboratory covariates.

CONCLUSIONS

In T2DM patients with NAFLD, a high or increasing aortic stiffness predicted development of advanced liver fibrosis on TE.

Diabetes and Risk of Arterial Stiffness: A Mendelian Randomization Analysis

We aimed to explore the causal association between type 2 diabetes (T2D) and increased arterial stiffness. We performed a Mendelian randomization (MR) analysis in 11,385 participants from a well-defined community study in Shanghai during 2011-2013. We genotyped 34 T2D-associated common variants identified in East Asians and created a genetic risk score (GRS). We assessed arterial stiffness noninvasively with the measurement of brachial-ankle pulse wave velocity (baPWV). We used the instrumental variable (IV) estimator to qualify the causal relationship between T2D and increased arterial stiffness. We found each 1-SD increase in T2D_GRS was associated with 6% higher risk in increased arterial stiffness (95% CI 1.01, 1.12), after adjustment of other metabolic confounders. Using T2D_GRS as the IV, we demonstrated a causal relationship between T2D and arterial stiffening (odds ratio 1.24, 95% CI 1.06, 1.47; P = 0.008). When categorizing the genetic loci according to their effect on insulin secretion or resistance, we found genetically determined decrease in insulin secretion was associated with increase in baPWV (βIV = 122.3 cm/s, 95% CI 41.9, 204.6; P = 0.0005). In conclusion, our results provide evidence supporting a causal association between T2D and increased arterial stiffness in a Chinese population.

Prognostic impact of clinic and ambulatory blood pressure components in high-risk type 2 diabetic patients: the Rio de Janeiro Type 2 Diabetes Cohort Study

BACKGROUND

The prognostic importance of tight clinic blood pressure (BP) control is controversial in diabetic patients. The objective was to investigate the prognostic impact of clinic and ambulatory BPs for cardiovascular morbidity and mortality in type 2 diabetes.

METHODS

In a prospective cohort study, 565 type 2 diabetic patients had clinical, laboratory and ambulatory BP monitoring (ABPM) data obtained at baseline and during follow-up. The primary endpoints were a composite of fatal and nonfatal cardiovascular events and all-cause mortality. Multivariable Cox survival and splines regression analyses assessed associations between each BP component [SBP, DBP and pulse pressure (PP)] and the endpoints.

RESULTS

After a median follow-up of 5.75 years, 88 total cardiovascular events and 70 all-cause deaths occurred. After adjustments for cardiovascular risk factors, clinic SBP and DBPs were predictive of the composite endpoint but not of all-cause mortality, whereas all ambulatory BP components were predictors of both endpoints. Ambulatory systolic and PPs were the strongest predictors and achieved ambulatory BPs during follow-up improved risk prediction in relation to baseline values. When categorized at clinically relevant cut-off values, risk began only at clinic BPs at least 140/90 mmHg, whereas for ambulatory BPs it began at lower values (≥120/75 mmHg for the 24-h period).

CONCLUSION

ABPM provides more valuable information regarding cardiovascular risk stratification than office BPs and should be performed, if possible, in every high-risk type 2 diabetic patient. Achieved 24-h ambulatory BPs less than 120/75 mmHg are associated with significant cardiovascular protection and, if confirmed by other studies, may be considered as BP treatment targets.

Arterial stiffness is elevated in normotensive type 2 diabetic patients with peripheral neuropathy

BACKGROUND AND AIMS

Arterial stiffness, a measure of macrovascular damage predictive of poor cardio-vascular outcomes, is strongly related to age and hypertension (HT). In diabetic patients peripheral neuropathy (PN) has been found to be associated with increased arterial stiffness, which might be due to the concomitant presence of HT. The aim of this study was to examine in type-2 diabetic patients, the relationship between arterial stiffness and presence or absence of PN and HT separately.

METHODS AND RESULTS

Arterial stiffness was measured with the gold standard carotid-femoral pulse wave velocity (PWV) in 447 type-2 diabetic subjects of whom 66% were hypertensive, 53% had PN, and 40% had both. Patients with PN were older, more often hypertensive and had higher PWV than those free of PN. Patients were separated according to the presence or absence of PN and HT. PWV values above the 90th percentile age- and blood pressure-adjusted reference range (PWV+) were different across these groups (p < 0.005) with the following respective prevalences: 27.2%, 53.4%, 33.3% and 30.6%. Only PWV+ was significantly associated with PN and hypertension in the interaction analysis.

CONCLUSION

Well controlled hypertensive patients did not have elevated arterial stiffness compared to normotensive patients. This might be due to anti-hypertensive treatment although our study design does not allow us to confirm it. A strong association between PN and arterial stiffness was only present in normotensive patients, suggesting that normotensive type 2 diabetic patients with PN and elevated arterial stiffness should be carefully managed to prevent future macrovascular complications.

Increased aortic stiffness predicts future development and progression of peripheral neuropathy in patients with type 2 diabetes: the Rio de Janeiro Type 2 Diabetes Cohort Study

AIMS/HYPOTHESIS

Diabetic peripheral neuropathy (DPN) is a chronic microvascular complication that is strongly associated with poor glycaemic control and also with a worse prognosis. We aimed to evaluate the predictors of the development and progression of DPN in a cohort of high-risk patients with type 2 diabetes.

METHODS

In a prospective study, 477 patients with type 2 diabetes were clinically assessed for the presence of DPN at baseline and after a median follow-up of 6.2 years (range 2-10 years). Clinical laboratory data were obtained at study entry and throughout the follow-up. Aortic stiffness was assessed by the carotid-femoral pulse wave velocity (cf-PWV) at baseline. Multivariate Poisson regression analysis was used to examine independent predictors of the development/progression of DPN.

RESULTS

At baseline, 135 patients (28%) had DPN, and during follow-up 97 patients (20%) had either a new development or a worsening of DPN. Patients who showed a development or progression of DPN were taller and had a longer duration of diabetes, a greater prevalence of other microvascular complications and hypertension, greater aortic stiffness and poorer glycaemic control than patients who did not have new or progressive neuropathy. After adjustments for the baseline prevalence of DPN, the patient's age and sex, and the time interval between DPN assessments; an increased aortic stiffness (cf-PWV >10 m/s) were predictive of new/progressive DPN (incidence rate ratio 2.04, 95% CI 1.28, 3.23; p = 0.002). Other independent predictors were the mean first-year HbA1c level (p = 0.05), nephropathy (p = 0.006), arterial hypertension (p = 0.06) and height (p = 0.03).

CONCLUSIONS/INTERPRETATION

Increased aortic stiffness at baseline predicts the future development or progression of peripheral neuropathy, independent of diabetic metabolic control, suggesting a physiopathological link between macrovascular and microvascular abnormalities in type 2 diabetes.

Correlates of aortic stiffness progression in patients with type 2 diabetes: importance of glycemic control: the Rio de Janeiro type 2 diabetes cohort study

OBJECTIVE

The correlates of serial changes in aortic stiffness in patients with diabetes have never been investigated. We aimed to examine the importance of glycemic control on progression/regression of carotid-femoral pulse wave velocity (cf-PWV) in type 2 diabetes.

RESEARCH DESIGN AND METHODS

In a prospective study, two cf-PWV measurements were performed with the Complior equipment in 417 patients with type 2 diabetes over a mean follow-up of 4.2 years. Clinical laboratory data were obtained at baseline and throughout follow-up. Multivariable linear/logistic regressions assessed the independent correlates of changes in cf-PWV.

RESULTS

Median cf-PWV increase was 0.11 m/s per year (1.1% per year). Overall, 212 patients (51%) increased/persisted with high cf-PWV, while 205 (49%) reduced/persisted with low cf-PWV. Multivariate linear regression demonstrated direct associations between cf-PWV changes and mean HbA1c during follow-up (partial correlation 0.14, P = 0.005). On logistic regression, a mean HbA1c ≥7.5% (58 mmol/mol) was associated with twofold higher odds of having increased/persistently high cf-PWV during follow-up. Furthermore, the rate of HbA1c reduction relative to baseline levels was inversely associated with cf-PWV changes (partial correlation -0.11, P = 0.011) and associated with reduced risk of having increased/persistently high aortic stiffness (odds ratio 0.82 [95% CI 0.69-0.96]; P = 0.017). Other independent correlates of progression in aortic stiffness were increases in systolic blood pressure and heart rate between the two cf-PWV measurements, older age, female sex, and presence of dyslipidemia and retinopathy.

CONCLUSIONS

Better glycemic control, together with reductions in blood pressure and heart rate, was the most important correlate to attenuate/prevent progression of aortic stiffness in patients with type 2 diabetes.

Arterial stiffness in diabetes mellitus

Arterial stiffness is an age-related process that is a shared consequence of numerous diseases including diabetes mellitus (DM), and is an independent predictor of mortality both in this population and in the general population. While much has been published about arterial stiffness in patients with DM, a thorough review of the current literature is lacking. Using a systematic literature search strategy, we aimed to summarize our current understanding related to arterial stiffness in DM. We review key studies demonstrating that, among patients with established DM, arterial stiffness is closely related to the progression of complications of DM, including nephropathy, retinopathy, and neuropathy. It is also becoming clear that arterial stiffness can be increased even in pre-diabetic populations with impaired glucose tolerance, and in those with the metabolic syndrome (METS), well before the onset of overt DM. Some data suggests that arterial stiffness can predict the onset of DM. However, future work is needed to further clarify whether large artery stiffness and the pulsatile hemodynamic changes that accompany it are involved in the pathogenesis of DM, and whether interventions targeting arterial stiffness are associated with improved clinical outcomes in DM. We also review of the potential mechanisms of arterial stiffness in DM, with particular emphasis on the role of advanced glycation endproducts (AGEs) and nitric oxide dysregulation, and address potential future directions for research.

Treatment with continuous subcutaneous insulin infusion is associated with lower arterial stiffness

AIMS

To investigate the relationship between arterial stiffness and insulin treatment mode [continuous subcutaneous insulin infusion (CSII) versus multiple daily injections (MDI)] in type 1 diabetes patients.

METHODS

Cross-sectional study, from 2009 to 2011, including 601 Caucasian type 1 diabetes patients, 58 and 543 treated with CSII and MDI, respectively. Arterial stiffness was measured as pulse wave velocity (PWV) (SphygmoCor, AtCor Medical). Adjustment included gender, age, diabetes duration, HbA1c, heart rate, mean arterial pressure, P-creatinine, urinary albumin excretion rate (UAER), smoking, total daily insulin dose, antihypertensive treatment, previous cardiovascular disease (CVD), total cholesterol and statin treatment. Albuminuria was UAER ≥30 mg/24-h, and CVD included myocardial infarction, revascularization, peripheral arterial disease and stroke.

RESULTS

CSII- versus MDI-treated patients were 48 versus 57 % men, 51 ± 11 versus 54 ± 13 years old (mean ± SD), had 33 ± 12 versus 32 ± 16 years diabetes duration and HbA1c 7.8 ± 0.9 % (62 ± 10 mmol/mol) versus 8.0 ± 1.2 % (64 ± 13 mmol/mol) (P ≥ 0.08 for all). PWV was lower in CSII- versus MDI-treated patients (9.3 ± 2.8 vs. 10.4 ± 3.4 m/s; P = 0.016). In fully adjusted analysis, CSII treatment was significantly (P = 0.038) associated with lower PWV, whereas HbA1c-level was not (P = 0.93).

CONCLUSIONS

In type 1 diabetes patients, CSII treatment was associated with lower arterial stiffness independent of other risk factors, while HbA1c was not. Although glucose variability was not assessed, our results suggest that glucose variability and not HbA1c-level affect arterial stiffness. This needs confirmation in randomised prospective studies.

Relationships between reduced heart rate variability and pre-clinical cardiovascular disease in patients with type 2 diabetes

AIMS

Reduced heart rate variability (HRV), an early sign of diabetic cardiovascular autonomic neuropathy (CAN), is associated with worse cardiovascular outcomes. The objective was to evaluate relationships between HRV parameters and three pre-clinical cardiovascular disease markers (left ventricular hypertrophy [LVH], aortic stiffness and carotid atherosclerosis) in type 2 diabetes.

METHODS

In a cross-sectional study, 313 patients with type 2 diabetes performed 24-h Holter monitoring, carotid ultrasonography (intima-media thickness and plaques measurements), aortic pulse wave velocity measurement and echocardiography (left ventricular mass index [LVMI] measurement). Time-domain HRV parameters were the standard deviation of all normal RR intervals (SDNN), the standard deviation of the averaged normal RR intervals for all 5min segments (SDANN), the root mean square of differences between adjacent R-R intervals (rMSSD), and the percentage of adjacent R-R intervals that varied by >50ms (pNN50). Multivariate linear and logistic regressions assessed associations between HRV parameters and the three markers of pre-clinical cardiovascular disease.

RESULTS

Patients with reduced HRV had longer diabetes duration, greater prevalences of microvascular complications, lower physical fitness, and higher heart rate, glycated hemoglobin, albuminuria and LVMI than patients with normal HRV. On multivariate regressions, after adjustments for several confounders, reduced SDNN and SDANN were independently associated with LVH and aortic stiffness. No HRV parameter was associated with carotid atherosclerosis.

CONCLUSIONS

Two reduced HRV parameters, SDNN and SDANN, which reflect cardiovascular autonomic imbalance, were associated with LVH and aortic stiffness, markers of pre-clinical cardiovascular disease. These findings may offer insights into physiopathological mechanisms linking CAN to worse cardiovascular prognosis.

Arterial stiffness, renal function and renal blood flow in patients with coronary artery disease, arterial hypertension and type 2 diabetes mellitus

Aim. To investigate the relationship between changes in indicators of arterial stiffness of various types of vessels, hemodynamic pulsatility, renal function and renal blood flow in patients with coronary artery disease (CAD) and arterial hypertension in the presence or absence of type 2 diabetes mellitus (T2DM). Materials and Methods. The study included 96 patients with CAD and arterial hypertension; among them, 54 subjects had T2DM and 42 did not. Сarbohydrate and lipid metabolism, renal function, stiffness of various types of arteries, parameters of hemodynamic pulsatility and renal blood flow were investigated. Results. Arterial stiffness of various types of vessels was increased in the T2DM group: carotid?femoral pulse wave velocity as a marker of aortic stiffness (a vessel of the elastic type) was increased by 16% (p

Factors associated with abnormal T-wave axis and increased QRS-T angle in type 2 diabetes

Frontal plane T-wave axis and QRS-T angle are novel electrocardiographic ventricular repolarization parameters that have been scarcely evaluated in type 2 diabetes. The aim was to investigate the factors associated with these parameters of abnormal ventricular repolarization in a cross-sectional analysis of 594 patients with type 2 diabetes. Clinical, laboratory, 2D-echocardiographic, ambulatory blood pressure (BP) monitoring, aortic pulse wave velocity (PWV) and carotid ultrasonographic data were obtained. Digital 12-lead ECG was recorded, and frontal plane T-wave axis and QRS-T angle were automatically measured. T-wave axis was considered abnormal if >75° or <15° and QRS-T angle if ≥73° in men and ≥67° in woman. Associations were assessed by bivariate tests and multivariate logistic regressions. One hundred and four (20.9 %) patients had abnormal T-wave axis, and 84 (14 %) had increased QRS-T angle. Patients with abnormal ventricular repolarization were older and had greater prevalence of micro- and macrovascular diabetic complications than patients with normal repolarization. They had higher office and ambulatory BPs, greater prevalence of the non-dipping pattern, and greater left ventricular mass, aortic PWV and carotid intima-media thickness. On multivariate analysis, abnormal ventricular repolarization parameters were independently associated with left ventricular hypertrophy, non-dipping pattern, higher ambulatory systolic BPs, glycated hemoglobin and common carotid intima-media thickness, and with the presence of coronary artery disease. In conclusion, abnormal frontal plane T-wave axis and QRS-T angle are independently associated with several markers of pre-clinical atherosclerotic disease; whether these associations represent additional cardiovascular risk in type 2 diabetes shall be confirmed in prospective studies.

Decreased stroke volume−brachial pulse pressure ratio in patients with type 2 diabetes over 50 years: the role of peripheral neuropathy

BACKGROUND AND AIMS

To document the stroke volume to pulse pressure ratio (SV/PP, an index of total arterial compliance) and its correlates in patients with type 2 diabetes (T2DM) aged over 50 years whose peripheral neuropathy and silent myocardial ischemic (SMI) status were known.

METHODS AND RESULTS

A total of 360 patients with T2DM aged ≥ 50 years, without cardiac history or symptom, left ventricular systolic dysfunction, dilatation and hypokinesia, were retrospectively enrolled. The SV/PP was calculated from echocardiographic left ventricular measurements and brachial blood pressure at rest. Peripheral neuropathy was defined as the presence of any two or more of the following: neuropathic symptoms, decreased distal sensation, or decreased or absent ankle reflexes. SMI was defined as an abnormal stress myocardial scintigraphy and/or stress echocardiography. A low SV/PP ratio (<0.53 ml/m²/mmHg, first tertile) was associated with age, creatinine clearance, 24 h urinary albumin excretion rate, peripheral neuropathy, hypertension, serum total cholesterol and triglycerides levels (p < 0.05-0.0001). In multivariate analysis, age (OR 1.1 [1.0-1.2], p < 0.01), triglycerides (OR 1.5 [1.2-2.0], p = 0.01) and peripheral neuropathy (OR 2.2 [1.2-3.9], p = 0.009) were independently associated with a low SV/PP. The patients with peripheral neuropathy had lower SV (p < 0.01) and higher PP (p < 0.05) than those without, and only lower SV after adjustment for age and nephropathy. Similar results were obtained in the patients with and without SMI.

CONCLUSION

Peripheral neuropathy was independently associated with decreased SV/PP, mainly through decreased SV, in patients with T2DM over 50 years.

Prognostic impact of aortic stiffness in high-risk type 2 diabetic patients: the Rio deJaneiro Type 2 Diabetes Cohort Study

OBJECTIVE

The prognostic importance of carotid-femoral pulse wave velocity (PWV), the gold standard measure of aortic stiffness, has been scarcely investigated in type 2 diabetes and never after full adjustment for potential confounders. The aim was to evaluate the prognostic impact of carotid-femoral PWV for cardiovascular morbidity and all-cause mortality in a cohort of 565 high-risk type 2 diabetic patients.

RESEARCH DESIGN AND METHODS

Clinical, laboratory, ambulatory blood pressure (BP) monitoring, and carotid-femoral PWV data were obtained at baseline. The primary end points were a composite of fatal and nonfatal cardiovascular events and all-cause mortality. Multiple Cox survival analysis was used to assess the associations between carotid-femoral PWV, as a continuous variable and categorized at 10 m/s, and the end points.

RESULTS

After a median follow-up of 5.75 years, 88 total cardiovascular events and 72 all-cause deaths occurred. After adjustments for potential cardiovascular risk factors, including micro- and macrovascular complications, ambulatory BP, and metabolic control, carotid-femoral PWV was predictive of the composite end point but not of all-cause mortality both as a continuous variable (hazard ratio 1.13 [95% CI 1.03-1.23], P = 0.009 for increments of 1 m/s) and as categorized at 10 m/s (1.92 [1.16-3.18], P = 0.012). On sensitivity analysis, carotid-femoral PWV was a better predictor of cardiovascular events in younger patients (<65 years), in those with microvascular complications, and in those with poorer glycemic control (HbA1c ≥7.5% [58.5 mmol/mol]).

CONCLUSIONS

Carotid-femoral PWV provides cardiovascular risk prediction independent of standard risk factors, glycemic control, and ambulatory BPs and improves cardiovascular risk stratification in high-risk type 2 diabetes.

Impact of diabetes mellitus on arterial stiffness in a representative sample of an urban Brazilian population

BACKGROUND

Independent of other cardiovascular (CV) risk factors, increased arterial stiffness has been established as a predictor of morbidity and mortality. The main aim of this study was to investigate the impact of diabetes on arterial stiffness in a representative sample of an urban Brazilian population plus Amerindians.

METHODS

A total of 1,415 individuals from the general population were randomly selected plus 588 Amerindians from a native community in Brazil. In addition, a sub-sample of 380 individuals from the general population had 5-year follow-up data. Pulse wave velocity (PWV) was measured with a non-invasive automatic device (Complior, Colson; Garges les Gonesses, France) and increased arterial stiffness was defined as PWV ≥ 12 m/s.

RESULTS

In the overall group, diabetic individuals had higher frequencies of increased arterial stiffness and hypertension. They also had higher values of PWV, body mass index, total cholesterol, triglycerides, systolic and diastolic blood pressures compared to non-diabetic individuals (p < 0.01). In an analysis stratified by hypertension, PWV values and increased arterial stiffness frequency were higher in diabetic individuals in both groups (hypertensive and non-hypertensive) (p < 0.05). Furthermore, higher risk for increased arterial stiffness was observed in the diabetic individuals from the overall group (OR = 2.27; CI = 1.47-3.52, p < 0.001) and from the hypertensive group (OR = 2.70; CI = 1.58-4.75, p < 0.001), adjusted for covariates. Regarding the ethnic stratification, diabetic individuals from Amerindian, White, and Mulatto (mixed-race) groups had higher PWV values and a greater frequency of increased arterial stiffness compared to non-diabetic individuals. Both diabetic and non-diabetic individuals had higher PWV values after 5 years. There was no significant difference in the 5-year PWV progression in diabetic compared to non-diabetic individuals.

CONCLUSIONS

These results confirm, in a sample of Brazilian population, that the presence of diabetes is associated with increased arterial stiffness and it may contribute in part to increased cardiovascular risk in diabetic patients.

Central pulse pressure and its hemodynamic determinants in middle-aged adults with impaired fasting glucose and diabetes: the Asklepios study

OBJECTIVE

Pulse pressure (PP), a strong predictor of cardiovascular events in type 2 diabetes, is a composite measure affected by several hemodynamic factors. Little is known about the hemodynamic determinants of central PP in type 2 diabetes or whether abnormalities in central pulsatile hemodynamics are already present in individuals with impaired fasting glucose (IFG). In a population-based study, we aimed to compare central PP and its hemodynamic determinants among adults with normal fasting glucose (n = 1654), IFG (n = 240), and type 2 diabetes (n = 33).

RESEARCH DESIGN AND METHODS

We measured carotid pressure, left ventricular outflow, aortic root diameter, carotid artery flow, and distension in order to measure various structural and hemodynamic arterial parameters.

RESULTS

IFG was associated with a greater mean arterial pressure (MAP) but was not associated with intrinsic aortic stiffening or abnormal aortic pulsatile indices after adjustment for MAP. After adjustment for age, sex, and MAP, type 2 diabetes was associated with a higher aortic root characteristic impedance (Zc), aortic root elastance-thickness product (Eh), and aortic root pulse wave velocity (but not aortic root diameter), a greater carotid-femoral pulse wave velocity, and lower total arterial compliance and wave reflection magnitude. Carotid size, Zc, distensibility, or Eh did not significantly differ between the groups.

CONCLUSIONS

Type 2 diabetes, but not IFG, is associated with greater large artery stiffness, without abnormalities in aortic root diameter or carotid stiffness. Subjects with type 2 diabetes demonstrate a decreased reflection magnitude, which may indicate an increased penetration of pulsatile energy to distal vascular beds.

Combined examination of glyceryl trinitrate-mediated vascular dilation with flow-mediated vascular dilation is essential for assessment of vascular function in type 2 diabetes

Aims/Introduction

In order to characterize the impaired vascular function in type 2 diabetes (DM) patients, we evaluated the flow‐mediated vascular dilation (FMD) with glyceryl trinitrate‐mediated vascular dilation (NMD) using ultrasonography.

Materials and Methods

A total of 111 DM patients and 42 healthy control participants were studied. The maximal dilatation of FMD and NMD (%FMD and %NMD, respectively), the beginning time (T) of dilatation after stimulation and the velocity (V) of the vascular dilatation were also measured.

Results

Among DM patients, 49% had impaired %NMD, which affects the results of %FMD. In DM patients with normal %NMD, the %FMD was also significantly lower than that in control participants, although the T and the V were not impaired. In contrast, both the T and the V were disturbed in the DM patients with low %NMD. Multiple linear regression analysis showed that %NMD was independently correlated with albuminuria. Our results indicate that the impaired FMD in DM is be affected by low NMD, and impaired endothelial function already exists even in DM patients whose vascular smooth muscle function is still retained, and also albuminuria is the clinical feature of DM with low %NMD.

Conclusions

Examination of NMD, not only FMD, should be carried out as it offers the possibility of clarifying vascular function in DM patients.

Relationship between Stage of Diabetic Retinopathy and Pulse Wave Velocity in Japanese Patients with Type 2 Diabetes

Objectives. We investigated the relationship between the stage of diabetic retinopathy and pulse wave velocity (PWV). Methods. This was a cross-sectional study of 689 patients (406 men and 283 women) with type 2 diabetes who were admitted to our hospital from 2004 to 2007. Brachial-ankle pulse wave velocity (baPWV) was measured by an arterial pressure measurement device as PWV/ABI. Diagnosis of diabetic retinopathy was made by ophthalmologists based on the Davis classification: no diabetic retinopathy (NDR), simple retinopathy (SDR), pre-proliferative retinopathy (pre-PDR), and proliferative retinopathy (PDR). Results. There was a significant difference in PWV between patients without diabetic retinopathy (1657.0 ± 417.9 m/s (mean ± SD)) and with diabetic retinopathy (1847.1 ± 423.9 m/s) (P < 0.001). In addition, the stage of diabetic retinopathy was associated with aortic PWV (1657.0 ± 417.9 m/s in NDR (n = 420), 1819.4 ± 430.3 m/s in SDR (n = 152), 1862.1 ± 394.0 m/s in pre-PDR (n = 54), and 1901.1 ± 433.5 m/s in PDR (n = 63) (P < 0.001)). Conclusions. In patients with diabetic retinopathy, even in those with SDR, PWV was higher than that in patients without diabetic retinopathy. Physicians should therefore pay attention to the value of PWV and macroangiopathy regardless of the stage of diabetic retinopathy.

Increasing age associated with elevated cardio-ankle vascular index scores in patients with type 2 diabetes mellitus

OBJECTIVE

The study investigated the relationship between arterial stiffness calculated using the cardio-ankle vascular index (CAVI), diagnosis of type 2 diabetes mellitus and type 2 diabetes-related cardiovascular complications, in patients with type 2 diabetes mellitus (type 2 diabetes) and nondiabetic patients.

METHODS

A retrospective cross-sectional study was conducted in patients with type 2 diabetes and age-matched nondiabetic patients. CAVI was measured using an automatic vascular screening system. Parameters associated with type 2 diabetes and cardiovascular complications were also measured.

RESULTS

A total of 51 patients with type 2 diabetes and 59 nondiabetic patients were enrolled in the study. Significantly higher CAVI scores were observed in patients with type 2 diabetes compared with nondiabetic patients (mean ± SD: 9.55 ± 1.13 versus 8.54 ± 0.94, respectively). Multivariate linear regression analyses demonstrated that age was the only significant factor influencing the CAVI score, in patients with type 2 diabetes.

CONCLUSION

Patients with type 2 diabetes had an increased risk of arterial stiffness, based on the CAVI score, compared with nondiabetic patients; this, in turn, could increase their risk of developing other cardiovascular complications.

The association between regional arterial stiffness and diabetic retinopathy in type 2 diabetes

OBJECTIVES

Although several studies have reported that PWV is associated with diabetic retinopathy, it remains controversial as to which segment provides the PWV that might best reflect the presence of retinopathy. The aim of this study was to determine the pulse wave velocity (PWV) of arterial segments that is most closely associated with diabetic retinopathy in subjects without a history of macrovascular complications.

METHODS

After excluding subjects with a history of ischemic heart disease, peripheral artery disease, ischemic stroke, renal insufficiency, overt proteinuria, and other nondiabetic ophthalmic lesions or insufficient retinal examinations, a total of 494 subjects were analyzed by cross-sectional study. The central PWVs, including the heart-femoral (hf), heart-carotid (hc), heart-ankle (ha), and carotid-brachial (cb) segments, and the peripheral PWVs, including brachial-ankle (ba) and femoral-ankle (fa), were measured for each subject.

RESULTS

The group with diabetic retinopathy exhibited significantly higher hfPWV, hcPWV, haPWV and baPWV, but notcbPWV, faPWV or augmentation index (AI). Age, duration of diabetes, systolic and diastolic BP and pulse pressure were all positively associated with hfPWV, hcPWV, haPWV and baPWV. Quartiles of hfPWV were significantly associated with diabetic retinopathy after adjustment for covariates and known risk factors of diabetic retinopathy (P for trend = 0.023). Conversely, all quartiles of haPWV, hcPWV and baPWV lost significance after adjustment.

CONCLUSIONS

We found that diabetic retinopathy was most closely associated with hfPWV, suggesting the most reliable index of regional arterial stiffness index in retinopathy.

Factors associated with carotid intima-media thickness and carotid plaques in type 2 diabetic patients

OBJECTIVE

Factors associated with carotid atherosclerosis are unclear in type 2 diabetic patients. The aim was to investigate the independent correlates of carotid intima-media thickness (IMT) and plaques in these individuals.

METHODS

In a cross-sectional study, we measured carotid IMT at three sites (common carotid, bifurcation and internal carotid artery) and the severity of extracranial carotid artery (ECCA) atherosclerosis by plaque score in 441 type 2 diabetic patients. Nontraditional cardiovascular risk factors [ambulatory blood pressures (BPs), aortic stiffness, C-reactive protein and ankle-brachial index) were obtained. Multivariate linear and logistic regressions assessed the independent correlates of carotid IMT and ECCA plaque score.

RESULTS

Patients with greater carotid IMT or plaque scores had worse clinical and laboratory profile than those with lower IMT and plaque scores, including higher BPs, aortic stiffness and prevalences of diabetic complications. On multivariate analysis, carotid IMT and plaques were mainly associated with older age, male sex, current-past smoking and ambulatory BPs, but not with clinic BPs. Night-time pulse pressure was the most important modifiable determinant of increased carotid IMT. No microvascular complication was independently associated with carotid atherosclerosis, except retinopathy for plaque score. Additionally, internal carotid IMT and plaque score were associated with ankle-brachial index in the subgroup of patients without macrovascular diseases.

CONCLUSION

In type 2 diabetic patients, older age, male sex, smoking status and ambulatory BPs, particularly night-time pulse pressure, were the main independent correlates of ultrasonographic carotid atherosclerosis. This finding reinforces the importance of ambulatory BP monitoring in type 2 diabetes management.

Carotid intima-media thickness and arterial stiffness in type 1 diabetic patients with and without microangiopathy

INTRODUCTION

The aim of the study was to assess carotid intima-media thickness (CIMT) as a subclinical marker of atherosclerosis and arterial stiffness in type 1 diabetic patients in relation to microangiopathy.

MATERIAL AND METHODS

We included 87 type 1 diabetic patients (44 women, 43 men), median age 34 years (interquartile range [IQR] 29-43), median disease duration 10 years (IQR: 9-14), mean ± standard deviation (SD) glycated haemoglobin (HbA(1c)) 8.4 ±1.4%. Fifty patients had at least one microangiopathic complication. Intima-media thickness (IMT) of the common carotid artery was measured using high resolution ultrasonography. Arterial stiffness was assessed using digital volume pulse analysis and tonometric measurement of wave reflection and central haemodynamics.

RESULTS

SUBJECTS WITH MICROANGIOPATHY COMPARED WITH THOSE WITHOUT HAD HIGHER VALUES OF CIMT (MEDIAN [IQR]: 0.53 mm [0.45-0.60 mm] vs 0.47 mm [0.34-0.52 mm], p = 0.002), higher central augmentation index (CAI(x)) (mean ± SD: 120.2 ±19.4% vs. 110.5 ±17.1%, p = 0.016) and higher peripheral augmentation index (PAI(x)) (65.7 ±18.1% vs. 57.2 ±14.9%, p = 0.023). In the logistic regression analysis, the duration of diabetes, systolic and diastolic blood pressure, postprandial glycaemia, HbA(1c) and triglycerides predicted the presence of diabetic microangiopathy independently of age and sex. The CIMT, CAI(x) and PAI(x) were associated with the presence of diabetic microangiopathy only in the univariate model.

CONCLUSIONS

In type 1 diabetic patients with microangiopathic complications, increased carotid IMT and arterial stiffness were observed. The study confirms the role of traditional risk factors for late diabetic complications, such as the duration of the disease and metabolic control in the development of microangiopathy.

The cardiovascular effects of GLP-1 receptor agonists

Glucagon-like peptide-1 receptor (GLP-1R) agonists have been shown to regulate blood glucose concentrations by mechanisms including enhanced insulin synthesis/secretion, suppressed glucagon secretion, slowed gastric emptying, and enhanced satiety. GLP-1 receptors have also been identified in the heart, kidneys, and blood vessels, leading to the hypothesis that GLP-1R agonists may affect cardiovascular function or cardiovascular disease (CVD). The aim of this literature review was to assemble and assess preclinical and clinical data of potential medical importance regarding the cardiovascular effects of GLP-1R agonists. Preclinical studies with the GLP-1R agonists GLP-1, exenatide, or liraglutide provided evidence that GLP-1R stimulation favorably affects endothelial function, sodium excretion, recovery from ischemic injury, and myocardial function in animals. Similar observations have been made in exploratory studies on GLP-1 infusion in normal subjects and patients with type 2 diabetes. Post hoc analyses of phase III studies of patients with type 2 diabetes treated with exenatide(bid or qw) or liraglutide(qd) showed that these GLP-1R agonists reduced blood pressure, an effect largely independent of weight loss, and that liraglutide slightly increased heart rate. Preliminary data also indicated that GLP-1R agonists reduced markers of CVD risk such as C-reactive protein and plasminogen activator inhibitor-1. Ongoing studies are examining the effects of administering GLP-1R agonists to patients at risk of CVD, postangioplasty patients, post-CABG patients, and patients with heart failure. Additional studies should provide meaningful data to determine whether GLP-1R agonists provide unique treatment benefits to patients at risk for or with established CVD.