Stiffness and impaired blood flow in lower-leg arteries are associated with severity of coronary artery calcification among asymptomatic type 2 diabetic patients

Novel insights into the genetic architecture of pregnancy glycemic traits from 14,744 Chinese maternities

Glycemic traits are critical indicators of maternal and fetal health during pregnancy. We performed genetic analysis for five glycemic traits in 14,744 Chinese pregnant women. Our genome-wide association study identified 25 locus-trait associations, including established links between gestational diabetes mellitus (GDM) and the genes CDKAL1 and MTNR1B. Notably, we discovered a novel association between fasting glucose during pregnancy and the ESR1 gene (estrogen receptor), which was validated by an independent study in pregnant women. The ESR1-GDM link was recently reported by the FinnGen project. Our work enhances the findings in East Asian populations and highlights the need for independent studies. Further analyses, including genetic correlation, Mendelian randomization, and transcriptome-wide association studies, provided genetic insights into the relationship between pregnancy glycemic traits and hypertension. Overall, our findings advance the understanding of genetic architecture of pregnancy glycemic traits, especially in East Asian populations.

High Brachial Ankle Pulse Wave Velocity as a Marker for Predicting Coronary Artery Stenosis in Patients with Type 2 Diabetes

BACKGROUND

We evaluated the ability of brachial ankle pulse wave velocity (baPWV) to predict coronary artery stenosis (CAS) in patients with type 2 diabetes, and compared the predictive power of baPWV to that of well-known cardiovascular disease (CVD) risk calculators.

METHODS

The study group included 83 consecutive patients over 30 years old with type 2 diabetes who complained of vague chest discomfort. An automatic pulse waveform analyzer was used to measure baPWV. CAS was measured using multi-slice computed tomographic (MSCT) angiography.

RESULTS

Age, maximal baPWV, duration of diabetes, current smoking, the UK Prospective Diabetes Study (UKPDS) Risk Engine score, American College of Cardiology/American Heart Association (ACC/AHA) risk estimator score, the Framingham risk calculator score, and coronary artery calcium score were greater in patients with CAS than in those without CAS. An area under the curve (AUC) indicative of a predictive value for CAS (≥20%) was found for several parameters. The AUC of maximal baPWV, the UKPDS Risk Engine, the ACC/AHA ASCVD risk estimator, and the Framingham risk calculator were 0.672 (95% confidence interval [CI], 0.554 to 0.785; P=0.010), 0.777 (95% CI, 0.675 to 0.878; P<0.001), 0.763 (95% CI, 0.660 to 0.866; P<0.001), and 0.736 (95% CI, 0.629 to 0.843; P<0.001), respectively. The optimal cutoff value of baPWV for the detection of CAS was 1,650 cm/sec (sensitivity, 68.9%; specificity, 63.2%).

CONCLUSION

Maximal baPWV was closely related with CAS detected by MSCT coronary angiography in patients with type 2 diabetes. baPWV has the potential to be a useful, noninvasive screening tool for the prediction of occult CAS in patients with type 2 diabetes.

A hypothetical pathogenesis model for androgenic alopecia: clarifying the dihydrotestosterone paradox and rate-limiting recovery factors

Androgenic alopecia, also known as pattern hair loss, is a chronic progressive condition that affects 80% of men and 50% of women throughout a lifetime. But despite its prevalence and extensive study, a coherent pathology model describing androgenic alopecia's precursors, biological step-processes, and physiological responses does not yet exist. While consensus is that androgenic alopecia is genetic and androgen-mediated by dihydrotestosterone, questions remain regarding dihydrotestosterone's exact role in androgenic alopecia onset. What causes dihydrotestosterone to increase in androgenic alopecia-prone tissues? By which mechanisms does dihydrotestosterone miniaturize androgenic alopecia-prone hair follicles? Why is dihydrotestosterone also associated with hair growth in secondary body and facial hair? Why does castration (which decreases androgen production by 95%) stop pattern hair loss, but not fully reverse it? Is there a relationship between dihydrotestosterone and tissue remodeling observed alongside androgenic alopecia onset? We review evidence supporting and challenging dihydrotestosterone's causal relationship with androgenic alopecia, then propose an evidence-based pathogenesis model that attempts to answer the above questions, account for additionally-suspected androgenic alopecia mediators, identify rate-limiting recovery factors, and elucidate better treatment targets. The hypothesis argues that: (1) chronic scalp tension transmitted from the galea aponeurotica induces an inflammatory response in androgenic alopecia-prone tissues; (2) dihydrotestosterone increases in androgenic alopecia-prone tissues as part of this inflammatory response; and (3) dihydrotestosterone does not directly miniaturize hair follicles. Rather, dihydrotestosterone is a co-mediator of tissue dermal sheath thickening, perifollicular fibrosis, and calcification - three chronic, progressive conditions concomitant with androgenic alopecia progression. These conditions remodel androgenic alopecia-prone tissues - restricting follicle growth space, oxygen, and nutrient supply - leading to the slow, persistent hair follicle miniaturization characterized in androgenic alopecia. If true, this hypothetical model explains the mechanisms by which dihydrotestosterone miniaturizes androgenic alopecia-prone hair follicles, describes a rationale for androgenic alopecia progression and patterning, makes sense of dihydrotestosterone's paradoxical role in hair loss and hair growth, and identifies targets to further improve androgenic alopecia recovery rates: fibrosis, calcification, and chronic scalp tension.

Relation between baseline plaque features and subsequent coronary artery remodeling determined by optical coherence tomography and intravascular ultrasound

Atherosclerosis often leads to myocardial infarction and stroke. We examined the influence of baseline plaque characteristics on subsequent vascular remodeling in response to changes in plaque size. Using optical coherence tomography (OCT) and intravascular ultrasound (IVUS), we examined 213 plaques from 138 patients with acute coronary syndrome at baseline and repeated IVUS at the 12-month follow-up. The change in external elastic membrane (EEM) area for each 1 mm2 change in plaque area (i.e., the slope of the regression line) was calculated as a measure of vascular remodeling capacity. In plaques with static positive remodeling, the slope was smaller than in plaques without static positive remodeling. In addition, the slope of the regression line for lesions with a large plaque burden was much smaller than that for lesions with a small plaque burden. Multivariate linear regression analysis showed that diabetes, calcification and static positive remodeling were inversely and independently associated with the level of change in EEM area/change in plaque area. Lesions with a large plaque burden, calcifications or static positive remodeling had less remodeling capacity, and calcification and static positive remodeling were independent predictors of reduced subsequent remodeling. Therefore, calcifications and static positive remodeling could be used as morphological biomarkers to predict decreased subsequent arterial remodeling.

Volume elastic modulus of the brachial artery and coronary artery stenosis in patients with suspected stable coronary artery disease

This study aimed to examine the association between the non-invasive measurement of the brachial artery volume elastic modulus (V E), an index of arterial stiffness, and the presence of coronary artery stenosis in patients with suspected stable coronary artery disease (CAD). A total of 135 patients with suspected stable CAD (87 men, mean age, 64 ± 12 years) underwent oscillometric measurement of the brachial artery to obtain V E. Coronary angiography was thereafter carried out to diagnose CAD, defined as having ≥75 % stenosis in the epicardial coronary arteries. V E was significantly higher in patients with CAD (1.94 ± 0.34 mmHg/%) than in those without CAD (1.71 ± 0.35 mmHg/%, P < 0.001). In multiple logistic regression analysis, V E was an independent predictor for the presence of CAD (odds ratio 1.19 per 0.1 mmHg/% increase, 95 % CI 1.04-1.51) even after adjusting for multiple potential confounders including the Framingham risk score (FRS). The area under the curve of the receiver operating characteristic curve analysis for discriminating CAD increased significantly after the addition of V E to the FRS (from 0.75 to 0.81, P = 0.034). The category-free net reclassification improvement and the integrated discrimination improvement by adding V E to the FRS were 0.476 (95 % CI 0.146-0.806) and 0.086 (95 % CI 0.041-0.132), respectively. In conclusion, the brachial V E was significantly associated with the presence of coronary artery stenosis. The additional measurement of V E to the FRS improved the ability to identify patients with coronary artery stenosis among those with suspected stable CAD.

Coronary artery calcification and large artery stiffness in renal transplant recipients

PURPOSE

Coronary artery calcification (CAC) is an independent predictor of cardiovascular (CV) events in renal transplant recipients (RTR). Carotid-femoral pulse wave velocity (PWV), a non-invasive measure of large artery stiffness, also predicts CV events in RTR. The study investigated the relationship between CAC and PWV in RTR and assessed the performance of PWV measurement in predicting CAC.

PATIENTS/METHODS

The study was performed as cross-sectional analysis in 104 RTR. CAC was determined as total calcium score (CS) and calcium mass (CM). Carotid-femoral PWV was also measured. Sensitivity, specificity and receiver operating characteristic (ROC) curve were used to assess the performance of PWV as diagnostic test for presence of CAC.

RESULTS

CAC was found in 69% of participants. PWV was higher in RTR with CAC than in RTR without CAC (10.2±2.2 vs. 8.6±15; p<0.001). In univariate analysis CS was significantly correlated with age, duration of hypertension, waist circumference, PWV, hemoglobin concentration, and serum glucose. In multiple linear regression analysis CS was independently associated with age only, but not with PWV. Sensitivity and specificity of PWV>7.6m/s as cut-off for detecting CAC>0 was 0.889 and 0.406, respectively. Sensitivity and specificity of PWV>10.2m/s as cut-off for detecting severe CAC (CS>400) was 0.319 and 0.969, respectively.

CONCLUSIONS

The study confirmed high prevalence of coronary artery calcification in renal transplant recipients. The study does not support the hypothesis that aortic stiffness is independently associated with coronary artery calcification in RTR. PWV measurement may be useful in excluding severe CAC in RTR.

Enhanced clinical pharmacy service targeting tools: risk-predictive algorithms

RATIONALE, AIMS AND OBJECTIVES

This study aimed to determine the value of using a mix of clinical pharmacy data and routine hospital admission spell data in the development of predictive algorithms. Exploration of risk factors in hospitalized patients, together with the targeting strategies devised, will enable the prioritization of clinical pharmacy services to optimize patient outcomes.

METHODS

Predictive algorithms were developed using a number of detailed steps using a 75% sample of integrated medicines management (IMM) patients, and validated using the remaining 25%. IMM patients receive targeted clinical pharmacy input throughout their hospital stay. The algorithms were applied to the validation sample, and predicted risk probability was generated for each patient from the coefficients. Risk threshold for the algorithms were determined by identifying the cut-off points of risk scores at which the algorithm would have the highest discriminative performance. Clinical pharmacy staffing levels were obtained from the pharmacy department staffing database.

RESULTS

Numbers of previous emergency admissions and admission medicines together with age-adjusted co-morbidity and diuretic receipt formed a 12-month post-discharge and/or readmission risk algorithm. Age-adjusted co-morbidity proved to be the best index to predict mortality. Increased numbers of clinical pharmacy staff at ward level was correlated with a reduction in risk-adjusted mortality index (RAMI).

CONCLUSIONS

Algorithms created were valid in predicting risk of in-hospital and post-discharge mortality and risk of hospital readmission 3, 6 and 12 months post-discharge. The provision of ward-based clinical pharmacy services is a key component to reducing RAMI and enabling the full benefits of pharmacy input to patient care to be realized.

Endovascular treatment of critical ischemia in the diabetic foot: new thresholds, new anatomies

This review discusses the role of endovascular treatment in diabetic patients with critical limb ischemia (CLI). Angioplasty of the femoropopliteal region achieves similar technical success and limb salvage rates in diabetic and nondiabetic patients. Angioplasty in as many as possible tibial vessels is accompanied by more complete and faster ulcer healing as well as better limb salvage rates compared to isolated tibial angioplasty. Targeted revascularization of a specific vessel responsible for the perfusion of a specific ulcerated area is a promising new approach: it replaces revascularization of the angiographically easiest-to-access tibial vessel, even if this is not directly responsible for the perfusion of the ulcerated area, by revascularization of area-specific vascular territories. In conclusion, the endovascular approach shows very high efficacy in ulcer healing for diabetic patients with CLI. Larger prospective studies are now needed to estimate the long-term results of this approach.

Diabetes and its chronic complications in the She ethnic minority group of China

OBJECTIVE

According to recent reports, the development of type 2 diabetes in China has soared at an alarming rate. However, most of the investigations were based on Han people, who account for the majority of people in China. Little is known about the prevalence of diabetes its chronic complications in the She people, who have their own traditional lifestyle and hereditable background, different from other Asian population. The present study investigated the prevalence of type 2 diabetes and associated risk factors in the adult population of She nationals.

SUBJECTS AND METHODS

A total of 5,385 participants entered into the analysis eventually, including 2,308 men and 3,077 women. An oral glucose tolerance test was performed in subjects without diagnosed diabetes. Liver function, cardiovascular risk (brachial-ankle pulse wave velocity, estimated glomerular filtration rate, and abnormal Minnesota codes findings), uric acid, and neuropathy were tested to assess the profiles of associated risks.

RESULTS

In general, the self-reported diabetes rate was 9.5%. After age and sex standardization, the prevalence of diabetes was 6.1% (6.7% for men and 5.7% for women) in She Chinese people. In logistic regression models, age, family history of diabetes, alcohol use, total cholesterol, and triglycerides were all significantly associated with the risk of diabetes in this cross-sectional study (all P<0.05). In all, 47.4% had cardiovascular risks, 19.4% had liver dysfunction, and 6.2% had hyperuricemia. For women, compared with the first quartile, log-transformed homeostasis model assessment for insulin resistance of the fourth quartile was significantly higher (P<0.05), and log-transformed homeostasis model assessment for β cells was also higher in the second, third, and fourth quartiles (all P<0.05). The prevalences of polyneuropathy in impaired fasting glucose (IFG), impaired glucose tolerance (IGT), IFG/IGT, and diabetes mellitus (DM) were 16.1%, 13.1%, 18.6%, and 28.4% separately, which was higher than that in normal glucose tolerance. The prevalences of polyneuropathy in IFG/IGT and DM were higher than that in IGT.

CONCLUSIONS

The present study revealed that a total of 6.1% She people suffered from type 2 diabetes, which was lower than the average level of China, but the standardized prevalence of prediabetes was higher, 20.6%. Early peripheral neuropathy screening should be performed in the prediabetes population. The Toronto Clinical Neuropathy Scoring System is convenient to assess diabetic polyneuropathy in clinical practice and should be tested regularly for people in prediabetes. Liver dysfunction, headache, and insomnia, appearing before type 2 diabetes, should be assessed regularly to avoid deterioration.

Serum γ-glutamyltransferase and associated damage among a She Chinese population

OBJECTIVE

It has been suggested that serum γ-glutamyltransferase is independently associated with cardiovascular mortality and atherosclerosis. The present study is to investigate the relationship between serum γ-glutamyltransferase and potential associated damage in an adult She Chinese population.

METHOD

A multistage, stratified, cluster, random sampling method was used to select an ethnically representative group of individuals aged 20-80 years in the general population. Brachial-ankle pulse-wave velocity was used to assess arterial stiffness in the general population and the Toronto Clinical Neuropathy Scoring System was used to detect diabetic peripheral polyneuropathy among populations with diabetes.

RESULTS

A total of 5385 subjects were entered into the analysis. Serum γ-glutamyltransferase levels were classified into four groups using the 25th, 50th and 75th percentiles as cut points (males: < 20, 20-29, 29-52 and > 52 U/l; females: < 13, 13-18, 18-25 and > 25 U/l). As compared with the first quartile, the relative risks of arterial stiffness were 1.418, 1.667 and 2.394 in the other three categories, respectively (test for trend P < 0.05). After adjustment in five models, serum γ-glutamyltransferase was still a risk factor of arterial stiffness. We found inverted U-shape curves in both genders and the third quartile (male: 29 52 U/l; female: 18-25 U/l) had the highest odds ratios of 1.640 and 1.529, respectively.

CONCLUSIONS

We demonstrated that high serum γ-glutamyltransferase concentrations were directly associated with the increased risk of arterial stiffness, in general, and with peripheral polyneuropathy in subjects with diabetes in an ethnic She Chinese population. Alcohol use, gender, BMI and blood pressure were related to serum γ-glutamyltransferase and were involved in the relationship between serum γ-glutamyltransferase and brachial-ankle pulse-wave velocity.

Arterial stiffness measured as pulse wave velocity is highly correlated with coronary atherosclerosis in asymptomatic patients

AIM

Carotid-femoral pulse wave velocity is a well-known predictor of all-cause and cardiovascular mortality. Few studies have evaluated the relationship between brachial-ankle pulse wave velocity (ba-PWV) and coronary artery disease. We conducted this study to elucidate the relationship between arterial stiffness measured by ba-PWV and coronary atherosclerosis.

METHODS

An automatic waveform analyzer was used to measure the ba-PWV. Multidetector computed tomography coronary angiography was used to assess the coronary artery calcium (CAC) score and to detect coronary stenosis. A total of 654 patients, including 358 women and 296 men (mean age, 54.5 ± 9.4 years), were recruited during the period March 2005 to June 2008.

RESULTS

One hundred and twenty-seven patients (19.4%) had at least one stenotic coronary vessel. Mean ba-PWV and mean CAC scores were significantly higher in the stenotic group than in the normal control (15.94 ± 3.07 m/s vs. 14.39 ± 0.98 m/s; 293.1 ± 435.9 vs. 29.8 ± 110.8, respectively; both p < 0.001). The adjusted OR for coronary stenosis increased as ba-PWV increased (p for trend = 0.0001). Using ba-PWV < 14.0 m/s as the reference group, we found that ba-PWV between 14.0-18.0 m/s and ba-PWV > 18.0 m/s were significantly associated with coronary stenosis (OR, 2.48; CI, 1.56-3.93 and OR, 3.16; CI, 1.68-5.95, respectively). The cutoff point at 15.64 m/s using the ROC curve showed a sensitivity of 64.5%, specificity of 65.6%, and an AUC of 0.662 in predicting coronary artery stenosis. Ba-PWV had an additional power for correlating coronary artery disease with the Framingham risk score.

CONCLUSIONS

Ba-PWV correlated well with coronary atherosclerosis. Lifestyle modification is an efficacious therapeutic intervention for preventing the progression of arterial stiffness. This non-invasive technique can assist in the early detection of cardiovascular disease and should be included in community screening programs.

Advanced coronary artery calcification and cerebral small vessel diseases in the healthy elderly

BACKGROUND

Coronary artery calcification (CAC) scores are widely accepted to predict risk of coronary heart diseases and are associated with atherosclerosis in other vasculatures. Cerebral small vessel diseases (SVDs), including white matter lesions (WML), silent lacunar infarction (SLI) and cerebral microbleeds (CMB), are considered to develop in conjunction with pro-atherogenic conditions, measured by CAC scores.

METHODS AND RESULTS

Of 672 individuals aged ≥65 years that underwent health screening, 312 subjects with brain magnetic resonance imagings (MRIs) were enrolled in this study. The distribution of baseline characteristics among individuals with or without MRIs was not different. Clinical and laboratory information was collected and CAC scores were measured using multi-detector computed tomography. Cerebral SVD were independently assessed by 2 raters who were unaware of the CAC scores. The prevalence of CAC (CAC>0) was 71.7% in men and 50.0% in women. The associations between moderate-to-extensive CAC (CAC score ≥100) and WML (adjusted odds ratio and 95% confidence interval, 4.99 and 1.33-18.73), SLI (5.04 and 1.86-13.63) and CMB (6.07 and 1.54-23.94) remained significant after adjusting for relevant confounders.

CONCLUSIONS

This study documents significant associations between CAC and cerebral SVDs. The findings suggest that SVDs in the brain and CAC in the heart may develop under similar systemic pathogenic processes.

The relationship between coronary artery calcification score, plasma osteoprotegerin level and arterial stiffness in asymptomatic type 2 DM

Because T2DM increases the risk of coronary atherosclerosis and CAD and new noninvasive techniques to assess CVD risk have gained considerable popularity, it is important to know how these tools relate to each other. The aim of this study was to evaluate the relationship between the extent of coronary artery calcification measured by MDCT, plasma OPG levels, baPWV and the established cardiovascular risk factors in Korean patients with T2DM. From November 2006 to December 2007, 110 asymptomatic Korean patients with T2DM without prior evidence of CAD were assessed (mean age 57.2 years). CAC imaging was performed using a 40-slice MDCT. Serum OPG levels were measured by an enzyme-linked immunosorbent assay (Oscotec, Korea) from the serum samples of each subject. We measured the baPWV as an index of arterial stiffness. In addition, we measured fasting glucose, HbA(1)C, hsCRP and lipid profiles. A total of 74 patients (67.3%) had minimal or insignificant CAC (<10). The CACS, OPG and baPWV showed significant positive correlations with each other. The CACS was significantly associated with the baPWV, smoking and use of a statin. The baPWV was significantly associated with age, duration of DM, total cholesterol and CACS by multiple linear regression models of the dependent variables of CACS or baPWV. CAC and baPWV were significant predictors of each other (r = 0.359, P = 0.014 and r = 0.361, P = 0.004). The results of this study showed that CAC, baPWV and serum OPG levels were significantly correlated with each other in asymptomatic Korean patients with T2DM. Furthermore, our results suggest that arterial stiffness, as determined by baPWV, may predict the extent of coronary calcification by MDCT.

The value of brachial-ankle pulse wave velocity as a predictor of coronary artery disease in high-risk patients

BACKGROUND AND OBJECTIVES

Arterial stiffness has been known as an independent contributory factor for coronary artery disease (CAD). Brachial-ankle pulse wave velocity (baPWV) is widely used as a simple noninvasive measure of arterial stiffness. The aim of our study was to test whether baPWV had predictive value for CAD in the subset of patients with high pretest probability.

SUBJECTS AND METHODS

We enrolled 174 consecutive patients who were referred for evaluation of suspected CAD, and who underwent both baPWV measurement and computed tomography (CT) for coronary artery calcium scoring (CACS) as part of a diagnostic work-up. Subsequently, 160 of those patients underwent invasive coronary angiography. The CAD indices consisted of 1) CACS, 2) modified Gensini scoring system, and 3) presence of obstructive CAD and 4) multi-vessel obstructive CAD.

RESULTS

baPWV correlated with CACS (r=0.25, p=0.001), but not with modified Gensini scoring (r=0.10, p=0.19). However, after adjustment for factors influencing PWV, baPWV no longer correlated with CACS (r=0.14, p=0.14). By receiver operating characteristic (ROC) curve analysis, baPWV was neither a sensitive nor specific index for predicting the presence of obstructive CAD or multi-vessel obstructive CAD (sensitivity: 53% and 59%; specificity: 50% and 55%, respectively).

CONCLUSION

Our findings demonstrated that baPWV is associated with CACS, however, this may be primarily attributed to common risk factors, such as age. Furthermore, baPWV may be of limited value in identifying patients at risk for CAD.

Usefulness of brachial-ankle pulse wave velocity as a predictive marker of multiple coronary artery occlusive disease in Korean type 2 diabetes patients

Multiple coronary artery occlusive disease (multiple CAOD) is the most fatal and frequently observed coronary artery disease in type 2 diabetes patients, but no simple, non-invasive screening tool is available yet. The aim of this study is to evaluate the arterial stiffness in type 2 diabetes patients using brachial-ankle pulse wave velocity (baPWV), to demonstrate the correlation between arterial stiffness and multiple CAOD, and to suggest the cutoff point of baPWV for predicting multiple CAOD in Korean type 2 diabetes patients. One hundred and eighty-one diabetes and 262 non-diabetes patients were enrolled in the study. Routine anthropometric and serologic data were collected. baPWV was measured the day before coronary angiography, and the severity of CAOD was assessed with Gensini score after angiography. baPWV and Gensini score were significantly increased in diabetes patients and Gensini score had a positive correlation with baPWV. Subjects in the highest tertile of baPWV showed odds ratio of 3.06 for multiple CAOD compared to the lowest tertile. In ROC curve, baPWV at 1635 cm/s showed 73% sensitivity and 75% specificity with AUC 0.76 in diabetes patients in detecting multiple CAOD. Therefore, baPWV may be utilized a screening tool for predicting multiple CAOD, especially in type 2 diabetes patients.

Using brachial-ankle pulse wave velocity to associate arterial stiffness with cardiovascular risks

BACKGROUND AND AIMS

This study aimed to elucidate the relationship between brachial-ankle pulse wave velocity (baPWV) and conventional cardiovascular risk factors.

METHODS AND RESULTS

A total of 192 subjects with low to intermediate risk was enrolled in a cardiovascular evaluation program. A multiple regression model was built to find significant cardiovascular biomarkers for predicting baPWV. A logistic regression model was developed to associate baPWV and other biomarkers with the risk of cardiac diastolic dysfunction. A total of 123 men (mean age: 52.6+/-12.0) and 69 women (mean age: 51.7+/-10.4) was included. Age, blood pressure, C-reactive protein, serum homocysteine, heart rate, and blood urea nitrogen were positively predictive of increased pulse wave velocity. In turn, baPWV increased the risk (odds ratio: 1.257 for each m/s, 95% CI: 1.105 approximately 1.430, p<0.001) and high-density lipoprotein decreased the risk for cardiac diastolic dysfunction (0.962 for each mg/dl, 95% CI: 0.925 approximately 1.000, p=0.05). The correlation between baPWV and Framingham 10-year risk was moderate (men: r=0.306, p=0.002; women r=0.548, p<0.001).

CONCLUSION

The results suggest that baPWV is a composite risk factor for early atherosclerotic change and a predictor for the development of diastolic dysfunction and long-term cardiovascular risk.

Reduced leg blood flow during submaximal exercise in type 2 diabetes

It is unclear whether impaired cardiac and/or vascular function contribute to exercise intolerance in patients with type 2 diabetes.

PURPOSE

Magnetic resonance imaging (MRI) was used to determine whether reductions in cardiac output and/or femoral arterial blood flow contribute to reduced aerobic capacity in patients with type 2 diabetes.

METHODS

Cardiac and femoral arterial blood flow MRI scans were performed at rest and during low-intensity leg exercise in eight patients with type 2 diabetes and 11 healthy individuals. Maximal aerobic capacity VO(2 max) and maximal oxygen pulse were also determined in all participants.

RESULTS

V O(2 max) was 20% lower and maximal oxygen pulse was 16% lower in patients with type 2 diabetes (P < 0.05), whereas maximal heart rate was the same between groups. Low-intensity exercise induced a 20% increase in heart rate and cardiac output as well as a 60-70% increase in femoral blood flow in both groups (P < 0.05). Femoral arterial blood flow indexed to thigh lean mass was reduced during exercise in patients with type 2 diabetes compared with healthy individuals. Stroke volume indexed to fat-free mass was lower in patients with type 2 diabetes, but greater heart rate allowed cardiac output to be maintained during submaximal exercise.

CONCLUSIONS

These findings suggest that impaired femoral arterial blood flow, an indirect marker of muscle perfusion, affects low-intensity exercise performance in patients with type 2 diabetes. However, because of lower exercising stroke volume, we propose that femoral arterial blood flow and, possibly, cardiac output, limit V O(2 max) in patients with type 2 diabetes.

Noninvasive assessment of preclinical atherosclerosis

Initially considered as a semipermeable barrier separating lumen from vessel wall, the endothelium is now recognised as a complex endocrine organ responsible for a variety of physiological processes vital for vascular homeostasis. These include the regulation of vascular tone, luminal diameter, and blood flow; hemostasis and thrombolysis; platelet and leucocyte vessel-wall interactions; the regulation of vascular permeability; and tissue growth and remodelling. The endothelium modulates arterial stiffness, which precedes overt atherosclerosis and is an independent predictor of cardiovascular events. Unsurprisingly, dysfunction of the endothelium may be considered as an early and potentially reversible step in the process of atherogenesis and numerous methods have been developed to assess endothelial status and large artery stiffness. Methodology includes flow-mediated dilatation of the brachial artery, assessment of coronary flow reserve, carotid intimamedia thickness, pulse wave analysis, pulse wave velocity, and plethysmography. This review outlines the various modalities, indications, and limitations of available methods to assess arterial dysfunction and vascular risk.

Coronary artery calcification, common carotid artery intima-media thickness and aortic pulse wave velocity in patients on peritoneal dialysis

An increasing body of evidence suggests that atherosclerosis in patients with uremia differs from that found in general population in terms of advancement and localization of vascular lesions. It has also been suggested that different non-invasive techniques of vascular system evaluation are designed to show different types of lesions (i.e. vascular calcification, stiffness or 'classical' atherosclerosis). The aim of the study was to search for possible associations between results obtained with three different non-invasive methods of vascular system assessment in three different vascular sites in patients treated with peritoneal dialysis (PD). 61 patients (28 F, 33 M), mean age of 50.4+/-13.6 years, on maintenance PD for a median period of 10 months (range 1-96 months) were included. Coronary artery disease (CAD) was present in 21 subjects. In all subjects coronary artery calcification score (CaSc) using multi-row spiral computed tomography (MSCT), aortic pulse wave velocity (AoPWV) and ultrasound-based common carotid artery intima-media thickness (CCA-IMT) were performed as methods for assessing coronary calcium burden, arterial stiffness and atherosclerosis, respectively. Median value of CaSc equaled 11.5 Agatston units (range 0-5502.8 units). Median AoPWV was 10.4 m/s (range 7.56-18.1 m/s), and median CCA-IMT-0.6 mm (range 0.3-1.0 mm). In 16 patients (26.2%) at least one plaque in at least one common carotid artery was found on ultrasound. CaSc correlated with AoPWV (R=0.32, p<0.01) and with CCA-IMT (R=0.35, p<0.005), whereas no association was found between AoPWV and CCA-IMT. AoPWV, but not CaSc nor IMT correlated with blood pressure. The values of CCA-IMT and AoPWV increased together with consecutive Agatston categories (with p<0.001 for differences in AoPWV and p<0.05 for CCA-IMT). Patients with at least one plaque found in at least one CCA and patients with CAD were characterized with significantly higher values of CaSc, IMT and PWV, when compared to plaque-free and CAD- negative subjects, respectively. Association between CaSc and both IMT and PWV may suggest that the mechanism of three assessed vascular pathologies may be based, to some extent, on the process of pathologic calcium-phosphate deposition. Lack of correlation found between PWV and IMT may suggest that aortic stiffness and carotid atherosclerosis may partially differ in their pathologic background and/or are dissociated in time.

Effect of weight loss and nutritional intervention on arterial stiffness in type 2 diabetes

OBJECTIVE

There is increased stiffness of the large central arteries in type 2 diabetic patients, and obesity is a risk factor. However, the effect of intentional weight loss on arterial stiffness is uncertain, and the purpose of the current study was to assess this effect.

RESEARCH DESIGN AND METHODS

Arterial stiffness was assessed by measuring aortic pulse wave velocity (aPWV) at baseline and at completion of a 1-year weight loss intervention. Metabolic control of type 2 diabetes was also appraised.

RESULTS

Mean weight loss at 1 year in 38 volunteers with type 2 diabetes was 7.8%. There were improvements in HbA1c, LDL cholesterol, homeostasis model assessment of insulin resistance, and inflammatory markers (plasminogen activator inhibitor-1, tumor necrosis factor-alpha, interleukin-6, and C-reactive protein). There was also a significant improvement in aPWV at completion of weight loss intervention, from 740 to 690 cm/s (P < 0.05).

CONCLUSIONS

Moderate weight loss improves arterial stiffness in type 2 diabetes.

Coronary artery calcification, serum lipids, lipoproteins, and peripheral inflammatory markers in adolescents and young adults with type 1 diabetes

OBJECTIVE

To determine whether coronary artery calcification (CAC), elevated fasting lipids, and lipoproteins and peripheral inflammatory markers are present in insulin-dependent diabetic adolescents and young adults several years after diagnosis.

STUDY DESIGN

Hispanic insulin-dependent diabetics (n = 32) diagnosed a mean of 7.8 +/- 4.5 years ago (range, 3 to 16 years), with a mean glycosylated hemoglobin concentration at the time of the study of 8.8% +/- 2.3% and a mean chronological age of 16.1 +/- 4.4 years, were evaluated. Healthy patients (n = 15) with a chronological age (CA) of 15.2 +/- 2.2 years served as control subjects. CAC was assessed by multiple slice computed tomography, and total CAC score in Agatston units was calculated. Fasting lipids, C-reactive protein, apolipoprotein (Apo) A, Apo B, and metalloproteinase-9 (MMP-9) concentrations were measured in all subjects.

RESULTS

Neither adolescents with type 1 diabetes nor healthy control subjects presented with evidence of CAC. Fasting lipids, Apo A, Apo B, CRP, and MMP-9 concentrations were similar between diabetic subjects and control subjects. However, 34.4% and 25.0% of our type 1 diabetic subjects had elevated total and LDL cholesterol levels (>200 and >130 mg/dL, respectively), whereas 15.6% and 28.1% had elevated triglyceride and Apo B concentrations (>150 mg/dL and >100 mg/dL, respectively). In addition, 28.1% and 34.4% presented with elevated CRP and MMP-9 levels (>2 mg/L and >80 ng/mL, respectively). Total, LDL and HDL cholesterol, triglycerides, Apo B, CRP, and MMP-9 concentrations correlated positively with duration of the disease and with glycosylated hemoglobin levels.

CONCLUSIONS

Although the study adolescents with type 1 diabetes did not present any radiologic evidence of CAC at this stage of the disease, they remain a high-risk group for the development of microvascular and macrovascular artery disease, as risk factors such as elevated lipoproteins and proinflammatory markers are already present in a significant percentage of patients studied.

Low blood flow estimates in lower-leg arteries predict cardiovascular events in Japanese patients with type 2 diabetes with normal ankle-brachial indexes

OBJECTIVE

To examine the association of baseline measures in lower-leg arteries and conventional cardiovascular risk factors with the incidence of cardiovascular disease (CVD) events in type 2 diabetic patients with normal ankle-brachial indexes (ABIs) (>0.9).

RESEARCH DESIGN AND METHODS

We studied 129 type 2 diabetic patients and 35 age-matched nondiabetic subjects with no apparent CVD consecutively admitted to our hospital. At baseline, total flow volume and resistive index, as an index of vascular resistance, at the popliteal artery was evaluated using gated two-dimensional cine-mode phase-contrast magnetic resonance imaging. Patients were followed 4.8 +/- 1.5 years (range 3.0-8.2) or until their first event of CVD.

RESULTS

On follow-up, 16 patients developed primary CVD events. Patients with CVD had lower blood flow (P < 0.01) and higher vascular resistance (P < 0.05) than patients without CVD. When the patients were grouped into tertiles according to their levels of total flow volume (129.6-85.5, 85.3-63.3, and 62.7-23.8 ml/min), Kaplan-Meier analysis showed a higher probability of developing CVD events in patients in the lowest than in patients in the highest (P = 0.0199, log-rank test) tertile. Multivariate Cox proportional hazards analysis revealed that the lowest tertile for flow volume (hazard ratio [HR] 8.60, 95% CI 1.61-45.97, P = 0.012), hypertension (3.99, 1.12-14.25, P = 0.033), and smoking status (12.01, 1.21-119.28, P = 0.034) were significant independent predictors of CVD events.

CONCLUSIONS

We have demonstrated that low blood flow estimates in lower-leg arteries may be predictive for CVD events among Japanese patients with type 2 diabetes even though they have a normal ABI.

Influence of nebivolol and enalapril on metabolic parameters and arterial stiffness in hypertensive type 2 diabetic patients

OBJECTIVE

To compare the effects of a cardioselective beta-blocker (nebivolol) with those of an angiotensin-converting enzyme inhibitor (enalapril) on parameters of insulin sensitivity, peripheral blood flow and arterial stiffness during one extended glucose clamp experiment.

DESIGN

A randomized, double-blind crossover trial, consisting of two 12-week treatment phases separated by a 4-week wash-out phase.

METHODS

Patients with type 2 diabetes and arterial hypertension were randomly assigned to one of two treatment sequences (nebivolol-enalapril, enalapril-nebivolol). Haemodynamic, metabolic and other laboratory measurements were carried out on the first and last day of each treatment period by means of a glucose clamp experiment that also involved the measurement of blood flow and arterial stiffness.

RESULTS

Twelve patients were included in this study, of which two dropped out early. Efficacy parameters were therefore available for 10 patients. There was no significant difference in any of the primary efficacy parameters. Moreover, the effects on blood pressure did not significantly differ between both treatments. Six adverse events happened during treatment with nebivolol compared with two during treatment with enalapril, but only one was regarded as possibly related to the treatment.

CONCLUSIONS

This pilot study shows that the combined measurement of insulin sensitivity, blood flow and arterial stiffness is feasible. Nebivolol and enalapril did not show different effects with regard to these parameters in hypertensive diabetic patients. If these results are confirmed in larger clinical trials, this would argue against the reservations against beta-blockers as drugs of first choice in patients with diabetes because of potential metabolic side-effects.