Association of diabetes mellitus with coronary atherosclerosis and myocardial lesions. An autopsy study from the Honolulu Heart Program

Risk of atrial fibrillation in individuals with dysglycemia and diabetes

OBJECTIVE

Diabetes is a risk factor for atrial fibrillation (AF), and increases the risk of thromboembolic events in persons with AF. However, the link between the two conditions is not fully elucidated. Few studies have investigated the association of dysglycemia and incident AF. We investigated the risk of incident AF and prognosis according to diabetes status.

RESEARCH DESIGN AND METHODS

The Copenhagen Primary Care Laboratory Database was merged with data on medical prescriptions, in- and outpatient contacts and vital status. The risk of AF according to diabetes status was investigated by use of Cox regression models.

RESULTS

Of 354.807 individuals with a hemoglobin A1c (HbA1c) measurement, 28.541 (8 %) had known diabetes, 13.038 (4 %) had new onset diabetes and 27.754 (8 %) had prediabetes (HbA1c 42-47 mmol/mol). Persons with dysglycemia (HbA1c > 42 mmol/mol) and diabetes were older, more were men, they had lower level of education and were more likely to be living alone. We observed a gradual increase in risk of developing AF from HbA1c levels of 40 to 60 mmol/mol. In adjusted analyses we found a stepwise increase in hazard of AF from normoglycemia over prediabetes to persons with diabetes (no diabetes: 1.00 [ref.]; prediabetes: 1.12 [1.08-1.16]; new-onset diabetes: 1.16 [1.10-1.22]; known diabetes: 1.15 [1.11-1.20]). Persons with known diabetes had a significant higher hazard of stroke, cardiovascular and all-cause mortality.

CONCLUSION

Increasing levels of HbA1c were associated with an increased hazard of developing AF. Persons with new onset of diabetes and those with known diabetes had similar hazard of developing AF, however persons with known diabetes had a significant higher hazard of stroke, cardiovascular- and all-cause mortality.

Diabetes Duration and Subclinical Myocardial Injury: The Atherosclerosis Risk in Communities Study (ARIC)

BACKGROUND

Diabetes exerts adverse effects on the heart, and a longer diabetes duration is associated with greater heart failure risk. We studied diabetes duration and subclinical myocardial injury, as reflected by high-sensitivity cardiac troponin (hs-cTnT).

METHODS

We analyzed 9052 participants without heart failure or coronary heart disease (mean age 63 years, 58% female, 21% Black, 15% with diabetes) at The Atherosclerosis Risk in Communities Study (ARIC) Visit 4 (1996 to 1998). Diabetes duration was calculated based on diabetes status at Visits 1 (1987 to 1989) through 4, or using self-reported age of diabetes diagnosis prior to Visit 1. We used multinomial logistic regression to determine the association of diabetes duration with increased (≥14 ng/L) or detectable (≥6 ng/L) Visit 4 hs-cTnT, relative to undetectable hs-cTnT, adjusted for demographics and cardiovascular risk factors.

RESULTS

The prevalence of increased Visit 4 hs-cTnT was higher in persons with longer diabetes duration, from 12% for those with diabetes 0 to <5 years up to 31% among those with diabetes for ≥15 years (P for trend <0.0001). New onset diabetes at Visit 4 was associated with 1.92× higher relative risk (95% CI, 1.27-2.91) of increased hs-cTnT than no diabetes. Longer diabetes duration was associated with greater myocardial injury, with duration ≥15 years associated with 9.29× higher risk (95% CI, 5.65-15.29) for increased hs-cTnT and 2.07× (95% CI, 1.24-3.16) for detectable hs-cTnT, compared to no diabetes.

CONCLUSIONS

Longer diabetes duration is strongly associated with subclinical myocardial injury. Interventional studies are needed to assess whether the prevention and delay of diabetes onset can mitigate early myocardial damage.

Duration of Diabetes and Incident Heart Failure: The ARIC (Atherosclerosis Risk In Communities) Study

OBJECTIVES

This study assessed the association of diabetes duration with incident heart failure (HF).

BACKGROUND

Diabetes increases HF risk. However, the independent effect of diabetes duration on incident HF is unknown.

METHODS

We included 9,734 participants (mean age 63 years, 58% women, 22% Black) at ARIC (Atherosclerosis Risk In Communities) Visit 4 (1996-1998) without HF or coronary heart disease. We calculated diabetes duration at Visit 4 (baseline), utilizing diabetes status at the first 4 ARIC visits spaced 3 years apart, and self-reported diagnosis date for those with diabetes diagnosed before Visit 1. We used Cox regression to estimate associations of diabetes duration with incident HF, accounting for intercurrent coronary heart disease and other risk factors. We performed analyses stratified by age (<65 years or ≥65 years), race, sex, and glycemic control (hemoglobin A1C [HbA1C] consistently <7%, vs HbA1C ≥7%), with tests for interaction.

RESULTS

Over 22.5 years of follow-up, there were 1,968 HF events. Compared to those without diabetes, HF risk rose with longer diabetes duration, with the highest risk among those with ≥15 y diabetes duration (HR: 2.82; 95% CI: 2.25-3.63). Each 5-year increase in diabetes duration was associated with a 17% (95% CI: 11-22) relative increase in HF risk. Similar results were observed across HF subtypes. The HF and diabetes duration associations were stronger among those aged <65 years, those with HbA1C ≥7%, those with a body mass index ≥30 kg/m2, women, and Blacks (all P interactions <0.05).

CONCLUSIONS

Delaying diabetes onset may augment HF prevention efforts, and therapies to improve HF outcomes might target those with long diabetes duration.

Relationship between insulin resistance, coronary plaque, and clinical outcomes in patients with acute coronary syndromes: an analysis from the PROSPECT study

Background

We investigated the association of insulin resistance (IR) with coronary plaque morphology and the risk of cardiovascular events in patients enrolled in the Providing Regional Observations to Study Predictors of Events in Coronary Tree (PROSPECT) study.

Methods

Patients with acute coronary syndromes (ACS) were divided based on DM status. Non-DM patients were further stratified according to homeostasis-model-assessment IR (HOMA-IR) index as insulin sensitive (IS; HOMA-IR ≤ 2), likely-IR (LIR; 2 < HOMA-IR < 5), or diabetic-IR (DIR; HOMA-IR ≥ 5). Coronary plaque characteristics were investigated by intravascular ultrasound. The primary endpoint was major adverse cardiac events (MACE); a composite of cardiac death, cardiac arrest, myocardial infarction, and rehospitalization for unstable/progressive angina.

Results

Among non-diabetic patients, 109 patients (21.5%) were categorized as LIR, and 65 patients (12.8%) as DIR. Patients with DIR or DM had significantly higher rates of echolucent plaque compared with LIR and IS. In addition, DIR and DM were independently associated with increased risk of MACE compared with IS (adjusted hazard ratio [aHR] 2.29, 95% confidence interval [CI] 1.22–4.29, p = 0.01 and aHR 2.12, 95% CI 1.19–3.75, p = 0.009, respectively).

Conclusions

IR is common among patients with ACS. DM and advanced but not early stages of IR are independently associated with increased risk of adverse cardiovascular events.

Trial Registration ClinicalTrials.gov Identifier: NCT00180466.

Quantification of atherosclerotic plaque volume in coronary arteries by computed tomographic angiography in subjects with and without diabetes

Background

Diabetes mellitus (DM) is considered a cardiovascular risk factor. The aim of this study was to analyze the prevalence and volume of coronary artery plaque in patients with diabetes mellitus (DM) vs. those without DM.

Methods

This study recruited consecutive patients who underwent coronary computed tomography (CT) angiography (CCTA) between October 2016 and November 2017. Personal information including conventional cardiovascular risk factors was collected. Plaque phenotypes were automatically calculated for volume of different component. The volume of different plaque was compared between DM patients and those without DM.

Results

Among 6381 patients, 931 (14.59%) were diagnosed with DM. The prevalence of plaque in DM subjects was higher compared with nondiabetic group significantly (48.34% vs. 33.01%, χ² = 81.84, P < 0.001). DM was a significant risk factor for the prevalence of plaque in a multivariate model (odds ratio [OR] = 1.465, 95% CI: 1.258–1.706, P < 0.001). The volume of total plaque and any plaque subtypes in the DM subjects was greater than those in nondiabetic patients significantly (P < 0.001).

Conclusion

The coronary artery atherosclerotic plaques were significantly higher in diabetic patients than those in non-diabetic patients.

Aged garlic extract reduces low attenuation plaque in coronary arteries of patients with diabetes: A randomized, double-blind, placebo-controlled study

Several previous studies have demonstrated that aged garlic extract (AGE) inhibits the progression of coronary artery calcification and non-calcified plaque (NCP) in the general population. However, its effects on plaque progression in patients with diabetes have not yet been investigated, at least to the best of our knowledge. This study investigated whether AGE reduces the coronary plaque volume measured by cardiac computed tomography angiography (CCTA) in patients with diabetes mellitus (DM). A total of 80 participants with DM with a median age of 57 years were prospectively assigned to consume 2,400 mg AGE/day (after completion, 37 participants) or placebo (after completion, 29 participants) orally. Both groups underwent CCTA at baseline and follow-up 365 days apart. In total, 66 participants completed the study. Coronary plaque volume, including total plaque (TP), dense calcium (DC), fibrous, fibro-fatty and low-attenuation plaque (LAP) volumes were measured based upon pre-defined intensity cut-off values using semi-automated software (QAngio CT). Changes in various plaque types were normalized to the total coronary artery length. The non-parametric Wilcoxon rank-sum test was performed to examine the differences in plaque formation between the 2 groups. No significant differences were found in the baseline characteristics between the AGE and placebo groups. Compared with the placebo group, the AGE group exhibited a statistically significant regression in normalized LAP [median and standard deviation (SD) -0.2 (18.8) vs. 2.5 (69.3), P=0.0415]. No differences were observed in TP, fibrous, or fibrofatty plaque volumes between the AGE and placebo group. On the whole, this study indicated that the %LAP change in the AGE group was significantly greater than that in the placebo group in patients with diabetes. However, further studies are warranted to evaluate whether AGE has the ability to stabilize vulnerable plaque and decrease adverse cardiovascular events.

Comparative effects of lipid lowering, hypoglycemic, antihypertensive and antiplatelet medications on carotid artery intima-media thickness progression: a network meta-analysis

Background

Carotid artery intima-media thickness (cIMT) progression is a surrogate marker of atherosclerosis with a high predictive value for future CVD risk. This study evaluates the comparative efficacies of lipid lowering, hypoglycemic, antihypertensive and antiplatelet medications on cIMT progression.

Methods

We conducted a network meta-analysis (NMA) to evaluate the relative efficacies of several drug classes in modifying cIMT progression. After a literature search in several electronic databases, studies were selected by following predetermined eligibility criteria. An inverse variance-heterogeneity model was used for NMA. Sensitivity analyses were performed to check the reliability of the overall NMA, and transitivity analyses were performed to examine the effects of modifiers on the NMA outcomes.

Results

Data were taken from 47 studies (15,721 patients; age: 60.2 years [95% confidence interval (CI) 58.8, 61.6]; BMI: 27.2 kg/m² [95% CI 26.4, 28.0]; and gender: 58.3% males [95% CI 48.3, 68.3]). Treatment duration was 25.8 months [95% CI 22.9, 28.7]. Of the 13 drug classes in the network, treatment with phosphodiesterase III inhibitors was the most effective in retarding annual mean cIMT against network placebo (weighted mean difference (WMD) − 0.059 mm [95% CI − 0.099, − 0.020) followed by the calcium channel blockers (WMD − 0.055 mm [95% CI − 0.099, 0.001]) and platelet adenosine diphosphate inhibitors (WMD − 0.033 mm [95% CI − 0.058, 0.008]). These 3 drug classes also attained the same positions when the NMA was conducted by using first-year changes in mean cIMT. In transitivity analyses, longer treatment duration, higher body mass index (BMI), and a higher baseline cIMT were found to be independently associated with a lesser reduction in annual mean cIMT. However, in a multivariate analysis with these 3 modifiers, none of these factors was significantly associated with annual change in mean cIMT. In the placebo group, age was inversely associated with annual change in mean cIMT independently.

Conclusion

Phosphodiesterase III inhibitors and calcium channel blockers are found more effective than other drug classes in retarding cIMT progression. Age, BMI, and baseline cIMT may have some impact on these outcomes.

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0817-1) contains supplementary material, which is available to authorized users.

Cardiovascular outcomes of dipeptidyl peptidase-4 inhibitors in patients with type 2 diabetes on insulin therapy

AIMS

To compare the hazard of cardiovascular diseases between DPP-4 inhibitor users and non-users who were on insulin therapy.

METHODS

We conducted a population-based cohort study. 2652 patients with type 2 diabetes mellitus (T2DM) under insulin therapy were enrolled during 1997-2010. The incidence rates per 1000 person-years (PYs) of stroke, coronary heart disease (CAD) and heart failure were compared between 1326 DPP-4 inhibitor users and 1326 propensity score matched non-users. Multivariable Cox proportional hazards model was used to evaluate excess risk of the DPP-4 inhibitor non-users.

RESULTS

After adjustment of age, gender, comorbidities, drugs used and diabetes duration; the incidence rate per 1000 PYs were 21.70 and 9.88 in DPP-4 inhibitor non-users and users; DPP-4 inhibitor users had lower hazard ratio (HR) of stroke (adjusted HR: 0.59, 95% CI: 0.42-0.83, p value: 0.002) compared with non-users. The incidence rates per 1000 PYs of CAD and heart failure of control versus users were 19.85 versus 13.54 and 5.56 versus 4.78; the adjusted HRs of CAD and heart failure were 0.86 and 1.11. Both were non-significant.

CONCLUSION

This nationwide study demonstrated that insulin plus DPP-4 inhibitor users had significantly lower risk of stroke as compared with non-users.

Duration of Diabetes and Prediabetes During Adulthood and Subclinical Atherosclerosis and Cardiac Dysfunction in Middle Age: The CARDIA Study

OBJECTIVE

To determine whether the duration of diabetes and duration of prediabetes estimated during a 25-year period in early adulthood are each independently associated with coronary artery calcified plaque (CAC) and abnormalities in left ventricular structure and function later in life.

RESEARCH DESIGN AND METHODS

Participants were 3,628 white and black adults aged 18-30 years without diabetes or prediabetes at baseline (1985-1986) in the Coronary Artery Risk Development in Young Adults (CARDIA) Study. Durations of diabetes and prediabetes were estimated based on their identification at examinations 7, 10, 15, 20, and 25 years later. CAC was identified by computed tomography at years 15, 20, and 25. Left ventricular structure and function were measured via echocardiogram at year 25.

RESULTS

Of the 3,628 individuals, 12.7% and 53.8% developed diabetes and prediabetes, respectively; average (SD) duration was 10.7 (10.7) years and 9.5 (5.4) years. After adjustment for sociodemographic characteristics and other cardiovascular risk factors, and mutual adjustment for each other, the hazard ratio for the presence of CAC was 1.15 (95% CI 1.06, 1.25) and 1.07 (1.01, 1.13) times higher for each 5-year-longer duration of diabetes and prediabetes, respectively. Diabetes and prediabetes duration were associated with worse subclinical systolic function (longitudinal strain [Ptrend < 0.001 for both]) and early diastolic relaxation (e' [Ptrend 0.004 and 0.002, respectively]). Duration of diabetes was also associated with a higher diastolic filling pressure (E-to-e' ratio [Ptrend 0.001]).

CONCLUSIONS

Durations of diabetes and prediabetes during adulthood are both independently associated with subclinical atherosclerosis and left ventricular systolic and diastolic dysfunction in middle age.

Imaging of coronary atherosclerosis in various susceptible groups

Coronary artery disease (CAD) is the leading cause of death and disability worldwide. Atherosclerosis, which is the primary pathophysiologic mechanism for the development of plaque leading to CAD, is a multifactorial process resulting from a complex interplay between genetic susceptibility and various risk factors such as hypertension (HT), dyslipidaemia, diabetes mellitus (DM) and smoking. In addition, influences from other disease states such as chronic kidney disease (CKD), obesity and the metabolic syndrome as well as gender and ethnic diversity also contribute to the disease process. Insights from pathological observations and advances in cellular and molecular biology have helped us understand the process of plaque formation, progression and rupture leading to events. Several intravascular imaging techniques such as intravascular ultrasound (IVUS), Virtual histology IVUS (VH-IVUS) and optical coherence tomography (OCT) allow in vivo assessment of plaque burden, plaque morphology and response to therapy. In addition, non invasive assessment using coronary artery calcium (CAC) score allows risk stratification and plaque burden assessment whilst computed tomography coronary angiography (CTCA) allows evaluation of luminal stenosis, plaque characterisation and quantification. This review aims to summarise the results of invasive and non-invasive imaging studies of coronary atherosclerosis seen in various high-risk populations including DM, metabolic syndrome, obesity, CKD and, gender differences and ethnicity. Understanding the phenotype of plaques in various susceptible groups may allow potential development of personalised therapies.

Atheroma Progression in Obese Early-stage Diabetic Japanese Patients in Response to Glycemic Control: Sub-analysis from the DIANA Study

AIM

Diabetes is accompanied by abdominal obesity, which produces various metabolic abnormalities. While metabolic factors have been considered to promote the development of coronary atherosclerosis in the early-stage of diabetes, it remains unknown whether the presence of obesity in early-stage diabetics affects the natural history of coronary atherosclerosis. We herein investigated the characteristics of the disease substrate in obese early-stage diabetics.

METHODS

The DIANA (DIAbetes and diffuse coronary NArrowing) study was a serial evaluation of angiographic disease progression in early-stage diabetics with coronary artery disease. A total of 252 study subjects were stratified into non-obese (n=168) and obese groups (n=84). Obesity in Japanese subjects was defined as a body mass index ≥25 kg/m(2) according to the statement about Japanese obesity from the Japan Society for the Study of Obesity. Coronary atherosclerotic changes were evaluated by a quantitative computed analysis. The total lesion length (TLL=total length of all atherosclerotic lesions) was compared between the groups.

RESULTS

The obese patients were younger (p=0.0002) and had higher levels of fasting (p=0.002) and postprandial insulin (p=0.01), and higher triglyceride levels (p=0.02). On serial angiographic evaluations, obese patients had greater disease progression, reflected by a larger percent change in the TLL (24.7±13.7 vs. 7.4±10.0%, p=0.04). However, the improvement of abnormal glucose tolerance was associated with a slowing of disease progression in both non-obese (-0.9±10.7 vs. ＋15.0±11.2%, p=0.04) and obese (＋4.2±22.8 vs. ＋55.5±26.5%, p=0.005) patients.

CONCLUSIONS

Obese patients with early-stage diabetes exhibit profound disease progression. Glycemic control attenuated the progression of their coronary atherosclerosis. Our findings indicate progressive but modifiable disease in obese early-stage diabetics under optimal glycemic management.

Role of cardiac MRI in diabetes

Diabetes and insulin resistance have a variety of detrimental effects on cardiovascular health and outcomes. Cardiac magnetic resonance offers a non-invasive means to obtain many layers of information at a tissue level, including fibrosis, edema, intramyocardial motion, triglyceride content, and myocardial energetics. The role of cardiovascular magnetic resonance is particularly important in the evaluation of recognized and unrecognized coronary artery disease. In this review, we address the current state-of-the-art in cardiac magnetic resonance imaging - for both clinical and investigational use - as it applies to diabetic cardiovascular disease.

Coronary artery disease in patients with atypical chest pain with and without diabetes mellitus assessed with coronary CT angiography

INTRODUCTION

Coronary artery disease (CAD) in diabetes mellitus (DM) is often widespread when diagnosed. Non-invasive coronary calcium scoring and coronary CT angiography (CAC-score/CCTA) are accurate in the detection of CAD. This study compared CAD characteristics as identified by CCTA between patients with and without DM with atypical chest pain.

METHODS

CAD was defined as CAC-score >0 and/or presence of coronary plaque. Several CAD characteristics (number of affected segments, obstructive (>50% stenosis) CAD and CAD distribution) were compared on a per patient and segment basis. Subanalysis of duration of DM (<5 or >5 years) and gender was performed.

RESULTS

A total of 1148 patients (63.3% men, mean age 57.7±10.7), of whom 99 (8.6%) suffered from DM, were referred for CCTA. There was no difference in the prevalence of CAD between patients with and without DM (53.5% vs 50.9%, p=0.674). However patients with DM showed more affected coronary segments compared with patients without DM (2.5±3.4 vs 1.7±2.4, p=0.003). Multivariate analysis indicated that DM was an independent predictor of obstructive CAD (OR 2.16, 95% CI 1.23 to 3.78), as were age, women, and Diamond-Forrester score. In our study, obstructive CAD was more prevalent in women than in men (DM 40.0% vs 14.1%, p=0.003; non-DM 16.8% vs 8.4%, p<0.001). Patients suffering from DM >5 years showed more distal plaques (11.2% vs 7.7%, p=0.030).

CONCLUSIONS

Patients with atypical chest pain and DM showed more extensive CAD, as well as more obstructive CAD, particularly in women. Diabetes duration (>5 years) was not associated with more obstructive coronary disease or different plaque morphology, although more distal disease was present.

Is diabetes mellitus a heart disease equivalent in women? Results from an international study of postmenopausal women in the Raloxifene Use for the Heart (RUTH) Trial

BACKGROUND

Several studies have concluded that diabetes mellitus and heart disease carry similar risk for future cardiovascular disease (CVD). Most of these studies were too small to quantify independent risks specific to women. The purpose of this study was to determine whether diabetes mellitus is a coronary heart disease (CHD) risk equivalent for prediction of future CHD and CVD events in women.

METHODS AND RESULTS

The Raloxifene Use for the Heart (RUTH) trial was an international, multicenter, double-blind, randomized, placebo-controlled trial of raloxifene and CVD outcomes in 10 101 postmenopausal women selected for high CHD risk. Of these, 3672 had a history of diabetes mellitus without known CHD, and 3265 had a history of CHD without known diabetes mellitus. Cox proportional hazard models were used to compare cardiovascular outcomes in these 2 groups. Mean age at baseline was 67.5 years; median follow-up was 5.6 years. There were 725 deaths, including 450 cardiovascular deaths. In age-adjusted analyses, diabetic women had an increased risk of all-cause mortality compared with women with CHD. Although the overall risk of CHD and CVD was lower in diabetic women compared with women with CHD, the risk of fatal CHD, fatal CVD, and all-cause mortality was similar (hazard ratio [95% confidence interval]: 0.85 [0.65-1.12], 0.99 [0.78-1.25], and 1.18 [0.98-1.42], respectively, after adjusting for age, lifestyle factors, CHD risk factors, statin use, and treatment assignment).

CONCLUSIONS

In the RUTH trial, diabetes mellitus was a CHD risk equivalent in women for fatal, but not nonfatal, CHD and CVD.

Impact of diabetes and glycaemic control on peripheral artery disease in Japanese patients with end-stage renal disease: long-term follow-up study from the beginning of haemodialysis

AIMS/HYPOTHESIS

End-stage renal disease (ESRD) patients with diabetes have been regarded as being at the highest risk of cardiovascular disease. We therefore investigated the relationship between diabetes and the incidence of peripheral artery disease (PAD) in new haemodialysis patients.

METHODS

We enrolled 1,513 ESRD patients who had just begun haemodialysis therapy. They were divided into two groups: those with (n = 739) and those without diabetes (n = 774). The endpoint was the development of PAD, defined as ankle brachial pressure index ≤ 0.9 or toe brachial pressure index <0.7 in patients with an ankle brachial pressure index >0.9.

RESULTS

According to the Kaplan-Meier method, the 10 year event-free rate for development of PAD and lower limb amputation was significantly lower in the diabetes group than in the non-diabetes group (60.3% vs 82.8%, HR 2.99, 95% CI 2.27, 3.92, p<0.0001 and 93.9% vs 98.9%, HR 5.59, 95% CI 2.14, 14.7, p = .0005 for PAD and lower limb amputation, respectively). In patients with diabetes, quartile analysis of HbA1c levels showed that the highest quartile group (≥ 6.8% [51 mmol/mol]) had significant development of PAD and lower limb amputation compared with lower quartile groups (PAD HR 1.63, 95% CI 1.17, 2.28, p = .0038; lower limb amputation HR 2.99, 95% CI 1.17, 7.70, p = .023).

CONCLUSIONS/INTERPRETATION

Diabetes was a strong predictor of PAD after initiation of haemodialysis therapy in patients with ESRD. In addition, higher HbA1c levels were associated with increased risk of developing PAD and requiring limb amputation in such diabetic populations.

Lipoprotein lipase mediated fatty acid delivery and its impact in diabetic cardiomyopathy

Although cardiovascular disease is the leading cause of diabetes-related death, its etiology is still not understood. The immediate change that occurs in the diabetic heart is altered energy metabolism where in the presence of impaired glucose uptake, glycolysis, and pyruvate oxidation, the heart switches to exclusively using fatty acids (FA) for energy supply. It does this by rapidly amplifying its lipoprotein lipase (LPL-a key enzyme, which hydrolyzes circulating lipoprotein-triglyceride to release FA) activity at the coronary lumen. An abnormally high capillary LPL could provide excess fats to the heart, leading to a number of metabolic, morphological, and mechanical changes, and eventually to cardiac disease. Unlike the initial response, chronic severe diabetes "turns off" LPL, this is also detrimental to cardiac function. In this review, we describe a number of post-translational mechanisms that influence LPL vesicle formation, actin cytoskeleton rearrangement, and transfer of LPL from cardiomyocytes to the vascular lumen to hydrolyze lipoprotein-triglyceride following diabetes. Appreciating the mechanism of how the heart regulates its LPL following diabetes should allow the identification of novel targets for therapeutic intervention, to prevent heart failure. This article is part of a Special Issue entitled Triglyceride Metabolism and Disease.

Duration and type of therapy for diabetes: impact on cardiac risk stratification with stress electrocardiographic-gated SPECT myocardial perfusion imaging

BACKGROUND

Stress electrocardiogram(ECG)-gated single photon emission computed tomography (SPECT) imaging is highly effective in risk stratification of diabetic patients for adverse cardiac events. While patients with diabetes are predisposed to a more aggressive progression of vascular disease, the impact of its duration and type of therapy on risk stratification are unknown.

METHODS

From the Hartford Hospital Nuclear Cardiology clinical database, 886 diabetic patients who underwent exercise or pharmacologic stress ECG-gated SPECT were identified, with complete follow-up regarding the occurrence of adverse cardiac events and information regarding the duration of diabetes and the type of therapy (insulin vs oral medication only) at the time of testing. Images were interpreted using the American College of Cardiology/ASNC standard 17-segment scoring model.

RESULTS

Of the 886 diabetic patients, 98 (11%) suffered cardiac death or non-fatal myocardial infarction during follow-up (2.5 ± 1.6 years). A receiver operator characteristics curve demonstrated that diabetes ≥10 years in duration provided the maximal sum of sensitivity and specificity for the prediction of adverse cardiac outcomes. Multivariate analysis identified the following as independent predictors of adverse outcome: Post-stress ejection fraction (EF) <40% (P = .001), age (P = .004), insulin therapy (P = .031), diabetes duration >10 years (P = .038), summed stress score (SSS) >8 (P = .046). For patients with an SSS >8, diabetes duration and type of therapy significantly enhanced risk stratification. Similar findings emerged for patients with a post-stress EF <40%.

CONCLUSION

For diabetic patients undergoing stress ECG-gated SPECT myocardial perfusion imaging, disease duration and type of therapy provide independent and incremental prognostic information. Integration of these variables with this cardiovascular imaging technology significantly enhances cardiac risk stratification.

Diabetes duration is associated with increased thin-cap fibroatheroma detected by intravascular ultrasound with virtual histology

BACKGROUND

Coronary plaque classified as thin-cap fibroatheroma (TCFA) is believed to be associated with plaque rupture and coronary heart disease-related events. Although an association between duration of diabetes and increased coronary heart disease risk has been demonstrated, the relationship between TCFA and diabetes duration is unknown.

METHODS AND RESULTS

Prospective registry of diabetic patients undergoing diagnostic coronary angiography and intravascular ultrasound (IVUS) enrolled in a diabetic gene and biomarker banking registry. Plaque composition in the most diseased 10-mm segment of a single coronary artery was assessed using IVUS virtual histology and was classified by phenotype as IVUS-defined adaptive intimal thickening, pathological intimal thickening, TCFA, fibroatheroma, or fibrocalcific. Patients (n=54) were stratified by duration of diabetes (<10 or > or = 10 years). Patients with diabetes > or = 10 years were older, less likely to have a history of tobacco use, had higher total cholesterol levels, and were more likely to be treated with insulin compared with patients with diabetes <10 years. Longer duration of diabetes was associated with greater plaque burden in the most diseased 10-mm segment (60.4% [53.4% to 66.8%] versus 50.2% [47.7% to 58.4%], P=0.008). The proportion of IVUS-defined TCFA in the > or = 10-year group was greater than the <10-year group (54.4% [11.6% to 77.5%] versus 10.8% [0.0% to 26.1%], P=0.009). This association persisted after adjustment for multiple comparisons, clinical characteristics, and diabetes treatment.

CONCLUSIONS

In this cohort, longer duration of diabetes was associated with IVUS-defined TCFA, a plaque phenotype associated with risk of rupture and coronary heart disease events.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00428961.

Effect of diabetes on progression of coronary atherosclerosis and arterial remodeling: a pooled analysis of 5 intravascular ultrasound trials

OBJECTIVES

Our goal was to characterize coronary atherosclerosis progression and arterial remodeling in diabetic patients.

BACKGROUND

The mechanisms that underlie adverse cardiovascular outcomes in diabetic patients have not been well characterized.

METHODS

A systematic analysis was performed in 2,237 subjects in randomized controlled studies of atherosclerosis progression. The pattern of arterial remodeling, extent of coronary atherosclerosis, and disease progression was compared in subjects with and without diabetes.

RESULTS

In association with more risk factors, diabetic patients demonstrated a greater percent atheroma volume (PAV) (40.2 +/- 0.9% vs. 37.5 +/- 0.8%, p < 0.0001) and total atheroma volume (TAV) (199.4 +/- 7.9 mm(3) vs. 189.4 +/- 7.1 mm(3), p = 0.03) on multivariate analysis. A stronger correlation was observed between PAV and glycated hemoglobin (r = 0.22, p = 0.0003) than fasting glucose (r = 0.09, p < 0.0001), although the difference just failed to meet statistical significance after controlling for study. Diabetic patients exhibited a smaller lumen (291.1 +/- 104.8 mm(3) vs. 306.5 +/- 108.2 mm(3), p = 0.005) but no difference in external elastic membrane (494.9 +/- 166.9 mm(3) vs. 498.8 +/- 167.2 mm(3), p = 0.61) volumes. More rapid progression of PAV (0.6 +/- 0.4% vs. 0.05 +/- 0.3%, p = 0.0001) and TAV (-0.6 +/- 2.5 mm(3) vs. -2.7 +/- 2.4 mm(3), p = 0.03) was observed in diabetic patients on multivariate analysis. Smaller external elastic membrane (482.5 +/- 160.7 mm(3) vs. 519.9 +/- 166.9 mm(3), p = 0.03) and lumen (276.0 +/- 100.3 mm(3) vs. 310.1 +/- 105.6 mm(3), p = 0.001) volumes were observed in diabetic patients treated with insulin despite the presence of a similar TAV (206.5 +/- 88.6 mm(3) vs. 209.9 +/- 90.2 mm(3), p = 0.84). Intensive low-density lipoprotein cholesterol lowering in patients improved the rate of plaque progression, but only to the level observed in nondiabetic patients with suboptimal lipid control.

CONCLUSIONS

Diabetes is accompanied by more extensive atherosclerosis and inadequate compensatory remodeling. Accelerated plaque progression, despite use of medical therapies, supports the need to develop new antiatherosclerotic strategies in diabetic patients.

Metabolic effects of time-released garlic powder tablets in type 2 diabetes mellitus: the results of double-blinded placebo-controlled study

Late complications in type 2 diabetic patients are commonly associated with accelerated development of atherosclerosis. In type 2 diabetes mellitus, non-enzymatic glycosylation of apo-B that is a function of hyperglycaemia is an efficient biochemical way of low-density lipoprotein atherogenic modification. So, proper metabolic control is needed to prevent late complications of diabetes. The study was performed to estimate the effects of time-released garlic powder tablet Allicor on the parameters of metabolic control and plasma lipids in type 2 diabetes mellitus. The metabolic action of Allicor was investigated in the 4-week double-blinded placebo-controlled study in 60 type 2 diabetic patients. Fasting blood glucose was measured daily, and serum fructosamine as well as cholesterol and triglyceride levels were determined at the baseline, after 1, 2, 3 and 4 weeks. It has been demonstrated that treatment with Allicor resulted in better metabolic control due to the lowering of fasting blood glucose, serum fructosamine and serum triglyceride levels. The results of this study may allow recommending garlic powder tablets Allicor for the treatment of type 2 diabetes mellitus along with dietary treatment and/or sulfonylurea derivatives to achieve better metabolic control. The benefits from garlic preparations may lead to the reduction of cardiovascular risk in diabetic patients.

Exercise training does not improve myocardial diastolic tissue velocities in Type 2 diabetes

Background

Myocardial diastolic tissue velocities are reduced already in newly onset Type 2 diabetes mellitus (T2D). Poor disease control may lead to left ventricular (LV) systolic dysfunction and heart failure. The aim of this study was to assess the effects of exercise training on myocardial diastolic function in T2D patients without ischemic heart disease.

Methods

48 men (52.3 ± 5.6 yrs) with T2D were randomized to supervised training four times a week and standard therapy (E), or standard treatment alone (C) for 12 months. Glycated hemoglobin (HbA_1c), oxygen consumption (VO_2max), and muscle strength (Sit-up) were measured. Tissue Doppler Imaging (TDI) was used to determine the average maximal mitral annular early (Ea) and late (Aa) diastolic as well as systolic (Sa) velocities, systolic strain (ε) and strain rate (έ) from the septum, and an estimation of left ventricular end diastolic pressure (E/Ea).

Results

Exercise capacity (VO_2max, E 32.0 to 34.7 vs. C 32.6 to 31.5 ml/kg/min, p = .001), muscle strength (E 12.7 to 18.3 times vs. C 14.6 to 14.7 times, p < .001), and HbA_1c (E 8.2 to 7.5% vs. C 8.0 to 8.4%, p = .006) improved significantly in the exercise group compared to the controls (ANOVA). Systolic blood pressure decreased in the E group (E 144 to 138 mmHg vs. C 146 to 144 mmHg, p = .04). Contrary to risk factor changes diastolic long axis relaxation did not improve significantly, early diastolic velocity Ea from 8.1 to 7.9 cm/s for the E group vs. C 7.4 to 7.8 cm/s (p = .85, ANOVA). Likewise, after 12 months the mitral annular systolic velocity, systolic strain and strain rate, as well as E/Ea were unchanged.

Conclusion

Exercise training improves endurance and muscle fitness in T2D, resulting in better glycemic control and reduced blood pressure. However, myocardial diastolic tissue velocities did not change significantly. Our data suggest that a much longer exercise intervention may be needed in order to reverse diastolic impairment in diabetics, if at all possible.

Large and Small Vessels Atherosclerosis: Similarities and Differences

Atherosclerosis is a systemic, multifocal disease leading to a various symptoms and clinical events. Beyond disparities related to the organs involved, some differences might exist according to whether the lesions occur in the large (proximal) or small (distal) arteries. Atherosclerotic lesions occur predominantly in the large vessels first, and more distal lesions occur with aging. Proximal lesions are usually more evolving, especially with higher rates of unstable plaques in the proximal segments of coronary arteries. Racial differences regarding lesion distribution exist, with higher rates of distal lesions observed in races other than caucaians. Despite conflicting results found in each vascular territory, there is a suggestion of a stronger association between large vessel disease and smoking and dyslipidemia, whereas diabetes appears more specific for small vessel disease. Hypertension is more frequently reported in intracranial than in extracranial cerebrovascular disease. Preliminary studies report inflammatory markers preferably associated to large-vessel atherosclerosis. Proximal lesions in 1 territory are more frequently associated with concomitant lesions in other territories. Geometric, hemodynamic, and histologic particularities in large and small vessels may at least partially explain these differences, and some recent data point out different biologic properties of the endothelium according to its location.

Current perioperative treatment of patients with type 1 and type 2 diabetes

Diabetes mellitus is rapidly increasing, diabetic patients are likely to undergo surgical procedures more than non-diabetic patients, the hospital stay of diabetic patients is longer, and diabetic patients have increased mortality and morbidity. The correct treatment of diabetic patients in the perioperative period is crucial to improve clinical outcomes. Diabetic patients must be carefully evaluated for cardiovascular risk, keeping in mind micro- and macroangiopathic diabetic complications. Metabolic control deserves great attention because hyperglycemia is related to increased complications and worse outcomes. Insulin infusion regimens to achieve near normoglycemia must be implemented in surgical and critically ill patients.

The Activity of Aldose Reductase Is Elevated in Diabetic Mouse Heart

The importance of aldose reductase (AR) has been implicated in the pathogenesis of diabetic complications, although the alterations in the expression and activity of AR during hyperglycemia in the heart have not been well characterized. We investigated the expression and enzyme activity of AR in a murine diabetic model. Three weeks after the induction of hyperglycemia with streptozotocin, the level of AR mRNA was significantly reduced in the cardiac ventricles of BDF-1 mice. In contrast, the activity of AR was significantly elevated in the heart without any significant change in the protein level. In these mice, the level of cardiac thiobarbituric acid-reactive substances was unaltered, whereas the level of reduced glutathione (GSH) was significantly increased. Daily administration of insulin for 3 weeks completely normalized the level of AR mRNA and the enzyme activity. On the other hand, daily administration of an antioxidant, N-acetylcysteine significantly reduced the level of AR mRNA in the heart with a concomitant elevation in the enzyme activity. These results suggest that the activity of AR in the heart is affected by GSH dynamics. Augmented AR activity at the early stage of hyperglycemia may perturb glycolysis and affect cardiac performance.

Screening Asymptomatic Diabetic Patients for Coronary Artery Disease

Given the elevated risk of cardiovascular events and the higher prevalence of silent coronary artery disease (CAD) in diabetic versus non-diabetic patients, screening asymptomatic diabetic patients for CAD is an appealing concept. However, many factors argue against implementing a broad-based screening program at the present time. Foremost is the lack of any published data demonstrating that a prospectively applied screening program improves outcome in asymptomatic diabetic patients. The true prevalence of CAD, and in particular prognostically important CAD, in this population is uncertain. Consensus documents recommend more aggressive treatment of hypertension and hyperlipidemia solely on the basis of diabetes status, without differentiation based on the presence or absence of identifiable CAD. There is no evidence that use of anti-ischemic medication can alter the natural history of CAD in these patients. Retrospectively performed studies using stress single-photon emission computed tomography (SPECT) imaging have reported that approximately 50% and 20% of patients have abnormal and high-risk images, respectively. However, the only prospectively designed study, the DIAD (Detection of Ischemia in Asymptomatic Diabetics) study, reported a much lower percentage of abnormal SPECT images (16%) and images with a very large (>/=10% of the left ventricle) defect (1%). The financial implications of screening all asymptomatic diabetic patients determined to be at intermediate and high risk by clinical scoring systems is enormous. Clearly more data are needed to address this issue. Future studies should consider possible methods to enrich the patient subset that might benefit from screening and should include carefully performed cost-effective analyses.

Diabetes and dyslipidaemia

The risk of developing cardiovascular disease (CVD) is higher and the prognosis poorer for diabetic than for non-diabetic individuals. Diabetic dyslipidaemia is characterized by hypertriglyceridaemia, low levels of high-density lipoprotein cholesterol (HDL-C) and the presence of small, dense low-density lipoprotein (LDL) particles. Increased physical activity and weight loss are the first steps in managing diabetic dyslipidaemia. A secondary goal is to achieve non-HDL-C targets with cholesterol-lowering therapy. Improved glycaemic control, the first priority in managing hypertriglyceridaemia, can also aid in lowering levels of LDL-C. Lipid-lowering therapy should be initiated if lifestyle changes and glycaemic control fail to reduce LDL-C levels to <100 mg/dl (5.5 mmol/l), regardless of the status of CVD, coronary heart disease or peripheral vascular disease, and to reduce triglyceride levels of > or =150 mg/dl (8.3 mmol/l). Many diabetic patients may need oral hypoglycaemic agents or insulin to achieve adequate glycaemic control. Intensive insulin therapy can provide tight glycaemic control and reduce elevated triglyceride levels.

Increased Gene Expression of Glutathione Peroxidase-3 in Diabetic Mouse Heart

Increased incidence of heart disease is reported in patients with diabetes. To elucidate a molecular profile of expressed genes during the progression of diabetes, a cDNA array was screened in the hearts of mice treated with streptozotocin (200 mg/kg, i.v.). Among the genes investigated, the plasma type glutathione peroxidase, GPX-3, was predominantly up-regulated in diabetic mice compared with control mice. In northern blot analysis, a significant increase in GPX-3 expression was observed as early as 5 d after the induction of hyperglycemia. On day 21, a nearly three-fold induction was demonstrated. Daily administration of insulin (0.2 U/d, s.c.) for 21 d almost completely abolished the increase in GPX-3 mRNA in streptozotocin-treated mice, suggesting that the expression level of the GPX-3 gene was dependent on insulin and serum glucose. Increased GPX-3 may play a significant role in protecting cardiomyocytes from oxidative stress caused by hyperglycemia.

Diastolic dysfunction and mortality in diabetic patients on hemodialysis: a 4.25-year controlled prospective study

Among patients on hemodialysis, the mortality rate is higher in individuals with diabetes than in nondiabetic individuals, especially due to cardiovascular causes. The objective of the present study was to evaluate the role of echocardiographic abnormalities to predict mortality in diabetic patients starting hemodialysis. A 4.25-year prospective study was carried out with 40 diabetic and 28 nondiabetic patients starting hemodialysis in five dialysis centers in the metropolitan area of Porto Alegre, Brazil, between August 1996 and June 1999. Cardiovascular status was evaluated based on World Health Organization criteria, resting electrocardiogram (ECG), myocardial scintigraphy (at rest and after dipyridamole administration), and M-mode and Doppler echocardiography. Left ventricular diastolic function was classified into the following filling patterns: normal, impaired relaxation, pseudonormal, or restrictive. The survival rate was analyzed by Kaplan-Meier curves and predictors of death by Cox's proportional-hazards model. At the end of the study, the overall mortality rate was higher in patients with diabetes [19/40 (47.5%)] than in those without diabetes [2/28 (7.1%), P=.0013, log rank test]. Pseudonormal and restrictive filling patterns (HR: 3.2; 95% CI: 1.2-8.8; P=.02) and presence of diabetes (HR: 4.7; 95% CI: 1.03-21.4; P=.04) were associated with mortality. In conclusion, left ventricular diastolic dysfunction (LVDD) was the main predictor of mortality in this cohort of diabetic and nondiabetic patients starting dialysis. Intensive treatment of cardiovascular risk factors before the start of dialysis and during the treatment might reduce the mortality rate in diabetic patients.

Cardiovascular disease morbidity and mortality in patients with type 1 diabetes mellitus : management strategies

There is an increased risk of cardiovascular disease (CVD) mortality and morbidity in patients with type 1 diabetes mellitus compared with the general population as shown by epidemiologic studies measuring cardiovascular endpoints, as well as by autopsy, angiographic, and coronary calcification studies. Most of the excess CVD risk associated with type 1 diabetes is concentrated in the subset of approximately 35% of patients who develop diabetic nephropathy (after 20 years of diabetes duration), who also typically have dyslipidemias, elevated blood pressure, and hyperglycemia, factors contributing to CVD. For reasons that remain speculative, the relative risks from CVD are higher in women than in men with type 1 diabetes compared with the general population, which effectively eliminates the gender differences in CVD. As in the general population and in patients with type 2 diabetes, education and lifestyle changes, interventions to reduce hyperglycemia, blood pressure, micro-albuminuria, lipid control, and the use of aspirin are important management areas in order to reduce the increased risk of CVD. Whether management with aspirin and statins should be started in type 1 diabetic patients at a younger age or at a lower risk score than in the general population is still under investigation. There is a need for a better understanding of the pathophysiology of vascular complications in type 1 diabetes, more specific risk engines in type 1 diabetes, and accurate estimations of the absolute and relative risk for CVD in order to improve management of CVD in these high-risk patients.

Clinical features, triage, and outcome of patients presenting to the ED with suspected acute coronary syndromes but without pain: a multicenter study

We studied the impact on triage and outcome of patients presenting to the emergency department (ED) with symptoms suggestive of an acute coronary syndromes (ACS) but without a complaint of pain. Data from a prospective clinical trial of patients with symptoms suggesting an ACS in the EDs of 10 US hospitals comparing patient demographics, clinical variables, and outcomes was used to perform a secondary analysis. Of 10,783 subjects, a final diagnosis of an ACS was confirmed in 24% of which 35% had acute myocardial infarction (AMI) and 65% unstable angina pectoris (UAP). Pain was absent in 6.2% of patients with acute ischemia and in 9.8% of those with AMI. Compared to similar patients who presented with pain, patients with painless ischemia were older, were more commonly women, had more cardiac and related diseases. Among patients with AMI, fewer patients without pain were admitted to critical care units compared to similar patients with pain. Among patients with AMI, logistic regression predicting lack of pain identified age, heart failure and diabetes, with only age and heart failure among all with ACS. After controlling for clinical features, lack of pain during acute ischemia predicted increased hospital mortality. We concluded that age and heart failure are independently associated with painless ACS, in addition to diabetes among those with AMI. Lack of pain predicts increased hospital mortality in patients with ACI through mechanisms that remain to be elucidated. There is a need for greater awareness in the general public of the different manifestations of ACS to enhance the recognition of and prompt response to their symptoms.

Coronary anatomy and left ventricular ejection fraction in patients with type 2 diabetes admitted for elective coronary angiography

Patients with diabetes mellitus (DM) have more severe coronary artery disease and a two- to fourfold higher risk for myocardial infarction and death as compared to patients without DM. In this study, we analyzed coronary anatomy, left ventricular ejection fraction, and cardiac risk factors in patients with DM referred for coronary angiography and compared them with findings in nondiabetic patients. Coronary anatomy was assessed in a total of 6,234 patients and left ventricular ejection fraction in a subset of 4,767 (76.5%) patients. Diabetic patients (n = 641) were older (60.8 +/- 9.6 vs. 58.5 +/- 10.5 years; P < 0.0001) and had higher rates of hypertension (65% vs. 47%; P < 0.0001). Three-vessel disease (DM 44.7% vs. no DM 25.4%; P < 0.0001) and reduced left ventricular ejection fraction (DM 58.4% +/- 15.2 vs. no DM 63.9% +/- 13.2; P < 0.0001) were significantly associated with DM. After adjustment for age and other vascular risk factors, the presence of DM was associated with a higher atherosclerotic burden. We conclude that advanced coronary heart disease and left ventricular dysfunction are highly prevalent in diabetic patients, independent of age and other cardiovascular risk factors. Thus, cardiac assessment in diabetic patients should, in addition to optimal diabetic control, involve screening for left ventricular dysfunction.

Yield of stress single-photon emission computed tomography in asymptomatic patients with diabetes

BACKGROUND

Patients with diabetes without clinically apparent coronary artery disease are at increased risk of cardiac death. The value of screening stress testing in these patients remains controversial. The goal of this study was to examine the yield of stress single-photon emission computed tomography (SPECT) in asymptomatic diabetic patients.

METHODS

The results of stress SPECT in patients without prior myocardial infarction or coronary revascularization were compared in asymptomatic diabetics (n = 1738) versus symptomatic diabetic patients (n = 2998), asymptomatic nondiabetic patients (n = 6215), and symptomatic nondiabetic patients (n = 16,214).

RESULTS

Abnormal scans were present in 58.6% of asymptomatic diabetic patients, approximately equal to the percentage in symptomatic diabetic (59.5%) (P = not significant) and higher than in asymptomatic nondiabetic (46.2%) (P <.001) and symptomatic nondiabetic (44.4%) (P <.001) patients. The breakdown of high-risk scans followed a similar pattern in the 4 patient subsets: asymptomatic diabetic, 19.7% versus symptomatic diabetic, 22.2% (P =.051); asymptomatic nondiabetic, 11.1% (P <.001); and symptomatic nondiabetic, 12.5% (P <.001). Patients with diabetes had more electrocardiographic and scan evidence for silent myocardial infarction versus those without diabetes.

CONCLUSIONS

Asymptomatic diabetic patients have a high prevalence of both abnormal and high-risk SPECT scans. The finding that approximately 1 in 5 of these individuals has a high-risk scan suggests a potentially more widespread application of screening stress SPECT in asymptomatic diabetic patients to identify those with severe coronary artery disease.

The significant effect of diabetes duration on coronary heart disease mortality: the Framingham Heart Study

OBJECTIVE

The risk of coronary heart disease (CHD) in type 2 diabetes is two- to threefold higher than in the general population, but the effect of diabetes duration on CHD risk has not been well characterized. We hypothesized that duration of diabetes is an important predictor of incident CHD among people with diabetes.

RESEARCH DESIGN AND METHODS

The duration of diabetes (fasting glucose > or =126 mg/dl, random glucose > or =200 mg/dl, or use of an oral hypoglycemic agent or insulin) was assessed in participants with diabetes in the original and offspring cohorts of the Framingham Heart Study. Only subjects with diabetes diagnosed between the ages of 30 and 74 years, without a history of ketoacidosis, and free of cardiovascular disease at the baseline evaluation were included. Cox proportional hazards models were used to estimate the hazard ratio of incident CHD events and mortality over a 12-year follow-up period; models were adjusted for known CHD risk factors.

RESULTS

Among 588 person-exams with diabetes (mean age 58 +/- 9 years, 56% men), there were 86 CHD events, including 36 deaths. After adjustment for age, sex, and CHD risk factors, the risk of CHD was 1.38 times higher for each 10-year increase in duration of diabetes (95% CI 0.99-1.92), and the risk for CHD death was 1.86 times higher (1.17-2.93) for the same increase in duration of diabetes.

CONCLUSIONS

Duration of diabetes increases the risk of CHD death independent of coexisting risk factors. Further research is necessary to understand the pathophysiology of this increased risk.

Different remodelling against left ventricular overload between diabetic and non-diabetic haemodialysis patients

1. Diabetes mellitus is significantly associated with the occurrence of congestive heart failure in end-stage renal disease patients undergoing maintenance haemodialysis. In the present study, we asked whether the left ventricular remodelling against sustained pressure and/or volume overload to the left ventricle may be different between diabetic and non-diabetic haemodialysis patients. 2. Left ventricular parameters, including left ventricular mass index (LVMI), interventricular septal wall thickness (IVST) and relative left ventricular wall thickness (rLVWT), were assessed in 486 patients receiving maintenance haemodialysis (145 diabetic and 341 non-diabetic patients) using transthoracic echocardiography. Plasma concentrations of B-type natriuretic peptide (BNP), measured with an immunoradiometric assay, were used as a humoral parameter indicating left ventricular wall stress. 3. In non-diabetic patients, the plasma BNP concentration correlated with LVMI (r = 0.245; P = 0.0001), IVST (r = 0.250; P = 0.0001) and rLVWT (r = 0.149; P = 0.006). Furthermore, LVMI was correlated with mean blood pressure and pulse pressure and IVST and rLVWT were correlated with pulse pressure. 4. In contrast, none of the measured factors was correlated with LVMI and IVST in diabetic patients. Plasma BNP concentrations were positively correlated with end-systolic and end-diastolic left intraventricular dimensions and were inversely correlated with rLVWT and left ventricular fractional shortening in diabetic patients, but not in non-diabetic patients. 5. In conclusion, a sustained increase in left ventricular wall stress is likely to elicit eccentric left ventricular remodelling in diabetic haemodialysis patients, whereas it causes concentric left ventricular remodelling in non-diabetic haemodialysis patients. This difference in left ventricular remodelling against left ventricular overload may be associated with the high incidence of congestive heart failure in diabetic haemodialysis patients.

Diabetes and evidence of atherosclerosis are major risk factors for adverse outcome after elective thoracic aortic surgery

BACKGROUND

To predict risk after elective repair of ascending aorta and aortic arch aneurysms, we studied 464 consecutive patients.

METHODS

Adverse outcome (stroke or hospital death) was analyzed in 372 patients who underwent proximal repair and 92 patients who underwent aortic arch replacement from 1986 to the present. Preoperative risk factors with a P value less than.2 in a univariate analysis were entered into a multivariate model, and an equation incorporating independent risk factors was derived separately for proximal aorta and arch surgery.

RESULTS

Age more than 65 years (P =.04), diabetes (P =.02), cause (P =.01), and prolonged total cerebral protection time (duration of hypothermic circulatory arrest and selective cerebral perfusion, P =.001) were significant univariate risk factors for elective proximal aortic repair. Diabetes (P =.005, odds ratio 5.1), atherosclerosis (P =.003, odds ratio 4.0), and dissection (P =.048, odds ratio 2.5) were independent factors. For elective arch surgery, female sex (P =.07), age more than 65 years (P =.04), coronary artery disease (P =.02), diabetes (P =.06), cause (P =.07), and prolonged total cerebral protection time (P =.025) were univariate risk factors. Female sex (P =.05, odds ratio 4.7), coronary artery disease (P =.02, odds ratio 6.5), diabetes (P =.13, odds ratio 4.0), and total cerebral protection time (P =.03, odds ratio 1.02/min) were independent factors. To calculate risk of adverse outcome (P), enter 1 if factor is present, 0 if absent, and estimate total cerebral protection time (in minutes). [equation: see text].

CONCLUSION

In this large series of patients, the presence of diabetes and manifestations of atherosclerosis emerge as extremely important risk factors for adverse outcome after ascending aorta or arch surgery, displacing age. Multivariate equations derived from these data allow more precise calculation of risk for each individual contemplating elective surgery.

Coronary atherosclerosis in diabetes mellitus: a population-based autopsy study

OBJECTIVES

The study was conducted to test the hypothesis that the prevalence of coronary atherosclerosis is greater among diabetic than among nondiabetic individuals and is similar for diabetic individuals without clinical coronary artery disease (CAD) and nondiabetics with clinical CAD.

BACKGROUND

Persons with diabetes but without clinical CAD encounter cardiovascular mortality similar to nondiabetic individuals with clinical CAD. This excess mortality is not fully explained. We examined the association between diabetes and coronary atherosclerosis in a geographically defined autopsied population, while capitalizing on the autopsy rate and medical record linkage system available via the Rochester Epidemiology Project, which allows rigorous ascertainment of coronary atherosclerosis, clinical CAD, and diabetes.

METHODS

Using two measures, namely a global coronary score and high-grade stenoses, the prevalence of atherosclerosis was analyzed in a cohort of autopsied residents of Rochester, Minnesota, age 30 years or older at death, while stratifying on diabetes, clinical CAD diagnosis, age, and gender.

RESULTS

In this cohort, diabetes was associated with a higher prevalence of atherosclerosis. Among diabetic decedents without clinical CAD, almost three-fourths had high-grade coronary atherosclerosis and more than half had multivessel disease. Without diabetes, women had less atherosclerosis than men, but this female advantage was lost with diabetes. Among those without clinical CAD, diabetes was associated with a global coronary disease burden and a prevalence of high-grade atherosclerosis similar to that observed among nondiabetic subjects with clinical CAD.

CONCLUSIONS

These findings provide mechanistic insights into the excess risk of clinical CAD among diabetic individuals, thereby supporting the need for aggressive prevention of atherosclerosis in all diabetic individuals, irrespective of clinical CAD symptoms.

Diabetes mellitus and coronary heart disease

Diabetes mellitus, especially type 2 diabetes, is a growing concern in America. Longitudinal trends show that obesity is more prevalent than in the past, and the incidence of type 2 diabetes is also increasing. Type 2 diabetes typically doubles the CHD risk in men and triples the risk in women. Intervening to control lipid levels and blood pressure has been shown to be especially helpful in preventing CHD, but the impact of better glycemic control on CHD risk is less convincing, especially in clinical trials. Revascularization studies in diabetics show that coronary bypass surgery is related to better outcomes than angioplasty procedures.

New diagnostic criteria for diabetes and coronary artery disease: insights from an angiographic study

OBJECTIVES

The goal of this research was to study coronary atherosclerosis in patients with type 2 diabetes compared with patients without diabetes according to the new definition of diabetes advocated by the American Diabetes Association in 1997.

BACKGROUND

Patients with diabetes (fasting plasma glucose above 7.0 mM/L) have a higher risk of cardiovascular death. The correlation with the pattern and severity of their coronary atherosclerosis, especially in the new patients with "mild" diabetes (7.0 mM/L < or = fasting plasma glucose < 7.8 mM/L), remains unclear.

METHODS

A cohort of 466 patients undergoing coronary angiography but free of any previous infarction, coronary intervention and insulin therapy were prospectively recruited. Ninety-three had diabetes (fasting plasma glucose > 7.0 mM/L or hypoglycemic oral treatment). Five angiographic indexes were calculated to describe severity and extent of coronary atherosclerosis.

RESULTS

Overall, patients with diabetes had more diffuse coronary atherosclerosis, a greater prevalence of mild, moderate and severe stenoses and a two-fold higher occlusion rate than patients without diabetes, even after adjustment for age, gender, body mass index, hypertension, lipid parameters, smoking, family history of cardiovascular events and ischemic symptoms. Patients with "mild diabetes" had a coronary atherosclerosis pattern more similar to patients with normal fasting plasma glucose than to patients formerly defined as diabetic according to the World Health Organization criteria, except that they had a higher prevalence of <50% stenoses.

CONCLUSIONS

In patients with type 2 diabetes, those with 7.0 mM/L < or = fasting plasma glucose < 7.7 mM/L have a slightly greater prevalence of mildly severe lesions that may partly explain their higher cardiovascular event rate.

Decrease in carotid intima media thickness after 1 year of cilostazol treatment in patients with type 2 diabetes mellitus

A multicenter exploratory study at three university hospitals was performed to evaluate the effect of oral cilostazol on intima media thickness (IMT) in diabetic patients. A total of 141 patients was recruited in this study and randomized into a cilostazol group and a placebo (control) group. One hundred and twenty patients completed the study (i.e. 60 on cilostazol and 60 on placebo). Biochemical profiles and the IMT of the common carotid artery (CCA) determined by high-resolution B-mode ultrasonography were measured at 0, 6, and 12 months after the oral administration of 100--200 mg of cilostazol or placebo (i.e. two or four times daily for 12 months). Clinical and biochemical characteristics, the treatment modality, and microvascular diabetic complications after randomization were not significantly different between the two groups after the study. In the cilostazol treatment group, left CCA average IMT significantly decreased from 0.94+/-0.03 to 0.91+/-0.02 mm at 6 months (P<0.05), and thereafter increased to 0.92+/-0.01 mm (P>0.05) at 12 months, whereas in the control group, it increased from 0.92+/-0.03 to 0.93+/-0.01 mm at 6 months (P>0.05), and to 0.94+/-0.01 mm at 12 months (P>0.05). As for the right CCA average IMT, it decreased from 0.83+/-0.03 to 0.82+/-0.01 mm at 6 months (P<0.05), and to 0.81+/-0.01 mm at 12 months (P<0.05) in the cilostazol group, whereas it increased from 0.87+/-0.03 to 0.89+/-0.01 mm at 6 months (P<0.05), and to 0.90+/-0.01 mm at 12 months (P<0.05) in the control group (P<0.05). After correction for risk factors such as blood pressure, smoking, and lipid profiles, there were significant changes in left and right CCA average IMT for both groups (P<0.05). Left and right CCA average IMT was significantly different between the two groups (P<0.05). After making statistical corrections for blood pressure, smoking, and lipid profiles, the differences between these two groups remained significant (P<0.05). Meanwhile, there were no differences between the groups in the change of risk factors such as BMI, blood pressure, blood sugar, HbA(1c), and lipid profiles. Generally, cilostazol was well tolerated and the most common side effect in the cilostazol group was headache (12/60), mostly early in the treatment regimen. The results suggest that oral cilostazol may be helpful in the treatment of atherosclerosis in type 2 diabetic patients, although conventional cardiovascular risk factors remained unmodified.