Ultrasonic tissue characterization of carotid plaque improves the prediction of cardiovascular events in diabetic patients: a pilot study

Precision prognostics for cardiovascular disease in Type 2 diabetes: a systematic review and meta-analysis

BACKGROUND

Precision medicine has the potential to improve cardiovascular disease (CVD) risk prediction in individuals with Type 2 diabetes (T2D).

METHODS

We conducted a systematic review and meta-analysis of longitudinal studies to identify potentially novel prognostic factors that may improve CVD risk prediction in T2D. Out of 9380 studies identified, 416 studies met inclusion criteria. Outcomes were reported for 321 biomarker studies, 48 genetic marker studies, and 47 risk score/model studies.

RESULTS

Out of all evaluated biomarkers, only 13 showed improvement in prediction performance. Results of pooled meta-analyses, non-pooled analyses, and assessments of improvement in prediction performance and risk of bias, yielded the highest predictive utility for N-terminal pro b-type natriuretic peptide (NT-proBNP) (high-evidence), troponin-T (TnT) (moderate-evidence), triglyceride-glucose (TyG) index (moderate-evidence), Genetic Risk Score for Coronary Heart Disease (GRS-CHD) (moderate-evidence); moderate predictive utility for coronary computed tomography angiography (low-evidence), single-photon emission computed tomography (low-evidence), pulse wave velocity (moderate-evidence); and low predictive utility for C-reactive protein (moderate-evidence), coronary artery calcium score (low-evidence), galectin-3 (low-evidence), troponin-I (low-evidence), carotid plaque (low-evidence), and growth differentiation factor-15 (low-evidence). Risk scores showed modest discrimination, with lower performance in populations different from the original development cohort.

CONCLUSIONS

Despite high interest in this topic, very few studies conducted rigorous analyses to demonstrate incremental predictive utility beyond established CVD risk factors for T2D. The most promising markers identified were NT-proBNP, TnT, TyG and GRS-CHD, with the highest strength of evidence for NT-proBNP. Further research is needed to determine their clinical utility in risk stratification and management of CVD in T2D.

Precision Prognostics for Cardiovascular Disease in Type 2 Diabetes: A Systematic Review and Meta-analysis

Background Precision medicine has the potential to improve cardiovascular disease (CVD) risk prediction in individuals with type 2 diabetes (T2D). Methods We conducted a systematic review and meta-analysis of longitudinal studies to identify potentially novel prognostic factors that may improve CVD risk prediction in T2D. Out of 9380 studies identified, 416 studies met inclusion criteria. Outcomes were reported for 321 biomarker studies, 48 genetic marker studies, and 47 risk score/model studies. Results Out of all evaluated biomarkers, only 13 showed improvement in prediction performance. Results of pooled meta-analyses, non-pooled analyses, and assessments of improvement in prediction performance and risk of bias, yielded the highest predictive utility for N-terminal pro b-type natriuretic peptide (NT-proBNP) (high-evidence), troponin-T (TnT) (moderate-evidence), triglyceride-glucose (TyG) index (moderate-evidence), Genetic Risk Score for Coronary Heart Disease (GRS-CHD) (moderate-evidence); moderate predictive utility for coronary computed tomography angiography (low-evidence), single-photon emission computed tomography (low-evidence), pulse wave velocity (moderate-evidence); and low predictive utility for C-reactive protein (moderate-evidence), coronary artery calcium score (low-evidence), galectin-3 (low-evidence), troponin-I (low-evidence), carotid plaque (low-evidence), and growth differentiation factor-15 (low-evidence). Risk scores showed modest discrimination, with lower performance in populations different from the original development cohort. Conclusions Despite high interest in this topic, very few studies conducted rigorous analyses to demonstrate incremental predictive utility beyond established CVD risk factors for T2D. The most promising markers identified were NT-proBNP, TnT, TyG and GRS-CHD, with the highest strength of evidence for NT-proBNP. Further research is needed to determine their clinical utility in risk stratification and management of CVD in T2D.

Spectral analysis of ultrasound backscatter for non-invasive measurement of plaque composition

Carotid atherosclerotic plaque composition may be an important indication of patient risk for future cerebrovascular events. Ultrasound spectral analysis has the potential to provide a robust measure of plaque composition in vivo if the backscatter transfer function can be sufficiently isolated from the effects of attenuation from overlying tissue, receive and transmit transfer functions from the ultrasound system and transducer, and diffraction. This study examines the usefulness of the nonlinearly generated second harmonic portion of the backscatter signal and the effects of a variety of attenuation compensation techniques for noninvasively characterizing human carotid plaque using spectral analysis and machine learning. Post-beamformed ultrasound backscatter radiofrequency (RF) data were acquired from 6 normal subjects and 119 carotid endarterectomy patients prior to surgery. Plaque obtained following surgery was histologically processed, and regions of interest (ROI) corresponding to homogenous tissue types (fibrous/fibro-lipidic, hemorrhagic and/or necrotic core and calcified) were selected from RF data. Both the harmonic and fundamental power spectra for each ROI was obtained and normalized by data from a uniform phantom (0.5 dB/cm-MHz slope of attenuation). Additional attenuation compensation approaches were compared to simply using the reference phantom: (1) optimum power spectral shift estimation, (2) one-step adventitial, or (3) two-step adventitial. Spectral parameters extracted from both the fundamental and harmonic estimates of the backscatter transfer function of 363 ROI's from 152 plaque specimens were used to train and test random forest and support vector machine classification models. The best results came from using spectral parameters derived from both the fundamental and second harmonic bands with a predictive accuracy of 65-68%, kappa statistic of 0.49-0.54, and accuracies of 84% for fibrous, 68-74% for hemorrhagic and/or necrotic core, and 78-81% for calcified ROI's. The result indicated that the nonlinearly generated second harmonic portion of backscatter is useful for carotid plaque tissue characterization and that a reference phantom approach with a 0.5 dB/cm-MHz slope of attenuation works as well as more complicated approaches.

Vascular ultrasound for cardiovascular risk stratification in asymptomatic patients with type-2 diabetes

AIMS

To identify new independent vascular markers to predict cardiovascular events in patients with type-2 diabetes (T2D), and their incremental value compared to the Swedish National Diabetes Register (NDR) risk score.

METHODS

A retrospective cohort study was conducted on 1332 asymptomatic patients with T2D, free from prior CV event, assessed for a cardiovascular work-up, including Duplex ultrasonography to detect plaque on carotid and femoral arteries. The extent of atherosclerosis was rated as atherosclerosis burden score (ABS). Patients were followed up to 5 years and the occurrence of cardiovascular events recorded.

RESULTS

A total of 82 patients (6.2%) experienced a cardiovascular event, including 34 (2.6%) myocardial infarction, 18 (1.4%) cardiac revascularisation and 17 (1.3%) stroke. The independent determinants of these events were male sex (HR = 1.81 [1.13-2.88], p = 0.013) and ABS ≥ 2 (HR = 1.98 [1.21-3.25], p = 0.007). The NDR risk score performed poorly to predict cardiovascular events (area under the curve = 0.56 [0.49-0.63], p = 0.11), whereas screening for atherosclerotic plaques provided significant incremental prognostic value over the NDR score (model χ2 increase: +231%, p = 0.002).

CONCLUSION

Duplex ultrasonography to screen for atherosclerotic plaques improve the estimation of cardiovascular prognosis on top of clinical data and could be routinely used to improve cardiovascular risk stratification.

Associations of continuous glucose monitoring-assessed glucose variability with intima-media thickness and ultrasonic tissue characteristics of the carotid arteries: a cross-sectional analysis in patients with type 2 diabetes

BACKGROUND

The association between glucose variability and the progression of atherosclerosis is not completely understood. We aimed to evaluate the associations of glucose variability with the progression of atherosclerosis in the early stages.

METHODS

We conducted a cross-sectional analysis to investigate the associations of glucose variability, assessed by continuous glucose monitoring, with intima-media thickness (IMT) and gray-scale median (GSM) of the carotid arteries, which are different indicators for the progression of atherosclerosis. We used baseline data from a hospital-based multicenter prospective observational cohort study among Japanese patients with type 2 diabetes without a history of cardiovascular diseases aged between 30 and 80 years. Continuous glucose monitoring was performed by Freestyle Libre Pro, and glucose levels obtained every 15 min for a maximum of eight days were used to calculate the metrics of glucose variability. IMT and GSM were evaluated by ultrasonography, and the former indicates thickening of intima-media complex in the carotid artery wall, while the latter indicates tissue characteristics.

RESULTS

Among 600 study participants (age: 64.9 ± 9.2 (mean ± SD) years; 63.2%: men; HbA1c: 7.0 ± 0.8%), participants with a larger intra- and inter-day glucose variability had a lower GSM and most of these associations were statistically significant. No trend based on glucose variability was shown regarding IMT. Standard deviation of glucose (regression coefficient, β = - 5.822; 95% CI - 8.875 to - 2.768, P < 0.001), glucose coefficient of variation (β = - 0.418; - 0.685 to - 0.151, P = 0.002), mean amplitude of glycemic excursion (β = - 1.689; - 2.567 to - 0.811, P < 0.001), mean of daily differences (β = - 6.500; - 9.758 to - 3.241, P < 0.001), and interquartile range (β = - 4.289; - 6.964 to - 1.614, P = 0.002) had a statistically significant association with mean-GSM after adjustment for conventional cardiovascular risk factors, including HbA1c. No metrics of glucose variability had a statistically significant association with IMT.

CONCLUSIONS

Continuous glucose monitoring-assessed glucose variability was associated with the tissue characteristics of the carotid artery wall in type 2 diabetes patients without cardiovascular diseases.

Notable Underlying Mechanism for Pancreatic β-Cell Dysfunction and Atherosclerosis: Pleiotropic Roles of Incretin and Insulin Signaling

Under healthy conditions, pancreatic β-cells produce and secrete the insulin hormone in response to blood glucose levels. Under diabetic conditions, however, β-cells are compelled to continuously secrete larger amounts of insulin to reduce blood glucose levels, and thereby, the β-cell function is debilitated in the long run. In the diabetic state, expression levels of insulin gene transcription factors and incretin receptors are downregulated, which we think is closely associated with β-cell failure. These data also suggest that it would be better to use incretin-based drugs at an early stage of diabetes when incretin receptor expression is preserved. Indeed, it was shown that incretin-based drugs exerted more protective effects on β-cells at an early stage. Furthermore, it was shown recently that endothelial cell dysfunction was also associated with pancreatic β-cell dysfunction. After ablation of insulin signaling in endothelial cells, the β-cell function and mass were substantially reduced, which was also accompanied by reduced expression of insulin gene transcription factors and incretin receptors in β-cells. On the other hand, it has been drawing much attention that incretin plays a protective role against the development of atherosclerosis. Many basic and clinical data have underscored the importance of incretin in arteries. Furthermore, it was shown recently that incretin receptor expression was downregulated in arteries under diabetic conditions, which likely diminishes the protective effects of incretin against atherosclerosis. Furthermore, a series of large-scale clinical trials (SPAED-A, SPIKE, LEADER, SUSTAIN-6, REWIND, PIONEER trials) have shown that various incretin-related drugs have beneficial effects against atherosclerosis and subsequent cardiovascular events. These data strengthen the hypothesis that incretin plays an important role in the arteries of humans, as well as rodents.

Clinical utility of carotid ultrasonography: Application for the management of patients with diabetes

Carotid ultrasonography is a non-invasive, simple and inexpensive modality to assess the severity of atherosclerosis. This article reviews related articles, summarizes the rationale for the application of carotid ultrasonography in clinical practice, and addresses the features and the limitations of carotid ultrasonography in cardiovascular risk prediction. Numerous large studies have confirmed that various carotid ultrasound measures, such as carotid intima-media thickness, the presence or absence of carotid plaque, plaque number and plaque area, can be independent predictors of cardiovascular diseases in individuals with and without diabetes mellitus. Furthermore, many studies showed that the use of carotid intima-media thickness (especially maximum intima-media thickness, including plaque thickness) and/or carotid plaque in addition to traditional risk factors significantly improved the prediction of the occurrence of cardiovascular diseases, while controversy remains. Several studies showed that the progression of carotid intima-media thickness also can be a surrogate end-point of cardiovascular events. However, the accumulated evidence has not been sufficient. Further study with sufficient power should be carried out. As plaque disruption, which plays a crucial role in the pathogenesis of cardiovascular events, is dependent on the content of lipid in the atheroma and the thickness of the fibrous cap, tissue characterization of a plaque might be useful for determining its fragility. Interestingly, recent studies have shown that ultrasonic tissue characterization of carotid lesions could improve the prediction ability of future cardiovascular diseases. Thus, carotid ultrasonography is a useful modality for better clinical practice of atherosclerosis in patients with diabetes.

Aromatase inhibitor use is a risk factor of carotid plaque presence in endocrine-responsive breast cancer patients

BACKGROUND/AIMS

The aromatase inhibitors (AIs) are well known anti-hormonal therapy in endocrine-responsive breast cancer patients. It can lead to dyslipidemia and be the risk factor of cardiovascular disease due to low estrogen level. However, some recent studies comparing AIs with placebo have shown controversial results. The aim of this study was to investigate lipid profiles, measurement of carotid intima-media thickness (IMT) and the presence of plaque among endocrine-responsive breast cancer treated with AIs compared to ones that were not treated with AIs.

METHODS

A total of 85 postmenopausal women, who underwent breast cancer surgery during the age of 50 to 64 without history of statin use were included. There were 42 patients who were treated with AIs over 1 year (group 1) and 43 patients without AIs use (group 2). Serum total cholesterol, high density lipoprotein cholesterol, triglycerides, fasting blood glucose, carotid IMT, and presence of plaque were assessed.

RESULTS

The baseline characteristics were similar between two groups and there was no significant difference in carotid IMT irrespective of AIs administration. However, ultrasonographic evaluation of carotid artery revealed that the presence of plaque in AI users was significantly higher than in non-AI users (66.7% vs. 41.9%, p = 0.02; odds ratio, 4.21 in adjusted model; p = 0.01). History of diabetes was also the significant risk factor for the plaque formation.

CONCLUSION

There was no significant difference in lipid profile itself between two groups, but more importantly the presence of the plaque was much higher indicating possible detrimental effect of AI on cardiovascular system.

Ultrasound Tissue Characterization of Carotid Plaques Differs Between Patients with Type 1 Diabetes and Subjects without Diabetes

The aim of the study was to investigate ultrasound tissue characterization of carotid plaques in subjects with and without diabetes type 1 (T1D). B-mode carotid ultrasound was performed to assess the presence and type of plaque in a group of 340 subjects with and 304 without T1D, all of them without cardiovascular disease. One hundred and seven patients with T1D (49.5% women; age 54 ± 9.8 years) and 67 control subjects without diabetes who had at least one carotid plaque were included in the study. The proportion of subjects who had only echolucent plaques was reduced in the group of patients with T1D (48.6% vs. 73.1%). In contrast, the proportion with only echogenic (25.2% vs. 7.5%) and calcified plaques (9.4% vs. 1.5%) was increased compared with subjects without diabetes. Moreover, having at least one echogenic plaque was more frequent in T1D patients compared with subjects without diabetes (49.5% vs. 26.9% p = 0.005). In addition to diabetes (OR 2.28; p = 0.026), age (OR 1.06, p = 0.002) was the other variable associated with echogenic plaque existence in multiple regression analysis. Patients with T1D exhibit a differential pattern of carotid plaque type compared with subjects without diabetes, with an increased frequency of echogenic and extensively calcified plaques.

Molecular imaging of diabetes and diabetic complications: Beyond pancreatic β-cell targeting

Diabetes is a chronic non-communicable disease affecting over 400 million people worldwide. Diabetic patients are at a high risk of various complications, such as cardiovascular, renal, and other diseases. The pathogenesis of diabetes (both type 1 and type 2 diabetes) is associated with a functional impairment of pancreatic β-cells. Consequently, most efforts to manage and prevent diabetes have focused on preserving β-cells and their function. Advances in imaging techniques, such as magnetic resonance imaging, magnetic resonance spectroscopy, positron emission tomography, and single-photon-emission computed tomography, have enabled noninvasive and quantitative detection and characterization of the population and function of β-cells in vivo. These advantages aid in defining and monitoring the progress of diabetes and determining the efficacy of anti-diabetic therapies. Beyond β-cell targeting, molecular imaging of biomarkers associated with the development of diabetes, e.g., lymphocyte infiltration, insulitis, and metabolic changes, may also be a promising strategy for early detection of diabetes, monitoring its progression, and occurrence of complications, as well as facilitating exploration of new therapeutic interventions. Moreover, molecular imaging of glucose uptake, production and excretion in specified tissues is critical for understanding the pathogenesis of diabetes. In the current review, we summarize and discuss recent advances in noninvasive imaging technologies for imaging of biomarkers beyond β-cells for early diagnosis of diabetes, investigation of glucose metabolism, and precise diagnosis and monitoring of diabetic complications for better management of diabetic patients.

Prognostic tools for cardiovascular disease in patients with type 2 diabetes: A systematic review and meta-analysis of C-statistics

BACKGROUND

Diabetes is associated with an increased risk for cardiovascular diseases (CVD). Risk prediction models are tools widely used to identify individuals at particularly high-risk of adverse events. Many CVD risk prediction models have been developed but their accuracy and consistency vary.

OBJECTIVE

This study reviews the literature on available CVD risk prediction models specifically developed or validated in patients with diabetes and performs a meta-analysis of C-statistics to assess and compare their predictive performance.

METHODS

The online databases and manual reference checks of all identified relevant publications were searched.

RESULTS

Fifteen CVD prediction models developed for patients with diabetes and 11 models developed in a general population but later validated in diabetes patients were identified. Meta-analysis of C-statistics showed an overall pooled C-statistic of 0.67 and 0.64 for validated models developed in diabetes patients and in general populations respectively. This small difference in the C-statistic suggests that CVD risk prediction for diabetes patients depends little on the population the model was developed in (p = 0.068).

CONCLUSIONS

The discriminative ability of diabetes-specific CVD prediction models were modest. Improvements in the predictive ability of these models are required to understand both short and long-term risk before implementation into clinical practice.

Atherosclerosis imaging to refine cardiovascular risk assessment in diabetic patients: Computed tomography and positron emission tomography applications

The lifetime cardiovascular risk of a diabetic patient is approximately 4-5 times higher than that of an age and sex matched individual without diabetes mellitus. Despite the well-publicized cardiovascular risk equivalence of diabetes mellitus, it has become apparent that not all diabetic patients are equally at high-risk and many patients may have a level of risk similar to that of the general population. Cardiovascular imaging has been employed to address the dilemma of a more accurate risk stratification of diabetic patients. Two randomized clinical trials aiming at uncovering the presence of unknown obstructive coronary artery disease (CAD) gave disappointing results. In fact, the number of patients with inducible myocardial ischemia and/or severe obstructive disease was lower than expected and the overall outcome was not improved after having brought the existence of CAD to light. Other techniques that may help identify a diabetic patient susceptible to suffer future events have therefore being explored. In this review we discuss two imaging tools that provide anatomical and functional information on pre-clinical coronary atherosclerosis: computed tomography for calcium scoring, and plaque characterization and myocardial ischemia detection and positron emission tomography using tracers to identify functionally unstable plaques. Despite the availability of several imaging techniques there remain numerous questions as to the utility of imaging to define risk in diabetes mellitus and an optimal approach has yet to be found.

Clinical Utility of Carotid Ultrasonography in the Prediction of Cardiovascular Events in Patients with Diabetes: A Combined Analysis of Data Obtained in Five Longitudinal Studies

Aim: It remains unclear whether measures used in carotid ultrasonography such as the intima–media thickness (IMT) and ultrasonic tissue characterization of the carotid using the gray-scale median (GSM) can add prognostic information beyond the conventional cardiovascular risk markers in pati ents with diabetes.

Methods: This study employed a combined analysis of data obtained in five longitudinal studies including a total of 3263 patients with diabetes but without apparent cardiovascular disease (CVD) at baseline. The associations between carotid ultrasonography measures and the first occurrence of CVD (488 cases), which were defined as cardiovascular death, coronary artery diseases, stroke, or peripheral artery disease, were analyzed.

Results: Common carotid artery (CCA)-mean-IMT, CCA-max-IMT, Max-IMT, plaque-GSM, and the presence of low-GSM echolucent plaques at baseline were prognostic factors for CVD even after adjustment for conventional risk factors. Time-dependent receiver-operating-characteristic (ROC) curve analysis indicated that the use of CCA-mean-IMT, CCA-max-IMT, and Max-IMT in addition to the conventional risk factors improved significantly the prediction of occurrence of CVD. Increments in the CCA-mean-IMT (hazard ratio [HR] 2.37 for every 0.1-mm/year increment [95% confidence interval [CI]: 1.63–3.47], p < 0.001), Max-IMT (HR 1.51 for every 0.1-mm/year increment [95% CI: 1.07–2.14], p = 0.020), and Mean-GSM (HR 0.22 for every 10-U/year increment [95% CI: 0.06–0.76], p = 0.016) during the observation period were also prognostic factors for CVD even after adjusting for the baseline value of the respective measure.

Conclusions: Addition of carotid ultrasonography measures to conventional risk factors significantly improved the stratification of patients by cardiovascular risk. Changes over time in carotid ultrasonography measures may be used as therapeutic outcome measures.

Abbreviations: CAC, coronary artery calcium; CCA, common carotid artery; CVD, cardiovascular disease; DM, diabetes mellitus; FRS,Framingham Risk Score; GSM, gray-scale median; HR, hazard ratio; IMT, intima–media thickness; PAD, peripheral artery disease

Association between carotid plaque characteristics and acute cerebral infarction determined by MRI in patients with type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) might aggravate the carotid plaque vulnerability, and increase the risk for ischemic stroke. Few studies reported the acute stroke subtype with carotid plaque characteristics in T2DM patients. This study aimed to investigate the association between carotid plaque characteristics and acute cerebral infarct (ACI) lesion features determined by MRI in T2DM patients.

METHODS

Patients with acute cerebrovascular syndrome in internal carotid artery territory were recruited. All patients were stratified into T2DM and non-T2DM groups and underwent both carotid and brain MRI scans. Ipsilateral carotid plaque morphological and compositional characteristics, intracranial and extracranial carotid artery stenosis were also determined. Stroke subtype based on the Trial of ORG 10172 in Acute Stroke Treatment classification and ACI lesion patterns were evaluated.

RESULTS

Of the recruited 140 patients, 68 (48.6%) patients had T2DM (mean age 64.16 ± 11.38 years, 40 males). T2DM patients exhibited higher prevalence of carotid type IV-VI lesions, larger plaque burden as well as larger lipid-rich necrotic core (LRNC) compared with non-T2DM patients. Among the patients with carotid LRNC on symptomatic side, more concomitant large perforating artery infarct patterns and larger ACI size in the internal carotid artery territory were found in T2DM group than those in non-T2DM group. Carotid plaque with LRNC% > 22.0% was identified as an independent risk factor for the presence of ACI lesions confined to the carotid territory in T2DM patients, regardless of other risk factors.

CONCLUSIONS

This study shows that more concomitant large perforating artery infarct patterns and larger ACI size in the internal carotid artery territory were found in the T2DM patients with ipsilateral carotid LRNC plaque than those in non-T2DM patients. Quantification of the carotid plaque characteristics, particularly the LRNC% by MRI has the potential usefulness for stroke risk stratification.

A Review on Carotid Ultrasound Atherosclerotic Tissue Characterization and Stroke Risk Stratification in Machine Learning Framework

Cardiovascular diseases (including stroke and heart attack) are identified as the leading cause of death in today's world. However, very little is understood about the arterial mechanics of plaque buildup, arterial fibrous cap rupture, and the role of abnormalities of the vasa vasorum. Recently, ultrasonic echogenicity characteristics and morphological characterization of carotid plaque types have been shown to have clinical utility in classification of stroke risks. Furthermore, this characterization supports aggressive and intensive medical therapy as well as procedures, including endarterectomy and stenting. This is the first state-of-the-art review to provide a comprehensive understanding of the field of ultrasonic vascular morphology tissue characterization. This paper presents fundamental and advanced ultrasonic tissue characterization and feature extraction methods for analyzing plaque. Additionally, the paper shows how the risk stratification is achieved using machine learning paradigms. More advanced methods need to be developed which can segment the carotid artery walls into multiple regions such as the bulb region and areas both proximal and distal to the bulb. Furthermore, multimodality imaging is needed for validation of such advanced methods for stroke and cardiovascular risk stratification.

Ultrasound and Biochemical Diagnostic Tools for the Characterization of Vulnerable Carotid Atherosclerotic Plaque

Stroke is a leading cause of morbidity and mortality worldwide, and characterization of vulnerable carotid plaque remains the spearhead of scientific research. Plaque destabilization, the key factor that induces the series of events leading to the clinical symptoms of carotid artery disease, is a consequence of complex mechanical, structural and biochemical processes. Novel imaging and molecular markers have been studied as predictors of disease outcome with promising results. The aim of this review is to present the current state of research on the association between ultrasound-derived echogenicity indices and blood parameters indicative of carotid plaque stability and activity. Bibliographic research revealed that there are limited available data. Among the biomarkers studied, those related to oxidative stress, lipoproteins and diabetes/insulin resistance are associated with echolucent plaques, whereas adipokines are associated with echogenic plaques. Biomarkers of inflammation and coagulation have not exhibited any conclusive relationship with plaque echogenicity, and it is not possible to come to any conclusion regarding calcification-, apoptosis- and neo-angiogenesis-related parameters because of the extremely limited bibliographic data.

Carotid plaque calcification predicts future cardiovascular events in type 2 diabetes

OBJECTIVE

The presence of carotid plaques is associated with future cardiovascular events, with local plaque composition being an independent outcome predictor. We examined the association between ultrasonographically determined carotid plaque calcification and incident major adverse cardiovascular events (MACE) and death in type 2 diabetes (T2D).

RESEARCH DESIGN AND METHODS

We enrolled 581 patients with T2D who underwent routine carotid ultrasonography. Plaques were classified as echolucent (lipid rich), heterogenous, and echogenic (calcific). We collected demographic, anthropometric, and clinical data at baseline and followed the patients for up to 9 years.

RESULTS

Plaques were detected in 81.8% of the patients (echolucent in 16.4%, heterogenous in 43.2%, and echogenic in 22.2%). During follow-up (4.3 ± 0.1 years), 58 deaths (27 cardiovascular) and 236 fatal and nonfatal MACE occurred. In univariate analyses, presence versus absence of any carotid plaque was associated with incident MACE, and the hazard ratio (95% CI) progressively increased from echolucent (1.97 [0.93-3.44]), to heterogeneous (3.10 [2.09-4.23]), to echogenic (3.71 [2.09-5.59]) plaques. Compared with echolucent plaques, echogenic plaques were associated with incident MACE independently from confounders. This association was attenuated after adjusting for the degree of stenosis, but in patients with stenosis ≤30%, echogenic plaque type still predicted total and atherosclerotic MACE, even after further adjusting for mean intima-media thickness.

CONCLUSIONS

In T2D, carotid plaque calcification predicts MACE, especially in patients with a low degree of stenosis. The biology of atherosclerotic calcification in diabetes needs to be further elucidated to understand the basis of this association.

The risk factors associated with ultrasonic tissue characterization of carotid plaque in type 2 diabetic patients

AIMS

Little is known about the related factors of plaque echogenicity in diabetic subjects.

METHODS

This was a single-center, retrospective, study investigating a subgroup of patients of a previously published trial. We enrolled 179 middle-aged and older Japanese type 2 diabetic patients with carotid plaque, and examined the parameters related with echogenicity of carotid plaque evaluated by gray-scale median (GSM).

RESULTS

Proportion of males and body mass index (BMI) were significantly higher and HDL-cholesterol was significantly lower in the patients with low GSM (< 48) plaques (n = 89) as compared to those without it (n = 90). A multiple logistic regression analysis with gender, BMI, and HDL-cholesterol as independent variables and the presence of low GSM plaques as an objective variable showed that male (odds ratio (OR) 2.36, 95%CI 1.05-5.31, p = 0.037) and BMI (OR 1.12 [1.01-1.24], p = 0.029) were independently associated with low GSM plaques. Another multiple logistic regression analysis with gender, BMI, and low-HDL-cholesterolemia (HDL-C < 40 mg/dl) as independent variables showed that low-HDL-cholesterolemia (OR 2.30 [1.03-5.13], p = 0.042) and BMI (OR 1.11 [1.00-1.22], p = 0.046) were independently associated with low GSM plaques.

CONCLUSIONS

Our study suggests that gender, BMI and low-HDL-cholesterol are important determinants of the content of the vascular wall in diabetic subjects.