Remodeling of coronary arteries in diabetic patients-an intravascular ultrasound study

Investigating the relationship between intracranial atherosclerotic plaque remodelling and diabetes using high-resolution vessel wall imaging

BACKGROUND

Intracranial atherosclerosis, a leading cause of stroke, involves arterial plaque formation. This study explores the link between plaque remodelling patterns and diabetes using high-resolution vessel wall imaging (HR-VWI).

AIM

To investigate the factors of intracranial atherosclerotic remodelling patterns and the relationship between intracranial atherosclerotic remodelling and diabetes mellitus using HR-VWI.

METHODS

Ninety-four patients diagnosed with middle cerebral artery or basilar artery atherosclerosis were enrolled. Their basic clinical data were collected, and HR-VWI was performed. The vascular area at the plaque (VAMLN) and normal reference vessel (VAreference) were delineated and measured using image postprocessing software, and the Remodelling index (RI) was calculated. According to the value of the RI, the patients were divided into a positive remodelling (PR) group, intermediate remodelling (IR) group, negative remodelling (NR) group, PR group and non-PR (N-PR) group.

RESULTS

The PR group exhibited a higher prevalence of diabetes and serum cholesterol levels than the IR and NR groups [45.2%, 4.54 (4.16, 5.93) vs 25%, 4.80 ± 1.22 and 16.4%, 4.14 (3.53, 4.75), respectively, P < 0.05]. The diabetes incidence was also significantly greater in the PR group than in the N-PR group (45.2% vs 17.5%, P < 0.05). Furthermore, the PR group displayed elevated serum triglyceride and cholesterol levels compared to the N-PR group [1.64 (1.23, 2.33) and 4.54 (4.16, 5.93) vs 4.54 (4.16, 5.93) and 4.24 (3.53, 4.89), P < 0.05]. Logistic regression analysis revealed diabetes mellitus as an independent influencing factor in plaque-PR [odds ratio (95% confidence interval): 3.718 (1.207-11.454), P < 0.05].

CONCLUSION

HR-VWI can clearly show the morphology and signal characteristics of intracranial vascular walls and plaques. Intracranial atherosclerotic plaques in diabetic patients are more likely to show PR, suggesting poor plaque stability and a greater risk of stroke.

Carotid Artery Remodeling Is Segment Specific: An In Vivo Study by Vessel Wall Magnetic Resonance Imaging

OBJECTIVE

Early atherosclerosis is often undetected due in part to compensatory enlargement of the outer wall, termed positive remodeling. Variations in hemodynamic conditions and clinical factors influence the patterns of remodeling. The carotid artery provides an opportunity to examine these variations because of the unique geometry of the carotid bulb. This study aimed to determine differences in remodeling of the common, internal, and bifurcation segments of the carotid using magnetic resonance imaging.

APPROACH AND RESULTS

Carotid arteries of 525 subjects without history of cardiovascular disease were imaged by magnetic resonance imaging. The carotid artery was divided into 3 segments: common carotid artery; bifurcation; and internal carotid artery. Remodeling patterns were characterized using linear regression analysis of lumen and total vessel areas (dependent variables) compared with maximum wall thickness (independent variable) for each segment, adjusted for age, sex, and height. The common carotid artery demonstrated a pattern consistent with positive remodeling, whereas the bifurcation demonstrated negative remodeling. The internal carotid artery demonstrated a mixed pattern of outer wall expansion and lumen constriction. Females and subjects with diabetes mellitus showed more positive remodeling, hypertension was associated with attenuated positive remodeling, and those with hypercholesterolemia showed more negative remodeling.

CONCLUSIONS

In this cohort of 55- to 80-year-old individuals without history of cardiovascular disease, the pattern of early carotid artery remodeling was segment specific and appeared to be associated with sex and clinical characteristics. These findings provide the groundwork for longitudinal studies to define local and systemic factors such as hemodynamic and clinical conditions on carotid artery remodeling.

In Vivo and In Vitro Analysis in Coronary Artery Disease Related to Type 2 Diabetes

AIM

The leading cause of morbidity and mortality in patients with type 2 diabetes mellitus (DM) is coronary artery disease (CAD), a condition often asymptomatic but severe in these patients. Although glucose metabolism impairment and oxidative stress are known actors in the endothelial dysfunction/remodeling that occurs in diabetic patients, the relationship between cardiovascular disorders and DM is not fully understood. We have performed both an in vivo imaging and in vitro molecular analysis to investigate diabetic-specific CAD alterations.

METHODS

Computed tomography coronary angiography (CTCA) was performed in a group of 20 diabetic patients with CAD (DM⁺CAD⁺), 20 non-diabetic with CAD (DM^-CAD⁺), 10 diabetic non-CAD patients (DM⁺CAD^-), and 20 non-diabetic healthy subjects (HS). Imaging quantitative parameters such as calcium score (Cascore), calcified plaque volume (CPV), non-calcified plaque volume (NCPV), total plaque volume (TPV), remodeling index (RI), and plaque burden were extracted for each CAD subject. Moreover, the expression levels of superoxide dismutase 2 (SOD2) and liver X receptor alpha (LXRα) genes were analyzed in the peripheral blood mononuclear cells, whereas hyaluronan (HA) concentrations were evaluated in the plasma of each subject.

RESULTS

Imaging parameters, such as Cascore, CPV, RI, and plaque burden, were significantly higher in DM⁺CAD⁺ group, compared to DM^-CAD⁺ (P = 0.019; P = 0.014; P < 0.001, P < 0.001, respectively). SOD2 mRNA was downregulated, while LXRα gene expression was upregulated in DM⁺CAD^-, DM⁺CAD⁺, and DM^-CAD⁺ groups compared to HS (P = 0.001, P = 0.03, and P = 0.001 for SOD2 and P = 0.006, P = 0.008, and P < 0.001 for LXRα, respectively). Plasmatic levels of HA were higher in DM^-CAD⁺, DM⁺CAD^-, and DM⁺CAD⁺ groups, compared to HS (P = 0.001 for the three groups). When compared to DM^-CAD⁺, HA concentration was higher in DM⁺CAD^- (P = 0.008) and DM⁺CAD⁺ (P < 0.001) with a significant difference between the two diabetic groups (P = 0.003). Moreover, HA showed a significant association with diabetes (P = 0.01) in the study population, and the correlation between HA levels and glycemia was statistically significant (ρ = 0.73, P < 0.001).

CONCLUSION

In our population, imaging parameters highlight a greater severity of CAD in diabetic patients. Among molecular parameters, HA is modulated by diabetic CAD-related alterations while SOD2 and LXRα are found to be more associated with CAD but do not discriminate between diabetic and non-diabetic subgroups.

Intravascular Ultrasonic Imaging of Coronary Arterial Remodeling in Heart Transplant Recipients

The purpose of this study was to evaluate long-term changes of transplant coronary arteries, including vessel, plaque, and lumen areas. There are limited long-term data on vessel remodeling after heart transplantation. We analyzed serial intravascular ultrasound images of the left anterior descending coronary artery (LAD) in 54 heart transplantation recipients. Nine patients (16.7%) had a history of rejection. Proximal left anterior descending artery segments were matched among time points, a ≥20-mm long segment was analyzed every 1 mm, and results were normalized for analysis length and reported as mm(3)/mm. During follow-up, vessel area decreased (-0.48 ± 1.3 mm(3)/mm/year), and plaque area did not change (-0.01 ± 0.47 mm(3)/mm/year). As a result, lumen area decreased (-0.52 ± 1.34 mm(3)/mm/year). The change in mean lumen area was well correlated to the change in mean vessel area (r = 0.94, p <0.01) but not to the change in mean plaque area (r = -0.27, p = 0.05). In conclusion, lumen loss occurred during long-term follow-up of patients who underwent heart transplantation, primarily secondary to negative remodeling (decrease in vessel dimensions).

Doppler ultrasound detection of preclinical changes in foot arteries in early stage of type 2 diabetes

BACKGROUND

There are few reports regarding the changes within the vessels in the initial stage of type 2 diabetes. The aim of this study was to estimate the hemodynamic and morphological parameters in foot arteries in type 2 diabetes subjects and to compare these parameters to those obtained in a control group of healthy volunteers.

MATERIAL/METHODS

Ultrasound B-mode, color Doppler and pulse wave Doppler imaging of foot arteries was conducted in 37 diabetic patients and 36 non-diabetic subjects to determine their morphological (total vascular diameter and flow lumen diameter) and functional parameters (spectral analysis).

RESULTS

In diabetic patients, the overall vascular diameter and wall thickness were statistically significantly larger when compared to the control group in the right dorsalis pedis artery (P=0.01; P=0.001), left dorsalis pedis artery (P=0.007; P=0.006), right posterior tibial artery (P=0.005; P=0.0005), and left posterior tibial artery (P=0.007; P=0.0002). No significant differences were observed in both groups in flow lumen diameters and blood flow parameters (PSV, EDV, PI, RI). In the diabetic group, the level of HbA1c positively correlated with flow resistance index in the right dorsalis pedis artery (r=0.38; P=0.02), right posterior tibial artery (r=0.38; P=0.02) and left posterior tibial artery (r=0.42; P=0.009). The pulsatility index within the dorsalis pedis artery decreased with increased trophic skin changes (r=-0.431, P=0.009).

CONCLUSIONS

In the diabetic group, overall artery diameters larger than and flow lumina comparable to the control group suggest vessel wall thickening occurring in the early stage of diabetes. Doppler flow parameters are comparable in both groups. In the diabetic group, the level of HbA1c positively correlated with flow resistance index and negative correlation was observed between the intensity of trophic skin changes and the pulsatility index.

High HbA1c levels correlate with reduced plaque regression during statin treatment in patients with stable coronary artery disease: results of the coronary atherosclerosis study measuring effects of rosuvastatin using intravascular ultrasound in Japanese subjects (COSMOS)

Background

The incidence of cardiac events is higher in patients with diabetes than in people without diabetes. The Coronary Atherosclerosis Study Measuring Effects of Rosuvastatin Using Intravascular Ultrasound in Japanese Subjects (COSMOS) demonstrated significant plaque regression in Japanese patients with chronic coronary disease after 76 weeks of rosuvastatin (2.5 mg once daily, up-titrated to a maximum of 20 mg/day to achieve LDL cholesterol <80 mg/dl).

Methods

In this subanalysis of COSMOS, we examined the association between HbA1c and plaque regression in 40 patients with HbA1c ≥6.5% (high group) and 86 patients with HbA1c <6.5% (low group).

Results

In multivariate analyses, HbA1c and plaque volume at baseline were major determinants of plaque regression. LDL cholesterol decreased by 37% and 39% in the high and low groups, respectively, while HDL cholesterol increased by 16% and 22%, respectively. The reduction in plaque volume was significantly (p = 0.04) greater in the low group (from 71.0 ± 39.9 to 64.7 ± 34.7 mm³) than in the high group (from 74.3 ± 34.2 to 71.4 ± 32.3 mm³). Vessel volume increased in the high group but not in the low group (change from baseline: +4.2% vs −0.8%, p = 0.02). Change in plaque volume was significantly correlated with baseline HbA1c.

Conclusions

Despite similar improvements in lipid levels, plaque regression was less pronounced in patients with high HbA1c levels compared with those with low levels. Tight glucose control during statin therapy may enhance plaque regression in patients with stable coronary disease.

Trial registration

ClinicalTrials.gov, Identifier NCT00329160

Effect of hypertension on coronary remodeling patterns in angiographically normal or minimally atherosclerotic coronary arteries: an intravascular ultrasound study

Whether there is any particular role of hypertension in remodeling process has not been completely understood yet. The aim of this study was to assess the association between hypertension and remodeling patterns in normal or minimally atherosclerotic coronary arteries. Seventy-nine patients who were free of significant coronary atherosclerosis were divided into two groups according to the absence (n = 39) or presence (n = 40) of hypertension; and standard intravascular ultrasound examination was performed in 145 segments. To determine the remodeling pattern in early atherosclerotic process, patients were also analyzed according to the level of plaque burden at the lesion site after the analysis of remodeling patterns. Positive remodeling was more prevalent in the hypertensive group (52.5% vs. 12.8%; P < .001) whereas negative remodeling was more common in diabetic patients (53.6% vs. 27.4%; P = .03). Mean remodeling index was 1.04 for hypertensives and 0.96 for normotensives (P = .03). There were no correlations between remodeling patterns and other risk factors such as age, family history, and hypercholesterolemia. Early atherosclerotic lesions (< 30%) exhibited more negative remodeling characteristics while intermediate pattern was observed more frequently in patients with high plaque burden (P = .006 and .02, respectively). Positive remodeling showed no association in this context (P = .07). This study demonstrated that minimal atherosclerotic lesions in hypertensives had a tendency for compensatory arterial enlargement. Positive remodeling may result from local adaptive processes within vessel wall or hemodynamic effects of blood pressure itself.

Influence of obesity and metabolic dysfunction on the endothelial control in the coronary circulation

Diseases of the coronary circulation remain the leading cause of death in Western society despite impressive advances in diagnosis, pharmacotherapy and post-event management. Part of this statistic likely stems from a parallel increase in the prevalence of obesity and metabolic dysfunction, both significant risk factors for coronary disease. Obesity and diabetes pose unique challenges for the heart and their impact on the coronary vasculature remains incompletely understood. The vascular endothelium is a major interface between arterial function and the physical and chemical components of blood flow. Proper function of the endothelium is necessary to preserve hemostasis, maintain vascular tone and limit the extent of vascular diseases such as atherosclerosis. Given its central role in vascular health, endothelial dysfunction has been the source of considerable research interest in diabetes and obesity. In the current review, we will examine the pathologic impact of obesity and diabetes on coronary function and the extent to which these two factors impact endothelial function. This article is part of a Special Issue entitled "Coronary Blood Flow".

Left ventricular dysfunction with reduced functional cardiac reserve in diabetic and non-diabetic LDL-receptor deficient apolipoprotein B100-only mice

Background

Lack of suitable mouse models has hindered the studying of diabetic macrovascular complications. We examined the effects of type 2 diabetes on coronary artery disease and cardiac function in hypercholesterolemic low-density lipoprotein receptor-deficient apolipoprotein B100-only mice (LDLR^-/-ApoB^100/100).

Methods and results

18-month-old LDLR^-/-ApoB^100/100 (n = 12), diabetic LDLR^-/-ApoB^100/100 mice overexpressing insulin-like growth factor-II (IGF-II) in pancreatic beta cells (IGF-II/LDLR^-/-ApoB^100/100, n = 14) and age-matched C57Bl/6 mice (n = 15) were studied after three months of high-fat Western diet. Compared to LDLR^-/-ApoB^100/100 mice, diabetic IGF-II/LDLR^-/-ApoB^100/100 mice demonstrated more calcified atherosclerotic lesions in aorta. However, compensatory vascular enlargement was similar in both diabetic and non-diabetic mice with equal atherosclerosis (cross-sectional lesion area ~60%) and consequently the lumen area was preserved. In coronary arteries, both hypercholesterolemic models showed significant stenosis (~80%) despite positive remodeling. Echocardiography revealed severe left ventricular systolic dysfunction and anteroapical akinesia in both LDLR^-/-ApoB^100/100 and IGF-II/LDLR^-/-ApoB^100/100 mice. Myocardial scarring was not detected, cardiac reserve after dobutamine challenge was preserved and ultrasructural changes revealed ischemic yet viable myocardium, which together with coronary artery stenosis and slightly impaired myocardial perfusion suggest myocardial hibernation resulting from chronic hypoperfusion.

Conclusions

LDLR^-/-ApoB^100/100 mice develop significant coronary atherosclerosis, severe left ventricular dysfunction with preserved but diminished cardiac reserve and signs of chronic myocardial hibernation. However, the cardiac outcome is not worsened by type 2 diabetes, despite more advanced aortic atherosclerosis in diabetic animals.

Three-vessel coronary disease in diabetics: personalized versus evidence-based revascularization strategy

A steady increase in the number of diabetic patients undergoing coronary revascularization has been recorded in recent years. The causes for this rise are found predominantly in the general demographic development of western industrialized nations, the epidemic progress and wide-spread of diabetes mellitus and changes in assignment behavior. In this article, the specific risk profile of diabetic coronary patients with three-vessel disease in percutaneous or surgical revascularization and tried and tested treatment concepts for this particularly challenging group of patients, with reference to the most recent study results will be presented. Particularly, the peculiarities of coronary heart disease in diabetic patients, the choice of revascularization method, different operative strategies for diabetic patients with coronary heart disease, and challenges faced during follow-up are discussed.

Rosiglitazone reverses endothelial dysfunction but not remodeling of femoral artery in Zucker diabetic fatty rats

OBJECTIVES

Endothelial dysfunction precedes atherogenesis and clinical complications in type 2 diabetes. The vascular dysfunction in Zucker diabetic fatty (ZDF) rats was evaluated at different ages along with the effect of treatment with rosiglitazone (Rosi) on endothelial function and mechanical remodeling.

METHODS

The Rosi treatment was given to ZDF rats for 3 weeks. The endothelium-dependent vasodilation and alpha-adrenoceptor-dependent vasoconstriction of femoral arteries were studied using an ex-vivo isovolumic myograph. The biomechanical passive property of the arteries was studied in Ca2+-free condition. The expressions of endothelial nitric oxide synthase (eNOS), alpha-adrenoceptor, matrix metalloproteinase 9 (MMP9), and elastase were evaluated.

RESULTS

Endothelium-dependent vasorelaxation of the femoral artery was blunted at low doses in ZDF rats at 11 weeks of age and attenuated at all doses in ZDF rats at 19 weeks of age. The expression of eNOS was consistent with the endothelium-dependent vasorelaxation. The alpha-adrenoceptor was activated and the mechanical elastic modulus was increased in ZDF rats at 19 weeks of age. The expressions of alpha-adrenoceptor, MMP9, and elastase were up regulated in ZDF rats at 19 weeks of age. Rosi treatment for 3 weeks restored endothelium-dependent vasorelaxation and the expression of eNOS and the adrenoceptor activation at the doses below 10-6 mole/L in ZDF rats at 19 weeks of age. Rosi treatment for 3 weeks did not, however, improve the mechanical properties of blood vessel, the expressions of alpha-adrenoceptor, MMP9, and elastase in ZDF rats.

CONCLUSION

The endothelial dysfunction and mechanical remodeling are observed as early as 19 weeks of age in ZDF rat. Rosi treatment for 3 weeks improves endothelial function but not mechanical properties.

Quantification of vasa vasorum density in multi-slice computed tomographic coronary angiograms: role of computed tomographic image voxel size

OBJECTIVE

This study is motivated by the possibility of using computed tomography (CT) to detect early coronary atherosclerosis by the increased CT values within the arterial wall resulting from vasa vasorum proliferation.

METHODS

Coronary arteries (n = 5) with early atherosclerotic changes were injected with Microfil and scanned (micro-CT). Noise was added to the CT projection data sets (to represent the radiation exposure of current clinical CT scanners) and then reconstructed to generate 3-dimensional images at different voxel sizes.

RESULTS

Higher CT values were detected because of contrast agent in vasa vasorum if voxel size was less than (150 microm)(3). Contrast in the main lumen increased the CT values dramatically at voxels greater than (100 microm)(3), whereas CT values of the same specimen without contrast in the main lumen remained constant.

CONCLUSIONS

Voxel sizes less than (200 microm)(3) are needed to quantitate arterial wall opacification due to vasa vasorum proliferation.