Validity and reliability of new intravascular ultrasound analysis software for morphological measurement of coronary artery disease

Comparison of quantitative measurements between two different intravascular ultrasound catheters and consoles: in vitro and in vivo studies

Previous studies suggested possible discordant quantitative measurements between different IVUS catheters and/or systems. The purpose of this study was to assess compatibility of two different IVUS catheters and consoles for quantitative measurements of coronary arteries. (1). In vitro study: IVUS imaging was performed in a concentric cylindrical phantom with 6 sections of known, cross-sectional diameter ranging from 3.0 to 8.0 mm. The lumen diameter (LD) and lumen cross-sectional area (LA) were measured and compared. To compare between 2 different IVUS consoles, IVUS images were obtained using a single IVUS catheter (catheter 1) connected to 2 different IVUS consoles (console 1 and 2). To compare between 2 different IVUS catheters, IVUS imaging was obtained using 2 different IVUS catheters (catheter 1 and 2) connected to a single IVUS console (console 2). (2). In vivo study: IVUS imaging was performed in 40 stented coronary arterial segments from 40 patients. The maximal stent diameter (Max SD), minimal stent diameter (minSD), and stent area (SA) were measured at both distal and proximal stent edges and compared between the two IVUS consoles (console 1 and 2) connected to a single IVUS catheter (catheter 1) (n = 20). IVUS imaging was also performed to compare between catheter 1 and 2 connected to IVUS console 2 (n = 20). Both in vitro and in vivo studies showed good correlation between the two IVUS consoles as well as two IVUS catheters. In conclusion, two IVUS catheters and consoles provide comparable IVUS measures both in vitro and in vivo.

Impact of visit-to-visit variability in blood pressure on coronary plaque as assessed by integrated backscatter intravascular ultrasound

INTRODUCTION

Visit-to-visit variability (VVV) in blood pressure (BP) has been reported to be a strong predictor of cardiovascular disease. However, the association between VVV in BP and coronary plaque composition has not been fully elucidated.

METHODS

One hundred-two consecutive patients with coronary artery disease (CAD) who underwent percutaneous coronary intervention (PCI) using integrated backscatter (IB) intravascular ultrasound (IVUS), and who had at least six clinic visits a year before PCI were included. We measured systolic and diastolic BP (SBP and DBP) at each visit and determined VVV in BP expressed as the standard deviation of the average BP. Grayscale and IB IVUS examinations were performed for the culprit lesion of a coronary artery just before PCI.

RESULTS

There were no significant associations between the average SBP or DBP and various IVUS parameters. However, VVV in SBP was positively correlated with both the percentage (%) of atheroma volume (β = 0.23, p = .02) and % lipid volume (β = 0.53, p < .0001). VVV in DBP was positively correlated with % lipid volume (β = 0.24, p = .01), while there was no significant correlation between VVV in DBP and % atheroma volume. A  multivariable linear regression analysis showed that VVV in SBP was independently associated with % atheroma volume (p = .04) and % lipid volume (p < .001).

CONCLUSIONS

Larger VVV in SBP was significantly associated with an increased plaque burden and lipid composition at the culprit lesion of a coronary artery in CAD patients. The improvement of VVV in SBP may contribute to the regression and stabilization of coronary plaques.

Association between abdominal fat distribution and coronary plaque instability in patients with acute coronary syndrome

BACKGROUND AND AIMS

This study aimed to assess possible association of detailed abdominal fat profiles with coronary plaque characteristics in patients with acute coronary syndrome (ACS).

METHODS AND RESULTS

In 60 patients with ACS, culprit arteries were evaluated at 1-mm intervals (length analyzed: 66 ± 28 mm) by grayscale and integrated backscatter intravascular ultrasound (IB-IVUS) before percutaneous coronary intervention. Standard IVUS indexes (as a volume index: volume/length), plaque components (as percent tissue volume) and fibrous cap thickness (FCT) were assessed by IB-IVUS. Plain abdominal computed tomography was performed to evaluate subcutaneous adipose tissue (SAT) area, visceral adipose tissue (VAT) area, and VAT/SAT ratio. While SAT area only correlated with vessel volume (r = 0.27, p = 0.04), VAT area correlated positively with vessel (r = 0.30, p = 0.02) and plaque (r = 0.33, p = 0.01) volumes and negatively with FCT (r = -0.26, p = 0.049), but not with percent plaque volume and plaque tissue components. In contrast, higher VAT/SAT ratio significantly correlated with higher percent lipid (r = 0.34, p = 0.008) and lower percent fibrous (r = -0.34, p = 0.007) volumes with a trend toward larger percent plaque volume (r = 0.19, p = 0.15), as well as thinner FCT (r = -0.53, p < 0.0001). In the multiple regression analysis, higher VAT/SAT ratio was independently associated with higher percent lipid with lower percent fibrous volumes (p = 0.03 for both) and thinner fibrous cap thickness (p = 0.0001).

CONCLUSION

Coronary plaque vulnerability, defined as increased lipid content with thinner fibrous cap thickness, appears to be more related to abnormal abdominal fat distribution, or so-called hidden obesity, compared with visceral or subcutaneous fat amount alone in patients with ACS.

Associations of coronary plaque characteristics by integrated backscatter intravascular ultrasound with detectability of vessel external elastic lamina using optical frequency domain imaging in human coronary arteries: A sub-analysis of the MISTIC-1 trial

OBJECTIVES

We sought to examine associations between plaque characteristics by intravascular ultrasound (IVUS) and detectability of external elastic lamina (EEL) by optical frequency domain imaging (OFDI) in human coronary arteries.

BACKGROUND

It is often challenging to detect EEL which represents vessel size by light-based imaging modalities due to light intensity attenuation through atherosclerotic plaque.

METHODS

IVUS and OFDI prior to stent implantation were sequentially investigated per protocol. We identified corresponding cross-sections by minimum lumen area (MLA) or just distally to side branches as anatomical landmarks. Plaque characterization was determined by integrated backscatter IVUS analysis. We categorized detectable EEL arc by OFDI into four groups: 0≤ and <1 quadrant (group 1), 1≤ and <2 quadrants (group 2), 2≤ and <3 quadrants (group 3), or 3≤ and <4 quadrants (group 4).

RESULTS

We prospectively studied 103 vessels in 93 patients with stable coronary artery disease. Corresponding 711 cross-sections were analyzed. Cross-sections with detectable EEL arc <2 quadrants (group 1 or 2) were observed in 86.1% of MLA sites but only in 29.3% of non-MLA sites (p < .05). Percentage plaque area (%PA) appeared to be the strongest predictor to detect EEL arc <2 quadrants with the cut-off of 60.3% (AUC 0.90; sensitivity 79.8%, specificity 85.5%). Lipid pool and calcification remained statistically significant in predicting detectable EEL arc <2 quadrants after adjustment with %PA.

CONCLUSIONS

Presence of large plaque burden, lipid pool, and calcification significantly predicts the detectability of EEL by OFDI assessment. Locations with detectable EEL arc <2 quadrants should thus be avoided for optimal stent landing zone.

Comparison between instantaneous wave-free ratio versus morphometric assessments by intracoronary imaging

Anatomical measurements obtained by intracoronary imaging devices are reported to correlate significantly with fractional flow reserve (FFR). Instantaneous wave-free ratio (iFR) is a nonhyperemic index of stenosis severity with discordant reports regarding its accuracy in relation to FFR. There is no information on the correlation of iFR with measurements derived from intracoronary imaging devices. The purpose of this study was to assess the relationship among iFR, intravascular ultrasound (IVUS), and optical frequency domain imaging (OFDI) parameters. Eighty lesions in 72 patients who underwent elective angiography and had intermediate lesions were enrolled. All lesions were assessed by iFR, FFR, IVUS, and OFDI. iFR was ≤ 0.89 in 21 (26%) lesions and FFR was ≤ 0.80 in 41 (51%) lesions. iFR correlated significantly with both IVUS-derived minimum lumen area (MLA) (r = 0.375, p = 0.003) and OFDI-derived MLA (r = 0.357, p = 0.005). FFR also correlated significantly with both IVUS-derived MLA (r = 0.472, p < 0.001) and OFDI-derived MLA (r = 0.445, p < 0.001). Among the lesions with FFR ≤ 0.80, iFR > 0.89 (mismatch) was observed in 20 lesions. There was no lesion with iFR ≤ 0.89 (reverse mismatch) among the lesions with FFR > 0.80. The lesion location among three major coronary vessels was related with the discrepancy between iFR and FFR (p = 0.007). In conclusion, iFR and FFR showed a significant correlation with IVUS and OFDI measurements. The discrepancy of iFR and FFR was associated with the lesion locations.

Impact of the triglyceride level on coronary plaque components in female patients with coronary artery disease treated with statins

Several studies have reported that elevated triglyceride (TG) levels may be more strongly associated with an increased risk of coronary artery disease (CAD) in females than in males. We examined gender differences in the relationship between TG levels and coronary atherosclerosis using integrated backscatter intravascular ultrasound (IB IVUS) in CAD patients treated with statins. Three hundred seventy-eight CAD patients (105 females and 273 males) who underwent percutaneous coronary intervention using IB IVUS, and who were already receiving statin treatment, were included. Gray-scale and IB IVUS examinations were performed for the non-culprit segment of a coronary artery and fasting serum TG concentrations were measured. We found that TG levels were significantly correlated with increased lipid (r = 0.40, p < 0.001) and decreased fibrous (r = - 0.37, p < 0.001) plaque components in females, but not in males. Low-density lipoprotein cholesterol and high-density lipoprotein cholesterol levels were not related to either the gray-scale or IB IVUS parameters in both genders. After adjustment for conventional coronary risk factors by a multivariate stepwise regression analysis, higher TG levels in females were independently associated with increased lipid (β = 0.31, p< 0.001) contents in coronary plaques. In conclusion, among CAD patients treated with statins, TG levels were associated with lipid-rich coronary plaques in females, but not in males. TG levels may be more important indicators of residual risk after statin treatment in females than in males.

Impact of von Willebrand factor on coronary plaque burden in coronary artery disease patients treated with statins

High von Willebrand factor (VWF) levels have been reported to be associated with an increased risk of cardiovascular events. However, the relationship between VWF levels and coronary atherosclerosis in patients with coronary artery disease (CAD) who have already received stain treatment is still unclear. We examined the association between VWF levels and coronary plaque as assessed by intravascular ultrasound (IVUS) in CAD patients treated with statins. Ninety-one CAD patients who underwent percutaneous coronary intervention under IVUS guidance, and who were already receiving statin treatment based on Japanese guidelines, were included. An IVUS examination was performed for the culprit lesion, and plasma VWF antigen levels were measured using enzyme-linked immuno sorbent assay. In all of the patients, the low-density lipoprotein cholesterol levels just before the IVUS examination were low (86 ± 26 mg/dL). The VWF levels were positively correlated with the plaque burden expressed as percent atheroma volume (PAV) (r = 0.39, P = .001), while there was no significant association between VWF and plaque composition. Multivariate stepwise regression analysis showed that higher VWF levels were independently associated with increased PAV (β=0.26, P = .01). In CAD patients who had already been treated with statins, higher VWF levels were associated with a higher coronary plaque burden, suggesting that a high VWF level may be a marker of the residual cardiovascular risk after statin treatment.

Effects of 4 Statins on Regression of Coronary Plaque in Acute Coronary Syndrome

BACKGROUND

There is no information on differences in the effects of moderate- and low-intensity statins on coronary plaque in patients with acute coronary syndrome (ACS). The aim of this study was to compare the effects of 4 different statins in patients with ACS, using intravascular ultrasound (IVUS).

METHODS AND RESULTS

A total of 118 patients with ACS who underwent IVUS before percutaneous coronary intervention and who were found to have mild to moderate non-culprit coronary plaques were randomly assigned to receive either 20 mg/day atorvastatin or 4 mg/day pitavastatin (moderate-intensity statin therapy), or 10 mg/day pravastatin or 30 mg/day fluvastatin (low-intensity statin therapy). IVUS at baseline and at end of 10-month treatment was available in 102 patients. Mean percentage change in plaque volume (PV) was -11.1±12.8%, -8.1±16.9%, 0.4±16.0%, and 3.1±20.0% in the atorvastatin, pitavastatin, pravastatin, and fluvastatin groups, respectively (P=0.007, ANOVA). Moderate-intensity statin therapy induced regression of PV, whereas low-intensity statin therapy produced insignificant progression (-9.6% vs. 1.8%, P<0.001). On multivariate linear regression analysis, moderate-intensity statin therapy (P=0.02) and uric acid at baseline (P=0.02) were significant determinants of large percent PV reduction. LDL-C at follow-up did not correlate with percent PV change.

CONCLUSIONS

Moderate-intensity statin therapy induced regression of coronary PV, whereas low-intensity statin therapy resulted in slight progression of coronary PV in patients with ACS. (Circ J 2016; 80: 1634-1643).

Plasma Glucagon-Like Peptide-1 and Tissue Characteristics of Coronary Plaque in Non-Diabetic Acute Coronary Syndrome Patients

BACKGROUND

The relationship between plasma glucagon-like peptide-1 (GLP-1) and coronary plaque characteristics in humans remains unclear.

METHODS AND RESULTS

A total of 85 culprit coronary vessels excluding the 10-mm culprit segments in non-diabetic patients with acute coronary syndrome (ACS) were examined using integrated backscatter intravascular ultrasound, performed using a 40-MHz intravascular catheter before PCI. All patients underwent 75-g oral glucose tolerance test (OGTT), and the plasma GLP-1 response was evaluated on the basis of the area under the GLP-1 concentration-time curve (GLP-1 AUC) from 0 to 120 min. Patients in the low GLP-1 AUC tertile had a significantly greater percentage lipid area than did patients in the intermediate and high tertiles (low tertile vs. intermediate tertile vs. high tertile: 57.3 ± 12.1% vs. 47.2 ± 15.4% vs. 46.3 ± 12.7%, P<0.01, ANOVA) and a smaller percentage fibrosis area (38.1 ± 9.4% vs. 44.6 ± 11.5% vs. 45.7 ± 9.0%; P=0.01, ANOVA). On multiple regression analysis, low GLP-1 AUC tertile was independently associated with percentage lipid area.

CONCLUSIONS

Low plasma GLP-1 during 75-g OGTT is associated with increased lipid content in non-diabetic patients with ACS, suggesting that plaque vulnerability is increased in this subgroup of patients.

Association between blood glucose variability and coronary plaque instability in patients with acute coronary syndromes

Background

Blood glucose variability is receiving considerable attention as a new risk factor for coronary artery disease. This study aimed to investigate the association between blood glucose variability and coronary plaque tissue characteristics.

Methods

In 57 patients with acute coronary syndrome, integrated backscatter intravascular ultrasound (IB-IVUS) and gray-scale IVUS were performed before balloon dilatation or stent implantation in the culprit vessels. Standard IVUS indices were evaluated for volume index (volume/length), and plaque components were measured by IB-IVUS for percent tissue volume. In addition to conventional glucose indicators, blood glucose variability in a stable state was determined by calculating the mean amplitude of glycemic excursions (MAGE) using a continuous glucose monitoring system.

Results

Higher MAGE values were significantly correlated with larger percent plaque volumes (r = 0.32, p = 0.015), and increased lipid (r = 0.44, p = 0.0006) and decreased fibrous (r = −0.45, p = 0.0005) plaque components. In contrast, HbA1c or fasting plasma glucose values were not significantly correlated with plaque volumes and percent plaque components. Homeostasis model assessment of insulin resistance values were positively correlated with vessel (r = 0.35, p = 0.007) and plaque (r = 0.27, p = 0.046) volumes, but not with percent plaque components. In multiple regression analysis, higher MAGE values were independently associated with increased lipid (β = 0.80, p = 0.0035) and decreased fibrous (β = -0.79, p = 0.0034) contents in coronary plaques.

Conclusions

Among all glucose indicators studied, only higher blood glucose variability was an independent determinant of increased lipid and decreased fibrous contents with larger plaque burden, suggesting blood glucose variability as one of the important factors related to coronary plaque vulnerability.

Impact of Indoxyl Sulfate, a Uremic Toxin, on Non-Culprit Coronary Plaque Composition Assessed on Integrated Backscatter Intravascular Ultrasound

BACKGROUND

Uremic toxin has emerged as an important determinant of cardiovascular risk. The aim of this study was to examine the relationship between serum uremic toxin and coronary plaque composition on integrated backscatter intravascular ultrasound (IB-IVUS).

METHODS AND RESULTS

IB-IVUS was performed in 47 patients with planned treatment for angina pectoris. Non-culprit intermediate plaque analyzed in this study had to be >5 mm apart from the intervention site. 3-D IB-IVUS analysis was performed to determine percent lipid volume (LV) and fibrous volume (FV). We also measured serum uremic toxins (indoxyl sulfate [IS], asymmetric dimethylarginine [ADMA], and p-cresol [PC]). Glomerular filtration rate correlated with IS (r=-0.329, P=0.04), but did not correlate with ADMA or PC. Percent LV correlated with IS (r=0.365, P=0.02), but did not correlate with ADMA or PC. Percent FV also correlated with IS (r=-0.356, P=0.03), but did not correlate with ADMA or PC. On multivariate regression, only IS was associated with percent LV (r=0.359, P=0.04) and percent FV (r=-0.305, P=0.04) independently of potentially confounding coronary risk factors.

CONCLUSIONS

Among the uremic toxins, serum IS might be a novel useful biomarker to detect and monitor lipid-rich coronary plaque on IB imaging.

Plasma microRNA-100 is associated with coronary plaque vulnerability

BACKGROUND

Although numerous studies have reported altered plasma levels of various microRNAs (miRNAs) in patients with cardiovascular disease, there are no data on the relationship between plasma miRNAs and vulnerable coronary plaque. In this study, we investigated whether plasma miRNAs might be a sensitive marker of coronary plaque vulnerability.

METHODS AND RESULTS

Integrated backscatter intravascular ultrasound (IB-IVUS) was performed in 32 consecutive patients with angina pectoris who underwent percutaneous coronary intervention. Three-dimensional analysis of IB-IVUS was performed to determine the percentage of lipid volume (%LV) and fibrous volume (%FV). Circulating miRNAs were measured in EDTA-plasma simultaneously obtained from the aorta and the coronary sinus (CS). Muscle-enriched (miR-133a, miR-208a, miR-499), vascular-enriched (miR-92a, miR-100, miR-126, miR-127, miR-145), and myeloid cell-enriched miRNAs (miR-155, miR-223) were measured. Plasma miR-100 was higher in the CS than in the aorta, but there were no significant differences in the levels of other miRNAs between the aorta and CS. Plasma miR-100 in the aorta was positively correlated with %LV (r=0.48, P<0.01) and negatively correlated with %FV (r=-0.41, P<0.05). Importantly, transcoronary concentration gradient of circulating miR-100 was more strongly correlated with %LV (r=0.53, P<0.01) and %FV (r=-0.56, P<0.01).

CONCLUSIONS

miR-100 might be released into the coronary circulation from vulnerable coronary plaques. This study provides insights into the role of miRNAs in coronary atherosclerotic disease.

Clinical validation of a novel software for quantitative analysis of coronary intravascular ultrasound

PURPOSE

CAAS IntraVascular (CAAS-IV) is a recently released software that provides options for sophisticated quantitative coronary ultrasound (QCU) analysis. The aim of this study was to validate CAAS-IV for QCU in diseased human coronaries.

METHODS

Ten preprocedural and 5 postprocedural IVUS studies were derived from daily practice. Intraobserver, interobserver, intersoftware (CAAS-IV vs. Curad) and interplatform (CAAS-IV vs. Volcano console) variability were assessed for cross-sectional area (CSA) measurements. Interobserver and intersoftware comparisons were made for volume measurements.

RESULTS

Measurements of lumen, EEM, plaque and stent CSA demonstrated small differences in the intraobserver (0.0±3.7%, -0.7±2.8%, -0.5±7.0% and -0.9±3.4%), interobserver (0.1±4.4%, 0.1±3.4%, -0.5±8.2% and -0.8±4.3%), intersoftware (-0.3±4.5%, 0.2±2.4%, 0.4±6.8% and -0.5±3.2%) and interplatform (0.7±7.9%, 0.9±4.0%, -1.1±12%, -1.8±3.6%) comparisons. For lumen, EEM, plaque and stent volume, the interobserver (-2.1±9.3%, 0.9±5.6%, 3.4±7.2% and -0.2±3.6%) and intersoftware (-2.2±6.2%, -2.6±6.1%, -2.7±12% and -4.1±3.2%) differences were substantially larger. Excluding large side-branches and calcifications, post-hoc measurements of lumen, EEM, plaque and stent volume showed small differences in the interobserver (-0.3±3.2%, 0.9±2.4%, 2.9±4.4% and -1.3±1.8%) and intersoftware (0.5±2.5%, -1.2±1.7%, -3.4±5.1% and -1.5±2.2%) comparisons. Analysis time for entire pullbacks was reduced by 19.2 [14.9-30.0]% using CAAS-IV (p<0.01).

CONCLUSIONS

CAAS-IV demonstrated reliable QCU with excellent agreement with previously validated software and the IVUS imaging console. Precision and reproducibility of measurements were high, proving CAAS-IV to be a valid option for QCU analysis in clinical practice and research. Interactive contour editing reduced analysis time by 20%.

Morphological features of non-culprit plaques on optical coherence tomography and integrated backscatter intravascular ultrasound in patients with acute coronary syndromes

AIMS

We sought to compare the morphological features of non-culprit plaques with >50% diameter stenosis in patients with acute coronary syndromes (ACS) with those of culprit plaques in patients with ACS and stable angina pectoris (SAP) using optical coherence tomography (OCT) and integrated backscatter intravascular ultrasound (IB-IVUS).

METHODS AND RESULTS

A total of 150 culprit and non-culprit coronary plaques (non-culprit vessels) in 150 patients with coronary artery disease were interrogated by OCT before percutaneous coronary intervention (PCI). Patients were categorized as follows: 73 culprit plaques in patients with ACS (ACS-C), 32 non-culprit plaques in patients with ACS (ACS-NC), and 45 culprit plaques in patients with SAP. The fibrous cap thickness was thinner in the ACS-C and ACS-NC groups than in the SAP group and was thinnest in the ACS-C group (ACS-C vs. ACS-NC vs. SAP, 60 vs. 82 vs. 114 μm, P < 0.001). IB-IVUS sub-analysis of 95 patients demonstrated that % lipid volume was greater and % fibrous volume was lower in the ACS-NC group than those in the SAP group (ACS-C vs. ACS-NC vs. SAP, 56.3 ± 11.0 vs. 59.9 ± 11.2 vs. 50.1 ± 13.9%, P < 0.05 and 39.5 ± 9.0 vs. 35.0 ± 9.0 vs. 43.9 ± 11.3%, P < 0.01, respectively).

CONCLUSION

Plaques of non-culprit vessels in patients with ACS had a thinner fibrous cap and a higher percentage of lipid content than culprit plaques in patients with SAP. However, the fibrous cap thickness was thinner in the culprit lesions in patients with ACS than in the non-culprit lesions in patients with ACS, while plaque compositions were not significantly different between the groups.

Effects of telmisartan on inflammatory cytokines and coronary plaque component as assessed on integrated backscatter intravascular ultrasound in hypertensive patients

BACKGROUND

Telmisartan has unique pleiotropic effects in addition to renin-angiotensin system (RAS)-inhibition effects. The aim of this study was to evaluate the effects of telmisartan on the coronary plaque component and local inflammatory cytokines.

METHODS AND RESULTS

A total of 50 patients with hypertension were randomized to 2 groups: the telmisartan group (additional treatment with telmisartan 80mg/day, n=25) or the control group (additional treatment with other anti-hypertensive drugs except RAS blockers, n=25) for 6 months. Tissue characteristics of target coronary plaque were analyzed using integrated backscatter intravascular ultrasound (IB-IVUS) before and after treatment. Plasma levels of inflammatory cytokines sampled in the coronary sinus (CS) and peripheral vein were also measured. Significant increases in fibrous volume (51.2±10.4 to 58.3±7.7%, P=0.03) and reductions in lipid volume (38.4±12.4 to 32.8±9.7%, P=0.03) were observed on IB in the telmisartan group, while there were no significant changes in the plaque component in the control group. CS levels of inflammatory cytokines (matrix metalloproteinase [MMP]3, tumor necrosis factor-α, high-sensitivity C-reactive protein and MMP9) were lower after than before treatment in the only telmisartan group (7.7±6.1 to 5.5±4.9ng/ml, 3.1±1.9 to 2.3±2.0pg/ml, 5.6±6.0 to 2.2±2.4mg/L, 36.1±39.3 to 19.9±27.5ng/ml, P=0.02, P=0.03, P=0.04, P=0.07, respectively).

CONCLUSIONS

Decreased local inflammatory response and plaque stabilization on IB imaging were observed after 6 months of telmisartan treatment. These findings might be associated with local anti-inflammatory and anti-arteriosclerotic effects of telmisartan.