Reference External Elastic Membrane Research Articles

A New Method to Optimize Stent Deployment by High-Definition Intravascular Ultrasound.

Optimal stent deployment by intravascular ultrasound (IVUS) improves outcome, but it can only be achieved in 50% of patients. We investigated the feasibility and effect of a new method of stent optimization on optimal stent deployment. IVUS analyses of 168 coronary segments were performed after angiography-guided stenting (AGS) and stent optimization in 29 patients (30 lesions). Minimum stent area (MSA), stent volume index (SVI), lumen area, external elastic membrane (EEM), and plaque burden (PB) were measured. Stent optimization included post-stent dilation with a balloon sized by high-definition (HD)-IVUS to the distal reference EEM diameter for stent underexpansion or malapposition, and stenting of PB >50% or edge dissection. After AGS, stent deployment was suboptimal in 77% of patients. After stent optimization, MSA and SVI were significantly larger than AGS. Adequate stent expansion - defined as MSA ≥5.4 mm² or ≥90% of distal reference lumen area - was significantly higher after stent optimization vs AGS (87% vs 56%, respectively; P=.02). Optimal stent deployment - a composite of adequate stent expansion, no malapposition, PB <50% at the stent edges, and no edge dissection - was markedly higher after stent optimization vs AGS (87% vs 35%, respectively; P<.01). After stent deployment and postdilation, stent results were suboptimal in two-thirds of patients. This simple online stent optimization by HD-IVUS was feasible and resulted in optimal stent deployment in the majority of patients. Randomized studies are warranted to compare the rate of optimal stent deployment and outcomes of this strategy vs other techniques.

A new intravascular ultrasound-guided stenting strategy compared with angiography on stent expansion and procedural outcomes in patients with positive lesion remodeling.

We investigated the role of a new intravascular ultrasound (IVUS)-guided stenting strategy versus angiography on optimal stent expansion (OSE) and procedural outcomes in patients with positive lesion remodeling. There are no IVUS criteria on how to achieve OSE. A total of 100 patients were assigned to a new IVUS-guided stenting strategy (IVUS group) versus angiography-guided stenting (Angio group). In the IVUS group, among patients with positive lesion remodeling, defined as a remodeling ratio (RR; lesion external elastic membrane (EEM) area/distal reference EEM area) >1.05, the stent was expanded with a balloon sized to the distal reference EEM diameter. In the Angio group, the stent was expanded by visual estimation. In both groups, IVUS was performed after postdilation. Minimum stent area (MSA) and stent volume index were significantly larger in the IVUS versus Angio group (7.1 ± 1.9 vs. 5.9 ± 1.5 mm2 , and 8.7 ± 2.1 vs. 7.5 ± 1.8 mm3 /mm, respectively; p < .01). The percentages of OSE, defined as an MSA ≥5.4 mm2 , MSA ≥90% of distal reference lumen area (DRLA), or MSA > DRLA, were significantly higher in the IVUS versus Angio group (80 vs. 56%, 78 vs. 54%, and 71 vs. 38%, respectively; p < .01). Stent underexpansion, malapposition, and residual reference segment stenosis were significantly higher in the Angio versus IVUS group (44 vs. 12%, 16 vs. 4%, and 12 vs. 0%, respectively; p < .05). In the IVUS group, owing to positive remodeling, there was no incidence of dissection or perforation. This new strategy of IVUS-guided stenting in patients with positive lesion remodeling, compared with angiography, significantly increased stent expansion and decreased stent underexpansion, malapposition, and residual reference segment stenosis with no complications.

Impact of IVUS-Derived Vessel Size on Midterm Outcomes After Stent Implantation in Femoropopliteal Lesions

Purpose: To identify intravascular ultrasound (IVUS) findings that predict midterm stent patency in femoropopliteal (FP) lesions. Materials and Methods: A retrospective analysis was undertaken of 335 de novo FP lesions in 274 consecutive patients (mean age 72.4±8.2 years; 210 men) who had IVUS assessment before and after successful stent implantation. The mean lesion length was 13.2±9.8 cm. The primary outcome was primary patency at 24 months, defined as freedom from major adverse limb event (MALE) and in-stent restenosis (ISR). MALE was defined as major amputation or any target lesion revascularization (TLR). ISR was defined by a peak systolic velocity ratio >2.4 by duplex ultrasonography. Logistic regression analyses were performed to identify independent predictors of stent patency at 24 months; the results are presented as the odds ratio (OR) and 95% confidence interval (CI). Receiver operator characteristic (ROC) curve analysis was performed to determine the optimal threshold for prediction of stent patency at 24 months. Results: Over the 24-month follow-up, 18 (7%) patients died and 43 (15%) of 286 lesions were responsible for MALE (42 TLRs and 1 major amputation). Primary patency was estimated at 82.5% (95% CI 78.1% to 86.9%) at 12 months and 73.2% (95% CI 67.9% to 78.5%) at 24 months. Multivariable analysis revealed that longer lesion length (OR 0.89, 95% CI 0.82 to 0.97, p<0.01) was an independent predictor of declining patency, while cilostazol use (OR 3.45, 95% CI 1.10 to 10.78, p=0.03) and increasing distal reference external elastic membrane (EEM) area (OR 1.18, 95% CI 1.02 to 1.37, p=0.03) were associated with midterm stent patency. ROC curve analysis identified a distal reference EEM area of 29.0 mm2 as the optimal cut-point for prediction of 24-month stent patency (area under the ROC curve 0.764). Kaplan-Meier estimates of 24-month primary patency were 83.7% (95% CI 78.3% to 89.2%) in lesions with a distal EEM area >29.0 mm2 vs 53.1% (95% CI 42.9% to 63.3%) in those with a distal EEM area ≤29.0 mm2 (p<0.001). Conclusion: In FP lesions with a larger distal vessel area estimated with IVUS, stent implantation can be considered as a reasonable treatment option, with the likelihood of acceptable midterm results.

Study of the features of coronary artery atheromatous plaque using intravascular ultrasound in patients with impaired glucose tolerance

ObjectiveWe used intravascular ultrasound (IVUS) to analyze the features of coronary artery atheromatous plaque in patients with impaired glucose tolerance and mild-to-moderate angiographic coronary stenosis. The aim was to determine the clinical significance of plaque characteristics as well as the relationship between hemoglobin A1c (HbA1c) levels and coronary artery lesions. MethodsHbA1c levels were evaluated in 85 patients (96 lesions), of whom 46 had impaired glucose tolerance (IGT Group) and 39 had normal blood glucose (NBG Group). IVUS was used to analyze the lesion vessel of both groups qualitatively and quantitatively. The external elastic membrane area (EEMA), minimal lumen area (MLA), plaque area (PA), and plaque burden (PB) were measured for both the target lesion and the reference segments (reference external elastic membrane area (REEMA), reference minimal lumen area (RMLA), reference plaque area (RPA), and reference plaque burden (RPB), respectively). ResultsHbA1c levels were significantly higher in the IGT Group than in the NBG Group (P < 0.05). In the IGT Group there was more soft plaque, eccentric plaque, and positive remodeling, and less calcification, while in the NBG Group there was much harder plaque and calcification, no reconstruction, and negative remodeling (P < 0.05). MLA was smaller in the IGT Group than in the NBG Group, while EEMA, PA, and PB were clearly greater (P < 0.05). In the meantime, RMLA was clearly smaller in the IGT Group than in the NBG Group, while RPA and RPB were greater (P < 0.05). HbA1c levels were positively correlated with PA and PB, and negatively correlated with MLA. ConclusionIVUS is very valuable for the evaluation of mild-to-moderate coronary lesions. The coronary artery lesions in patients with IGT are more serious and widespread than those in patients with NBG. HbA1c levels might be of some value in assessing the severity of coronary artery lesions.

Study on the Features of Coronary Artery Atheromatous Plaque for Patients with Impaired Glucose Tolerance when Applying Intravascular Ultrasound

Objective: By applying Intravascular Ultrasound (IVUS) to patients with mild-to-moderate coronary stenosis defined by Coronary Angiography (CAG), it is analyzed on the features of coronary artery atheromatous plaque for patients with impaired glucose tolerance and discussed about the clinical significance as well as the relationship between HbA1c levels and coronary artery lesion. Methods: HbA1c testing was applied to 85 patients (a total of 96 lesions) with 46 cases in Group of Impaired Glucose Tolerance (IGT Group) and 39 cases in Group of Normal Blood Glucose (NBG Group). IVUS was applied to qualitatively and quantitatively analyse the lesion vessel of both groups. Measurement was done both to target lesion for data of External Elastic Membrane Area (EEMA), Minimal Lumen Area (MLA), Plaque Area (PA), Plaque Burden (PB), and to the reference segments for data of Reference External Elastic Membrane Area (REEMA), Minimal Lumen Area (RMLA), Plaque Area (RPA), Plaque Burden (RPB). Results: The level of HbA1c in IGT Group was significantly higher than that in NBG Group (P < 0.05). For IGT Group, there were more soft plaque, eccentric plaque, positive remodeling and less calcification while for NBG Group, there were more performance for the hard plaque, calcification, no reconstruction and negative remodeling (P < 0.05). For IGT Group, MLA was less than NBG Group while EEMA, PA and PB were obviously higher than NBG Group (P < 0.05). In the meantime, RMAL was clearly less than NBG Group while RPA and RPB were higher than NBG Group (P < 0.05). HbA1c levels was positively correlated with PA, PB, but negatively correlated with MLA. Conclusion: IVUS shows a higher value to the evaluation of mild-to-moderate coronary lesions. The coronary artery lesions of IGT Group were more serious and widespread than that of NBG Group, and the level of HbA1c might provide some value for the judgment of the severity of coronary artery lesion.

Abstract 12148: Impact of Multiple Plaque Ruptures and Cavity Area on Intraprocedural Stent Thrombosis: Intravascular Ultrasound Analysis

Objectives: We examined characteristics of lesions in cases of intraprocedural stent thrombosis (IPST) using intravascular ultrasound (IVUS). Background: IPST is a rare complication occurring during percutaneous coronary intervention (PCI) that leads to poor outcomes. However, factors that contribute to IPST remain largely unknown. Methods: We retrospectively analyzed 1,504 consecutive stent-implanted lesions in 1,324 patients [326 with ST-segment elevation myocardial infarction (STEMI), 403 with non-ST-segment elevation acute coronary syndrome (NSTE-ACS), and 595 with stable angina]. IVUS characteristics of plaques that led to IPST were compared with those of a matched control (non-IPST) group (n = 15) without evidence of IPST matched by age; gender; lesion location; or STEMI, NSTE-ACS, or stable angina. Positive remodeling was defined as a lesion greater than the mean reference external elastic membrane cross-sectional area. Continuous variables were displayed as median and 1st and 3rd interquartile range. Results: IPST occurred in 5 (0.4%; 3 with STEMI, 2 with NSTE-ACS) of 1,324 patients during PCI. Plaque burden at the minimum lumen area site was significantly greater in the IPST group than in the non-IPST group (93.0% vs. 87.9%, P = 0.0035). All 5 culprit lesions that led to IPST had ruptured plaques with positive remodeling and attenuation. The maximum cavity area was larger in the IPST group than in the non-IPST group (4.6 [4.3, 6.5] mm2 vs. 0 [0, 1.9] mm2, P = 0.0011), whereas plaque rupture was also observed in 40% of subjects in the non-IPST group. Multiple plaque ruptures in the culprit lesion were far more common in the IPST group (80.0% vs. 6.7%, P = 0.0049). Conclusion: Multiple plaque ruptures and a larger cavity area were associated with IPST occurrence. IVUS assessment may help predict the development of IPST during PCI.

Intravascular ultrasound study of coronary artery remodeling and plaque composition in patients with coronary atherosclerotic heart disease

Objective To demonstrate the relationship between plaque composition and coronary artery remodeling in the same patient′s blood vessel. Methods A total of 48 coronary artery plaque were included in this study. Qualitative assessment and quantitative measurements of the lesion were performed in target lesions. The lesions were classified into soft plaque, fibrous plaque, calcified plaque and mixed plaque according to different degree of reflection of ultrasound signal. The remodeling index (RI) was defined as the ratio of external elastic membrane cross sectional area of lesion segment to the mean reference external elastic membrane cross sectional area. Results In comparison to hard plaque group, RI of soft plaque group was significantly larger in the same patient (1.08±0.15 vs 1.00±0.13, P=0.000). Soft plaque group presented with more positive remodeling than hard plaque group, but with P value more than 0.05 (83.3% vs 58.3%, P=0.057). The plaque area, lumen area and plaque burden were not different between two group (P>0.05). Conclusions The blood vessel was compensatively dilated in soft plaque segments and RI was significantly larger than in hard plaque segments. Coronary atherosclerotic vessel presented positive remodeling in the acute stage of inflammation. Key words: Endosonography; Coronary artery heart disease; Remodeling; Plaque; Atherosclerotic

Impact of Positive and Negative Lesion Site Remodeling on Clinical Outcomes: Insights From PROSPECT

This study investigated coronary artery remodeling patterns associated with clinical outcomes. In the prospective, multicenter PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree: An Imaging Study in Patients With Unstable Atherosclerotic Lesions) study, reported predictors of nonculprit lesion (NCL) major adverse cardiac events (MACE) were an intravascular ultrasound (IVUS) minimal lumen area (MLA) ≤4 mm(2), a plaque burden ≥70%, and a IVUS-virtual histology (VH) thin-cap fibroatheroma (TCFA), but not lesion site remodeling. Overall, 697 consecutive patients with an acute coronary syndrome were enrolled and underwent 3-vessel gray-scale and IVUS-VH; 3,223 NCLs were identified by IVUS. The remodeling index (RI) was calculated as the external elastic membrane area at the MLA site divided by the average of the proximal and distal reference external elastic membrane areas. First, one third of the patients were randomly selected to determine RI cutoffs related to NCL MACE (development cohort). Receiver-operating characteristic analysis showed that there were 2 separate cut points that predicted NCL MACE: RI= 0.8789 and RI= 1.0046 (area under the curve= 0.663). These cut points were used to define negative remodeling as an RI <0.88, intermediate remodeling as an RI of 0.88 to 1.00, and positive remodeling as an RI >1.00. Second, we used the remaining two-thirds of patients to validate these cut points with respect to lesion morphology and clinical outcomes (validation cohort). Kaplan-Meier curve analysis in the validation cohort showed that NCL MACE occurred more frequent (and equally) in negative and positive remodeling lesions compared with intermediate remodeling lesions. In this cohort, negative remodeling lesions had the smallest MLA, positive remodeling lesions had the largest plaque burden, and VH TCFA, especially VH TCFA with multiple necrotic cores, was most common in negatively remodeling lesions. The present study showed the novel concept that positive and negative lesion site remodeling was associated with unanticipated NCL MACE in the PROSPECT study. ( An Imaging Study in Patients With Unstable Atherosclerotic Lesions [PROSPECT]; NCT00180466).

What Is an Appropriate Reference Standard in the Quantitation of Plaque Surface Area by Intravascular Coronary Ultrasound?

We reevaluate the predictive accuracy of intravascular ultrasound (IVUS)-derived per cent plaque area stenosis (PAS) in significant coronary lesions (CLs) with or without proximal and distal reference vessel area adjustment. IVUS is valuable in defining moderate CL severity (30 to 70%) in left main (LM) or non-left main (NLM) coronaries using minimum luminal area (MLA) of ≤5.9 and ≤4 mm(2), respectively. Despite a strong correlation with severe CLs, PAS (≥ 70% for NLM and ≥67% for LM) remains underutilized because of confusion about an appropriate reference standard. We studied 120 patients with symptomatic moderate CLs (74 NLM, 46 LM) who underwent IVUS. In-lesion and adjusted PAS were derived by subtracting MLA from in-lesion and proximal or distal reference's external elastic membrane (EEM) area, respectively, divided by corresponding EEM area multiplied by 100. In-lesion PAS was correlated with MLA cutoffs of ≤5.9 and ≤7.5 mm(2) for LM and ≤4 mm(2) for NLM. Adjusted PAS strongly correlated with in-lesion PAS irrespective of reference segment (proximal reference, r = 0.879, p < 0.001; distal reference, r = 0.833, p < 0.001; mean proximal and distal reference, r = 0.896, p < 0.001). Considering MLA of ≤4 mm(2) (for NLM) and ≤5.9 mm(2) (for LM), in-lesion PAS of ≥70 and ≥67%, respectively, explained the majority of severe CLs but the sensitive LM MLA cutoff of ≤7.5 mm(2) showed higher predictive accuracy. Based on results, both in-lesion PAS and adjusted PAS can be used interchangeably and correlate strongly with MLA.

Positive Vascular Remodeling in Culprit Coronary Lesion is Associated With Plaque Composition: An Intravascular Ultrasound-Virtual Histology Study.

Background and ObjectivesThe relationship between the positive remodeling (PR) of a coronary artery and plaque composition has been studied only in a relatively small number of study population or non-culprit lesion. We evaluated the association between coronary plaque composition and coronary artery remodeling in a relatively large number of culprit lesions.Subjects and MethodsThe study population consisted of 325 consecutive patients with coronary artery disease that underwent intravascular ultrasound-virtual histology examination in a culprit lesion. The remodeling index (RI) was calculated as the lesion external elastic membrane (EEM) area divided by the average reference EEM area.ResultsThe lesions with PR (RI>1.05, n=97, mean RI=1.19±0.12) had a higher fibrous volume/lesion length (3.85±2.12 mm3/mm vs. 3.04±1.79 mm3/mm, p=0.003) and necrotic core volume/lesion length (1.26±0.89 mm3/mm vs. 0.90±0.66 mm3/mm, p=0.001) than those with negative remodeling (NR) (RI<0.95, n=132, mean RI=0.82±0.09). At the minimal luminal area site, the lesions with PR had a higher fibrous area (5.81±3.17 mm2 vs. 3.61±2.30 mm2, p<0.001), dense calcified area (0.73±0.69 mm2 vs. 0.46±0.43 mm2, p=0.001), and necrotic core area (1.93±1.33 mm2 vs. 1.06±0.91 mm2, p<0.001) than those with NR. RI showed significant positive correlation with fibrous volume/lesion length (r=0.173, p=0.002), necrotic core volume/lesion length (r=0.188, p=0.001), fibrous area (r=0.347, p<0.001), fibrofatty area (r=0.111, p=0.036), dense calcified area (r=0.239, p<0.001), and necrotic core area (r=0.334, p<0.001). Multivariate analysis showed that the independent factor for PR was the necrotic core volume/lesion length (beta=0.130, 95% confidence interval; 0.002-0.056, p=0.037) over the entire lesion.ConclusionThis study suggests that PR in a culprit lesion is associated with the necrotic core volume in the entire lesion, which is a characteristic of vulnerable plaque.

Abstract 17781: Relationship Between Epicardial Adipose Tissue and Coronary Arterial Remodeling as Assessed by Intravascular Ultrasound in Patients with Coronary Artery Disease

Background: Recently, the interest in epicardial adipose tissue (EAT) is rapidly growing. Several study suggest that EAT induces inflammation of the artery wall by secretion of pro-inflammatory proteins and plays a role in the pathogenesis of coronary artery disease. However, there is no information regarding the impact of EAT on coronary arterial remodeling and plaque vulnerability. Objectives: The aim of this study was to evaluate the relationship between EAT and intravascular ultrasound (IVUS) findings, mainly remodeling, in patients with coronary artery disease. Methods: One hundred and eight consecutive patients with de novo lesions located in native coronary artery were studied. The EAT thickness on the right ventricle was measured using transthoracic echocardiography, and arterial remodeling of culprit lesion was assessed by preinterventional IVUS. The remodeling index (RI) was calculated as lesion divided by the reference external elastic membrane cross-sectional area, Positive remodeling (PR) was defined as RI&gt;1.05, intermediate remodeling (IR) as between 0.95 and 1.05, and negative remodeling (NR) as &lt;0.95. IVUS findings included plaque characteristics-lipid rich, mixed and calcified plaque and plaque eccentricity. Results: There was significant relationship between EAT thickness and RI(r= 0.36, p=0.0001). Higher EAT thickness (≥10mm, n=55) were associated with higher BMI(25.2±3.6 kg/m 2 vs. 23.9±2.8 kg/m 2 , p=0.04), plasma triglyceride level (189.1±103.8 mg/dl vs. 146.1±80.9 mg/dl, p=0.02), and plasma urinary acid level(6.8±1.5mg/dl vs. 5.9±1.5 mg/dl, p=0.02). PR and more lipid rich and mixed plaque were observed in patients with higher EAT thickness than lower EAT thickness (PR ;43.6% vs. 18.9%,p=0.02. lipid rich and mixed plaque; 89% vs.66%,p=0.004). Multivariate analysis showed high EAT thickness was independent factor affecting coronary positive remodeling (OR3.05,p=0.02).There was no significant association EAT thickness and plaque eccentricity. Conclusion; High EAT thickness was significantly correlated with the coronary positive remodeling and non calcified plaque characteristics.

Relationship Between Coronary Arterial Remodeling, Fibrous Cap Thickness and High-Sensitivity C-Reactive Protein Levels in Patients With Acute Coronary Syndrome

Thin-capped fibroatheroma (TCFA) is a recognized precursor lesion for acute coronary syndrome (ACS). Positive remodeling (PR) is the predominant pattern of arterial remodeling in patients with ACS. The aim of this study was to evaluate the relationship between coronary arterial remodeling, fibrous cap thickness and high-sensitivity C-reactive protein (hs-CRP) concentration in patients with ACS. The 47 consecutive ACS patients were enrolled in this study. Arterial remodeling of culprit plaque was assessed by intravascular ultrasound, and fibrous cap thickness was measured by optical coherence tomography. The remodeling index (RI) was calculated as lesion divided by the reference external elastic membrane cross-sectional area, and PR was defined as RI >1.05 (PR group). TCFA were observed more frequently in the PR group than in the intermediate and negative remodeling (IR/NR) groups (59% vs 17%, P<0.01). RI was inversely correlated with fibrous cap thickness (r=0.47, P=0.02). hs-CRP levels were higher in the PR group than in the IR/NR groups (0.32 +/-0.26 vs 0.18 +/-0.14 mg/dl, P=0.02). Coronary arterial remodeling, fibrous cap thickness and hs-CRP level in patients with ACS are associated with each other. This result suggests that inflammation simultaneously contributes to both plaque growth and plaque instability.

Abstract 5599: Relationship between Coronary Arterial Remodeling and Fibrous Cap Thickness in Patients with Acute Coronary Syndrome

The aim of this study was to evaluate the relationship between coronary arterial remodeling and the thickness of fibrous cap in patients with acute coronary syndrome (ACS). Thin-capped fibroatheroma is recognized as a precursor lesion for ACS. Positive remodeling (PR) is predominant pattern of arterial remodeling in patients with ACS. However, the relationship between PR and the thickness of fibrous cap has not been elucidated in vivo. We enrolled 41 patients with ACS who underwent both intravascular ultrasound (IVUS) and optical coherence tomography (OCT). The arterial remodeling was assessed by IVUS and the thickness of fibrous cap was measured by OCT. The thin fibrous cap was defined as &lt;70μm in the thinnest part. Remodeling index (RI) was calculated as lesion divided by the reference external elastic membrane cross-sectional area and PR was defined as RI &gt; 1.05 (a PR group). Thin-capped fibroatheroma were observed more frequently in the PR group than in the intermediate and negative remodeling (IR/NR) groups (63% versus 16%, p=0.0057). RI was inversely correlated with the thickness of fibrous cap (r=−0.53, p=0.019). High-sensitive C-reactive protein (hs-CRP) levels were higher in the PR group than in the IR/NR groups (0.50±0.63mg/dL versus 0.20±0.15mg/dL, p&lt;0.05). Also, the hs-CRP levels were higher in patients with thin fibrous cap (0.54±0.71mg/dL versus 0.21±0.14mg/dL, p&lt;0.05). The coronary arterial remodeling, the thickness of fibrous cap and CRP level in patients with ACS were associated with each other. These results suggest that inflammatory process contributes to both plaque growth and plaque instability.

In vivo association between positive coronary artery remodelling and coronary plaque characteristics assessed by intravascular optical coherence tomography

Positive coronary arterial remodelling has been shown to be associated with unstable coronary syndromes and ex vivo histological characteristics of plaque vulnerability such as a large lipid core and high macrophage content. The aim of this study is to evaluate the in vivo association between coronary artery remodelling and underlying plaque characteristics identified by optical coherence tomography (OCT). OCT is a unique imaging modality capable of characterizing these important morphological features of vulnerable plaque. OCT and intravascular ultrasound imaging was performed at corresponding sites in patients undergoing catheterization. OCT plaque characteristics for lipid content, fibrous cap thickness, and macrophage density were derived using previously validated criteria. Thin-cap fibroatheroma (TCFA) was defined as lipid-rich plaque (two or more quadrants) with fibrous cap thickness <65 microm. Remodelling index (RI) was calculated as the ratio of the lesion to the reference external elastic membrane area. A total of 54 lesions from 48 patients were imaged. Positive remodelling compared with absent or negative remodelling was more commonly associated with lipid-rich plaque (100 vs. 60 vs. 47.4%, P = 0.01), a thin fibrous cap (median 40.2 vs. 51.6 vs. 87 microm, P = 0.003) and the presence of TCFA (80 vs. 38.5 vs. 5.6%, P < 0.001). Fibrous cap macrophage density was also higher in plaques with positive remodelling showing a positive linear correlation with the RI (r = 0.60, P < 0.001). Coronary plaques with positive remodelling exhibit characteristic features of vulnerable plaque. This may explain the link between positive remodelling and unstable clinical presentations.

Correlation Between Morphologic Characteristics and Local Temperature Differences in Culprit Lesions of Patients With Symptomatic Coronary Artery Disease

The purpose of this study was to investigate the possible correlation between morphologic and functional characteristics of culprit lesions (CL) in patients with acute coronary syndromes (ACS) and chronic stable angina (CSA). Intravascular ultrasound (IVUS) provides morphologic assessment and intracoronary thermography (ICT) evaluates the local inflammatory activation of CL. Eighty-one consecutive patients, 48 with ACS and 33 with CSA, were enrolled. Ratio of lesion to reference external elastic membrane area, indicated by IVUS, was defined as positive remodeling index (pRi) (> or =1) or negative remodeling index (nRi) (<1). We also investigated the existence of ruptured plaque (rp) in the CL. By ICT temperature difference (DeltaT) between the CL and the proximal vessel wall was measured. Patients with ACS had greater remodeling index than patients with CSA (1.15 +/- 0.18 vs. 0.90 +/- 0.12; p < 0.01), as well as increased DeltaT (0.08 +/- 0.03 degrees C vs. 0.04 +/- 0.02 degrees C; p < 0.01). Patients with pRi had higher DeltaT than patients with nRi (0.07 +/- 0.03 degrees C vs. 0.04 +/- 0.02 degrees C; p < 0.001). In patients with nRi there was no difference in DeltaT between ACS and CSA (p = 0.22). Patients with rp had increased DeltaT compared with patients without rp (0.09 +/- 0.03 degrees C vs. 0.05 +/- 0.02 degrees C; p < 0.01). Multivariate analysis showed that DeltaT was independently correlated with the presence of rp, pRi, and ACS. The present study showed that culprit lesions with plaque rupture and positive arterial remodeling have increased thermal heterogeneity, although in certain patients a discrepancy between morphogic and functional characteristics was observed. A combination of morphologic and functional examination may offer additional diagnostic and prognostic information.

Intravascular ultrasound assessment of remodelling and reference segment plaque burden in type-2 diabetic patients

Intravascular ultrasound (IVUS) assesses arterial remodelling by comparing the lesion external elastic membrane (EEM) with the reference segments; however, reference segments are rarely disease-free. The aim was to assess lesion and reference segment remodelling and plaque burden in patients with type-2 diabetes mellitus. We used pre-intervention IVUS to study 62 de novo lesions in 43 patients with type-2 diabetes mellitus. The lesion site was the image slice with the smallest lumen cross-sectional area (CSA). The proximal and distal reference segments were the most normal-looking segments within 5 mm proximal and distal to the lesion. Plaque burden was measured as plaque CSA/EEM CSA. The remodelling index was defined as lesion EEM CSA/mean reference EEM CSA. Reference segment plaque burden measured 0.54 +/- 0.09. The majority of lesions (83.9%) had negative remodelling (lesion EEM < reference). Similarly, the slope of the regression line relating EEM to plaque CSA within the lesion was less than the reference substantiating negative remodelling. The reference segment plaque burden correlated inversely with the difference between IVUS lumen and quantitative coronary angiographic artery size [slope = -0.12 (95% CI -0.17 to -0.07); P < 0.001] in all patients with type-2 diabetes mellitus. Lesions in type-2 diabetic patients are different from previous reports in non-diabetics. Lesions in type-2 diabetics are characterized by a large reference segment plaque burden and negative lesion site remodelling. These IVUS findings may explain the angiographic appearance of small arteries in diabetic patients.

Effect of Simvastatin on Coronary Lesion Site Remodeling: A Serial Intravascular Ultrasound Study

Background: Direct evidence of coronary artery remodeling can be derived only from serial changes in the external elastic membrane (EEM) and plaque area. The aim of the study was to assess the effect of simvastatin on coronary remodeling in serial intravascular ultrasound (IVUS) studies. Methods: In 39 male patients ECG-triggered transducer pullback IVUS was performed at baseline, after 3 months on a lipid-lowering diet (control period), and after another 12 months of simvastatin 40 mg/day. The lesion site was the image slice with maximum plaque burden at 3 months. Results: Absolute changes in the EEM area correlated significantly with changes in plaque area during the control period [B = 0.966, r = 0.792 (95% CI 0.71–1.22); p < 0.001] and during simvastatin treatment [B = 0.945, r = 0.822 (95% CI 0.73–1.16); p < 0.001], but there was no significant difference in the slope (ΔEEM/Δplaque) between the two time intervals. After 12 months of simvastatin, there was a significant reduction in the lesion EEM area of 4.6% (p = 0.006) and in the lesion plaque area of 5.9% (p < 0.001), but there was no change in reference measurements. As a result, the remodeling index was reduced by simvastatin from 1.01 ± 0.12 to 0.95 ± 0.09 (p < 0.001). Conclusion: Simvastatin decreases the remodeling index by reducing lesion, but not reference plaque and EEM area. However, simvastatin does not affect direct evidence of remodeling (ΔEEM/Δplaque) obtained using serial IVUS studies.

Static and serial assessments of coronary arterial remodeling are discordant: An intravascular ultrasound analysis from the Reversal of Atherosclerosis with Aggressive Lipid Lowering (REVERSAL) trial

Arterial remodeling is a major determinant of the clinical manifestations of coronary artery disease. Assessment of arterial remodeling with intravascular ultrasound (IVUS) used to rely on comparing the external elastic membrane (EEM) areas of lesion and reference sites at a single time point (static assessment). Recently, performance of serial IVUS provided the opportunity for direct assessment of remodeling. Our aim was to study the concordance of the static and serial methods. We identified 210 focal coronary lesions on the baseline IVUS interrogations of the REVERSAL trial. A follow-up IVUS was performed at 18 months. Static assessment was performed by calculating the remodeling index (RI) (lesion EEM area / reference EEM area) and serial assessment by comparing the changes in atheroma and EEM areas at follow-up. Using the serial method, there was a 1.24 mm2 increase in EEM area for every 1 mm2 increase in atheroma area at the lesion site, which was indicative of expansive (overcompensatory) remodeling. By using the static method, the RI was paradoxically lower at follow-up (1.062 +/- 0.15 at baseline vs 1.027 +/- 0.14 at follow-up, P < .001), indicating a trend toward constrictive remodeling. The reason for decreased RI at follow-up was the relatively larger expansion of the EEM areas at the reference sites. Static and serial assessments of arterial remodeling are discordant. This is due to concomitant remodeling of the reference sites used in the static assessment. Intravascular ultrasound performed at a single point in time does not reflect the dynamic remodeling response.

Determinants of Arterial Wall Remodeling During Lipid-Lowering Therapy

Coronary plaque progression and instability are associated with expansive remodeling of the arterial wall. However, the remodeling response during plaque-stabilizing therapy and its relationship to markers of lipid metabolism and inflammation are incompletely understood. Serial intravascular ultrasound (IVUS) data from the Reversal of Atherosclerosis with Aggressive Lipid Lowering Therapy (REVERSAL) trial were obtained during 18 months of intensive versus moderate lipid-lowering therapy. In a subgroup of 210 patients, focal coronary lesions with mild luminal narrowing were identified. Lumen area, external elastic membrane (EEM) area, and plaque area were determined at the lesion and proximal reference sites at baseline and during follow-up. The remodeling ratio (RR) was calculated by dividing the lesion EEM area by the reference EEM area. The relationship between the change in remodeling, change in plaque area, lipid profile, and inflammatory markers was examined. At the lesion site, a progression in plaque area (8.9+/-25.7%) and a decrease in the RR (-3.0+/-11.2%) occurred during follow-up. In multivariable analyses, the percentage change in plaque area (P<0.0001), baseline RR (P<0.0001), baseline lesion lumen area (0.019), logarithmic value of the change in high-sensitivity C-reactive protein (P=0.027), and hypertension at baseline (P=0.014) showed a significant, direct relation with the RR at follow-up. Lesion location in the right coronary artery (P=0.006), percentage change in triglyceride levels (P=0.049), and age (P=0.037) demonstrated a significant, inverse relation with the RR at follow-up. Changes in LDL cholesterol, HDL cholesterol, and treatment group demonstrated no significant associations. Constrictive remodeling of the arterial wall was observed during plaque-stabilizing therapy with statin medications and appears related to their antiinflammatory effects.

Remodeling Index Compared to Actual Vascular Remodeling in Atherosclerotic Left Main Coronary Arteries as Assessed With Long-Term (≥12 Months) Serial Intravascular Ultrasound

We present the remodeling index (RI) versus serial intravascular ultrasound (IVUS) data. The RI, derived by comparing lesion external elastic membrane (EEM) cross-sectional area versus the reference at one time point, is used in various IVUS studies as a substitute of true remodeling (change in EEM over time), assuming that it represents true remodeling. We studied 46 non-stenotic left main arteries using serial IVUS (follow-up 18 +/- 8 months). Plaques were divided into subgroups according to the follow-up RI: follow-up RI >1 (n = 27) versus follow-up RI < or =1 (n = 19). Lesions with a follow-up RI >1 had an increase in lumen despite an increase in plaque because of an increase in EEM. Conversely, lesions with a follow-up RI < or =1 had a reduction in lumen as a result of both a plaque increase and EEM decrease. Overall, the follow-up RI correlated directly with changes in lesion site EEM (baseline-to-follow-up). Although there was no correlation between the follow-up RI and changes in reference EEM area, changes in reference EEM area did correlate directly with changes in lesion EEM area. In nearly 90% of lesions with a follow-up RI >1, there was a previously documented increase in EEM area. Using multivariate linear regression analysis, the follow-up RI was dependent on the baseline RI, the increase in lesion EEM area, and the decrease in reference EEM area. The follow-up RI was not dependent on changes in lesion plaque area. The vast majority of left main lesions with a remodeling index >1 had evidence of a previous increase in lesion-site EEM area.