Intravascular Ultrasound Study Research Articles

Pathologic Intimal Thickening Plaque Phenotype: Not as Innocent as Previously Thought. A Serial 3D Intravascular Ultrasound Virtual Histology Study

Introduction and objectivesPathologic intimal thickening (PIT) has been considered a benign plaque phenotype. We report plaque phenotypic changes in a baseline/follow-up intravascular ultrasound-based virtual histology study. MethodsA total of 61 patients with stable coronary artery disease were analyzed from the HEAVEN trial (89 patients randomized between routine statin therapy vs atorvastatin 80mg and ezetimibe 10mg) with serial intravascular ultrasound imaging of nonculprit vessels. We compared changes in 693 baseline and follow-up 5-mm long segments in a novel risk score, Liverpool Active Plaque Score (LAPS), plaque parameters, and plaque composition. ResultsThe PIT showed the highest increase of risk score and, with fibrous plaque, also the LAPS. Necrotic core (NC) abutting to the lumen increased in PIT (22 ± 51.7; P = .0001) and in fibrous plaque (17.9 ± 42.6; P = .004) but decreased in thin cap fibroatheroma (TCFA) (⿿15.14 ± 52.2; P = .001). The PIT was the most likely of all nonthin cap fibroatheroma plaque types to transform into TCFA at follow-up (11% of all TCFA found during follow-up and 35.9% of newly-developed TCFA), but showed (together with fibrous plaque) the lowest stability during lipid-lowering therapy (24.7% of PIT remained PIT and 24.5% of fibrous plaque remained fibrous plaque). ConclusionsOver the 1-year follow-up, PIT was the most dynamic of the plaque phenotypes and was associated with an increase of risk score and LAPS (together with fibrous plaque), NC percentage (together with fibrous plaque) and NC abutting to the lumen, despite a small reduction of plaque volume during lipid-lowering therapy. The PIT was the main source for new TCFA segments.

IMPROVE-IT: what have we learned?

Recent studies and dyslipidemia treatment guidelines indicate that combination lipid-lowering therapy is frequently needed and its use has increased in recent years. Ezetimibe and simvastatin as a fixed dose is an efficacious treatment choice based on positive results of the recent IMProved Reduction of Outcomes: Vytorin Efficacy International Trial (IMPROVE-IT). In this review, we discuss recent controversies surrounding ezetimibe and provide clinical perspective on the results of the IMPROVE-IT study. IMPROVE-IT is the first trial that demonstrates a significant clinical benefit of a nonstatin hypolipidemic agent (ezetimibe) used in combination with statin (simvastatin) therapy in patients who have experienced an acute coronary syndrome. For almost a decade, the use of ezetimibe was limited by a relative lack of definitive evidence. However, the most recent Plaque Regression With Cholesterol Absorption Inhibitor or Synthesis Inhibitor Evaluated by Intravascular Ultrasound study showed greater coronary plaque regression by statin/ezetimibe combination compared with statin monotherapy. The results of the IMPROVE-IT trial are fostering new debate about the value of adjunctive low-density lipoprotein cholesterol lowering over and above a statin. Ezetimibe/simvastatin combination, either as a single pill or as the combined use of the individual compounds, represents a well-tolerated and efficacious choice for dyslipidemia treatment in high-risk subjects, including patients with diabetes. Limited additional risk for adverse events compared with simvastatin monotherapy is observed, and an individualized, patient-centered approach to therapy is recommended.

Clinical and morphological presentations of acute coronary syndrome without coronary plaque rupture — An intravascular ultrasound study

BackgroundAlthough acute coronary syndrome (ACS) mainly arises from plaque ruptures (PR), precise mechanisms underlying ACS without PR are unknown. We sought to examine clinical, angiographic and intravascular ultrasound (IVUS) characteristics of ACS without PR. Methods and resultsCulprit lesions of 161 ACS patients were categorized by the presence or absence of PR (PR group: n=57, Non-PR group: n=104). Lower abdominal circumference (86±10cm vs 90±9cm, p=0.02), lower prevalence of myocardial infarction (53% vs 82%, p=0.0002), and higher prevalence of definite vasospasm (15% vs 2%, p=0.006) were found in Non-PR group. Morphologically, Non-PR group was associated with simpler Ambrose classification (36% vs 14%, p=0.004), less hypoechoic plaque (45% vs 65%, p=0.04) and lower incidence of IVUS-detected thrombus (21% vs 54%, p<0.0001), compared with PR group. On quantitative IVUS, although minimum lumen area (MLA) was similar between the groups, vessel (14.2±5.4mm2 vs 17.5±5.1mm2, p=0.0002) and plaque (11.6±5.0mm2 vs 14.9±4.9mm2, p<0.0001) areas were significantly smaller at MLA site in Non-PR group than in PR group. On multivariate analysis, average plaque area was only an independent IVUS-predictor of non-rupture ACS (odds ratio: 0.85, p=0.01). ConclusionCompared to ACS with PR, non-rupture ACS arise from more hyperechoic (allegedly “stable”) plaque with smaller vessel and plaque area, leading to lower incidence of thrombotic occlusion. Coronary vasospasm might be a possible pathogenic mechanism underlying non-rupture ACS.

Rigid and elastic registration for coronary artery IVUS images.

Intravascular ultrasound (IVUS) has been widely used in diagnosis and interventional treatment of cardiac vessel diseases. The coronary artery IVUS images are usually polluted by motion artifacts caused by cardiac motion, pulsatile blood and catheter twist during continuous pullback acquisition. Strategies for rigid and elastic registration of coronary artery IVUS studies are developed to suppress the longitudinal motion and misalignment between successive frames. Rigid registration is performed by searching for the optimal matching for each frame in other cycles based on the cyclic variation of gray-scale features. The image sequence is gated to properly identify the frames in each cardiac phase. Then, elastic registration between frames is achieved through an optimization algorithm based on thin plate spline (TPS) to correct the misalignment of successive slices. Experimental results with in vivo image data shows that the rigid registration performs better than the offline ECG gating. The elastic mapping relation between lumen contours in successive frames is smooth and continuous. The serrated vessel wall borders in longitudinal cuts are smoothed after rigid registration while image segmentation and feature extraction are required. The point-to-point correspondence between lumen contours detected from two matched frames is obtained with elastic registration.

Relationship between markers of plaque vulnerability in optical coherence tomography and atherosclerotic progression in adult patients with heart transplantation

Cardiac allograft vasculopathy (CAV) is an accelerated form of coronary artery disease, and optical coherence tomography (OCT) provides detailed microstructural information. The current study was designed to test the hypothesis that markers of plaque vulnerability derived from OCT could predict CAV progression after heart transplantation (HTx). In 34 consecutive patients (median 3.1 years from HTx), intravascular ultrasound (IVUS) and OCT were performed in the left anterior descending artery (LAD) during routine annual coronary angiography. The presence of vulnerability markers, such as lipid pools, thin-cap fibroatheroma, macrophages and microchannels, was assessed in 100 consecutive frames of OCT in 20-mm segments of proximal LAD. The total number of appearances of vulnerable markers was defined as the vulnerability score (VS). Plaque volume (PV) was measured in the same study segment using IVUS at baseline and at 1-year follow-up, and the association between the baseline VS and the subsequent change in percent PV (PV / vessel volume × 100 [%PV]) was evaluated. Follow-up IVUS study was conducted after 12.5 ± 1.3 months. The mean VS was 59.9 ± 44.6. Compared with the initial %PV, the follow-up %PV increased in the study segment (25.6 ± 13.7% to 31.8 ± 17.5%, p < 0.001). The correlations between baseline VS and Δ%PV were significant in the study segment (r = 0.757, p < 0.001). On multivariable analysis, only the VS correlated significantly with Δ%PV. Our results demonstrate that the markers of plaque vulnerability in OCT can predict the progression of CAV. Therefore, in patients with HTx, OCT may aid in determining prognosis and guiding therapy related to CAV.

Clinical perspective of optical coherence tomography and intravascular ultrasound in STEMI patients

In the last years, the intravascular ultrasound study (IVUS) and further the optical coherence tomography (OCT) became two helpful tools to characterize of the atherosclerotic plaque.

Effect of rosuvastatin on atherosclerotic plaque stability: An intravascular ultrasound elastography study

ObjectivesThe present study aimed to investigate the effect of potent rosuvastatin therapy on plaque mechanical stabilization as seen on IVUSE. Methods14 purebred New Zealand rabbits were fed a high-cholesterol diet; the abdominal aorta endothelium was balloon-injured after 2 weeks; at week 13, 7 rabbits received rosuvastatin (1.5 mg/kg/day), and the other 7 received an equal volume of saline. IVUS images of abdominal aortas were acquired, and 2 consecutive frames near the end-diastole images in situ were used to construct an IVUS elastogram. ResultsControl rabbits showed a significant increase in shear strain (SS) and area strain (AS) in total plaques. The rosuvastatin group showed no change in SS and AS, but serum TG and LDL-C levels were reduced, with less lipid deposition, macrophage infiltration, production of proinflammatory cytokines and apoptosis in plaques. The changes in SS and AS from baseline between groups significantly differed (SS: 1.15 (1.96) % vs. −0.99 ± 2.83%, p = 0.013; AS: 1.25 (2.29) % vs. −1.67 ± 5.05%, p = 0.022). At follow-up, for controls, strain values were increased in the shoulder of eccentric plaques (SS: 2.66 ± 1.31% vs. 4.86 ± 1.93%, p = 0.016; AS: 4.45 ± 2.33% vs. 7.91 ± 2.74%, p = 0.009) but not the plaque body. Changes in SS and AS in the plaque shoulder differed between the control and rosuvastatin groups (SS: 2.20 ± 2.17% vs. −0.87 ± 3.31%, p = 0.028; AS: 2.10 (4.61) % vs. −2.75 ± 5.97%, p = 0.009). ConclusionRosuvastatin therapy in rabbits with atherosclerotic plaques led to less vulnerable plaque features. IVUSE is a very sensitive technique for detecting pharmacologically-induced mechanical changes in rabbit atherosclerotic plaques.

Serial Intravascular Ultrasound Findings After Treatment of Chronic Total Occlusions Using Drug-Eluting Stents

Morphologic changes after chronic total occlusion (CTO) treatment with drug-eluting stents (DESs) have not been assessed in detail. Our aim was to use both baseline and follow-up intravascular ultrasound studies to evaluate the morphologic changes and, especially, the changes in distal vessel size and the effect of subintimal stenting after treatment of CTOs with DES. We analyzed serial follow-up intravascular ultrasound (baseline and follow-up at 9 ± 2 months) after DES implantation into 40 CTOs. Overall, 33 CTOs were treated by the anterograde approach; and 7 were treated by the retrograde approach. Minimum lumen cross-sectional area (CSA) trended toward a decrease from baseline to follow-up (4.8 ± 1.7 vs 4.5 ± 1.7 mm(2), p = 0.10), although the minimum stent CSA (4.8 ± 1.7 vs 4.9 ± 1.7 mm(2), p = 0.26) did not change. The distal reference, but not the proximal reference lumen CSA, increased significantly at follow-up (3.8 ± 2.0 to 5.1 ± 2.3 mm(2), p = 0.0004). Late-acquired stent malapposition was seen in 17 patients (42.5%). In 8 CTOs (20%), a part of the stent was implanted into a subintimal space; in these 8 patients, maximum percent neointimal hyperplasia and minimum lumen area was similar in the subintimal segment compared with the adjacent intraplaque segment. The frequency of late-acquired stent malapposition was similar. In conclusion, after CTO treatment with DES, distal vessel enlargement was detected. Subintimal stenting after recanalization of CTO was not inferior compared with stenting within the plaque in terms of long-term morphologic impact.

Chronic vascular response after self-expanding nitinol stent implantation in superficial femoral arteries: a serial intravascular ultrasound analysis

The mechanical properties of the self-expanding nitinol stents (SENS) and chronic biological stimulation on the wall from the SENS have not been fully investigated. This study evaluated the mechanical vascular response to SENS implantation in superficial femoral artery (SFA) lesions using serial volumetric intravascular ultrasound (IVUS). Twenty-five symptomatic patients due to de novo SFA lesions scheduled for SENS placement were prospectively enrolled. Serial IVUS studies were performed immediately after crossing with a guidewire, immediately after the procedure, and at a 8-month follow-up. Serial IVUS volumetric analysis was conducted after stent deployment and at follow-up. Mean stent, lumen and neointimal areas were calculated as the volume divided by the stent length, and the calcium arc was measured. At follow-up, SENS had increased 40.6% in overall volume. The chronic stent expansion tended to be larger, and the mean neointimal area at the 8-month follow-up was significantly larger in less calcified lesions compared to heavily calcified lesions. As a result, the mean late lumen area loss was significantly larger in lesions with calcium arcs of 0° and in the first and second quadrants than in those with calcium arcs in the third and fourth quadrants (2.8±7.2, 1.3±5.6, 0.6±5.9, 1.2±5.4, -0.8±5.2 mm(2), respectively; p<0.001). SENSs continued to enlarge with intimal proliferation over 8months in all lesions. Although arterial calcium affected the degree of chronic stent expansion during the follow-up period, neointimal proliferation was smaller in heavily calcified lesion compared to less calcified lesion following SENS implantation.

Abstract 13930: Culprit Lesion in Patients With ST-elevation Myocardial Infarction is Severely Narrowed With Large Plaque Burden: A Combined Intravascular Ultrasound and Optical Coherence Tomography Study

Background: There have been controversies on the degree of stenosis of the culprit lesion in patients with ST-elevation myocardial infarction (STEMI). In the past it was thought the culprit lesion for STEMI had only mild to moderate stenosis. However, recent studies suggested that in fact the degree of the luminal narrowing might be severe at the culprit site. Aim: The aim of the current study was to investigate the severity and the detailed morphologic characteristics of the culprit lesion in patients with STEMI using intravascular ultrasound (IVUS) and optical coherence tomography (OCT). Methods and Results: A total of 111 STEMI patients (67.8±11.2 years, 89 male) who underwent percutaneous coronary intervention within 12 hours from symptom onset were included. TIMI flow grade 2 or 3 was achieved in 108 (97%) patients after thrombectomy. Both OCT and IVUS were performed. Minimum lumen cross-sectional area (MLA) and plaque burden (PB) were 3.14±1.45 mm 2 and 83.0±7.24% by IVUS. Patients were divided into 2 groups on the basis of MLA by IVUS: Group A (MLA &lt;4 mm 2 , n=104) and Group B (MLA &gt;4 mm 2 , n=7). Group A had a higher incidence of PB &gt;70% compared to Group B (99.0% vs 28.6%, p&lt;0.001). OCT revealed that lipid plaque, microchannel and macrophage were more frequent in Group A than in Group B. The incidence of plaque rupture tended to be higher in Group A than in Group B (Figure). Conclusions: Among STEMI patients, more than 90% of culprit lesions have a small MLA (&lt;4.0 mm 2 ) with large plaque burden. Severely narrowed culprit lesion had more features of vulnerability.

Abstract 11806: Not Glycemic Control Using Sitagliptin But Lipid Control is Associated With Change in Coronary Atherosclerosis in Patients With Type 2 Diabetes -A Serial Integrated Backscatter Intravascular Ultrasound Study

Introduction: Dipeptidyl peptidase-4 (DPP-4) inhibitors have anti-atherogenic effects in an animal model. However, clinical usefulness of DPP-4 inhibitors, particularly effects of these drugs on coronary atherosclerosis has not been fully evaluated. Hypothesis: We assessed the hypothesis that sitagliptin, a DPP-4 inhibitor, has beneficial effects on coronary atherosclerosis beyond its hypoglycemic action. Methods: A prospective, open-labeled, randomized multicenter study was performed at 6 Japanese centers. Twenty-eight patients with type 2 diabetes who have undergone elective percutaneous coronary intervention (PCI) were randomly assigned to either the sitagliptin group (group S) or control group (group C). Neither DPP-4 inhibitors nor glucagon-like peptide-1 analogues have been used in group C during study period. Non- PCI lesions were evaluated by integrated backscatter (IB)-intravascular ultrasound (IVUS) at the time of PCI and at 48-week follow-up. The primary end point was percentage change in plaque volume measured using grayscale IVUS and the secondary end point was changes in plaque compositions measured using IB-IVUS. Results: Grayscale IVUS analysis demonstrated that plaque volume tended to be decreased in both groups (group S: -1.7%; group C: -3.2%), but could not reach statistically significance. In addition, percentage changes in plaque volume did not differ between the 2 groups. On IB-IVUS analysis, a significant decrease in the lipid component (group S: from 200.1 to 179.8 mm3, p=0.02; group C: from 298.3 to 256.6 mm3, p=0.1) and an increase in the calcified component (group S: from 2.1 to 3.2 mm3, p=0.06; group C: from 2.3 to 4.8 mm3, p=0.04) were observed. Univariate and multivariate regression analyses showed that sitagliptin use did not correlate with a decrease in the lipid component, whereas percentage change in serum non high-density lipoprotein cholesterol (HDL-C) was an independent and significant predictor associated with change in the lipid component (β=0.454, p=0.04). Conclusions: Sitagliptin had no effects on coronary atherosclerosis in patients with type 2 diabetes. Not glycemic control but lipid control, particularly a decrease in non-HDL-C was associated with the reduction in lipid component.

Reduction of atherothrombotic burden before stent deployment in non-ST elevation acute coronary syndromes: Reduction of myocardial necrosis achieved with nose-dive manual thrombus aspiration (REMNANT) trial. A volumetric intravascular ultrasound study.

To test whether thrombus aspiration (TA) reduces the atherosclerotic burden in culprit lesions and "facilitate" percutaneous coronary intervention with stent (S-PCI) among patients with non-ST elevation acute coronary syndromes (NSTE-ACS). Evidence on the effects of TA adjunctive to S-PCI in NSTE-ACS is limited and controversial. TA was defined "aggressive" when using 7F devices or a catheter/artery ratio >0.6, "conservative" with 6F, and a catheter/artery ratio ≤0.6. Angiography and intravascular ultrasound (IVUS) were performed at baseline, after TA and after stent deployment. TA was accomplished in 61/76 patients (80%) with NSTE-ACS. The aspirated material was red thrombus in 23% and plaque fragments in 49% of cases. Compared with baseline, TA was associated with an 82% increase in minimal lumen diameter and a 15% reduction in diameter stenosis (P < 0.001 for both). After TA, IVUS documented a 24 and 16% increase in minimal lumen area and lumen volume, respectively (P < 0.001 for both), a 7% decrease in area stenosis through an 11% reduction of plaque + media volume (P < 0.001). When compared with "conservative", an "aggressive" TA was associated with a more pronounced reduction in percent area stenosis (P < 0.05) and an increase in percent stent expansion (P < 0.001). The plaque + media volume reduction after TA was correlated with stent expansion (r = 0.261, P = 0.046). Manual TA reduces atherothrombotic burden in culprit lesions of NSTE-ACS patients before S-PCI and, when deep plaque removal is obtained, TA optimizes subsequent stent expansion. © 2015 Wiley Periodicals, Inc.

Coronary Plaque Characteristics Affect No-Reflow During Primary Percutaneous Coronary Intervention: A Pooled Analysis of 14 Observational Studies Using Intravascular Ultrasound.

The association between coronary plaque composition and no-reflow during percutaneous coronary intervention (PCI) is still debated. We performed a systematic literature search using MEDLINE, Embase, Cochrane, and Ovid databases for intravascular ultrasound (IVUS) studies evaluating the relationship between coronary plaque characteristics and no-reflow after PCI. Fourteen observational trials were included in the meta-analysis, including 1457 patients (237 in the no-reflow group, 1220 in the normal reflow group). Pooled analysis indicated that the no-reflow group had a significantly higher absolute volume of fibrofatty plaque (weighted mean differences [WMD], 4.94 mm(3); 95% confidence interval [CI], 1.83-l8.06; P = .002), external elastic membrane cross-sectional area (EEM-CSA) (WMD, 3.40 mm2; 95% CI, 2.22-4.58; P = .00001), plaque area (WMD, 4.06 mm(2); 95% CI, 2.24-5.89; P = .0001), and artery remodeling index (WMD, 0.09; 95% CI, 0.06-0.13; P = .00001), and a smaller percentage of fibrous plaque (WMD, -5.89 %; 95% CI, -0.66 to -11.12; P = .03) than in the normal reflow group. There were no significant differences in the other plaque components between the two groups. This meta-analysis confirmed that high absolute volume of fibrofatty plaque, EEM-CSA, plaque area, and coronary artery remodeling index, and a decreased percentage of fibrous plaque as detected by IVUS in culprit lesions, are linked with the development of the no-reflow phenomenon after PCI.

Impact of statin therapy on coronary plaque composition: a systematic review and meta-analysis of virtual histology intravascular ultrasound studies.

BackgroundVirtual histology intravascular ultrasound (VH-IVUS) imaging is an innovative tool for the morphological evaluation of coronary atherosclerosis. Evidence for the effects of statin therapy on VH-IVUS parameters have been inconclusive. Consequently, we performed a systematic review and meta-analysis to investigate the impact of statin therapy on plaque volume and its composition using VH-IVUS.MethodsThe search included PubMed, Cochrane Library, Scopus and Embase (through 30 November 2014) to identify prospective studies investigating the effects of statin therapy on plaque volume and its composition using VH-IVUS.ResultsWe identified nine studies with 16 statin treatment arms and 830 participants. There was a significant effect of statin therapy in reducing plaque volume (standardized mean difference (SMD): −0.137, 95 % confidence interval (CI): −0.255, −0.019; P = 0.023), external elastic membrane volume (SMD: −0.097, 95 % CI: −0.183, −0.011; P = 0.027) but not lumen volume (SMD: −0.025, 95 % CI: −0.110, +0.061; P = 0.574). There was a significant reduction in fibrous plaque volume (SMD: −0.129, 95 % CI: −0.255, −0.003; P = 0.045) and an increase of dense calcium volume (SMD: +0.229, 95 % CI: +0.008, +0.450; P = 0.043), while changes in fibro-fatty (SMD: −0.247, 95 % CI: −0.592, +0.098; P = 0.16) and necrotic core (SMD: +0.011, 95 % CI: −0.144, +0.165; P = 0.892) tissue volumes were not statistically significant.ConclusionsThis meta-analysis indicates a significant effect of statin therapy on plaque and external elastic membrane volumes and fibrous and dense calcium volumes. There was no effect on lumen volume, fibro-fatty and necrotic tissue volumes.

Direct bioresorbable vascular scaffold implantation: Feasibility and midterm results.

To analyze the feasibility and safety of direct bioresorbable vascular scaffold (BVS) implantation without previous balloon dilation. Lesion preparation through predilation is recommended before BVS implantation. There is no information on the routine use of direct BVS implantation. One hundred fifty-three patients with a total of 200 coronary lesions, were treated with BVS. A baseline intravascular ultrasound study (IVUS) was performed in 171 lesions (86%), and after BVS implantation, the quality of scaffolding was assessed with an additional IVUS (83, 41%) or optical coherence tomography (77, 38%). Elective predilation was conducted in 50 lesions. In 150 lesions, direct BVS implantation was attempted. In 129 lesions (86%), the BVS was implanted successfully, and in the remaining 21 (14%), direct implantation failed. In these cases, the scaffolds were retrieved and successfully implanted after balloon angioplasty. Longer and C-type lesions, and a larger plaque burden, were associated with failure to directly cross the lesion. Balloon postdilation was needed in 34% of the lesions. Ten patients (6.6%) had a periprocedural myocardial infarction. One patient (0.6%) died 60 days after BVS implantation due to thrombosis of the scaffold. At follow-up, target lesion revascularisation was needed in eight patients (5%). After 12 ± 3 months, the remaining patients were symptom-free. Direct BVS implantation is safe and feasible in most soft coronary plaques.

Stabilization of atherosclerotic plaque by pitavastatin in Watanabe heritable hyperlipidemic rabbits: A serial tissue-characterizing intravascular ultrasound study

BackgroundTo examine the effects of pitavastatin on atherosclerotic plaque in Watanabe heritable hyperlipidemic (WHHL) rabbits using serial in vivo tissue-characterizing intravascular ultrasound. MethodsA total of 11 WHHL rabbits of 10–12 weeks of age were divided into two groups, control and pitavastatin-administered groups. A total of 29 atherosclerotic plaque segments from control group and 43 plaque segments from the pitavastatin group were serially imaged by 40MHz intravascular ultrasound in vivo with a tissue characterization software (iMAP™, Boston Scientific, Natick, MA, USA) at the baseline and the follow-up (16th week). ResultsThe level of low-density lipoprotein cholesterol was significantly decreased in pitavastatin group. During the follow-up period, plaque area was significantly increased in the control group, whereas it was not significantly changed in the pitavastatin group. The fibrotic, necrotic, and necrotic plus lipidic areas were significantly increased in the control group, while no significant change was revealed for tissue profile in pitavastatin group. The change in the percent areas of fibrotic and lipidic plus necrotic tissues were significantly different between the two groups especially in the superficial half portion of plaque. ConclusionsThese data indicate that pitavastatin could attenuate atherosclerotic plaque formation and that it could stabilize the plaque in WHHL rabbits. Considering the fact that these were observed even with a high follow-up level of cholesterol, these data might come from the pleiotropic effects of pitavastatin.

Intravascular ultrasound and optical coherence tomography imaging of coronary atherosclerosis.

Invasive imaging modalities, in particular intravascular ultrasound (IVUS) and optical coherence tomography (OCT), have become established tools for the in vivo study of coronary atherosclerosis. Their use in clinical studies has confirmed histopathological observations that certain important plaque features, such as thin fibrous caps and large lipid cores, are associated with plaque rupture, the precipitating event for the majority of myocardial infarctions. Serial imaging studies have also successfully been used for the evaluation of potential disease modifying pharmacological agents. Recent prospective IVUS studies have confirmed specific baseline imaging features associated with subsequent adverse clinical outcomes, although absolute event rates were too low for clinical utility. Development of hybrid IVUS-OCT imaging or integration of novel techniques, including near-infrared spectroscopy, plaque structural and endothelial shear stress, have great potential to improve our current ability to identify and stratify atheromatous plaques at risk of rupture.

Improving Cardiac Phase Extraction in IVUS Studies by Integration of Gating Methods.

Coronary intravascular ultrasound (IVUS) is a fundamental imaging technique for atherosclerotic plaque assessment. However, volume-based data retrieved from IVUS studies can be misleading due to the artifacts generated by the cardiac motion, hindering diagnostic, and visualization of the vessel condition. Then, we propose an image-based gating method that improves the performance of the preexisting methods, delivering a gating in an appropriate time for clinical practice. We propose a fully automatic method to synergically integrate motion signals from different gating methods to improve the cardiac phase estimation. Additionally, we present a local extrema identification method that provides a more accurate extraction of a cardiac phase and, also, a scheme for multiple phase extraction mandatory for elastography-type studies. A comparison with three state-of-the-art methods is performed over 61 in-vivo IVUS studies including a wide range of physiological situations. The results show that the proposed strategy offers: 1) a more accurate cardiac phase extraction; 2) a lower frame oversampling and/or omission in the extracted phase data (error of 1.492 ±0.977 heartbeats per study, mean ± SD); 3) a more accurate and robust heartbeat period detection with a Bland-Altman coefficient of reproducibility (RPC) of 0.23 s, while the second closest method presents an RPC of 0.36 s. The integration of motion signals performed by our method shown an improvement of the gating accuracy and reliability.

A Combined Optical Coherence Tomography and Intravascular Ultrasound Study on Plaque Rupture, Plaque Erosion, and Calcified Nodule in Patients With ST-Segment Elevation Myocardial Infarction: Incidence, Morphologic Characteristics, and Outcomes After Percutaneous Coronary Intervention.

This study sought to evaluate the incidence of plaque rupture (PR), plaque erosion (PE), and calcified nodule (CN) using optical coherence tomography (OCT) in patients with ST-segment elevation myocardial infarction (STEMI); to compare detailed morphologic plaque characteristics of PR, PE, and CN with optical coherence tomography and intravascular ultrasound; and to compare the post-procedure outcomes among PR, PE, and CN. The incidence and detailed morphologic characteristics of PR, PE, and CN in STEMI patients and their outcome after percutaneous coronary intervention (PCI) are unknown. A total of 112 STEMI patients who underwent PCI within 24 h [corrected] from symptom onset were included. Both optical coherence tomography and intravascular ultrasound were performed following aspiration thrombectomy. The incidence of PR, PE, and CN was 64.3%, 26.8%, and 8.0%, respectively. PE and CN, compared with PR, had more fibrous plaque (p < 0.001 and p < 0.001) and less thin-cap fibroatheroma (p < 0.001 and p < 0.001) as well as smaller plaque burden (p = 0.003 and p = 0.001) and remodeling index (p = 0.003 and p < 0.001). PE had greater plaque eccentricity index than PR and CN (p < 0.001 and p < 0.001). CN had greater calcified arc and shallower calcium than PR (p < 0.001 and p < 0.001) or PE (p < 0.001 and p < 0.001). More than one-half of CN had negative remodeling. PE had a lower incidence of no-reflow phenomenon after PCI than PR (p = 0.011). PE was the underlying mechanism in one-fourth of STEMI. PE was characterized by eccentric fibrous plaque. CN was characterized by superficial large calcium and negative remodeling. PE was associated with less microvascular damage after PCI.

Association of insulin resistance and coronary artery remodeling: an intravascular ultrasound study.

BackgroundThere are few studies that investigated the correlation between insulin resistance (IR) and the coronary artery remodeling. The aim of the study is to investigate the association of IR measured by homeostasis model assessment of insulin resistance (HOMA-IR) and coronary artery remodeling evaluated by intravascular ultrasound (IVUS).MethodsA total of 298 consecutive patients who received percutaneous coronary interventions under IVUS guidance were retrospectively enrolled. The value of HOMA-IR more than 2.5 was considered as IR positive. Metabolic syndrome was classified according to NCEP ATP III guidelines. The remodeling index was defined as the ratio of the external elastic membrane (EEM) area at the lesion site to the EEM area at the proximal reference site.ResultsA total of 369 lesions were analyzed (161 lesions in HOMA-IR positive and 208 lesions in HOMA-IR negative). Remodeling index was significantly higher in the HOMA-IR positive group compared with the negative group (HOMA-IR positive vs. negative: 1.074 ± 0.109 vs. 1.042 ± 0.131, p = 0.013). There was a significant positive correlation between remodeling index and HOMA-IR (p = 0.010). Analysis of HOMA-IR according to remodeling groups showed increasing tendency of HOMA-IR, and it was statistically significant (p = 0.045). Multivariate analysis revealed that only HOMA-IR was an independent predictor of remodeling index (r = 0.166, p = 0.018).ConclusionIncreased IR estimated by HOMA-IR was significantly associated with a higher remodeling index and positive coronary artery remodeling.