Effect of lipid-lowering therapy with atorvastatin on atherosclerotic aortic plaques detected by noninvasive magnetic resonance imaging

Association Between Aortic Wall Parameters on Multidetector Computed Tomography and Ruptured Plaques By Nonobstructive General Angioscopy

BACKGROUND

Nonobstructive general angioscopy (NOGA) can identify vulnerable plaques in the aortic lumen that serve as potential risk factors for cardiovascular events such as embolism. However, the association between computed tomography (CT) images and vulnerable plaques detected on NOGA remains unknown.

METHODS AND RESULTS

We investigated 101 patients (67±11 years; women, 13.8%) who underwent NOGA and contrast-enhanced CT before or after 90 days in our hospital. On CT images, the aortic wall thickness, aortic wall area (AWA), and AWA in the vascular area were measured at the thickest point from the 6th to the 12th thoracic vertebral levels. Furthermore, the association between these measurements and the presence or absence of NOGA-derived aortic plaque ruptures (PRs) at the same vertebral level was assessed. NOGA detected aortic PRs in the aortic lumens at 145 (22.1%) of the 656 vertebral levels. The presence of PRs was significantly associated with greater aortic wall thickness (3.3±1.7 mm versus 2.1±1.2 mm), AWA (1.33±0.68 cm2 versus 0.89±0.49 cm2), and AWA in the vascular area (23.2%±9.3% versus 17.2%±7.6%) (P<0.001 for all) on the CT scans compared with the absence of PRs. The frequency of PRs significantly increased as the aortic wall thickness increased. Notably, a few NOGA-derived PRs were detected on CT in near-normal intima.

CONCLUSIONS

The presence of NOGA-derived PRs was strongly associated with increased aortic wall thickness, AWA, and AWA in the vascular area, measured using CT. NOGA can detect PRs in the intima that appear almost normal on CT scans.

Magnetic Resonance Imaging of Intraplaque Hemorrhage and Plaque Lipid Content With Continued Lipid-Lowering Therapy: Results of a Magnetic Resonance Imaging Substudy in AIM-HIGH

BACKGROUND

Intraplaque hemorrhage (IPH) is associated with plaque progression and ischemic events, and plaque lipid content (% lipid core) predicts the residual atherosclerotic cardiovascular disease risk. This study examined the impact of IPH on lipid content change in the setting of intensive lipid-lowering therapy.

METHODS

In total, 214 AIM-HIGH (Atherothrombosis Intervention in Metabolic Syndrome with Low High-Density Lipoprotein/High Triglycerides: Impact on Global Health Outcomes) participants with clinically established ASCVD and low high-density lipoprotein cholesterol received cartoid MRI at baseline and 2 years to assess changes in carotid morphology and composition. Patients were randomized to extended-release niacin or placebo, and all received simvastatin with optional ezetimibe as necessary to lower low-density lipoprotein cholesterol to 40 to 80 mg/dL. Changes in lipid content and carotid morphology were tested using the Wilcoxon signed-rank test. Differences between subjects with and without IPH and between subjects assigned extended-release niacin or placebo were tested using the Wilcoxon rank-sum test. Linear regression was used to test the association of IPH and lipid content changes after adjusting for clinical risk factors.

RESULTS

Among 156 patients (61±9 years; 81% men) with complete MRI, prior statin use: <1 year, 26%; 1 to 5 years, 37%; >5 years, 37%. Triglycerides and ApoB decreased significantly, whereas high-density lipoprotein cholesterol and ApoA1 increased significantly over time. Plaque lipid content was significantly reduced (-0.5±2.4 %/year, P = 0.017) without a significant difference between the 2 treatment groups. However, the lipid content increased in plaques with IPH but regressed in plaques without IPH (1.2±2.5 %/year versus -1.0±2.2, P = 0.006). Additionally, IPH was associated with a decrease in lumen area (-0.4±0.9 mm2/year versus 0.3±1.4, P = 0.033). IPH remained significantly associated with increase in lipid content in multivariable analysis (54.4%, 95% CI: 26.8, 88.0, P < 0.001).

CONCLUSIONS

Carotid plaques under continued intensive lipid-lowering therapy moved toward stabilization. However, plaques with IPH showed greater increases in lipid content and greater decreases in lumen area than plaques without IPH.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT01178320.

Effect of Atheromatous Aorta on Thromboembolic Complications after Endovascular Aortic Aneurysm

Objective: The purpose of this study was to evaluate the effect of atheromatous aorta on thromboembolic complications after endovascular aortic aneurysm repair (EVAR) and to assess the risk factors for these complications. Materials and Methods: This retrospective study included patients who underwent EVAR for an abdominal aortic aneurysm at the Shizuoka Red Cross Hospital from 2007 to 2018. We defined atheromatous aorta as a thoracic shaggy aorta or abdominal aorta with neck thrombus. The main outcome was renal dysfunction and peripheral embolization (thromboembolic complications). We compared the incidence of thromboembolic complications between patients with normal aorta and atheromatous aorta. Moreover, we assessed the risk factors associated with thromboembolic complications in patients with atheromatous aorta. Results: Patients with atheromatous aorta had significantly more thromboembolic complications, such as renal dysfunction (24.5% vs. 3.9%; P<0.001) and peripheral embolization (12.3% vs. 0.0%; P<0.001) than those with normal aorta, respectively. We identified no risk factors associated with thromboembolic complications in patients with atheromatous aorta. Conclusion: Atheromatous aorta increases the risk of thromboembolic complications after EVAR. However, there is no established therapy for these thromboembolic complications. Further studies are necessary to determine the appropriate therapy, including appropriate preoperative medication, to prevent these complications.

Risk Factors of Aortic Plaque Progression Evaluated by Long-Term Follow-Up Data With Transesophageal Echocardiography

There are few longitudinal data regarding aortic plaque. This study aimed to examine chronological changes in aortic plaques with transesophageal echocardiography (TEE), and to clarify the risk factors of aortic plaque progression. Among 2,675 consecutive patients who underwent TEE, we retrospectively investigated 252 patients who underwent follow-up TEE with an interval >3 years. The thickness and morphology of aortic plaques were examined. Chronological changes in aortic plaques were investigated by comparing baseline and follow-up TEE. Clinical factors, laboratory data, and medications were evaluated. Among 252 study patients, the grade of aortic plaques was unchanged in 213 (group U), but progression was observed in 32 (group P) and regression in 7 patients (group R). Patients in group P were older; they had a higher prevalence of coronary artery disease, hypertension, smoking habit, and moderate or severe plaque at baseline TEE; more patients were using statins and no warfarin; and they had higher creatinine levels than those in group U. In multivariate analysis, moderate or severe plaques at baseline TEE were the strongest predictor of plaque progression. Among 50 patients who showed moderate or severe plaque at baseline TEE, smoking habit and no anticoagulation therapy were predictors of plaque progression. In conclusion, aortic plaques should be followed up using TEE in patients with moderate or severe plaque at baseline TEE.

The future of imaging in cardiovascular disease intervention trials: 2017 and beyond

PURPOSE OF REVIEW

As our understanding of cardiovascular disease has advanced over the past decades, multiple novel treatment strategies have been developed with the hope of reducing the global morbidity and mortality associated with this condition. Large-scale trials to test such novel therapies using clinical end points are expensive, leading to interest in phase II clinical trials with imaging-derived outcome measures.

RECENT FINDINGS

Noninvasive imaging techniques that assess changes in both atherosclerotic disease burden and plaque composition in response to therapy are well established. With the advent of molecular techniques and hybrid imaging, we now have the ability to assess disease activity alongside these standard anatomic assessments. This multifaceted approach has the potential to provide a more comprehensive assessment of the actions and efficacy of novel therapies in the carotids, aorta and coronary arteries.

SUMMARY

This review will examine how advanced noninvasive imaging strategies have been used to investigate drug efficacy in intervention trials to date, and crucially how these approaches are set to evolve and play a central role in developing the next generation of atherosclerotic medication.

Progression of coronary artery calcification at the crossroads: sign of progression or stabilization of coronary atherosclerosis?

Coronary artery calcification (CAC) has been strongly established as an independent predictor of adverse events, with a significant incremental prognostic value over traditional risk stratification algorithms. CAC progression has been associated with a higher rate of events. In parallel, several randomized studies and meta-analysis have shown the effectiveness of statins to slow progression and even promote plaque regression. However, evidence regarding the effect of routine medical therapy on CAC has yielded conflicting results, with initial studies showing significant CAC regression, and contemporaneous data showing rather the opposite. Accordingly, there is currently a great controversy on whether progression of CAC is a sign of progression or stabilization of coronary artery disease (CAD). The finding of inexorable CAC progression despite the implementation of intensive contemporaneous medical therapy suggests that further understanding of this phenomenon should be undertaken before the implementation of CAC as a surrogate endpoint for longitudinal studies, or for prospective follow-up of patients under routine medical treatment.

Off-Pump Double Coronary Bypass in a Case of Familial Hypercholesterolemia With Coarctation of the Aorta

Familial hypercholesterolemia is an uncommon disease that may be associated with atherosclerosis affecting coronary arteries and the ascending aorta. Coarctation of the aorta is rarely involved in this disease. The ideal surgical approach for management of coexisting coronary artery disease and coarctation of the aorta in a child with familial hypercholesterolemia is unclear. We report the case of a 14-year-old girl with familial hypercholesterolemia who underwent double coronary artery bypass grafting due to proximal lesions of both the left anterior descending artery and the right coronary artery.

Characterization of intracranial atherosclerotic stenosis using high-resolution MRI study--rationale and design

BACKGROUND

Intracranial atherosclerosis is a leading cause of stroke, but little is known about the composition of the intracranial atherosclerotic lesion and how intracranial plaque morphology is related to the risk of stroke. High-resolution magnetic resonance imaging (HR MRI) has been used in patients with extracranial carotid atherosclerosis as an in vivo tool to identify, with high-interrater agreement, histologically defined plaque components (i.e., intraplaque hemorrhage, fibrous cap, and lipid core), which have been shown to be predictors of recurrent stroke. With careful imaging the components of atherosclerotic plaque can be visualized in the intracranial arteries using HR MRI, but there are no reports of reproducibility or interrater reliability.

METHODS/STUDY DESIGN

The Characterization of intracranial atherosclerotic stenosis using high-resolution MRI (CHIASM) study is a single-center NIH-funded prospective observational study, to (1) demonstrate high -interrater agreement for identifying intracranial plaque components on HR MRI, (2) determine the frequency of these components in symptomatic versus asymptomatic plaques, and (3) estimate the 1-year rate of stroke in the territory of high-risk plaque components. CHIASM will recruit 90 patients with 50-99% intracranial atherosclerosis to undergo HRMRI of the intracranial artery plaque at enrollment and 1-year follow-up. Both symptomatic and asymptomatic subjects will be recruited.

CONCLUSION

Determination of good interrater reliability is an important first step in the development of HR MRI as a tool to predict risk in patients with intracranial atherosclerosis. This study will inform the design of future multicenter studies to determine the prevalence and prognosis of intracranial atherosclerotic plaque components. Such studies could lead to new understanding of the pathophysiological mechanisms of cerebral ischemia in patients with atherosclerotic intracranial stenosis, improvements in risk stratification, and potentially to new treatments of this common and serious disease.

Rosuvastatin may stabilize atherosclerotic aortic plaque: transesophageal echocardiographic study in the EPISTEME trial

OBJECTIVE

Large atheromatous aortic plaques (AAPs) have been associated with ischemic stroke. There is little evidence to guide the therapeutic strategy for ischemic stroke associated with large AAPs. This study sought to analyze the temporal profile of AAPs after rosuvastatin therapy in Japanese patients with acute ischemic stroke.

METHODS

The Efficacy of Post-stroke Intensive Rosuvastatin Treatment for aortogenic Embolic stroke (EPISTEME) trial was a prospective, randomized, open-label study. Acute ischemic stroke patients with dyslipidemia and AAPs ≥4-mm-thick on transesophageal echocardiography (TEE) were enrolled and randomly allocated to either the group treated with 5 mg/day rosuvastatin or the control group. The primary endpoint was the changes in volume and composition of AAPs on repeat TEE after 6 months. High-echoic plaque area was analyzed using binary images.

RESULTS

A total of 24 Japanese patients (rosuvastatin 12; control 12) were included in the primary analysis. Rosuvastatin substantially reduced low-density lipoprotein cholesterol (LDL-C) compared to control (-42.1% vs. 1.4%, P < 0.001). Percent changes of high-echoic plaque areas were significantly increased in the rosuvastatin group, while they were decreased in the control group (65.8% vs -14.7%, P < 0.001). There was a significant linear correlation between percent increase in high-echoic plaque area and LDL-C decrease (r=-0.434, P=0.002).

CONCLUSION

Treatment with 5-mg rosuvastatin for 6 months might induce atheromatous aortic plaque stabilization together with marked LDL-C reduction in Japanese patients with ischemic stroke, which could provide evidence on which to base the therapeutic strategy for aortogenic brain embolism.

Rationale and design of the EPISTEME trial: efficacy of post-stroke intensive rosuvastatin treatment for aortogenic embolic stroke

BACKGROUND

Large atheromatous aortic plaques (AAPs) are associated with stroke recurrence. Rosuvastatin is a potent lipid-lowering agent and suppresses carotid and coronary artery atherosclerosis. It is unclear whether rosuvastatin has anti-atherogenic effects against AAPs in stroke patients. We designed a clinical trial in stroke patients to analyze changes in AAPs after rosuvastatin treatment using repeated transesophageal echocardiography (TEE).

METHODS

This trial is a prospective randomized open label study. Inclusion criteria were patients were ischemic stroke with hypercholesterolemia and AAPs ≥ 4 mm in thickness. The patients are randomly assigned to either a group treated with 5 mg/day rosuvastatin or a control group. Primary endpoint is the changes in volume and composition of AAPs after 6 months using transesophageal echocardiography (TEE). Biochemical findings are analyzed. By using repeated TEE and binary image analysis, we will be able to compare the dynamic changes in plaque composition of AAPs before and after therapy in the two groups.

CONCLUSIONS

The EPISTEME trial will provide information on the changes in plaque volume and composition achieved by improvement of lipid profiles with rosuvastatin therapy in stroke patients with aortic atherosclerosis. The results of the study may provide evidence for a therapeutic strategy for aortogenic brain embolism. This study is registered with UMIN-CTR (UMIN000010548).

Carotid magnetic resonance imaging for monitoring atherosclerotic plaque progression: a multicenter reproducibility study

This study sought to determine the multicenter reproducibility of magnetic resonance imaging (MRI) and the compatibility of different scanner platforms in assessing carotid plaque morphology and composition. A standardized multi-contrast MRI protocol was implemented at 16 imaging sites (GE: 8; Philips: 8). Sixty-eight subjects (61 ± 8 years; 52 males) were dispersedly recruited and scanned twice within 2 weeks on the same magnet. Images were reviewed centrally using a streamlined semiautomatic approach. Quantitative volumetric measurements on plaque morphology (lumen, wall, and outer wall) and plaque tissue composition [lipid-rich necrotic core (LRNC), calcification, and fibrous tissue] were obtained. Inter-scan reproducibility was summarized using the within-subject standard deviation, coefficient of variation (CV) and intraclass correlation coefficient (ICC). Good to excellent reproducibility was observed for both morphological (ICC range 0.98-0.99) and compositional (ICC range 0.88-0.96) measurements. Measurement precision was related to the size of structures (CV range 2.5-4.9 % for morphology, 36-44 % for LRNC and calcification). Comparable measurement variability was found between the two platforms on both plaque morphology and tissue composition. In conclusion, good to excellent inter-scan reproducibility of carotid MRI can be achieved in multicenter settings with comparable measurement precision between platforms, which may facilitate future multicenter endeavors that use serial MRI to monitor atherosclerotic plaque progression.

Rosuvastatin improves plaque morphology in cerebral embolism patients with normal low-density lipoprotein and severe aortic arch plaque

The effect of rosuvastatin was investigated on complicated aortic arch plaque (CAP) morphology and lipid profiles in acute cerebral embolism (CE) patients with normal low-density lipoprotein-cholesterol (LDL-c) levels. Transesophageal echocardiography (TEE) studies were performed in 56 consecutive CE patients with LDL-c less than 140 mg/dL who were not taking lipid-lowering agents at baseline. CAP observed by TEE was defined as the presence of greater than 4-mm diameter, ulcerated, or mobile aortic plaque. Patients were divided into those with CAP versus without CAP (group A, n=24, age 69±8 years) and without CAP (group B, n=32, age 62±10 years). Of the 24 group A patients, 18 received 5 mg/d of rosuvastatin for 6 months and had follow-up TEE studies. In Group A, the baseline values of high-density lipoprotein-cholesterol (HDL-c) and apolipoprotein A-1 (ApoA-1) were significantly lower than in Group B (44±15 versus 55±15 mg/dL, P=.0059; 103±19 versus 137±25 mg/dL, P=.0006, respectively) and age and serum high-sensitivity C-reactive protein concentration were significantly higher (69±8 vs. 62±10 years, P=.0080; 2.34±3.05 vs. 0.67±1.00 mg/dL, P=.0054, respectively). By multivariate logistic regression analysis, ApoA-1 was shown to be an independent predictor of CAP (odds ratio=.894, 95% confidence intervals .800-.996, P=.0483). In the 18 group A patients receiving rosuvastatin for 6 months, aortic arch plaque diameter and serum LDL-c were significantly decreased (5.8±2.2 to 5.1±2.1 mm, P=.0377; 110±23 to 81±23 mg/dL, P=.0008, respectively), whereas serum HDL-c and ApoA-1 concentrations were significantly increased (42±8 to 52±9 mg/dL, P=.0002; 109±22 to 135±15 mg/dL, P=.0002, respectively). Plaques were morphologically improved in 11 patients, unchanged in 6, and worsened in 1. These data suggest that rosuvastatin improves plaque morphology concomitant with improving lipid profiles in CE patients with normal LDL-c levels.

A systematic review of the time course of atherosclerotic plaque regression

OBJECTIVE

We sought to determine the time required for lipid treatment to produce regression of atherosclerotic plaques.

BACKGROUND

The cholesterol content of atherosclerotic plaques contributes to their instability, and most acute cardiac events including myocardial infarction and sudden death are produced by coronary plaque disruption. We systematically reviewed the literature on atherosclerosis regression to identify the time required for cholesterol egress, plaque regression, and possible plaque stabilization. Such information may help decide when patients with statin side effects or other reasons for statin discontinuation could consider a reduction in the intensity of treatment.

METHODS

We performed a PubMed search to identify English language articles reporting atherosclerotic regression. Articles pertinent to the topic were reviewed in detail.

RESULTS

We identified 189 articles, 50 of which provided sufficient information to establish a rate of regression and 31 of which demonstrated plaque regression with statin therapy in the carotid (n = 11), coronary (n = 16), and aortic (n = 4) vascular beds. Plaque regression occurred after an average of 19.7 months of treatment.

CONCLUSION

Regression of atherosclerotic plaque using statin therapy in those studies documenting regression occurred after an average time of 19.7 months. This suggests that patients should undergo approximately two years of aggressive lipid reduction before considering a reduction of statin therapy.

Exploring the natural history of atherosclerosis with intravascular ultrasound

Intravascular ultrasound has emerged as the preferred imaging modality for the characterization of atherosclerotic plaque within the coronary arteries. Ultrasonic imaging reveals the presence of more extensive atheroma than suggested by conventional angiography in patients with coronary artery disease. The ability to precisely quantify atheroma volume in an arterial segment at different time points provides the unique opportunity to investigate the factors that influence the natural history of atheroma progression. Accordingly, serial intravascular ultrasound has been incorporated into a number of clinical trials that have evaluated the impact of medical therapies that modify established risk factors and novel pathological targets. This article will review the increasing role of imaging modalities in the assessment of atherosclerosis and factors that influence its natural history.

Statins reduce extensive aortic atheromas in patients with abdominal aortic aneurysms

OBJECTIVE

Statins have been used widely to reduce dyslipidemia and recently have been reported to have pleiotropic effects such as plaque reduction and stabilization. This study retrospectively evaluated the regression of extensive thoracic atheromas ("shaggy aorta") in abdominal aortic aneurysm (AAA) patients who underwent contrast-enhanced computed tomography (CECT) before and after statin administration.

MATERIALS AND METHODS

CECT was used to examine thoracic aortas of 29 patients (statin group; n = 22, non-statin group; n = 7) with extensive atheromas from the ostium of the left subclavian artery to that of the more proximal renal artery. Extensive thoracic atheroma was defined by: (1) thickness >5 mm, (2) involved circumference of thoracic aorta >50%, and (3) length >30 mm. The areas of atheroma (cm(2)) were measured before and after administration of statins, and the atheroma reduction ratio (ARR) was evaluated.

RESULTS

The area of atheroma decreased after administration of statins, and the ARR was significant (P <0.01). The ARR increased with all cases in non-statin group. No complications associated with extensive atheroma were observed during the follow-up period.

CONCLUSION

This pilot study indicates statins can reduce extensive thoracic atheromas and lower lipid concentrations.

MR imaging of the arterial vessel wall: molecular imaging from bench to bedside

Cardiovascular diseases remain the leading cause of morbidity and mortality in the Western world and developing countries. In clinical practice, in vivo characterization of atherosclerotic lesions causing myocardial infarction, ischemic stroke, and other complications remains challenging. Imaging methods, limited to the assessment luminal stenosis, are the current reference standard for the assessment of clinically significant coronary and carotid artery disease and the guidance of treatment. These techniques do not allow distinction between stable and potentially vulnerable atherosclerotic plaque. Magnetic resonance (MR) imaging is a modality well suited for visualization and characterization of the relatively thin arterial vessel wall, because it allows imaging with high spatial resolution and excellent soft-tissue contrast. In clinical practice, atherosclerotic plaque components of the carotid artery and aorta may be differentiated and characterized by using unenhanced vessel wall MR imaging. Additional information can be gained by using clinically approved nonspecific contrast agents. With the advent of targeted MR contrast agents, which enhance specific molecules or cells, pathologic processes can be visualized at a molecular level with high spatial resolution. In this article, the pathophysiologic changes of the arterial vessel wall underlying the development of atherosclerosis will be first reviewed. Then basic principles and properties of molecular MR imaging contrast agents will be introduced. Additionally, recent advances in preclinical molecular vessel wall imaging will be reviewed. Finally, the clinical feasibility of arterial vessel wall imaging at unenhanced and contrast material-enhanced MR imaging of the aortic, carotid, and coronary vessel wall will be discussed.

Intensive lipid lowering therapy with titrated rosuvastatin yields greater atherosclerotic aortic plaque regression: Serial magnetic resonance imaging observations from RAPID study

OBJECTIVE

Although previous randomized clinical trials established a basis for lipid guidelines worldwide, they employed fixed doses of statins throughout trials (fire-and-forget approach). In the real clinical setting, however, statin doses are titrated to achieve target low-density lipoprotein cholesterol (LDL-C) levels (treat-to-target approach). The major objective was to investigate whether intensive lipid-lowering therapy using the treat-to-target approach yielded greater regression of aortic plaques.

METHODS

We therefore performed a prospective, randomized trial comparing the effects of standard (achieve LDL-C levels recommended by the Japanese guidelines) and intensive (achieve 30% lower LDL-C levels than standard) rosuvastatin therapy for 1 year in 60 hypercholesterolemic patients with a primary endpoint of aortic atherosclerotic plaques evaluated by non-invasive magnetic resonance imaging (MRI).

RESULTS

Average doses were 2.9 ± 3.1 and 6.5 ± 5.1 mg/day for standard (n = 29) and intensive therapy group (n = 31), respectively. Although both therapies significantly reduced LDL-C and high-sensitivity C-reactive protein (hsCRP) levels, LDL-C reduction was significantly greater in the intensive group (-46 vs. -34%). MRI study showed that thoracic aortic plaques were significantly regressed in both groups, with greater regression of thoracic plaque in the intensive group (-9.1 vs. -3.2%, p = 0.01). Multivariate analyses revealed that thoracic plaque regression was significantly correlated with hsCRP reduction, but not with changes in serum lipids, endothelial function, or doses of rosuvastatin.

CONCLUSION

Intensive statin therapy with titration targeting lower LDL-C levels resulted in greater thoracic aortic plaque regression compared to standard therapy, which was correlated with hsCRP reduction, suggesting that intensive statin therapy could provide better clinical outcomes.

Effects of medical treatment on the prognosis and risk of embolic events in patients with severe aortic plaque

AIM

The optimal treatment strategy for patients with aortic atheroma is not well established because data regarding medical treatment for such patients are lacking, especially with respect to the Japanese population. The purpose of this study was to clarify the effects of medical treatment on the risk of embolic events and mortality in patients with severe aortic plaque.

METHODS

We retrospectively investigated 75 consecutive patients with severe aortic plaque detected on transesophageal echocardiography (TEE) between 1995 and 2005. The occurrence of embolic events and all-cause death in the period after TEE was assessed. The cumulative incidence of subsequent embolic events and death was evaluated in relation to specific medical treatments, including statins, antiplatelet drugs and warfarin.

RESULTS

Embolic events occurred in 27 patients (36%) and death occurred in 37 patients (49%) during follow-up (5.6±3.0 years). The patients who experienced embolic events had a significantly higher prevalence of previous embolic events, atrial fibrillation and hemodialysis than the patients who did not experience embolic events. Univariate and multivariate analyses showed that the use of statins and/or antiplatelet drugs was significantly associated with a low incidence of death but not with a low incidence of embolic events. On the other hand, warfarin exhibited neither beneficial nor harmful effects on the incidence of embolic events or death.

CONCLUSIONS

Statin and antiplatelet drugs have beneficial effects on the prognosis of patients with severe aortic plaque diagnosed on TEE.

An echo-guided case report of rapid regression of unstable mobile thrombus aortic atheroma after aggressive statin and antiplatelet combination therapy

We describe a case report that documented the efficacy and safety of medical therapy in stabilizing and resolving a complex and unstable aortic atheroma after a relatively short period. The patient had a large protruding, mobile, calcified nonulcerated atheroma involving the descending aorta and was therefore treated with aggressive combination therapy with high statin dosages (atorvastatin = 80 mg) and dual antiplatelet treatment (clopidogrel = 75 mg and aspirin = 100 mg). At follow-up, the echocardiogram showed a significant regression in the atheroma volume, with no signs suggestive of ulceration on its surface with the complete mobile component resolution.

Atorvastatin, etidronate, or both in patients at high risk for atherosclerotic aortic plaques: a randomized, controlled trial

BACKGROUND

Statins are not effective in reducing atherosclerotic plaques of the abdominal aorta, and accumulating evidence suggests that bisphosphonates have the potential to induce the regression of atherosclerotic plaques of the abdominal aorta.

METHODS AND RESULTS

A prospective, randomized, open-label, blinded-end-point trial involving 108 participants with hypercholesterolemia was conducted. Participants received 20 mg atorvastatin daily, 400 mg etidronate daily, or both drugs daily. The primary end point was the percent change in maximal vessel wall thickness of atherosclerotic plaques in the thoracic and abdominal aortas as measured by magnetic resonance imaging after 12 months of treatment. In both the combination therapy and atorvastatin groups, maximal vessel wall thickness of the thoracic aorta was reduced by 13.8% (95% confidence interval, -16.4 to -11.3) and 12.3% (95% confidence interval, -14.9 to -9.7), respectively. These reduction rates were comparable between groups (P=0.61). Meanwhile, in the etidronate group, maximal vessel wall thickness of the thoracic aorta remained unchanged (2.2%; 95% confidence interval, -0.3 to 4.8). Conversely, maximal vessel wall thickness of the abdominal aorta was reduced more effectively in the combination therapy group (-11.4%) than in the atorvastatin group (-0.9%; P<0.001) and the etidronate group (5.5%; P=0.006).

CONCLUSIONS

Atorvastatin plus etidronate combination therapy for 12 months significantly reduced both thoracic and abdominal aortic plaques, whereas atorvastatin monotherapy reduced only thoracic aortic plaques and etidronate monotherapy reduced only abdominal aortic plaques. The effectiveness of combination therapy in reducing atherosclerotic plaques in the abdominal aorta was significantly greater than for both atorvastatin and etidronate monotherapy.

CLINICAL TRIAL REGISTRATION

URL: http://www.umin.ac.jp/ctr/. Unique identifier: UMIN 000002635.

Beyond Coronary Stenosis: Coronary Computed Tomographic Angiography for the Assessment of Atherosclerotic Plaque Burden

Coronary computed tomographic angiography (CCTA) is emerging as a key non-invasive method for assessing cardiovascular risk by measurement of coronary stenosis and coronary artery calcium (CAC). New advancements in CCTA technology have led to the ability to directly identify and quantify the so-called "vulnerable" plaques that have features of positive remodeling and low density components. In addition, CCTA presents a new opportunity for noninvasive measurement of total coronary plaque burden that has not previously been available. The use of CCTA needs also to be balanced by its risks and, in particular, the associated radiation exposure. We review current uses of CCTA, CCTA's ability to measure plaque quantity and characteristics, and new developments in risk stratification and CCTA technology. CCTA represents a quickly developing field that will play a growing role in the non-invasive management of cardiovascular disease.

Study Design of PROCEDURE Study. A Randomized Comparison of the Dose-Dependent Effects of Pitavastatin in Patients with Abdominal Aortic Aneurysm with Massive Aortic Atheroma: Prevention of Cholesterol Embolization during Endovascular and Open Aneurysm Repair with Pitavastatin (PROCEDURE) Study

Outcomes of abdominal aortic aneurysm (AAA) repair have improved in the 2 decades since the emergence of endovascular aneurysm repair (EVAR). However, EVAR is considered a contraindication for shaggy aorta because of the high risk of shower embolization. Recently, statins have been implicated in preventing embolization in patients with shaggy aorta via its pleiotropic effects, including atheroma reduction and coronary artery stabilization. We selected pitavastatin, a statin with potent effects, discovered and developed by a Japanese company because it has shown excellent pleiotropic effects on atheromatous arteries in the Japanese population. A randomized comparison study of dose-dependent effects of pitavastatin in patients with AAA with massive atheromatous aortic thrombus (PROCEDURE study) has begun. PROCEDURE has an enrollment goal of up to 80 patients with AAA with massive aortic atheroma (excluding intrasac atheroma), randomly allocated into 2 groups receiving pitavastatin at a dose of 1 or 4 mg/day. The endpoints of the PROCEDURE study include change in atheroma volume, major adverse events related to shower embolization after aneurysm repair, and lipid-lowering effects. When complete, results of the PROCEDURE study should provide objective evidence to use statins preoperatively for AAA with massive aortic atheroma.

Medical treatment for small abdominal aortic aneurysms

BACKGROUND

Screening for abdominal aortic aneurysm (AAA) in selected groups is now performed in England, the USA and Sweden. Patients with aneurysms over 55 mm in diameter are generally considered for elective surgical repair. Patients with aneurysm diameters below or equal to 55 mm (termed 'small AAAs') are managed with aneurysm surveillance as there is currently insufficient evidence to recommend surgery in these cases. As more patients are screened, there will be an increasing number of small AAAs identified. There is interest in pharmaceutical interventions (for example angiotensin converting enzyme (ACE) inhibitors, antibiotics, beta-blockers, statins) which could be given to such patients to delay or reverse aneurysm expansion and reduce the need for elective surgical repair.

OBJECTIVES

To assess the effects of medical treatment on the expansion rate of small abdominal aortic aneurysms.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (May 2012) and CENTRAL (2012, Issue 5). Clinical trials databases were searched for details of ongoing or unpublished studies. The reference lists of articles retrieved by electronic searches were searched for additional citations.

SELECTION CRITERIA

We selected randomised trials in which patients with small AAAs allocated to medical treatment with the intention of retarding aneurysm expansion were compared to patients allocated to a placebo treatment, alternative medical treatment, a different regimen of the same drug or imaging surveillance alone.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data and assessed the risk of bias in the trials. Meta-analyses were used when heterogeneity was considered low. The two primary outcomes were the mean difference (MD) in aneurysm diameter and the odds ratio (OR) calculated to compare the number of individuals referred to AAA surgery in each group over the trial period.

MAIN RESULTS

Seven trials involving 1558 participants were included in this review; 457 were involved in four trials of antibiotic medication, and 1101 were involved in three trials of beta-blocker medication. Five of the studies were rated at a high risk of bias.Individually, all of the included trials reported non-significant differences in AAA expansion rates between their intervention and control groups.The two major drug groups were then analysed separately. For AAA expansion it was only possible to combine two of the antibiotic trials in a meta-analysis. This demonstrated that roxithromycin had a small but significant protective effect (MD -0.86 mm; 95% confidence interval (CI) -1.57 to -0.14). When referral to AAA surgery was compared (including all four antibiotic trials in the meta-analysis), non-significantly fewer patients were referred in the intervention groups (OR 0.96; 95% CI 0.59 to 1.57) than the control groups. When only the trials reporting actual elective surgery were included in a subgroup analysis, the result remained statistically non-significant (OR 1.17; 95% CI 0.57 to 2.42).For the beta-blocker trials, when all were combined in a meta-analysis, there was a very small, non-significant protective effect for propranolol on AAA expansion (MD -0.08 mm; 95% CI -0.25 to 0.10), and non-significantly fewer patients were referred to AAA surgery in the propranolol group (OR 0.74; 95% CI 0.52 to 1.05). Bronchospasm and shortness of breath were the main adverse effects from the beta-blockers. In one trial the adverse effects were reportedly so severe that the trial was stopped early after two years.

AUTHORS' CONCLUSIONS

There is some limited evidence that antibiotic medication may have a slight protective effect in retarding the expansion rates of small AAAs. The quality of the evidence makes it unclear whether this translates into fewer referrals to AAA surgery, owing mainly to the small sample sizes of the studies.Antibiotics were generally well tolerated with minimal adverse effects. Propranolol was poorly tolerated by patients in all of the beta-blocker trials and demonstrated only minimal and non-significant protective effects. Further research on beta-blockers for AAA needs to consider the use of drugs other than propranolol.In general, there is surprisingly little high quality evidence on medical treatment for small AAAs, especially in relation to the use of newer beta-blockers, ACE inhibitors and statins.

Current imaging modalities for atherosclerosis

Atherosclerotic disease is responsible for nearly half of all deaths in the western world. During the past three decades, considerable efforts have been made towards detection and assessment of atherosclerosis plaques in various vascular beds using different imaging techniques. Recently, both noninvasive and invasive modalities have frequently been used to refine cardiovascular risk assessment in high-risk individuals, to evaluate the natural history of atheroma burden and to reveal the impact of anti-atherosclerotic medical therapies on disease progression. In this review, we provide an overview of the currently available imaging modalities. This article will underscore arterial wall imaging to assess the impact of medical therapies on atherosclerosis and to develop the effective therapeutic strategies, resulting in the prevention of cardiovascular complications.

Advances in noninvasive imaging for evaluating clinical risk and guiding therapy in carotid atherosclerosis

Managing asymptomatic carotid atherosclerosis with a view to preventing ischemic stroke is a challenging task. As the annual risk of stroke in untreated asymptomatic patients on average is less than the risk of surgical intervention, the key question is how to identify those asymptomatic individuals whose risk of stroke is elevated and who would benefit from surgery, while sparing low-risk asymptomatic patients from the risks of surgical intervention. The advent of a multitude of noninvasive carotid imaging techniques offers an opportunity to improve risk stratification in patients and to monitor the response to medical therapies; assessing efficacy at individual and population levels. As part of this, plaque measurement techniques (using ultrasound, computed tomography or MRI) may be employed in monitoring plaque/component regression and progression. Novel imaging applications targeted to plaque characteristics, inflammation and neovascularization, including contrast-enhanced ultrasound and MRI, dynamic contrast-enhanced MRI, and fluorodeoxyglucose-PET, are also being explored. Ultimately, noninvasive imaging and other advances in risk stratification aim to improve and individualize the management of patients with carotid atherosclerosis.

Detection of subclinical atherosclerosis in familial hypercholesterolemia using non-invasive imaging modalities

OBJECTIVES

To investigate the extent of subclinical atherosclerosis in asymptomatic familial hypercholesterolemia (FH) patients using non-invasive images techniques.

PATIENTS, METHODS AND RESULTS

The atherosclerotic burden of 36 molecularly defined FH patients (18 males, 45.7±10.9 years) without evidence of cardiovascular disease receiving lipid-lowering treatment and 19 (47.8±11.3 years) controls was investigated. Descending thoracic aorta magnetic resonance imaging (MRI) was performed in a 1.5 T equipment with T1 and T2 sequences to characterize atherosclerotic plaques and to measure aortic wall volumen. Carotid intima-media thickness (cIMT) and presence of plaques were measured using B-mode carotid ultrasound. Mean aortic wall volumen, cIMT and atherosclerotic plaques in aorta were significantly higher in FH cases (P<0.001). A significant correlation between aortic wall volume and cIMT was observed (P<0.01). Aortic MRI detected plaques in 94% and carotid ultrasound in 14% of cases. Lipid-rich plaques were observed only in FH cases (33%) and were associated with family history of premature coronary artery disease (P<0.05).

CONCLUSIONS

Asymptomatic middle-aged FH patients have significantly higher atherosclerotic burden than controls. cIMT has shown a significant correlation with aortic wall volume and MRI allowed the detection of lipid-rich plaques in FH subjects that were associated with family history of premature coronary artery disease.

Imaging atherosclerosis in HIV: carotid intima-media thickness and beyond

Chronic immune activation and inflammation are associated with an increased risk of atherosclerosis in HIV-infected patients. In this review, we discuss the role of established and novel imaging modalities to define more accurately the structure and function of inflammation-mediated atherosclerosis in the context of HIV. Historically, carotid ultrasound studies were the first to show higher rates of subclinical atherosclerosis in HIV-infected subjects versus uninfected controls. However, computed tomography is the noninvasive gold standard for imaging the coronary arteries, and studies in HIV suggest a higher prevalence of noncalcified plaque. Endothelial dysfunction can be quantified by measuring flow-mediated brachial artery dilation by ultrasound and has been used extensively in antiretroviral switching trials and small pilot trials of therapeutics to assess cardiovascular risk in this population. In the future, novel imaging modalities such as intracoronary optical coherence tomography, positron emission tomography imaging of (18)F-fluorodeoxyglucose uptake, and molecular-targeted magnetic resonance imaging will characterize the burden of vulnerable plaque and other unique features of inflammatory atherosclerosis in HIV.

Associations between serum lipoprotein(a) levels and the severity of coronary and aortic atherosclerosis

To elucidate the associations between Lp(a) levels and coronary and aortic atherosclerosis, we performed aortic MRI in 143 patients undergoing coronary angiography. Severity of aortic atherosclerosis was represented as plaque scores. Of the 143 patients, 104 had coronary artery disease (CAD). Thoracic and abdominal aortic plaques were found in 89 and 131 patients. Lp(a) levels increased stepwise with the number of stenotic coronary vessels: 15.7 (CAD(-)), 21.2 (1-vessel), 21.4 (2-vessel), and 22.9 mg/dl (3-vessel) (P<0.05). For aortic atherosclerosis, 143 patients were divided into quartiles by plaque scores. Lp(a) did not differ among quartiles of thoracic plaques: 17.1, 19.0, 23.5, and 21.2 mg/dl (P=NS), whereas Lp(a) increased stepwise with quartiles of abdominal plaques: 17.1, 19.2, 19.1, and 24.0 mg/dl (P<0.05). Lp(a) was an independent factor for CAD and abdominal aortic plaques, but not thoracic plaques. Thus, Lp(a) levels were associated with aortic atherosclerosis, especially in abdominal aorta, as well as coronary atherosclerosis.

Cardiovascular MRI in clinical trials: expanded applications through novel surrogate endpoints

Recent advances in cardiovascular magnetic resonance (CMR) now allow the accurate and reproducible measurement of many aspects of cardiac and vascular structure and function, with prognostic data emerging for several key imaging biomarkers. These biomarkers are increasingly used in the evaluation of new drugs, devices and lifestyle modifications for the prevention and treatment of cardiovascular disease. This review outlines a conceptual framework for the application of imaging biomarkers to clinical trials, highlights several important CMR techniques which are in use in randomised studies, and reviews certain aspects of trial design, conduct and interpretation in relation to the use of CMR.

Imaging of atherosclerosis: magnetic resonance imaging

Atherosclerosis and its thrombotic complications are the major cause of morbidity and mortality in the industrialized countries. Despite advances in our understanding of the pathophysiology, pathogenesis, and new treatment modalities, the absence of an adequate non-invasive imaging tool for early detection limits both the prevention and treatment of patients with various degrees and anatomical localizations of atherothrombotic disease. An ideal clinical imaging modality for atherosclerotic vascular disease should be safe, inexpensive, non-invasive or minimally invasive, accurate, and reproducible, and the results should correlate with the extent of atherosclerotic disease and have high predictive values for future clinical events. High-resolution magnetic resonance imaging (MRI) has emerged as the most promising technique for studying atherothrombotic disease in humans in vivo. Most importantly, MRI allows for the characterization of plaque composition, i.e. the discrimination of lipid core, fibrosis, calcification, and intraplaque haemorrhage deposits. Magnetic resonance imaging also allows for the detection of arterial thrombi and in defining thrombus age. Magnetic resonance imaging has been used to monitor plaque progression and regression in several animal models of atherosclerosis and in humans. Emerging MRI techniques capable of imaging biological processes, including inflammation, neovascularization, and mechanical forces, may aid in advancing our understanding of the atherothrombotic disease. Advances in diagnosis do prosper provided they march hand-in-hand with advances in treatment. We stand at the threshold of accurate non-invasive assessment of atherosclerosis. Thus, MRI opens new strategies ranging from screening of high-risk patients for early detection and treatment as well as monitoring of the target lesions for pharmacological intervention. Identification of subclinical atherosclerosis and early treatment initiation has the potential to surpass conventional risk factor assessment and management in terms of overall impact on cardiovascular morbidity and mortality. Such strategy is currently under clinical investigation.

Marked regression of aortic plaque by intensive cholesterol-lowering therapy

A 65-year-old man with rheumatic combined valvular heart disease showed a persistent fever after cardiac catheterization. He was diagnosed with cholesterol embolism due to multiple mobile plaques in the descending thoracic aorta by transesophageal echocardiography (TEE) along with persistent eosinophilia, deteriorating renal function, and blue toe sign. He was treated with intensive cholesterol-lowering therapy for 3 years, resulting in marked regression of the aortic plaque on TEE.

Current techniques for MR imaging of atherosclerosis

Vessel wall imaging of large vessels has the potential to identify culprit atherosclerotic plaques that lead to cardiovascular events. Comprehensive assessment of atherosclerotic plaque size, composition, and biological activity is possible with magnetic resonance imaging (MRI). Magnetic resonance imaging of the atherosclerotic plaque has demonstrated high accuracy and measurement reproducibility for plaque size. The accuracy of in vivo multicontrast MRI for identification of plaque composition has been validated against histological findings. Magnetic resonance imaging markers of plaque biological activity such as neovasculature and inflammation have been demonstrated. In contrast to other plaque imaging modalities, MRI can be used to study multiple vascular beds noninvasively over time. In this review, we compare the status of in vivo plaque imaging by MRI to competing imaging modalities. Recent MR technological improvements allow fast, accurate, and reproducible plaque imaging. An overview of current MRI techniques required for carotid plaque imaging including hardware, specialized pulse sequences, and processing algorithms are presented. In addition, the application of these techniques to coronary, aortic, and peripheral vascular beds is reviewed.

Hyperhomocysteinemia is Associated with Aortic Atheroma Progression in Stroke/TIA Patients

Significance: Aortic arch (AA) atheroma and AA atheroma progression are independent risk factors for recurrent vascular events in stroke/transient ischemic attack (TIA) patients. Total homocysteine level (tHcy) is an independent risk marker for atherosclerosis including that found in AA. The purpose of this study was to prospectively test the association between AA atheroma progression and tHcy. Methods: This is a cohort study of 307 consecutive hospitalized stroke/TIA patients undergoing transesophageal echocardiogram (TEE) as a part of their clinical workup. Measurable AA atheroma was detected in 167 patients of whom 125 consented to a protocol-mandated follow-up TEE at 12 months. Patients had evaluation for vascular risk factors, dietary factors (folate, B12 and pyridoxine), and methylene tetrahydrofolate reductase (MTHFR) polymorphism. One hundred eighteen stroke/TIA patients had tHcy, acceptable paired AA images, and detailed plaque measurements. An increase by ≥1 grade of AA atheroma was defined as progression. Results: Of the 118 patients, 33 (28%) showed progression and 17 (14%) showed regression of their index arch lesion at 1 year. tHcy (≥14.0 μmol/l) was significantly associated with progression on both univariate (RR = 3.4, 95% CI 2.0–5.8) and multivariate analyses (adjusted RR = 3.6, 95% CI 2.2–4.6). The changes in AA plaque thickness (r² = 0.11; p < 0.001) and AA plaque area (r² = 0.08; p = 0.002) correlated with tHcy. tHcy was associated with change in plaque thickness over 12 months, independent of age, dietary factors, renal function and MTHFR polymorphism (Standardized β-coefficient 0.335, p = 0.02). Conclusions: Our results validate the association and a linear correlation between tHcy and progression of AA atheroma.

Imaging biomarkers of cardiovascular disease

Cardiovascular disease (CVD) is a leading cause of morbidity and mortality worldwide. Current clinical techniques that rely on stenosis measurement alone appear to be insufficient for risk prediction in atherosclerosis patients. Many novel imaging methods have been developed to study atherosclerosis progression and to identify new features that can predict future clinical risk. MRI of atherosclerotic vessel walls is one such method. It has the ability to noninvasively evaluate multiple biomarkers of the disease such as luminal stenosis, plaque burden, tissue composition and plaque activity. In addition, the accuracy of in vivo MRI has been validated against histology with high reproducibility, thus paving the way for application to epidemiological studies of disease pathogenesis and, by serial MRI, in monitoring the efficacy of therapeutic intervention. In this review, we describe the various MR techniques used to evaluate aspects of plaque progression, discuss imaging-based measurements (imaging biomarkers), and also detail their validation. The application of plaque MRI in clinical trials as well as emerging imaging techniques used to evaluate plaque compositional features and biological activities are also discussed.

Complex atheromatosis of the aortic arch in cerebral infarction

In many stroke patients it is not possible to establish the etiology of stroke. However, in the last two decades, the use of transesophageal echocardiography in patients with stroke of uncertain etiology reveals atherosclerotic plaques in the aortic arch, which often protrude into the lumen and have mobile components in a high percentage of cases. Several autopsy series and retrospective studies of cases and controls have shown an association between aortic arch atheroma and arterial embolism, which was later confirmed by prospectively designed studies. The association with ischemic stroke was particularly strong when atheromas were located proximal to the ostium of the left subclavian artery, when the plaque was ≥ 4 mm thick and particularly when mobile components are present. In these cases, aspirin might not prevent adequately new arterial ischemic events especially stroke. Here we review the evidence of aortic arch atheroma as an independent risk factor for stroke and arterial embolism, including clinical and pathological data on atherosclerosis of the thoracic aorta as an embolic source. In addition, the impact of complex plaques (≥ 4 mm thick, or with mobile components) on increasing the risk of stroke is also reviewed. In non-randomized retrospective studies anticoagulation was superior to antiplatelet therapy in patients with stroke and aortic arch plaques with mobile components. In a retrospective case-control study, statins significantly reduced the relative risk of new vascular events. However, given the limited data available and its retrospective nature, randomized prospective studies are needed to establish the optimal secondary prevention therapeutic regimens in these high risk patients.