Study design for a randomized, double-blind trial to assess the effect of 24 months of dosing with rosuvastatin on progression of carotid artery atheroma in moderately hypercholesterolemic patients with asymptomatic carotid stenois

Pharmacological interventions for asymptomatic carotid stenosis

BACKGROUND

Carotid artery stenosis is narrowing of the carotid arteries. Asymptomatic carotid stenosis is when this narrowing occurs in people without a history or symptoms of this disease. It is caused by atherosclerosis; that is, the build-up of fats, cholesterol, and other substances in and on the artery walls. Atherosclerosis is more likely to occur in people with several risk factors, such as diabetes, hypertension, hyperlipidaemia, and smoking. As this damage can develop without symptoms, the first symptom can be a fatal or disabling stroke, known as ischaemic stroke. Carotid stenosis leading to ischaemic stroke is most common in men older than 70 years. Ischaemic stroke is a worldwide public health problem.

OBJECTIVES

To assess the effects of pharmacological interventions for the treatment of asymptomatic carotid stenosis in preventing neurological impairment, ipsilateral major or disabling stroke, death, major bleeding, and other outcomes.

SEARCH METHODS

We searched the Cochrane Stroke Group trials register, CENTRAL, MEDLINE, Embase, two other databases, and three trials registers from their inception to 9 August 2022. We also checked the reference lists of any relevant systematic reviews identified and contacted specialists in the field for additional references to trials.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs), irrespective of publication status and language, comparing a pharmacological intervention to placebo, no treatment, or another pharmacological intervention for asymptomatic carotid stenosis.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodological procedures. Two review authors independently extracted the data and assessed the risk of bias of the trials. A third author resolved disagreements when necessary. We assessed the evidence certainty for key outcomes using GRADE.

MAIN RESULTS

We included 34 RCTs with 11,571 participants. Data for meta-analysis were available from only 22 studies with 6887 participants. The mean follow-up period was 2.5 years. None of the 34 included studies assessed neurological impairment and quality of life. Antiplatelet agent (acetylsalicylic acid) versus placebo Acetylsalicylic acid (1 study, 372 participants) may result in little to no difference in ipsilateral major or disabling stroke (risk ratio (RR) 1.08, 95% confidence interval (CI) 0.47 to 2.47), stroke-related mortality (RR 1.40, 95% CI 0.54 to 3.59), progression of carotid stenosis (RR 1.16, 95% CI 0.79 to 1.71), and adverse events (RR 0.81, 95% CI 0.41 to 1.59), compared to placebo (all low-certainty evidence). The effect of acetylsalicylic acid on major bleeding is very uncertain (RR 0.98, 95% CI 0.06 to 15.53; very low-certainty evidence). The study did not measure neurological impairment or quality of life. Antihypertensive agents (metoprolol and chlorthalidone) versus placebo The antihypertensive agent, metoprolol, may result in no difference in ipsilateral major or disabling stroke (RR 0.14, 95% CI 0.02 to1.16; 1 study, 793 participants) and stroke-related mortality (RR 0.57, 95% CI 0.17 to 1.94; 1 study, 793 participants) compared to placebo (both low-certainty evidence). However, chlorthalidone may slow the progression of carotid stenosis (RR 0.45, 95% CI 0.23 to 0.91; 1 study, 129 participants; low-certainty evidence) compared to placebo. Neither study measured neurological impairment, major bleeding, adverse events, or quality of life. Anticoagulant agent (warfarin) versus placebo The evidence is very uncertain about the effects of warfarin (1 study, 919 participants) on major bleeding (RR 1.19, 95% CI 0.97 to 1.46; very low-certainty evidence), but it may reduce adverse events (RR 0.89, 95% CI 0.81 to 0.99; low-certainty evidence) compared to placebo. The study did not measure neurological impairment, ipsilateral major or disabling stroke, stroke-related mortality, progression of carotid stenosis, or quality of life. Lipid-lowering agents (atorvastatin, fluvastatin, lovastatin, pravastatin, probucol, and rosuvastatin) versus placebo or no treatment Lipid-lowering agents may result in little to no difference in ipsilateral major or disabling stroke (atorvastatin, lovastatin, pravastatin, and rosuvastatin; RR 0.36, 95% CI 0.09 to 1.53; 5 studies, 2235 participants) stroke-related mortality (lovastatin and pravastatin; RR 0.25, 95% CI 0.03 to 2.29; 2 studies, 1366 participants), and adverse events (fluvastatin, lovastatin, pravastatin, probucol, and rosuvastatin; RR 0.76, 95% CI 0.53 to1.10; 7 studies, 3726 participants) compared to placebo or no treatment (all low-certainty evidence). The studies did not measure neurological impairment, major bleeding, progression of carotid stenosis, or quality of life.

AUTHORS' CONCLUSIONS

Although there is no high-certainty evidence to support pharmacological intervention, this does not mean that pharmacological treatments are ineffective in preventing ischaemic cerebral events, morbidity, and mortality. High-quality RCTs are needed to better inform the best medical treatment that may reduce the burden of carotid stenosis. In the interim, clinicians will have to use other sources of information.

The GALAXY Program: an update on studies investigating efficacy and tolerability of rosuvastatin for reducing cardiovascular risk

The GALAXY Program is a series of clinical studies investigating the efficacy and tolerability of rosuvastatin in line with the hypothesis that the statin with the greatest efficacy for improving the atherogenic lipid profile and beneficially modifying inflammatory markers will also slow progression of atherosclerosis and improve cardiovascular outcomes. Completed studies report that rosuvastatin is more effective than comparator statins in reducing low-density lipoprotein cholesterol, improving the lipid profile and enabling patients to achieve lipid goals, including revised, more stringent goals, even in high-risk patients. Studies have also reported that rosuvastatin can arrest and even regress atherosclerosis. Ongoing outcomes studies will determine whether these beneficial effects of rosuvastatin translate into reduced morbidity and mortality.

MRI of atherosclerosis

The emergence of high-resolution, rapid imaging methods has enabled MRI to noninvasively image the fine internal structure of atherosclerotic artery walls. This capability has, in turn, captured the interest of clinicians, who see it as an opportunity to assess disease severity based on the characteristics of atherosclerotic lesions themselves, rather than only their effects on the vessel lumen. MRI of atherosclerosis thus has the potential to be used in medical treatment decisions or to assess the effects of experimental treatment options. Given this potential, a number of research groups have been investigating MRI of atherosclerosis in an effort to establish the ability of MRI to determine atherosclerotic plaque burden, detect plaque composition, and ultimately identify vulnerable plaque before it leads to a clinical event. In this review, the current state of the art is summarized for the three primary vessel targets: the carotid artery, the aorta, and the coronary arteries.

Cardioprotective and other emerging effects of statins

The lipid-lowering properties of statins are accompanied by a number of other cardioprotective effects. These 'pleiotropic' actions affect almost the entire process of atherogenesis, from initial endothelial injury to the moment of plaque rupture and thrombosis. This paper discusses the nonlipid-lowering effects of statins that affect the initiation, progression, regression and repair of atherosclerosis lesions, as well as factors that affect plaque instability. The emergent anti-inflammatory, antioxidant and immunomodulatory properties of statins are extensive and diverse. Many of these properties, which are independent of cholesterol synthesis inhibition, help to reduce the ischaemic burden on the cardiovascular system. In addition, the immunomodulatory properties of statins may provide new indications for these agents in the treatment of autoimmune diseases.

Rosuvastatin: a new inhibitor of HMG-coA reductase for the treatment of dyslipidemia

Rosuvastatin (Crestor, AstraZeneca) is a synthetic statin that represents an advance on the pharmacologic and clinical properties of other agents in this class. Relative to other statins, rosuvastatin possesses a greater number of binding interactions with HMG-CoA reductase and has a high affinity for the active site of the enzyme. Rosuvastatin is relatively hydrophilic and is selectively taken up by, and active in, hepatic cells. Rosuvastatin has the longest terminal half-life of the statins and is only minimally metabolized by the cytochrome P450 (CYP 450) enzyme system with no significant involvement of the 3A4 enzyme. Consistent with this finding is the absence of clinically significant drug interactions between rosuvastatin and other drugs known to inhibit CYP 450 enzymes. In patients with hypercholesterolemia, rosuvastatin 10-40 mg has been shown to reduce low-density lipoprotein cholesterol (LDL-C) levels by 52-63%, as well as increase high-density lipoprotein cholesterol (HDL-C) levels by up to 14% and reduce triglycerides (TG) by up to 28%. Studies have shown that rosuvastatin is superior to atorvastatin, simvastatin and pravastatin in reducing LDL-C and favorably modifying other components of the atherogenic lipid profile. The significant decreases in LDL-C with rosuvastatin treatment should help to improve attainment of lipid goals and reduce the requirement for dose titration. In addition, the effects of rosuvastatin on HDL-C and TG levels will be of benefit in treating patients with abnormalities such as mixed dyslipidemia and the metabolic syndrome. Rosuvastatin is well tolerated, with a safety profile comparable with that of other currently available statins.

Carotid atherosclerotic wall imaging by MRI

High spatial resolution magnetic resonance imaging (MRI) is one of the most promising modalities for visualizing the carotid atherosclerotic plaque. MR allows direct visualization of the diseased vessel wall, is capable of characterizing plaque morphology, and can potentially monitor progression of the disease. Though ultrasound and angiography have been the principal methods for determining the severity of carotid atherosclerosis and the need for endarterectomy, these methods only measure percentage of vessel stenosis. There is strong evidence that this is not the best indicator for assessing clinical risk. Improved imaging techniques are therefore needed to reliably identify the high-risk plaques that lead to cerebrovascular events. This article focuses on the current state-of-the-art in MR carotid atherosclerotic plaque imaging to evaluate plaque morphology and composition.