HMG-CoA Reductase Inhibitors Suppress the Development and Progression of Carotid Artery Intimal-medial Thickening in Hypercholesterolemic Type 2 Diabetic Patients

[Effect of Statins on Glycemic Status and Plasma Adiponectin Concentrations in Patients with Type 2 Diabetes Mellitus and Hypercholesterolemia]

It is reported that statins have inconsistent effects on glycemic status and adiponectin concentrations in patients with type 2 diabetes mellitus (T2DM). We aimed to investigate the effect of statins on these variables in patients with T2DM and hypercholesterolemia. A control group comprising 24 patients with T2DM but without hypercholesterolemia was observed for more than 12 weeks, while 24 patients with T2DM and hypercholesterolemia were treated with statins for the same period (statin group). The percentage changes in the glycemic status [blood glucose and glycated hemoglobin (HbA1c)], and levels of plasma adiponectin [total and high molecular weight (HMW)] were compared between the two groups. The statin group had reduced percentage changes in HbA1c, blood glucose, and total and HMW-adiponectin concentration percentage changes that were similar to those in the control group. However, when matched for sex, age (±5 years) and HbA1c (±0.5%) with the control group, the pravastatin group had reduced percentage changes in the plasma HMW-adiponectin concentrations than the matched controls (p=0.023). However, there were no differences in the percentage changes in the plasma total adiponectin (p=0.137), HbA1c (p=0.202), or blood glucose concentrations (p=0.450) between the two groups. Pravastatin treatment had no effect on the glycemic status of patients with T2DM and hypercholesterolemia, but may reduce the percentage changes in the plasma HMW-adiponectin concentrations. Hence, patients with T2DM and hypercholesterolemia receiving long-term treatment with pravastatin might experience increased insulin resistance.

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.

Effect of number of ultrasound examinations on the assessment of carotid intima-media thickness changes over time: the example of the METEOR study

OBJECTIVE

To evaluate the effect of the number and positioning during follow-up of ultrasound examinations on the rate of change in carotid intima-media thickness (CIMT) using METEOR (Measuring Effects on Intima-Media Thickness: an Evaluation of Rosuvastatin) as an example.

METHODS

METEOR was a randomized, placebo-controlled trial showing that rosuvastatin reduced progression of 2-year change in CIMT among low-risk patients with subclinical atherosclerosis. In the full METEOR protocol, ultrasound examinations were performed twice before randomization, once each at 6, 12, and 18 months after randomization, and then twice at the end of study at 24 months. For the present study, 17 study designs were retrospectively constructed with varying number and position of ultrasound examinations during the study. Differences in the rate of change in maximum CIMT between these study designs were compared.

RESULTS

Variations in frequency of ultrasound visits gave results in the same direction and magnitude for the change in maximum CIMT for both groups (i.e. nonsignificant change for rosuvastatin and significant progression for placebo, and a significant difference between treatments). However, standard errors were larger when the number of exams reduced. This finding was consistent over different lengths of follow-up, sample sizes, and with CIMT measurements made on different locations.

CONCLUSION

Protocols with different number and timing of ultrasound examinations minimally affect the direction and magnitude of treatment effects on the rate of change in CIMT. However, reductions in exam frequency increase standard errors of rates of change, suggesting larger sample sizes would be required to have the same level of statistical power.

Effects of statins on progression of carotid atherosclerosis as measured by carotid intimal--medial thickness: a meta-analysis of randomized controlled trials

BACKGROUND

Carotid intimal-medial thickness (CIMT) as measured by B-mode ultrasonography is a surrogate marker for carotid atherosclerosis. Studies have found conflicting results for the effect of statins on carotid atherosclerosis progression by measuring CIMT. Hence, this meta-analysis was conducted to evaluate the impact of statin therapy on CIMT progression.

METHODS

A systematic search using PubMed, EMBASE, and Cochrane library databases was performed. Heterogeneity of the studies was analyzed by the Cochran Q statistics. The significance of common treatment effect was assessed by computing common mean difference between the control and treatment groups. A 2-sided alpha error of less than 0.05 was considered to be statistically significant.

RESULTS

In all, 11 trials (N = 3806) fulfilled the criteria for inclusion in the analysis. The study population included 67.2% males and 22.8% females. The mean age was 58.7 years. Treatment with statins (mean treatment duration of 25.6 months) resulted in a significant reduction in the mean low-density lipoprotein ([LDL]; mg/dL, before treatment 168.6 ± 33.3, after treatment 102.33 ± 27.9, P < .05). No significant changes in the levels of LDL cholesterol were noted in the control group. A total of 7 trials showed regression and 4 trials showed slowing of progression of CIMT. Pooled analysis of all 11 trials showed that there was a statistically significant benefit with statin therapy in slowing down the progression of CIMT and the common mean difference between statin therapy arm and placebo arm was -0.040 (CI: -0.052--0.028; P value < .001).

CONCLUSIONS

Statins therapy slows down the progression of carotid atherosclerosis as measured by CIMT, indicating benefits at subclinical stage of the disease process.

Ultrasound protocols to measure carotid intima-media thickness: a post-hoc analysis of the OPAL study

OBJECTIVE

Ultrasound protocols to measure carotid intima-media thickness (CIMT) differ in the number of carotid walls, segments and angles measured. No published evidence is available to help decide which approach is best, i.e. the most reproducible and providing the largest CIMT progression rate measured with highest precision. We compared different ultrasound protocols in a post-hoc analysis in the 'Osteoporosis Prevention and Arterial effects of tiboLone' (OPAL) study, a 3-year randomized controlled trial among healthy postmenopausal women.

RESEARCH DESIGN AND METHODS

Based on combinations of 60 CIMT measurements per participant (two sides, two walls, three segments, five angles), 66 theoretical protocols were constructed. Each protocol was assessed and ranked on: (1) reproducibility (intra-class correlation (ICC), mean difference of duplicate scans) and (2) CIMT progression rate and its precision (standard error) in the placebo group.

RESULTS

Duplicate scans at baseline and end of study were available for 675 women (89% of 759 subjects). ICC ranged from 0.69 to 0.88. Mean difference in CIMT of duplicate scans and its standard deviation, ranged from 0.0010 to 0.0137 mm and from 0.0561 to 0.1770, respectively. CIMT rate of progression ranged from -0.0001 to 0.0113 mm/year. The protocols with highest reproducibility and highest CIMT progression-precision were mean common CIMT protocols measuring both near and far wall at > or = 2 angles. The mean maximum protocol measuring three segments at > or = 2 angles performed best, yet with lower estimates as for common CIMT protocols.

CONCLUSIONS

In healthy middle-aged subjects mean common CIMT protocols that include measurements at both near and far walls at multiple (> or = 2) angles provide highest reproducibility combined with largest estimates of CIMT progression measured with high precision and are to be recommended in this population.

Statins: An essential component in the management of carotid artery disease

OBJECTIVE

We aimed to define the role of treatment using statins (3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors) in the management of patients with carotid artery disease.

LITERATURE SEARCH METHODS

We searched PubMed for studies evaluating the effect of statins on carotid IMT and the occurrence of cerebrovascular events.

LITERATURE SEARCH RESULTS

Current evidence indicates that routine statin therapy reduces carotid intima-media thickness progression and stroke risk. Additionally, statin treatment significantly reduces perioperative as well as long-term morbidity and mortality in patients undergoing carotid surgery or endovascular interventions. It would also be expected that statins would reduce coronary events in this high-risk population.

CONCLUSIONS

Statins should be considered as an essential component of the therapeutic approach of patients with carotid artery stenosis.

Stent material surface and glucose activate mononuclear cells of control, type 1 and type 2 diabetes subjects

In stent restenosis (ISR) has been described as an unaccomplished tissue healing and its rate is particularly high in diabetic patients. Evidence has been collected which relates the formation of ISR proteoglycan-rich neointimal tissue to the accumulation and protracted activation of macrophages around the stent metal struts. Here, the in vitro activation of mononuclear cells adhering to stainless steel (a material of choice in stent manufacturing) from control and diabetic (types 1 and 2) subjects was assessed in the presence of different glucose levels. The results showed that cells from the control and type 1 diabetes groups produced significantly higher levels of TGF-beta1 when adhering on stainless steel (p = 0.04 and p = 0.01), but a significant PDGF-BB secretion was observed only in control subjects. When tested at physiological glucose concentration, the effect of the stainless steel on control cells was more pronounced. The present study shows that mononuclear cells adhering onto stainless steel secrete growth factors relevant to ISR. Cells from diabetic subjects seem to secrete relatively higher levels of PDGF under hyperglycaemic conditions regardless of the substrate exposed thus offering an explanation for the higher incidence of restenosis in these patients.