New evidence for stroke prevention: scientific review

CONTEXT

Stroke is a major cause of morbidity and mortality, and the application of evidence for stroke prevention varies considerably.

OBJECTIVE

To review the most recent, high-quality evidence for primary and secondary stroke prevention.

DATA SOURCES AND STUDY SELECTION

Searches of MEDLINE, The Cochrane Library, and the ACP Journal Club were performed to identify English-language articles published from 1998 to 2001 that focused on primary and secondary stroke prevention. The references of each retrieved article were scanned, and experts in the field were contacted to identify additional relevant articles.

DATA EXTRACTION

Each of the articles was appraised, and its quality was graded with levels of evidence based on specific scientific methods that affect a study's validity.

DATA SYNTHESIS

For primary prevention of stroke, adequate blood pressure reduction, and treatment of hyperlipidemia, use of antithrombotic therapy in patients with atrial fibrillation and of antiplatelet therapy in patients with myocardial infarction are effective and supported by evidence from several randomized trials. Effective strategies for the secondary prevention of stroke include treatment of hypertension and hyperlipidemia, antithrombotic therapy for patients with atrial fibrillation, antiplatelet therapy, and carotid endarterectomy in patients with severe carotid artery stenosis.

CONCLUSIONS

Stroke is a major public health concern, and a significant body of evidence supports many primary and secondary prevention strategies.

Rationale for and role of thiazolidinediones in type 2 diabetes mellitus

Several classes of antihyperglycemic agents are available for the treatment of patients with type 2 diabetes. These agents, including thiazolidinediones, biguanides, insulin secretagogues, alpha-glucosidase inhibitors, and insulin, offer differing mechanisms of actions and can be used either alone or in combination. The thiazolidinediones are a newer class of oral antidiabetic agents that improve glycemic control and may preserve beta-cell function. Clinical trial data suggest that patients with type 2 diabetes experience progressive deterioration of beta-cell function. By decreasing insulin resistance, thiazolidinediones may preserve beta-cell function, and patients may experience prolonged glycemic control. The thiazolidinediones also exert beneficial effects on dyslipidemia, endothelial function, coagulation, and blood pressure. By improving these components of the metabolic syndrome, thiazolidinediones may reduce the incidence of both microvascular and macrovascular complications. This article provides an overview of the role of thiazolidinediones in the treatment of type 2 diabetes.

Update on the management of dyslipidemia

The third edition of guidelines from the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III [ATP III]) is discussed. The most recent classifications for low-density-lipoprotein (LDL) cholesterol, high-density-lipoprotein (HDL), total cholesterol, and triglycerides are provided. LDL cholesterol goals, cardiovascular risk assessment, therapeutic goals, and pharmacologic treatment options are discussed for both primary and secondary prevention of cardiovascular disease. In addition, the management of dyslipidemia in patients with diabetes and metobolic syndrome is addressed, and the differences between the old and new guidelines are highlighted. The ATP III guidelines may help health care professionals to better screen and categorize patients on the basis of their coronary heart disease (CHD) risk. The updated guidelines recommend more intensive lipid-lowering treatments for primary prevention in patients with two or more risk factors.

Lipoprotein abnormalities in hemodialysis and continuous ambulatory peritoneal dialysis patients

Lipid abnormalities are important variables in the development of vascular atherosclerotic lesions in ESRD patients while Lp(a) represents an independent risk factor. In order to evaluate lipid changes in HD and CAPD patients, serum cholesterol (TC), HDLc, LDLc, TG, apolipoproteins (AI,AII,B,E), Lp(a), and albumin levels were estimated in 109 ESRD dialyzed patients, 46 in HD and 63 in CAPD (mean duration 50 +/- 40 and 25 +/- 19 months, respectively), and 45 volunteers with high serum levels of C and TG, without renal insufficiency. Both HD and PD group revealed statistically significantly higher levels than controls for TC, TG, LDL-C, Apo-B,-E, while HDL-C levels were significantly lower. Except for the lower serum albumin levels in both dialyzed groups after six months lower ApoAI levels and higher ApoB levels were observed in HD and PD patients respectively. Lp(a) levels remained unchanged in HD group, while a statistically significant increase appeared in PD patients that was negative correlated with the decreased serum albumin levels. These results indicate that renal replacement modalities result in a different effect in lipoprotein metabolism that may play an important role in atherosclerotic vascular disease of dialyzed ESRD patients.

Oxidative stress, alpha-tocopherol therapy, and atherosclerosis

Atherosclerosis is the leading cause of morbidity and mortality in the United States. Evidence suggests that antioxidants, especially alpha-tocopherol (AT), have potential benefits with respect to cardiovascular disease. AT has been shown to decrease lipid peroxidation, to inhibit platelet adhesion, aggregation, and smooth muscle cell proliferation, to exert anti-inflammatory effects on monocytes, and to improve endothelial function. Low levels of AT are related to a higher incidence of cardiovascular disease and increased intakes appear to afford protection against cardiovascular disease. Although clinical trials with AT supplementation to date have been conflicting, the majority of evidence supports a benefit for AT supplementation in patients with pre-existing cardiovascular disease. Clearly, more clinical trials are required in individuals with increased oxidative stress before a definitive recommendation can be made with respect to AT supplementation in atherosclerosis.

[Effects of dietary intervention on hyperlipidemia in eight communities in Beijing]

Based on the data available from hyperlipidemia screening, 180 participants were recruited and divided into intervention group and control group. Dietary intervention lasted six months and dietary survey, anthropometry and serum lipid determination were performed and analyzed respectively before and after the intervention. The results showed the decreases of total calories, fat, cholesterol and oil by 13.20%, 24.75%, 24.40% and 22.43% respectively in participants of intervention group. The percentages of total calories provided by fat, carbohydrate and protein trended to be desirable and the reductions were also observed in body weight and BMI. There were 5.61% and 7.06% reductions in total serum cholesterol and low-density lipoprotein cholesterol in intervention group, while no significant reduction in the control group. These results indicated that the community-based dietary intervention could effectively improve dietary pattern, control body weight, decrease the level of total serum cholesterol and low-density lipoprotein cholesterol.

Prevention of cardiovascular diseases. Coronary artery disease, congestive heart failure, and stroke

Cardiovascular disease leads to significant morbidity and mortality in the older population. Results of risk reduction can be dramatic in terms of patient survival and quality of life. This article reviews evidence for cardiovascular risk factors and disease prevention in older adults. Interventions which reduce morbidity and mortality from coronary artery disease, heart failure, and cerebrovascular disease in the elderly population are examined. Attention is given to the role of cardiovascular disease in older women and in minorities, subsets not well-represented in many studies.

Calcium-D-glucarate

Calcium-D-glucarate is the calcium salt of D-glucaric acid, a substance produced naturally in small amounts by mammals, including humans. Glucaric acid is also found in many fruits and vegetables with the highest concentrations to be found in oranges, apples, grapefruit, and cruciferous vegetables. Oral supplementation of calcium-D-glucarate has been shown to inhibit beta-glucuronidase, an enzyme produced by colonic microflora and involved in Phase II liver detoxification. Elevated beta-glucuronidase activity is associated with an increased risk for various cancers, particularly hormone-dependent cancers such as breast, prostate, and colon cancers. Other potential clinical applications of oral calcium-D-glucarate include regulation of estrogen metabolism and as a lipid-lowering agent.

The surveillance of cholesterol management in the cardiac rehabilitation setting

PURPOSE

To evaluate the secondary prevention of coronary heart disease in the cardiac rehabilitation setting by quantifying the percentage of patients on lipid lowering therapy, the percentage of patients who have received diet counseling, and the percentage of patients with a lipid panel documented by discharge.

METHODS

The Web-based database of the Wisconsin Society for Cardiovascular and Pulmonary Rehabilitation, representing 1477 patients, was examined for patient outcomes. A survey was sent to programs to assess the processes in place to assist patients in managing cholesterol and reaching a low-density lipoprotein (LDL-C) goal of less than 100 mg/dL.

RESULTS

Most patients were taking cholesterol medications (median, 70.9%; 95% confidence interval [CI], 63.9-80.9). A minority of patients had an LDL-C at the goal level (median, 42.6%; 95% CI, 27.7-58.6), and a few patients had received individual dietary counseling from a registered dietitian (median, 17.9%; 95% CI, 4.8-56.2). The survey indicated that although all programs made an effort to determine cholesterol levels at cardiac rehabilitation entry, only one half of the programs required a lipid panel at discharge also.

CONCLUSIONS

There is a high degree of variation among cardiac rehabilitation programs in terms of surveillance and treatment of dyslipidemias for patients with coronary heart disease.

[Primary and secondary prevention in dyslipidemia in the elderly]

Cardiovascular disease (CVD) is the leading cause of mortality and a major cause of disability in advanced age. The relationship between coronary heart disease (CHD) and dyslipoproteinaemia is well known. The fact, however, that atherosclerosis is a systemic disease leads also to the consideration that patients suffering from cerebrovascular and peripheral arterial disease should benefit similarly from lipid lowering therapy as do patients with CHD. There is already growing evidence that the incidence of stroke may be markedly decreased by statin therapy. Though overall, the clinical significance of hypercholesterolaemia seems to decrease with increasing age, patients at age 65 to 75 tend to benefit even more than younger patients when elevated LDL-cholesterol is treated effectively. It should be noticed that prevention or postponement of cardiovascular events may also prevent premature functional limitations and disability in old age. Hence, it is suggested to screen elderly people with CVD for dyslipoproteinaemia and to treat elevated cholesterol levels by means of life style changes, nutritional therapy, and drug therapy. Treatment regimes should be considered depending upon complete risk stratification and geriatric assessment. Chronological age alone cannot be an argument to withhold a proven effective therapy from a growing segment of the population at risk.

Contemporary management of hyperlipidemia in women

OBJECTIVE

The objective of this paper is to review prospective, large-scale studies of lipid-lowering therapy and hormone replacement therapy, and to provide clinical recommendations for the management of hyperlipidemia in women within the context of the revised National Cholesterol Education Program (NCEP) guidelines.

METHODS

Recent English language literature derived from a MEDLINE search (January 1990-July 2001) and bibliographies of relevant papers were reviewed, and data were abstracted from identified papers.

RESULTS

Hyperlipidemia is largely undertreated in women. Previously, hormone replacement therapy (HRT) was considered first-line treatment for the management of hypercholesterolemia to prevent coronary artery disease (CAD) in women. Recent studies, however, show no benefit of HRT for secondary prevention of coronary events, despite its beneficial effects on lipids. Large-scale, controlled clinical trials indicate that women, even those with only moderately elevated cholesterol, benefit from the lipid-lowering effects of statins for both high-risk primary and secondary prevention of CAD. Based on this evidence, the recently revised NCEP guidelines recommend statins as first-line therapy for women with hyperlipidemia, an approach that is supported by the American Heart Association and the American College of Cardiology. With its emphasis on aggressive intervention for persons with multiple risk factors, the new guidelines substantially increase the number of women eligible for pharmacological therapy.

CONCLUSIONS

All women with hyperlipidemia should receive counseling regarding lifestyle approaches for lowering cholesterol. The decision to use HRT should be made in the context of other conditions hormones may affect. Alternative hormonal regimens for lipid management may include selective estrogen receptor modulators and phytoestrogens, but results of randomized clinical trials are necessary before firm recommendations can be made regarding their clinical value in preventing CAD.