Vascular disease

In medicine, vascular disease is "pathological processes involving any of the blood vessels in the cardiac or peripheral circulation. They include diseases of arteries; veins; and rest of the vasculature system in the body." Examples of vascular diseases include coronary heart disease, cerebrovascular disorders, and peripheral vascular disease.

Exercise
Separate to the question of the benefits of exercise; it is unclear whether doctors should spend time counseling patients to exercise. The U.S. Preventive Services Task Force (USPSTF), based on a systematic review of randomized controlled trials, found 'insufficient evidence' to recommend that doctors counsel patients on exercise. However, the American Heart Association, based on a non-systematic review, recommends that doctors counsel patients on exercise

Preventive diets
Dietary changes can potentially lead to large changes in the cholesterol.

Aspirin
Aspirin, in doses of less than 75 to 81 mg/d, can reduce the incidence of cardiovascular events. The U.S. Preventive Services Task Force 'strongly recommends that clinicians discuss aspirin chemoprevention with adults who are at increased risk for coronary heart disease'. The Task Force defines increased risk as 'Men older than 40 years of age, postmenopausal women, and younger persons with risk factors for coronary heart disease (for example, hypertension, diabetes, or smoking) are at increased risk for heart disease and may wish to consider aspirin therapy'. More specifically, high-risk persons are 'those with a 5-year risk ≥ 3%'. A risk calculator is available.

Regarding healthy women, the more recent Women's Health Study randomized controlled trial found insignficant benefit from aspirin in the reduction of cardiac events; however there was a signficant reduction in stroke. Subgroup analysis showed that all benefit was confined to women over 65 years old. In spite of the insignficant benefit for women < 65 years old, recent practice guidelines by the American Heart Association recommend to 'consider' aspirin in 'healthy women' <65 years of age 'when benefit for ischemic stroke prevention is likely to outweigh adverse effects of therapy'.

Antilipemic drugs
The U.S. Preventive Services Task Force (USPSTF) estimated that after 5 to 7 years of treatment with statins, the relative risk reduction of coronary heart disease events is decreased by approximately 30%. More recently, a meta-analysis reported an almost identical relative risk reduction of 29.2% in low risk patients treated for 4.3 years. A relative risk reduction of 19% in coronary mortality was found in a meta-analysis of patients at all levels of risk.

Various clinical practice guidelines have addressed the treatment of hypercholesterolemia. The American College of Physicians has addressed hypercholesterolemia in patients with diabetes. Their recommendations are:
 * Recommendation 1: Lipid-lowering therapy should be used for secondary prevention of cardiovascular mortality and morbidity for all patients (both men and women) with known coronary artery disease and type 2 diabetes.
 * Recommendation 2: Statins should be used for primary prevention against macrovascular complications in patients (both men and women) with type 2 diabetes and other cardiovascular risk factors.
 * Recommendation 3: Once lipid-lowering therapy is initiated, patients with type 2 diabetes mellitus should be taking at least moderate doses of a statin (the accompanying evidence report states "simvastatin, 40 mg/d; pravastatin, 40 mg/d; lovastatin, 40 mg/d; atorvastatin, 20 mg/d; or an equivalent dose of another statin").
 * Recommendation 4: For those patients with type 2 diabetes who are taking statins, routine monitoring of liver function tests or muscle enzymes is not recommended except in specific circumstances.

The National Cholesterol Education Program revised their guidelines ; however, their 2004 revisions have been criticized for use of nonrandomized, observational data.

Antioxidant vitamins
Antioxidant vitamins are not beneficial.

Initially, observational cohort cohort studies such as the Nurses' Health Study found associations between self-reported consumption of vitamin C (ascorbic acid) and vitamin E (α-tocopherol).

The Cambridge Heart Antioxidant Study (CHAOS) was an early randomized controlled trial of vitamin E and in spite of having worse baseline characteritics in the vitamin E group, found "in patients with angiographically proven symptomatic coronary atherosclerosis, alpha-tocopherol treatment substantially reduces the rate of non-fatal MI, with beneficial effects apparent after 1 year of treatment" and no effect oncardiovascular deaths. As noted in the table, the lack of a dose-response gradient makes causation less likely. The study also had less patients in the control group for uncertain reasons in spite of randomization.

In the year 2000, the HOPE study was the first negative randomized controlled trial of Vitamin E to be published. The HOPE study used 400 IU of vitamin E and followed high-risk patients for a mean of 4.5 years. At the time of the HOPE study, 1 of every 8 Americans reported taking vitamin E supplements.

Surprisingly, authors continued to cite positive results from earlier observations studies were refuted by the HOPE trial. These authors often cited the earlier CHAOS study.

In the year 2005, a meta-analysis concluded that Vitamin E supplementation may actually be harmful. After this publication, sales of vitamin E fell by 33%.

Subsequent trials confirmed the HOPE study. Vitamins C (500 mg) and E (400 IU) did not benefit males in the Physicians' Health Study II randomized controlled trial which started recruitment in 1997 and followed patients for a mean of 8 years. Vitamin E did not benefit women in the Women's Health Study randomized controlled trial which began recruitment in 1992 and followed women for an average of 10.1 years.

Omega-3 fatty acids (fish oil)
Omega-3 fatty acids may have small benefit, but results of randomized controlled trials are not consistent. The benefit may be at conferred on 2% of patients who take omega-3 fatty acids.

Homocysteine lowering
Lowering of homocystein blood concentration with folic acid, vitamin B12, and vitamin B6 is not beneficial.

A meta-analysis concluded that lowering homocysteine with folic acid and other supplements may reduce stroke. However, the two largest randomized controlled trials included in the meta-analysis had conflicting results. Lonn reported positive results ; whereas the trial by Toole was negative.

Since the meta-analysis, two additional trials have shown no reduction in cardiovascular endpoint despite successfully lowering the plasma homocysteine level.