Arteriosclerosis Support Group

Pathologically, the atheromatous plaque is divided into three distinct components:

1. The atheroma ("lump of porridge", from Athera, porridge in Greek,) is the nodular accumulation of a soft, flaky, yellowish material at the center of large plaques, composed of macrophages nearest the lumen of the artery, sometimes with
2. Underlying areas of cholesterol crystals, and possibly also
3. Calcification at the outer base of older/more advanced lesions.

Arteriosclerosis ("hardening of the artery") results from a deposition of tough, rigid collagen inside the vessel wall and around the atheroma. This increases the stiffness, decreases the elasticity of the artery wall. Arteriolosclerosis (hardening of small arteries, the arterioles) is the result of collagen deposition, but also muscle wall thickening and deposition of protein ("hyaline").

Calcification, sometimes even ossification (formation of complete bone tissue) occurs within the deepest and oldest layers of the sclerosed vessel wall.

Atherosclerosis causes two main problems. First, the atheromatous plaques, though long compensated for by artery enlargement, eventually lead to plaque ruptures and stenosis (narrowing) of the artery and, therefore, an insufficient blood supply to the organ it feeds. Alternatively, if the compensating artery enlargement process is excessive, then a net aneurysm results.

These complications are chronic, slowly progressing and cumulative. Most commonly, soft plaque suddenly ruptures (see vulnerable plaque), causing the formation of a blood clot (thrombus) that will rapidly slow or stop blood flow, e.g. 5 minutes, leading to death of the tissues fed by the artery. This catastrophic event is called an infarction. One of the most common recognized scenarios is called coronary thrombosis of a coronary artery causing myocardial infarction (a heart attack). Another common scenario in very advanced disease is claudication from insufficient blood supply to the legs, typically due to a combination of both stenosis and aneurysmal segments narrowed with clots. Kidney, intestinal and other arteries are also typically involved.

Atherosclerosis typically begins in early adolescence, is usually found in most major arteries, yet is asymptomatic and not detected by most diagnostic methods during life. It most commonly becomes seriously symptomatic when interfering with the coronary circulation supplying the heart or cerebral circulation supplying the brain, and is considered the most important underlying cause of strokes, heart attacks, various heart diseases including congestive heart failure and most cardiovascular diseases in general. Atheroma in arm or more often leg arteries and producing decreased blood flow is called Peripheral artery occlusive disease (PAOD).

According to United States data for the year 2004, for about 65% of men and 47% of women, the first symptom of atherosclerotic cardiovascular disease is heart attack or sudden cardiac death (death within one hour of onset of the symptom).

If atherosclerosis leads to symptoms, the symptoms (such as angina pectoris) can be treated. Non-pharmaceutical means are usually the first method of treatment, such as cessation of smoking and/or regular exercise. If these methods do not work, medicines are usually the next step in treating cardiovascular diseases, and with improvements, have increasingly become the most effective method over the long term. However, medicines are criticized for their expense, patented control and occasional undesired effects.

Lipoprotein imbalances, upper normal and especially elevated blood sugar, i.e. diabetes, high blood pressure, homocysteine, stopping smoking, taking anticoagulants (anti-clotting agents) which target clotting factors, taking Omega 3 oils from salt-water fish meats, exercising and losing weight are the usual focus of treatments which have proved to be helpful in clinical trials. The target serum cholesterol level is ideally equal or less than 4mmol/L (with triglycerides equal or less than 2mmol/L).

In general, the group of medications referred to as statins have been the most successful, with the lowest rates of undesirable side-effects, approach to reducing atherosclerotic disease events. The newest statin, rosuvastatin, has been the first to demonstrate regression of atherosclerotic plaque within the coronary arteries by IVUS evaluation, see the Effect of Very High-Intensity Statin Therapy reference below. However, for most people, changing their physiologic behaviors, from the usual high risk to greatly reduced risk, requires a combination of several compounds, taken on a daily basis and indefinitely. More and more human treatment trials have been done and are ongoing which demonstrate improved outcome for those people using more complex and effective treatment regimens which change physiologic behaviour patterns to more closely resemble those humans exhibit in childhood at a time before fatty streaks begin forming.

Lowering lipoprotein little a, a genetic variant of LDL, can be achieved with large daily doses of vitamin B3, niacin. Niacin also tends to shift LDL particle distribution to larger particle size and improve HDL functioning. Work on increasing HDL particle concentration and function, beyond the niacin effect, perhaps even more important, is slowly advancing. Combinations of statins, niacin, intestinal cholesterol absorption inhibiting supplements (ezetimibe and others, and to a much lesser extent fibrates have been the most successful in changing dyslipidemia patterns and improving clinical outcomes in secondary prevention. In primary prevention, cholesterol lowering agents have also reduced the mortality rates, (e.g. the AFCAPS/TexCAPS trail), however longer periods are sometimes required to demonstrate the effect because of the usual delay until enough people show the effects of advancing disease without effective treatment. Dietary changes to achieve this have been more controversial, generally far less effective and less widely adhered to with success.

Evidence has increased that people with diabetes, despite not having clinically detectable atherosclotic disease, have more severe debility from atherosclerotic events over time than even non-diabetics who have already suffered atherosclerotic events. Thus diabetes has been upgraded to be viewed as an advanced atherosclerotic disease equivalent.

Lowering homocysteine levels, including within the normal range and dietary supplements of Omega 3 oils, especially those from the muscle of some deep salt water living fish species, also have clinical evidence of significant protective effects as confirmed by 6 double blind placebo controlled human clinical trials.

Aerobic exercise, weight loss, and dietary changes can also help, but are generally much less effective and often more problematic for many to achieve and continue long term.

Medical treatments often focus predominantly on the symptoms. However, over time, the treatments which focus on decreasing the underlying atherosclerosis processes, as opposed to simply treating the symptoms resulting from the atherosclerosis, have been shown by clinical trials to be more effective.

Other physical treatments, helpful in the short term, include minimally invasive angioplasty procedures to physically expand narrowed arteries and major invasive surgery, such as bypass surgery, to create additional blood supply connections which go around the more severely narrowed areas.

High dose supplements of vitamin E or C, with the goal of improving antioxidant protection, have failed to produce any beneficial trends in human, double blind, clinical research trials. However, these trials have consistently used lower doses than those claimed to be effective and have ignored the short half life of high intakes of vitamin C in the body.

On the other hand, the statins, and some other medications have been shown to have significant antioxidant effects, perhaps part of their basis for major theraputic success.

The success of statin drugs in clinical trials is based on large reductions in actual human mortality rates. For example, in 4S, the first large placebo controlled, randomized clinical trial of a statin in people with advanced disease who had already suffered a heart attack, the overall mortality rate reduction for those taking the statin, vs. placebo, was 30%. For the subgroup of people in the trial who had Diabetes Mellitus, the mortality rate reduction between statin and placebo was 54%. 4S was a 5.4 year trial which started in 1989 and was published in 1995 after completion. Many later trials, using more aggressive statin treatments, especially in combination with additional treatment strategies, have shown greater reductions in mortality rates. The ASTEROID trial, mentioned above and in reference 3, has been the first to show actual disease volume regression; however, its design was not large enough or long enough to statistically "prove" the mortality reduction issue. The trials to test this issue with this agent are currently in progress; all current evidence and signs are that the outcomes will be very favorable.

Over the last about 18 years, the treatment data results have become so encouraging that some physician leaders are anticipating the day, probably within another 10 to 15 years, that clinical disability from atherosclerotic disease will become a disease only of the past, at least for those who enjoy the benefit of using the treatment advances.

In summary, the key to the more effective approaches has been better understanding of the widespread and insidious nature of the disease and to combine multiple different treatment strategies, not rely on just one or a few approaches. Additionally, for those approaches, such as lipoprotein transport behaviors, which have been shown to produce the most success, adopting more aggressive combination treatment strategies has generally produced better results, both before and especially after people are symptomatic. However, treating asymptomatic people remains controversial in the medical community.

Patients at risk for atherosclerosis-related diseases are increasingly being treated prophylactically with low-dose aspirin and a statin. The high incidence of cardiovascular disease led Wald and Law to propose a Polypill, a once-daily pill containing these two types of drugs in addition to an ACE inhibitor, diuretic and beta blocker and folic acid. They maintain that high uptake by the general population by such a Polypill would reduce cardiovascular mortality by 80%. It must be emphasized however that this is purely theoretical, as the Polypill has never been tested in a clinical trial.