Aspirin therapy in diabetes
For diabetics, atherosclerosis and vascular thrombosis are major contributors to the risk factor of death from complications of cardiovascular disease. A major mechanism is increased production of thromboxane, a potent vasoconstrictor and platelet aggregant. Researchers have found an excess thromboxane release in type 2 diabetics with cardiovascular disease. Aspirin blocks thromboxane synthesis by acetylating platelets.
Cyclo-oxgenase has been used as both a primary and secondary strategy to prevent cardiovascular events in nondiabetic persons. Large-scale collaborative trials in men and women with diabetes support the view that low-dose aspirin therapy should be prescribed as a secondary prevention strategy, if no contraindications exist. There is substantial evidence that low-dose aspirin therapy should also be used as a primary prevention strategy in men and women with diabetes who are at high risk for cardiovascular events. You know, after bypass surgery I take it, and every doctor I see asks if I continue to do so.
In terms of dosage, our research indicates that an enteric-coated aspirin as low as 75 mg is just as effective as higher doses in inhibiting thromboxane synthesis. It is thought that using enteric preparation theoretically allows for constant suppression of this process. Tests have been done with combination of aspirin with other antiplatelet drugs and none of these was found to be any more effective than aspirin alone.
Meta-analysis has shown that aspirin is efficacious in a wide variety of patients. Proportional benefits have been found in males and females with or without hypertension, those over 65 years and in both non-diabetics and diabetics. Absolute benefit was greater for those at high risk, that is diabetic people over 65 with hypertension. Tests have shown that aspirin therapy is associated with a reduced risk for myocardial infarction in women. This is also true for men. If one has an allergy to aspirin, clopidogrel can be substituted. Also, note that as you take ACE inhibitors and have established CVD, the benefits of aspirin may be lessened. Alternate antiplatelet agents may be considered for these people.
The following recommendations will help you understand if this is a conversation you need to have with your physician.
- Aspirin therapy should be used as a secondary prevention in diabetic people that have large vessel disease. This includes people with a history of heart attack bypass surgery, stroke or transient ischemic attack, peripheral vascular disease, claudicating, or angina.
- Aspirin therapy is suggested as a primary prevention strategy in high-risk people with type 1 or type 2 diabetes over 30 years of age if they have a family history of heart disease, smoke, have hypertension, are obese, and have albuminuria or high triglycerides.
- It is not suggested for those with an allergy to aspirin, or those who have a bleeding tendency, are on anticoagulant therapy, have had recent GI bleeding, or have active hepatic disease. It is also not recommended for people under 21 years because of the increased risk of Reye's syndromes.
Inflammation and heart disease
New research has shown that people with seemingly healthy cholesterol levels are at high risk of heart attacks because of painless inflammation in the bloodstream. This inflammation comes from many sources and triggers heart attacks by weakening the walls of blood vessels, making fatty buildups burst through. Inflammation can be measured with a test that checks for C-reactive protein, or CRP, a chemical necessary for fighting injury and infection. Diet and exercise can lower CRP as can statins and aspirin.
Doctors believe the condition often begins when fatty buildups that line the blood vessels become inflamed as white blood cells invade in a misguided defense attempt. Fat cells are also known to turn out these inflammatory proteins. Other possible triggers include high blood pressure, smoking and lingering infections, such as chronic gum disease.
The Centers for Disease Control and Prevention met in March to examine evidence and make recommendations on the CRP test, but have gone back to the drawing board after new research from Boston's Brigham and Women's was recently published. Dr. Ridker, who published the report, stated that "The CRP test can predict 15 to 25 years in the future." He hopes that a high CRP reading can help doctors persuade patients with low cholesterol that they need to exercise and diet. Just so that you don't think that Dr. Ridker's study was a small one, he based his results on an 8-year-follow-up of 27,939 volunteers, and doctors at prestigious hospitals such as the Cleveland Clinic, Ochsner Clinic and Emory use the test routinely as do physicians in the know around the country.
Homocysteine testing
During my last physical, the internist asked if I had been given a Homocysteine test by my cardiologist. Since the answer was no, she included it in my lab work. It came back normal, but as I researched just what this test was about, I knew I had an internist who was not only a friend, but a bright, well-read doctor. The research on Homocysteine testing may not be 100% conclusive, but read on. Those who believe in this testing suggest that it is second only to cholesterol as a potential risk factor for heart disease. High blood levels of Homocysteine, which is an amino acid, can damage artery walls and contribute to blocking of blood vessels. Its potential damaging effects have been suggested for at least thirty years, but only recently has it moved to center stage as a risk factor. New research suggests that for every ten percent rise in Homocysteine there is the same rise in the risk for developing coronary heart disease. People with levels of Homocysteine in the top fifth of the normal range have a 2.2 times higher risk of cardiovascular disease. In people with coronary heart disease, the risk of death four to five years after diagnosis was found to be proportional to the total amount of Homocysteine in the blood. There is research that concludes that testing for this amino acid is beneficial only for those with known heart disease, while others have found that a treat-all strategy reduced risk of CHD-related death by 11 % in men and 23% in women but saved more than $500,000 per life-year as compared to $50,000 per life year saved in the screen and treat group.
Now let's look at the controversial aspects of Homocysteine testing. As we stated before, this is an amino acid, which means it is one of the chemicals that forms proteins. Everyone produces it, mainly from eating animal products. Normally the substance is converted into other non-damaging amino acids. But in some people, this process is slow, and results in the accumulation of Homocysteine in the blood. Studies suggest that this problem is influenced by diet-specifically, low blood levels of vitamin B-6, B-12 and folic acid. When we spoke about testing for my Homocysteine level, I was relieved to know that it could be treated with folic acid. These vitamins convert Homocysteine into harmless amino acids. The controversy over how to treat comes from the lack of clinical studies where some people get the vitamins and others don't. In addition, optimal doses are currently known only where toxicity has been determined.
The American Heart Association suggests that you eat foods high in folic acid. Good sources of folic acid are citrus fruits, tomatoes, vegetables and grain products. Starting in 1998, grain and cereal products were fortified with folic acid so read the labels. B6 can be found in chicken, fish, pork, kidney and eggs as well as unmilled rice. The best sources for B12 are animal products, peanuts and walnuts. If you think you're not eating a good enough diet or you want more protection, take a multivitamin each day. If you are at high risk for heart disease, talk over the daily requirements with your physician and whether you need to protect yourself.
There are two other areas that you will want to discuss with your physician. One is metabolic syndrome and the risk of heart disease, and the other is a new study about HRT and its effects on a 16 percent lowering of heart attack in women with diabetes who had no history of heart attack. The jury is out on this one as trials will have to be done, but do ask and keep abreast of the research.
As new areas of research open, or if you have questions about what is happening in the field, feel free to contact us. We'll do our best to contact experts and research your questions. We are all in the same boat and need to help each other understand new data and take excellent care of our cardiovascular system. Eat well, exercise and keep coming back. We enjoy having you with us each month and wish you very good health.
BSP
