DEAR DR. ROACH: In the past year, I have had numerous TIAs. I also have an abdominal aortic aneurism and blockages in my carotids. Could a dislodged plaque be the cause of my TIAs? -- D.G.
ANSWER: A transient ischemic attack is a temporary loss of brain (or sometimes spinal cord or retina) function. It is similar to a stroke, except that a stroke represents permanent death of the cells, while a TIA means the cells were able to recover.
TIAs, like strokes, can be caused by blood clots of small blood vessels, by cholesterol plaque or a clot dislodging and blocking blood vessels in the brain, and by other less-common causes. You are known to have blockages in your large blood vessels (the carotids are the major arteries to the brain); in someone like you, the doctor should be using multiple strategies to prevent further TIAs and especially a stroke, which can be devastating.
Lifestyle modification remains the first important step. This means a healthy diet, regular moderate exercise (at a level appropriate for your health situation) and tobacco cessation if appropriate. Blood pressure control (especially given your abdominal aortic aneurism) is critical, and may mean that you need medication to get the blood pressure down to levels below what we used to aim for. Most people with TIAs will benefit from statin treatment and anti-platelet treatment, such as aspirin.
A TIA is a warning sign: Take it seriously. If you haven’t been as good as you could be with your lifestyle, or if your doctor hasn’t been as aggressive as possible, now is the time.
DEAR DR. ROACH: I am 70 years old, retired, with no prior major health issues, and I have never had heart issues. My primary care physician referred me to a cardiologist to follow up on concerns regarding my heart health. The cardiologist has recommended a chemically induced stress test. I am not questioning the need for the test; however, I am concerned about the safety and effectiveness of this test method as compared with a treadmill stress test. In researching this online on reputable sites, there are pros and cons; the cons include serious concerns -- as serious as potentially causing a heart attack. I also noted that the Food and Drug Administration issued such a warning to doctors a few years ago. -- G.M.
ANSWER: A stress test is most commonly done to evaluate for coronary artery disease, blockages in the arteries of the heart, in people with symptoms that might be heart disease. The “stress” part involves increasing heart blood flow, because blockages in the arteries lead to reduced flow to areas of the heart, and these can be evaluated by EKG, a nuclear dye study, or by echocardiogram.
The heart rate can be increased by exercise or by medication. The most commonly used medications now are adenosine and dobutamine (although there are others). Dobutamine works directly on the heart to increase heart rate, which in turn generates more blood flow to the heart. Adenosine works by increasing blood flow in the blood vessels.
I always use exercise when possible. The medications usually are safe, but very rarely something goes wrong and the medicine needs to be stopped, and it takes a few seconds to wear off. You are right that the FDA warned about adenosine (and a related drug, regadenoson) that it can very rarely cause heart attacks. Exercise can be stopped immediately. Also, the amount of exercise someone can do in a standardized protocol gives additional information.
If someone can’t exercise enough, most commonly due to arthritis or neurological disease, then medications are required, but exercise is preferred when possible.
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Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or request an order form of available health newsletters at 628 Virginia Dr., Orlando, FL 32803. Health newsletters may be ordered from www.rbmamall.com.
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