Research shows TIA increases the risk of a heart attack by 200 percent
I recently helped manage a patient who had been diagnosed with a TIA: transient ischemic attack. The patient’s only symptom was double vision. A TIA is sometimes referred to as a ministroke. This is a disservice, since it makes a TIA sound like it should be taken lightly.
Ischemia is reduced or blocked blood flow to the tissue, due to a clot or narrowing of the arteries. Symptoms may last less than five minutes. However, a TIA is a warning shot that needs to be taken very seriously. It may portend life-threatening or debilitating complications that can be prevented with a combination of medications and lifestyle modifications.
Is TIA common?
It is diagnosed in anywhere from 200,000 to 500,000 Americans each year (Stroke. Apr 2005;36(4):720-3; Neurology. May 13 2003;60(9):1429-34). The operative word is “diagnosed,” because it is considered to be significantly underdiagnosed. TIA incidence increases with age (Stroke. Apr 2005;36(4):720-3).
What is a TIA? The definition has changed from one purely based on time (less than 24 hours) to differentiate it from a stroke, to one that is tissue based. It is a brief episode of neurological dysfunction caused by focal brain ischemia or retinal ischemia — low blood flow in the back of the eye — without evidence of acute infarction (tissue death) (N Engl J Med. Nov 21 2002;347(21):1713-6).
It has been shown that tissue death and/or lesions can occur on diffusion-weighted MRI. In other words, TIA has a rapid onset with potential to cause temporary muscle weakness, with difficulty in activities such as walking, speaking and swallowing, as well as dizziness and double vision.
Why take a TIA seriously if its debilitating effects may be temporary? TIAs have potential complications, from increased risk of stroke to heightened depressive risk to even death.
After a TIA, stroke risk goes up dramatically. Even within the first 24 hours, stroke risk can be 5 percent (Neurology 2011 Sep 27; 77:1222). According to one study, the incidence of stroke is 11 percent after seven days, which means that almost one in 10 people will experience a stroke after a TIA (Lancet Neurol. Dec 2007;6(12):1063-72).
Even worse, the probability that a patient will experience a stroke reaches approximately 30 percent after five years (Albers et al., 1999).
In a recent epidemiological study, the incidence of a heart attack after a TIA increased by 200 percent (Stroke. 2011; 42: 935-940). These are patients without known heart disease.
Interestingly, the risk of heart attacks was much higher in those under 60 years of age, and continued for years after the event. Just because you may have not had a heart attack within three months after a TIA, this is an insidious effect; the average time frame for patients was five years from TIA to heart attack. Even patients taking statins to lower cholesterol were at higher risk of heart attack after a TIA.
TIAs decrease overall survival by 4 percent after one year, by 13 percent after five years, and by 20 percent after nine years, especially in those over age 65, according to a study published in Stroke online, Nov. 10.
The reason younger patients had a better survival rate, the authors surmise, is that their comorbidity (additional diseases) profile was more favorable.
In a cohort (particular group of patients) study that involved over 5,000 participants, TIA was associated with an almost 2.5-times increased risk of depressive disorder (Stroke. 2011 Jul;42(7):1857-61). Those who had multiple TIAs had a higher likelihood of depressive disorder. Unlike with stroke, in TIA it takes much longer to diagnose depression, about three years after the event.
What can you do?
Awareness and education are important. While 67 percent of stroke patients receive education about their condition, only 35 percent of TIA patients do (JAMA. 2005 Mar 23;293(12):1435). Many risk factors are potentially modifiable, with high blood pressure being at the top of the list, as well as high cholesterol, increasing age (over 55) and diabetes.
Secondary prevention (preventing recurrence) and prevention of complications are similar to those of stroke protocols. Medications may include aspirin, antiplatelets and anticoagulants. Lifestyle modifications include the Mediterranean and DASH diet combination I elaborated on in my Dec. 22 article, “Stroke prevention is the best treatment.” Patients should not start an aspirin regimen for chronic preventive use without the guidance of a physician.
In researching this article, I realized that there are not many separate studies for TIA since they are usually clumped with stroke studies. This underscores its seriousness. If you or someone you know has a TIA, the patient needs to see a neurologist and a primary care physician and/or cardiologist immediately.
Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management. For further information, go to the website www.medicalcompassmd.com and/or consult your personal physician.