Battery of tests didn’t predict stroke

Dear Dr. Roach: My stepfather had a series of screening tests done by a commercial company. He received a good report. However, two or three weeks after the screening, he suffered a stroke. My confidence in the screening program was shaken! How accurate are these tests? — R.M.

I am sorry about your stepfather, and hope he recovers.

Even if the tests were performed with the best techniques available, screening tests are unable to identify all risks. Many strokes come from plaque in the major arteries, which provide the blood supply to the brain, and are part of the screening. The plaque can also be in the arch of the aorta. The arch is the first part of this major blood vessel, and the carotid arteries come off the aorta in the arch. The arch is not normally visualized.

However, strokes can come from diseased blood vessels inside the brain. Heart rhythm problems, which can come and go and might not be picked up on during the screening, can also lead to stroke, as can blood clots elsewhere in the body that go through a septal defect (”hole”) in the heart and from there to the brain.

Screening tests can miss several potential sources of stroke. This can lead to an inappropriate sense of security, which could keep a person from seeking medical attention quickly in the event of symptoms. Even for areas that the screening test can see, it is possible to have a false negative test.

After a stroke, doctors try hard to identify the underlying cause, so it can be treated if possible. Your stepfather should have undergone a thorough evaluation. If a cause is identified, it would be appropriate to see whether the screening test was wrong or if the stroke was from a cause that was not looked for in the battery of tests he got.

There are some people who have strokes for which no cause can be identified.