Stress Test False Positive or...?

[tomswift]

Hi,
Help! My wife had a stress test recently because her family doctor just purchased stress test equipment(note: she has had no symptoms of heart problems but has diabetes). She was the 4th person to have the test on this equipment. According to the results stress images reveal a large sized perfusion abnormality of moderate to severe intensity in the lateral and anterolateral walls . Stress images also showed a medium sized perfusion abnormality of mild to moderate intensity in the interoseptal and inferiolateral walls. Grade V stage. Gated SPECT revealed abnormal left ventricular function with an ejection fraction of 36%. There was severe hypokinesis in the inferior, lateral, anterolateral, and inferolateral walls of the left ventricle. There is diminished systolic wall thickening in these regions as well. Images would appear to show that heart is not functioning while under stress.
Family doctor and specialist are recommending Standard Angiogram.
Wife and I have doubts about the validity of the test because she was the 4th patient to have it(at least 1 other patient had an abnormal reading). Also there is a percentage of false positives in females.
When we suggested a CTA doctors balked saying that she would still need a Standard Angiogram.
Are we wrong in wanting the CTA first(we would pay entire cost of test) then if indicated have the Standard Angiogram.
Thank you for reading and hopefully replying.

[kenkeith]

Yes, it is ture,  I believe the satistics is about 20% for false positives.  There are a number of reasons why this can happen. The problem is that this phenomenon is very common.

"Given the extraordinary number of false positives, there's a lot of gray in interpreting these tests. Hospital staff, in fact, call nuclear medicine "unclear" medicine. It's common knowledge that you can often see just about anything you want to see on a nuclear image of the heart. Abnormalities in the bottom of the heart, the "inferior" wall, are especially common due to the overlap of the diaphragm with the heart muscle, yielding the appearance of reduced blood flow. Defects in the front of the heart heart are common in females with large breasts for the same reasons.

The problem: The uncertainty inherent in nuclear stress tests opens the door to the unscrupulous or lazy practitioner. Any blip, tick, or imperfection on the nuclear images serve as carte blanche to drag you into the hospital for procedures.

This abusive practice is, in my experience, shockingly common for two reasons: 1) It pays better to do heart catheterizations, and 2) Defensive medicine.

What's the disincentive? Only doing the right thing and maintaining a clear conscience. Slim reasons for many of my colleagues--and a lot less money".
____________________________

I understand the frustration. Your wife has diabetes and often that condition results in what is termed silent ischemia (no symptoms) so it is reasonable to assume the possibility of significant blockage that may require stent(s). Your wife's doctor is assuming there will be stent implants, therefore, a cath angiogram would be more appropiate.  And if true, that would justify a cath angiogram and no CTA.

Requesting a CTA is no different than getting a second opinion so I don't see why there would be an objection.  Sometimes a second opinion is rewarding...It is difficult to second quess a doctor's assessment, but due to the new technology and the probability of false postive, it may be a good idea. ..it wouldn't do any harm.

Thanks for the question.

Ken

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[erijon]

My understanding is that false positives with profusion imaging are the result of shadows which are determined to be areas of poor profusion that are due to attenuation or poor image quality. This individual is showing abnormal left ventricular function with gated spect, hypokinesis ad wall thinning as in a dilation. I don't think these are the findings that are often a false positive.

I would think this is a reasonable request, just my 2 cents......

Jon

[kenkeith]

Thanks for good and helpful information.  I didn't know that!...but you do mean perfusion, don't you! ;).

Thanks for your comment.

[erijon]

I do, just can't seem to spell today..............