False negative on thallium stress test?

Short HX: history of chest pain, short of breath, do not excercise, overweight (15lbs?) 1st angio = 60% LAD, 2nd angio= 50% LAD, high cholesterol (just over 200). Recent thallium stress shows no "significant" blockages. My family has HX of heart disease. Question is: Can a nuclear stress show false positive? What are the percentages of false negative? Some mild discomfort shortly after the stress test. Is there any significance to this? Should I request a third angio? In addition, I have a Hiatial Hernia which I've heard can have the same symptoms of chest pain.

[quintby]

Every medical test has false negatives because neither humans nor machines operate with 100% accuracy.  However you are in very serious jeopardy whenever you receive a false negative result on a Cardiolite stress tests. That's because of an astonishing fact about cardiologists in the U.S: they are willing to accept the fact that, even in they could administer and interpret cardiolite or thallium stress tests with 0% errors, that 2%-3% of their patients whose coronary arteries receive the most desirable rating of "normal" actually have coronary arteries in the LEAST desirable and most severely diseased state, known as "3-vessel disease" 3-vessel disease means that you have not just one seriously blocked coronary artery, not just two seriously blocked coronary arteries but rather have 3 or more coronary arteries which are perilously close to becoming totally blocked and causing  a myocardial infarction.
If you respond "That can't be!", I'm here to tell you from personal experience that it can be true, and is true. 13 months after being given a "normal" test result after I had undergone a thallium/Cardiolite-type Nuclear stress scan test, I awoke to find myself lying in a bed in the ICU of a major Heart Center. A nurse was standing there and I asked why I was there. She responded, "Honey, you collapsed 10 days ago and had to undergo emergency 'high-risk' quintuple coronary artery bypass surgery in order to survive." "Triple bypass?" I asked incredulously.  "No, not triple. Quintuple. You had 5 coronary arteries that needed bypassing."
I asked my cardiologist how I could have needed a quintuple bypass when my test said my arteries were normal. He shrugged and said, "Reading the results of a nuclear stress scan of your heart mainly entails comparing how the nuclear material settles into various different areas of your heart. We can tell which artery is bad by comparing the area it feeds to the other areas. But if all your arteries are bad, then the heart tissue all looks the same, just like the tissue all looks the same if your arteries are all normal. It's almost impossible to distinguish "all-bad" from "all normal".

Ridiculous, laughable primitive. But absolutely true. If your doctor says all your arteries are normal, he really means that they're either all-good or all-bad.

[erijon]

Sorry, but most of what you say here is just not true. It all depends on the patients symptoms. I spend many hours each week volunteering with a cardiac care center and get to talk to many cardiologists. If a patient has a normal nuclear stress test and symptoms are present, they always proceed to an angiogram to be sure. That is the normal protocol as outlined by the NIH. You had your issues 13 months after a clean stress tests, plenty of time for things to change. CAD is a dynamic process with periods of slow and aggressive progression. Had you complained about symptoms after your test you would have had a cath and more would have been learned. It still may not have prevented you problems as arteries can go from 50% to 90% very quickly, or over a long period of time.

The actual numbers on a Nuclear Stress test is an overall accuracy of 85%, with a sensitivity of 80% meaning finding CAD when there is none and 97% specificity, finding no heart disease when there is none. That does leave room for some fall through the system, but overall pretty accurate and much less invasive than an angiogram.

Jon