Percent of blockage that shows up in a Thallium stress test

[rodney cierllo]

In a previous question that was asked, you stated that a significant blockage must be present for the Thallium stress test to detect it. What would be the least percentage of blockage that would show up on this test? On the other hand, in another previous question, you stated too that any blockage less than 70% is considered insignificant. I'm confused. If I had a Thallium stress test done and was told I had a 40% or 60% blockage then I would consider that signnificant. Please clarify this fo me. Thank you.

[CCF CARDIO MD - DLB]

Speaking in generalizations, a Thallium test usually picks up blockages that are about 70% in severity. Most blockages less than 70% do not require surgery or angioplasty, but are better treated with medication. I would not, however, classify a 50% blockage as completely insignificant, but this level of blockage would not be expected to cause symptoms.