The AAC/AHA guidelines if blockage is less than 70% and not causing any problem does not require intervention (stent or bypass). As one ages there tends to be a buildup of plague and 10 to 20% seems reasonable. An echo will not dx any blockage.
There is evidence of vessels blockage diagnosed by an autopsy in returning casualities of the war.
The stress test will introduce a chemical dye into your system, and if there any blockages it will usually show at the time of exertion as well as any chest discomfort. Then usually at rest the pain or chest discomfort ceases.
There is a physician at the time of the test who monitors the individuals vital signs and will quickly terminate the test if indicated...and there is equipment available for treatment of any ill effects, and the test can be terminated at the request of the individual at any time because of pain or fatigue, etc. NBo need to worry.
I mean nuclear thallium stress test.