70 % Mid LAD Blockage As Evidence From CTA. .rca

70 % mid LAD blockage as evidence from CTA. .rca may had 20 -40 % blockage and same in another. Had nuke stress with questionable ischemia anterior wall. 13 minutes on machine till they said I was in cardiac zone they said I could stop. Mild tightness. 56yo. Doing sprint and Olympic triathlons 2003 -2012. 2012 swimming 2 mile pool swims at least twice a week with 10k runs on Opposite Day. Then had knee surgery and have been extreme sedentary last 2.5 years. Couch potato type. Suggestions