This may not in anyway be your problem but having heart disease for years and experiencing some of the same angina and fatigue you mentioned l would ask doc to do echo to see if heart is pumping enough blood and ask about smaller veins in the heart possible blockages as this is more common with age and called hardening of the arteries.
There are meds that will help open up smaller veins in the heart.
These meds have helped me along with my heart disease.
Hope you get well soon.

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