Neil Armstrong, the first man to walk on the moon, died in 2012 at age 82 after what should have been routine heart surgery. When nurses removed wires linked to a temporary pacemaker, he bled profusely into the membrane surrounding the heart. He died a week later.

The medical details, disclosed this week by The Times, have prompted questions from both doctors and readers. Did Mr. Armstrong need open-heart surgery in the first place? What went wrong, and why?

Here are some answers from leading heart surgeons.

Mr. Armstrong went to the hospital complaining of severe chest pain. Don’t people with chest pain from blocked arteries get stents to open them up?

It depends on what sort of blockage a person has, said Dr. Michael Mack, a heart surgeon at Baylor Scott & White The Heart Hospital — Plano.

Three major arteries feed blood into the heart. In Mr. Armstrong, the most important, the left anterior descending artery, was not blocked, according to records received by The Times. The other two, the circumflex and the right coronary artery, were blocked completely.