lot of people have lot of heart disease, in america and most western countries, and now even (or especially) in the global south.
my first reco, based on a couple years of reading, is go 'whole food plant-based' diet -- i.e. vegan and also subtracting oil (along with too much fat, generally) - and of course drastically reducing sugar. in theory that reverses the athleroslcosorosisisiisis (artery hardening), blockages, etc.
big or 'extreme' change, but not necessarily more extreme than getting stents.
the 'whole food plant based' label seems to be most healthy based on what i've read/seen.
dr. greger's books are about as mainstream as you can get, and his website has tons of bite-sized videos (and plenty of youtubes):
the story of his grandma is trippy, and hacker-ish -- she was helped by self-researcher and non-medical doctor, Nathan Pritikin.