Diet almost certainly played the definitive role in his wife's blocked artery. Dietary cholesterol - which is a main root cause of blocked arteries - ONLY comes from animal fat. If you don't eat animal based products you’ll have much lower dietary cholesterol, and barring a genetic issue, much lower serum cholesterol and a better HDL (“good” cholesterol) to LDL (“bad” cholesterol) cholesterol ratio. High serum cholesterol is most likely why she had a blocked artery.

That being said, the problem was (IMO) not high “protein,” but high animal meat based protein.

[edit] added qualifiers to and definitions of “cholesterol” to make my point clearer.

Serum cholesterol