Does a plant based diet actually reverse heart disease

I have read literature from Colin Campbell, Esselstyn and Ornish and watched Forks over knives and I still don’t understand how this works.

When one forgoes eating animal products they usually aren’t consuming saturated/trans fat and dietary cholesterol which we know causes plaque build up in the arteries. I can see how eating plant based diet prevents more build up from occuring but I don’t know how it removes plaque that is already there. Are the plant based meals themselves the cause of the removal or is the lack of consuming saturated fats causing this removal. If the latter example is true and someone were to fast for a [long](https://en.wikipedia.org/wiki/Angus_Barbieri’s_fast) period of time,which I don’t recommend, wouldn’t they also reverse heart disease ?