> Angioplasty can save the lives of heart-attack patients. But for patients with stable coronary disease, who comprise a large share of angioplasty patients? It has not been shown to extend life expectancy by a day
They state "save the lives of heart-attack patients". That (partially) supports the statement, since saving a life is definitely increasing their lifespan.
The rest of the quote is stating the inverse though, that not all angioplasty recipients live longer (converse? meh, you know what I mean). And that it might be over-proscribed. Neither of those have anything to do with it's ability to prolong life in other cases.
How do you mean that?
http://harvardmagazine.com/2013/03/a-cardiac-conundrum
> Angioplasty can save the lives of heart-attack patients. But for patients with stable coronary disease, who comprise a large share of angioplasty patients? It has not been shown to extend life expectancy by a day