That's what they call in medical terms a "widow maker". I'd get something done right away - unless you are not married :)
Hi there. The result is Single vessel disease in the Left Artery Descending. Usually they will treat it if its over 80%, so it may mean a stent if they can place one. It could need to be treated with a bypass. Your cardiologist would have all the info including your past records and is clearly best placed and qualified to advise you. They should be able to sort you without major difficulty! Keep us posted