60 years old woman being assessed prior to surgery where she will be under general anesthesia. In her past medical history, you learn she suffered a myocardial infarction complicated by congestive heart failure. Also, she was a smoker for 35 years, where she would smoke a pack a day but 3 years ago stopped due to her cardiac illnesses. She is hypertensive and also suffers from hypercholesteremia. What would be the greatest risk factor that would cause her cardiac complications postoperatively?