In a study of 276 patients in the Trial of Invasive versus Medical therapy in the Elderly (TIME), it was found that drug therapy is just as effective as surgery for prolonging the lives of elderly patients with angina. The participating patient group was 42% female and the average age was 80 years. At the time of enrollment, the average patient was being treated with 2.5 drugs to control angina and was still experiencing relatively severe symptoms. Rates of survival were similar at 6 months, 1 year, and 4 years for patients on drug therapy and for those who had surgery such as bypass or angioplasty; survival rates for both groups decreased as time passed. Survival rates were poor for those who were 80 or older, with previous heart failure, and poor heart-pumping ability. Lead author Dr. Matthias Pfisterer of the University Hospital in Basel, Switzerland, concluded, "Our results showed that long-term mortality is similar in invasively treated patients and those treated with optimal drug therapy. Chest pain relief and improved quality of life are also similar, but invasively managed patients reach this benefit earlier."