The cost per QALY for elderly patients treated within 3 hours was given as 500. This was produced by dividing the total cost by total benefit of 21.2 extra QALYs. Other QALY results were presented graphically. Costs per QALY were given for ages: under 45,45-54, 55-64 and 65 and over. They were further broken down by hours from onset of symptoms before treatment into 3 categories: 0-3 hours, 4-6 hours and 7-24 hours. Lowest costs per QALY are 500 for patient aged over 65 years treated within 3 hours to approximately 3,200 for patients aged 45-54 years treated between 7 and 24 hours after the onset of symptoms. Costs per QALY were higher for younger age groups in each category and higher for each age group the longer therapy was delayed.