Three factors were associated with a significant survival benefit following surgery, the extent of coronary disease, the patient’s overall medical risk and the year of the operation. Patients with more extensive coronary obstruction treated surgically had the greatest improvement in survival. Patients with a poor prognosis because of factors other than the extent of coronary obstruction, older age, severe angina, had a greater absolute improvement in survival after coronary bypass surgery than did those who were treated medically.
Improved survival after surgery is not confined to select subgroups of patients. Therapeutic recommendations must be based on individualized assessment of expected risks and benefits of surgery.