The Coronary Artery Surgery Study (
CASS) randomized 780 patients to an initial strategy of coronary surgery or medical
therapy. Of medically randomized patients, 6% had surgery within 6 months and a total of 40% had surgery by 10 years.
At 10 years, there was no difference in cumulative survival (medical, 79% vs. surgical, 82%; NS) and no difference in percentage free of death and nonfatal
myocardial infarction (medical, 69% vs. surgical, 66%; NS). Patients with an ejection fraction of less than 0.50 exhibited a better survival with initial surgery treatment (medical, 61% vs. surgical, 79%; p = 0.01). Conversely, patients with an ejection fraction greater than or equal to 0.50 exhibited a higher proportion free of death and
myocardial infarction with initial medical
therapy (medical, 75% vs. surgical, 68%; p = 0.04) although long-term survival remained unaffected (medical, 84% vs. surgical, 83%; p = 0.75). There were no significant differences either in survival and freedom from nonfatal
myocardial infarction, whether stratified on presence of
heart failure, age,
hypertension, or number of vessels diseased. Thus, 10-year follow-up results confirm earlier reports from
CASS that patients with
left ventricular dysfunction exhibit long-term benefit from an initial strategy of surgical treatment. Patients with mild
stable angina and normal left ventricular function randomized to initial medical treatment (with an option for later surgery if symptoms progress) have survival equivalent to those patients randomized to initial surgery.