Circulation, Vol 86, 121-130, Copyright © 1992 by American Heart Association
BACKGROUND. The 18-year effect of bypass surgery compared with medical
therapy on survival, incidence of myocardial infarction, and relief of
angina was evaluated in 686 randomized patients with stable angina in the
Veterans Affairs Cooperative Study of Coronary Artery Bypass Surgery.
METHODS AND RESULTS. The primary treatment comparisons were made according
to intent to treat; 44% of the entire medical cohort had bypass surgery
during a median follow-up of 16.8 years. Overall 18-year survival rates
were 33% for medicine compared with 30% for surgery (p = 0.60). Survival
rates for high-risk patients without left main disease, which had shown a
significant advantage for surgical therapy up to 11 years, were 23%
medicine versus 24% surgery for patients with three- vessel disease and
impaired left ventricular function (p = 0.49) and 22% versus 25% for those
with multiple clinical risk factors (p = 0.12). For patients with
two-vessel disease, who had significantly better survival with medical
therapy at 11 years, rates were similar at 18 years in the two treatment
groups (34% medicine versus 30% surgery, p = 0.09). Cumulative 18-year
myocardial infarction rates (fatal plus nonfatal) were 41% in medical and
49% in surgical patients (13% perioperative infarction rate), p = 0.15.
Nonfatal infarction rates were lower with medical than with surgical
therapy (32% versus 44%, p = 0.015), but fatal infarction rates were
similar (14% medicine versus 13% surgery, p = 0.62). The combined rate of
myocardial infarction or death was also lower with medical therapy (75%
versus 82%, p = 0.016). In contrast, surgery reduced mortality after
myocardial infarction by 35% at 10 years (p less than 0.001) but only by
13% at 18 years (p = 0.09). The percent of medical and surgical patients
who were angina- free was 3% versus 22% (p less than 0.001) at 1 year and
4% versus 12% (p less than 0.001) at 5 years compared with rates of 6%
versus 5% (p greater than 0.50) at 10 years and 3% versus 4% (p greater
than 0.50) at 15 years. CONCLUSIONS. The benefits of coronary artery bypass
surgery on survival, symptoms, and postinfarction mortality were transient
and lasted fewer than 11 years. The benefits began to diminish after 5
years, when graft closure accelerated. Surgery was effective in reducing
mortality only for patients with a poor natural history. Low-risk patients,
who had a good prognosis with medical therapy, derived no survival benefit
with surgical therapy at any time during the follow-up period. Regardless
of risk, surgery also did not reduce the incidence of myocardial infarction
or the combined incidence of infarction or death.
ARTICLES
Eighteen-year follow-up in the Veterans Affairs Cooperative Study of Coronary Artery Bypass Surgery for stable angina. The VA Coronary Artery Bypass Surgery Cooperative Study Group
Cooperative Studies Program, VA Medical Center, West Haven, Conn 06516.