Abstract
Objectives Optimal timing of coronary artery bypass grafting (CABG) after acute myocardial infarction
(AMI) remains the subject of fierce debate. Therefore, the recommended deferral ranges
from immediate intervention to surgery 4 weeks after infarction. Especially, the increasing
cohorts of patients at old age or with poor left ventricular function, whose mortality
rates are additionally enhanced, may profit from focused analyses. This study aims
at clarifying the appropriate timing of CABG after AMI, with special regard to high-risk
patients (Age >70 years, left ventricular ejection fraction (LVEF) <30%).
Methods Retrospective analysis was performed in 3475 patients who had undergone isolated
CABG between 2005 and 2009. Those 1168 patients with previous AMI (<30 days) were
categorized in groups, depending on deferral of surgery: <6 hours after AMI (A), 6
hours–1 day (B), 2–3 days (C), 4–10 days (D), 11–20 days (E), and 21–30 days (F).
Furthermore, subgroups with an age >70 years or a LVEF <30% were examined.
Results The mortality rates in groups A–F were 14.8, 10.2, 8.8, 4.2, 2.3, and 2.0%, whereas
only the values of groups A–D were significantly increased versus the mortality rate
of patients without previous AMI (1.9%). In patients over 70 years, we observed operative
mortalities of 26.3, 14.3, 11.9, 6.1, 4.2, and 3.1% (groups A–F) versus 2.5% (no previous
AMI), while 27.4, 15.4, 11.7, 6.0, 3.7, and 2.8% (groups A–F) versus 2.7% (no previous
AMI) of patients with a LVEF <30% died during the first 30 days after surgery. In
both subanalyses of high-risk patients, the enhanced mortalities of groups A–E reached
significance. Multivariate analysis of operative risk factors revealed that CABG within
10 days after AMI and age over 60 years are independently associated with operative
mortality.
Conclusions CABG early after AMI (<10 days) is accompanied by significantly increased mortality,
especially in elderly patients or in patients with a severely impaired LVEF. At least
the critical time period of 3 days should be avoided–whenever the hemodynamics is
stable enough.
Keywords
acute myocardial infarction - coronary artery bypass grafting - surgical timing -
operative mortality - delayed revascularization
