Influence of time elapsed between myocardial infarction and coronary artery bypass grafting surgery on operative mortality.
OBJECTIVE
Optimal timing for CABG surgery after myocardial infarction (MI) remains controversial. We examined the influence of patient age and time elapsed between MI and isolated CABG surgery on operative mortality.


METHODS
Perioperative data of 13,545 patients who underwent isolated CABG surgery from 1991 to 2005 were reviewed. A previous MI was found in 7219 patients, classified among groups A-E whether they underwent surgery less than 6h (A, n=26), between 6 and 24h (B, n=51), between 1 and 7 days (C, n=313), between 8 and 30 days (D, n=917), or more than 30 days (E, n=5912) after the event. Crude percentages and odds ratio estimates of operative mortality were calculated.


RESULTS
In patients who had no history of MI, the mortality rate was 1.7%, while it was, respectively, 19.2, 9.8, 8.6, 3.2, and 2.4% in patients from groups A to E. Among 6589 patients over 65 years of age, 3027 had no history of MI. Their mortality was 2.4%, compared to, respectively, 35.7, 13.8, 11.3, 5.1, and 3.9% for those belonging to groups A-E. Overall odds ratio estimates of operative mortality were 3.92 (p=0.19), 5.08 (p=0.002), 4.33 (p=0.0001), 1.50 (p=0.08), and 1.18 (p=0.24) for groups A-E, respectively.


CONCLUSIONS
Operative mortality is not influenced by a history of MI sustained more than 30 days prior to isolated CABG surgery, but is highly and most significantly increased between 6h and 1 week after MI, especially in older patients. That critical period should be avoided whenever possible.
Voisine
Pierre
P
Division of Cardiac Surgery, Laval Hospital, 2725 chemin Sainte-Foy, Sainte-Foy, Que., Canada G1V 4G5. pierre.voisine@chg.ulaval.ca
Mathieu
Patrick
P
Doyle
Daniel
D
Perron
Jean
J
Baillot
Richard
R
Raymond
Gilles
G
Métras
Jacques
J
Dagenais
François
F
D000367:Age Factors; D000368:Aged; D001026:Coronary Artery Bypass / Q000401:mortality*; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality / Q000601:surgery*; D011792:Quebec / Q000453:epidemiology; D012008:Recurrence; D013997:Time Factors