Abstract :
A prospective study of 7,590 consecutive patients undergoing
isolated coronary artery bypass grafting at five
medical centers in Maine, New Hampshire, and Vermont
between July 1987 and December 1990 assessed changes
in patient characteristics over time. Variables included
age, sex, surgical priority, ejection fraction, left ventricular
end-diastolic pressure, and left main coronary artery
stenosis of 90% or greater. Trends were assessed for each
variable and for predicted mortality using linear regression.
The mean age increased significantly, whereas
ejection fraction decreased. The percentage of urgent
cases increased, whereas the elective cases became less
frequent. No changes were observed in the percentages
of emergent cases, female patients, or patients with
severe left main coronary artery disease. The predicted
in-hospital mortality rose significantly from 4.2% to 5.2%
(p 0.001). The increase in urgent surgical intervention was
the most substantial contributor. Subgroup analyses did
not support a systematic misclassification of elective
patients into the urgent group. This study demonstrates
that the characteristics of the cohort of patients undergoing
coronary artery bypass grafting changed substantially
from 1987 to 1990. These changes should be considered
when interpreting surgical outcomes.
