CHANGES IN PATIENTS UNDERGOING CORONARY-ARTERY BYPASS-GRAFTING - 1987-1990

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 ch anges in patient characteristics over time. Variables included age, se x, surgical priority, ejection fraction, left ventricular end-diastoli c pressure, and left main coronary artery stenosis of 90% or greater. Trends were assessed for each variable and for predicted mortality usi ng linear regression. The mean age increased significantly, whereas ej ection fraction decreased. The percentage of urgent cases increased, w hereas the elective cases became less frequent. No changes were observ ed in the percentages of emergent cases, female patients, or patients with severe left main coronary artery disease. The predicted in-hospit al mortality rose significantly from 4.2% to 5.2% (p < 0.001). The inc rease in urgent surgical intervention wa!, the most substantial contri butor. Subgroup analyses did not support a systematic misclassificatio n 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.