Preoperative risk factors and aorta-coronary bypass graft patency.

The relationship between graft patency and the presence of presurgical prognostic factors was studied in 636 patients who have undergone aorta-coronary bypass operation. We have found a positive correlation between vein graft patency and both coronary artery constriction score (p less than 0.01) and diastolic blood pressure (p less than 0.05). In patients studied up to one year after surgery, high graft patency was associated with both higher diastolic pressures (p less than 0.03) and higher cholesterol levels (p less than 0.001). However, high cholesterol levels also were associated with coronary arterial obstruction. In patients studied more than a year after operation, high constriction scores before the operation were associated with improved graft patency (p less than 0.03). Our findings indicate that short-term prognosis of the grafts is related mainly to hemodynamic variables.