Coagulation factors influencing thrombosis of aorta-coronary bypass grafts.

Thirty patients in whom all aorta-coronary artery vein grafts became occluded within one year of operation, as demonstrated by cardiac catheterization, were evaluated for hypercoagulability. A total of 59 grafts were constructed in these patients. At operation, blood flows of 35 to 90 c.c. per minute were measured through the grafts. In 23 of the 30 patients, the blood was to be hypercoagulable, as evidenced by a low level of antithrombin III activity, high thrombin generation index, high factor VII values, or high platelet adhesivity. Another group of 11 patients (total number of grafts, 23) had all grafts patent at cardiac catheterization. These patients had flows through the grafts ranging from 20 to 125 c.c. per minute. None of the patients with patent grafts had hypercoagulable blood. The status of runoff was comparable between the patients with open grafts and those with occluded grafts.