The Annals of Thoracic Surgery, Vol 31, 204-210, Copyright © 1981 by The Society of Thoracic Surgeons
Influence of aspirin and dipyridamole on patency of coronary artery bypass grafts
JE Mayer Jr, WG Lindsay, W Castaneda and DM Nicoloff
A prospective randomized trial was performed to determine if the
administration of inhibitors of platelet function would improve the patency
of coronary artery bypass grafts. Patients were operated on for intractable
angina with angiographically demonstrable lesions. The left internal
mammary artery (IMA) was used for bypass of lesions of the left anterior
descending coronary artery (LAD). Saphenous vein grafts were used for the
LAD if the IMA was inadequate and for all other vessels. Treated patients
received 1,300 mg of aspirin and 100 mg of dipyridamole (Persantine) orally
each day. Control patients received neither drug. Patients returned 3 to 6
months after operation for repeat angiography. Results were analyzed by
chi-square. One hundred seventy-four patients entered the study from June,
1973, through December, 1975, and 113 were analyzed. In the control group,
66 patients had 27 IMA-LAD grafts and 93 saphenous vein grafts. In the
treatment group, 47 patients underwent 18 IMA-LAD grafts and 75 saphenous
vein grafts. Ninety-eight of the 120 grafts (82%) were patent in the
control group, and 87 of 93 grafts (94%) were patent in the treatment group
(x2 = 6.34, p less than 0.02). Of the 45 IMA-LAD grafts in both groups,
only 1 was occluded, a patency of 98%. In the control group, 72 of 93
saphenous vein grafts (77%) were patent. In the treatment group, 69 of 75
(92%) were patent (x2 = 6.54, p less than 0.02). The results of the study
show a 15% difference between the two groups in the early patency of
saphenous vein grafts. We continue to use aspirin and dipyridamole to
improve the patency of saphenous vein bypass grafts.
