Collateral circulation before and after coronary artery reconstruction.

The changes in collateral circulation after coronary artery reconstruction were analyzed in 75 patients with 177 bypass grafts and 18 complementary gas endarterectomies. The quantity of collateral circulation was directly proportional to the degree of coronary obstruction. The changes in collateral circulation depended on the success of coronary surgery or on the progression of the disease in coronary vessels. So, when the grafts remained patent, the collaterals disappeared and when the grafts became occluded, the collateral circulation returned to the preoperative level. Progressive obstruction of the coronaries caused increased collateral circulation.