Do coronary collaterals influence the outcome of bypass graft surgery?

The importance of coronary collateralization on the outcome of bypass grafting was evaluated in patients recatheterized one year after surgery. Because the severity of coronary artery disease correlated with the extent of collateralization, and ventricular function with previous myocardial infarction, we performed a matched pair study where differences in these variables were eliminated between pairs which differed only with respect to the extent of collateralization visualized during angiography. From a data bank of 814 operated patients, 143 matched pairs were formed. In the matched pair series of patients collaterals appear to provide some degree of additional blood flow to ischemic areas to allay resting symptoms before surgery, but collaterals are inadequate to meet the additional requirements of pacing-induced stress. The 2 groups were indistinguishable one year after bypass surgery. As the non-collateralized group was more symptomatic before surgery, it demonstrated greater subjective benefit from the procedure, however, this would be obscured in a consecutive series where collateralization generally correlates with severity of coronary artery disease.