Effect of direct revascularization surgery on coronary collateral circulation in man

In 63 consecutive patients with significant coronary artery disease (more than 75 percent stenosis), the effects of direct myocardial revascularization on coronary collateral channels were studied 6 to 29 days (mean 13.4 days) after operation. Collateral vessels were identified preoperatively and their angiographic regression or reappearance after operation was noted. In 15 patients (23 percent), there was no evidence of collateral flow before or after operation. The remaining 48 patients had 186 collateral channels preoperatively. Postoperatively, 84 (45 percent) of these collateral vessels were no longer apparent, 75 (40 percent) were unchanged and 27 (15 percent) were identical with the preoperative vessels but the pattern of blood flow was reversed. The findings suggest that in the presence of established collateral channels, direct revascularization acutely alters existing flow and pressure gradients in a complex manner. Collateral channels disappear or remain unchanged when a gradient is decreased or maintained; collateral flow is reversed when a gradient is increased. These data may permit (1) objective preoperative estimation of distal vessel runoff in vessels with collateral channels, and (2) evaluation of the completeness of revascularization in assessing long-term postoperative results.