Regression of intercoronary collateral vessels in mongrel dogs after coronary bypass grafting

Four dogs underwent direct revascularization of a chronically occluded circumflex artery with an internal mammary artery bypass graft. Preoperative coronary cineangiograms demonstrated well developed intercoronary collateral vessels supplying the circumflex arterial bed. Intraoperative measurements of retrograde circumflex arterial flow and pressure were consistent with the presence of large collateral vessels. Closed chest postoperative estimates of the potential collateral circulation were obtained by advancing a Judkins catheter to the internal mammary wedge position. The graft wedge pressure was equated to the retrograde circumflex pressure. After coronary bypass grafting, the interval coronary angiographic and hemodynamic studies indicated that well developed collateral vessels regressed within the first postoperative month to capacities in the range of those found in normal dogs.