[Myocardial blood flow distribution immediately following experimental aortocoronary bypass and 1 year...

A 75--90% stenosis of the left circumflex coronary artery (CCA) was induced over a period of 40 days in 11 mongrel dogs. Coronary blood flow and the distribution of myocardial blood flow (MBF, tracer-microspheres) was measured at rest and after maximal coronary dilatation in 8 dogs before and within 1 hour after coronary bypass. In 3 dogs these measurements are performed 1 year after bypass op. During coronary stenosis distribution of myocardial blood flow in the area supplied by the CCA was unhomogeneous, the subendocardium receiving less. Within 1 hour after opening the graft, MBF to the subendocardium was improved but the unequal distribution not completely abolished. One year after bypass op, however, the quantity and distribution of MBF appear to be normal although revascularized myocardium was perfused in part via coronary collaterals.