Flow characteristics in single and sequential aorto-coronary by-pass grafts.

Thirty five patients, operated upon with an aorto-coronary by-pass graft to left anterior descending artery and to a major diagonal branch, were prospectively analysed. The patients were divided into two comparable groups, in whom a single graft technique and a sequential graft technique was used respectively. Flows through the by-passes were measured electromagnetically during the operation. Flow to left anterior descending artery was significantly higher through an isolated by-pass than through a sequential by-pass. Flow to diagonal branch showed no significant difference in the two groups. The resistance of the intramyocardial coronary bed of the left anterior descending artery was lower with single than with sequential by-pass technique, while no difference existed between the resistance of intramyocardial coronary bed of the diagonal branch with both techniques. Blood velocity was higher in single by-pass to the left anterior descending artery than in the peripheral segment of sequential vein graft directed to the anterior descending artery.