The response to papaverine in coronary artery bypass graft flows.

During coronary artery bypass surgery graft flows were measured. The measurements were made after cardiopulmonary bypass had been discontinued. The recordings were made over a ten year period and a total of 1,151 grafts in 720 patients are included. Except where the flow down a graft was large, 20 mg of Papaverine were injected into the graft and this usually resulted in the flow increasing by at least 100%. A satisfactory response was not achieved in 32 of the 538 grafts in which Papaverine was injected but subsequent probing of the distal anastomosis achieved a markedly improved flow in 80%.