Tension on coronary bypass conduits. A neglected cause of real or potential obstruction of saphenous vein grafts.

Of 41 saphenous vein aorta-coronary bypass grafts from 21 patients, abnormal graft tension was judged to be present at necropsy in 6 grafts (15 per cent) from 5 patients (24 per cent). Five (33 per cent) of 15 grafts placed to the right coronary system and one (3 per cent) of 26 grafts to the left coronary system were under excess tension. The abnormal tension appeared to result from the insertion of grafts too short to accommodate normal or abnormal distention of the right atrium and ventricle (graft to distal right coronary or posterior descending coronary artery) or of the pulmonary trunk (graft to left coronary system) after discontinuation of cardiopulmonary bypass or development of acute congestive cardiac failure.