A patent internal mammary artery graft decreases the risk of reoperative coronary artery bypass surgery.

In order to evaluate the potential risks of a patent internal mammary artery bypass at reoperative coronary artery bypass grafting, we have reviewed the records of 233 consecutive patients undergoing reoperative coronary artery bypass grafting between 1 January 1991 and 31 December 1993, including 209 patients having an occluded mammary graft or no mammary graft (Group I) and 24 patients having a patent mammary graft (Group II). With regard to preoperative patient characteristics, the only significant differences between the groups were: Group II patients had a higher preoperative left ventricular ejection fraction than did Group I patients (63.7% +/- 8.9% vs. 52.1% +/- 10.1%, p < 0.001); and Group II patients had received fewer grafts per patient than had patients in Group I (2.2 +/- 1.1 vs 3.6 +/- 1.4 grafts per patient, p < 0.001). There were no entry injuries to the grafts or to the heart in either of the groups. No perioperative mortality was encountered in Group II, while 11 patients died in Group I (p < 0.05). Group II had a significantly higher incidence of reexploration for post-operative bleeding, whereas Group I had a significantly higher incidence of low postoperative cardiac output. The incidence of all other perioperative complications did not differ between the groups. The results of this study support the use of mammary grafts even in patients who are likely to need repeat coronary artery bypass grafting and certainly does not disqualify such patients from a 2nd operation.