Reply to the Editor:
We read the letter from Donatelli and associates with great interest. We wonder whether the disappointing results reported by this team might be due to the size of their experience with the inferior epigastric artery (IEA). We believe that more than 38 operations and 23 angiograms are needed to gain reliable experience with a new graft.
The midterm patency rate of the IEA that we recently published in this Journalwas based not only on the 29 postoperative angiograms that Donatelli and associates mentioned in their letter, but also on a total of 77 angiograms obtained between 6 and 43 months (average 14.8 months) after the operation. On this basis, we have reported that the overall patency rate of the IEA used as a coronary artery bypass graft was 79%. We have also shown that the patency rate of the IEA remained stable after the first postoperative year (75% patency rate within the first postoperative year versus 86% after the first postoperative year).
1
It is correct that most of the IEAs that we have grafted were directed to the right coronary artery system; our choice of the right coronary artery as a target vessel for IEA grafting was certainly never made on the basis of the quality of its runoff. Our policy is to bypass the left anterior descending artery and its diagonal branches with the pedicled left internal thoracic artery (ITA) and to direct the pedicled right ITA to the circumflex artery rather than to the right coronary artery, which is often diffusely diseased. Therefore we believe we have tested the IEA on the most unfavorable coronary artery. To support this opinion, we would like to mention that the patency rate of free ITAs grafted to the right coronary artery was 75%, whereas it was 78% when the ITA was grafted to the circumflex and 84% when grafted to the left anterior descending coronary artery.
2
We agree with Donatelli's group that the chances for the IEA to remain patent could be better if it was grafted to a coronary artery with a good runoff. However, is seems to us more important that the stenosis of the recipient coronary artery should be severe enough to avoid any risk of competitive flow. We have recently shown that the most important predictor for perfect patency of the IEA in our hands was the severity of the stenosis of the recipient artery. Most of the poor angiographic results (occluded or stringlike grafts) that we have observed in our study were found in the presence of only moderate coronary artery stenosis. In a recent study, Cremer and colleagues
3
grafted 50 IEAs to either the left anterior descending or diagonal arteries. The patency rate of the IEA, taken from 23 angiograms obtained from 1 to 6 months after the operation, was 82.6%. In another study, Calafiore and associates 4
grafted 86 IEAs. By using a conduit-to-conduit technique that permitted them to avoid the need to construct aortoepigastric anastomoses, they improved the midterm patency rate of the IEA to 95.2%.On the basis of these results and our own experience, we believe, contrary to Donatelli and associates, that it is too early to draw a final conclusion about the role of the IEA. We believe there is at present no reason to reject this artery as a coronary artery bypass graft.
References
- Coronary artery bypass grafting with the inferior epigastric artery.J THORAC CARDIOVASC SURG. 1995; 109: 553-560
- Free (aorta-coronary) internal mammary artery graft.J THORAC CARDIOVASC SURG. 1986; 92: 827-831
- The inferior epigastric artery for coronary bypass grafting: functional assessment and clinical results.Eur J Cardiothorac Surg. 1993; 7: 423-427
- Composite arterial conduits for a wider arterial myocardial revascularization.Ann Thorac Surg. 1994; 58: 185-190
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© 1995 Mosby, Inc. Published by Elsevier Inc. All rights reserved.
