Reply: Can you really turn a vein into an artery?

Reply to the Editor:

The authors reported no conflicts of interest.

The Journal policy requires editors and reviewers to disclose conflicts of interest and to decline handling or reviewing manuscripts for which they may have a conflict of interest. The editors and reviewers of this article have no conflicts of interest.

The choice of conduit to supplement the left internal thoracic artery (LITA) during coronary artery bypass grafting remains a subject of debate. Saphenous vein graft (SVG) is prone to failure, and its failure can occur in up to 12% of patients within the first 6 months postcoronary artery bypass grafting and in up to 46% within 1 year., In contrast, data supporting the use of additional arterial grafts are strong. Clinical outcomes are improved with addition of other arterial grafts to LITA–left anterior descending coronary artery, reducing the rates of early major adverse cardiac and cerebrovascular events and conferring a survival benefit after 15 years compared with SVG or percutaneous interventions. The choice of right internal mammary artery as the second arterial graft is often obvious for anatomical reasons and its excellent patency rates (96.9%), even if it is used as a free graft. In a recent study of 1325 patients who received in situ bilateral internal thoracic artery grafts to left coronary bed as a part of total arterial revascularization, the rate of graft failure after 18 years of follow-up was 1.6% for LITA, 2.9% for right internal mammary artery, and as high as 20.7% for the radial artery, which was used as a free graft to the right coronary bed.

Hwang and colleagues reported that the use of SVG as a part of composite graft (SVG off the LITA) confers similar results as the use of multiple arterial grafts. The 10-year patency rates reported by Hwang and colleagues were excellent: 96.6% in the composite SVG group and 91.4% in the multiple arterial group. These findings are supported by the report of Lobo Filho and colleagues. They attribute these remarkable results to the use of valveless vein segments, to the avoidance of the proximal aortic anastomosis, and to the physiological effects of the proximal anastomosis to the LITA.

While the “unique results in certain hands” are certainly commendable, it is hard to prove that “veins can be turned in to arteries” with similar outcomes and patency rates as multiarterial revascularization. Confirmation from additional studies and investigators will be needed before widespread use of this technique. In the meantime, while composite grafts using SVG off an arterial graft constitute an interesting alternative, most surgeons would probably prefer not to risk the compromise of the LITA–left anterior descending coronary artery graft. In the end, no matter how good the vein extension or Y-grafting technique is, one might argue nothing is better than an undisturbed arterial graft.