Double internal mammary grafts superior to LIMA plus radial artery grafts

Double internal mammary grafts superior to LIMA plus radial artery grafts

Arterial grafts used for coronary revascularisation are better than venous grafts. But radial artery is a free graft while internal mammary artery is taken as a live graft with its proximal end arising from the subclavian artery. Ruttmann and colleagues [1] compared the use of a second internal mammary artery versus radial artery for coronary artery bypass grafting. Perioperative adverse cardiac and cerebrovascular events were significantly lower in the double internal mammary grafting group compared one internal mammary artery plus radial artery group (1.4% versus 7.6%, P<0.001).

The fact that internal mammary arteries are less susceptible to atherosclerosis is the main reason for extra benefit with double internal mammary grafts. Radial artery has a lower capacity to release nitric oxide, which seems to have a role in the susceptibility of the radial artery to atherosclerosis [2]. Right internal mammary artery can be used as an in situ graft by routing it through the transverse sinus of the pericardium.

Though there was higher risk of deep sternal infections in previous studies of dual internal mammary artery grafts, the incidence of sternal dehiscence was not higher in the study by Ruttmann and colleagues, probably because of the use of skeletonized mammary artery grafts rather than the conventional pedicled grafts. Skeletonized mammary artery grafts are known to have lower incidence of sternal ischemia.

References

  1. Ruttmann E, Fischler N, Sakic A, Chevtchik O, Alber H, Schistek R, Ulmer H, Grimm M. Second internal thoracic artery versus radial artery in coronary artery bypass grafting: a long-term, propensity score-matched follow-up study. Circulation. 2011 Sep 20;124(12):1321-9. doi: 10.1161/CIRCULATIONAHA.111.030536. Epub 2011 Sep 6. PMID: 21900082.
  2. He GW, Liu ZG. Comparison of nitric oxide release and endothelium-derived hyperpolarizing factor-mediated hyperpolarization between human radial and internal mammary arteries. Circulation. 2001 Sep 18;104(12 Suppl 1):I344-9. doi: 10.1161/hc37t1.094930. PMID: 11568080.