The right internal thoracic artery: the forgotten conduit--5,766 patients and 991 angiograms

The right internal thoracic artery (RITA) is biologically identical to the left ITA, yet is rarely used in coronary artery bypass graft surgery (CABG). We examined the results and long-term patency of RITA grafts.

Between 1986 and 2008, 991 consecutive RITA graft angiograms for postoperative cardiac symptoms were evaluated by two independent observers. Grafts were considered nonpatent if they had a greater than 80% stenosis, string sign, or total occlusion. Patency was examined over time by coronary territory, whether in situ or free RITA, and compared with other conduits. Clinical results were collected prospectively and by the National Death Index.

A total of 5,766 patients had a RITA graft as part of a bilateral ITA CABG procedure. Operative mortality was 1.1%; deep sternal infection 1.5%. Of 7,780 coronary conduits studied, 991 RITA conduits were examined; a mean of 100±60 months postoperatively (1 to 288 months). Overall ten-year RITA patency was 90%. The RITA graft patency to the left anterior descending artery (LAD; n=149) was 95% at 10 years and 90% at 15 years. Ten-year RITA patency to the circumflex marginal (Cx; n=436) was 91%, right coronary artery (n=199) was 84% (p<0.001), and posterior descending artery (n=207) was 86%. Ten-year RITA and LITA patencies to the LAD were identical (95% vs 96%) and to the Cx (91% vs 89%), respectively. In situ RITA (n=450) and free RITA (n=541) had similar ten-year patencies (89% vs 91%; p=0.44). The RITA patency was always better than the radial artery (p<0.01) and saphenous vein grafts (p<0.001). Atheromatous changes were not seen in the RITA angiograms. Ten-year survival of patients with RITA and LITA for triple-vessel coronary disease was 89%.

Late patencies of RITA are excellent, equivalent to the LITA for identical territories, always better than radial arteries and saphenous vein grafts, and remain free of atheroma. Use of RITA in addition to LITA is associated with excellent survival in triple-vessel coronary disease. More extensive use of the RITA in CABG is recommended.