Are Two Internal Thoracic Grafts Better Than One?: Analysis of 4247 Cases between 1996- 2010

Objectives: Bilateral internal thoracic artery (ITA) grafting is associated with improved survival. However, many surgeons are reluctant to use this revascularization technique in patients with co-morbidities such as diabetes and in elderly patients due to the risk of sternal infection and the excellent survival obtained with single ITA (SITA).

The purpose of this study is to compare early and long-term outcome of bilateral ITA (BITA) grafting to that of SITA and other conduits such as saphenous veins and radial artery in patients with multi-vessels coronary disease.

Methods: Two thousands seven hundreds and seventy six patients who underwent BITA grafting between 1996 and 2010 were compared with 1471 who underwent SITA grafting

Results. Patients undergoing SITA were older, more often female, more likely to have chronic obstructive lung disease, EF<30%, Recent MI, Diabetes, previous CABG, renal insufficiency, peripheral vascular disease and emergency operation. They also had significantly higher mean Euro-score (7.6 + 4.3 vs. 5.4 + 3.9 in the BITA group P< 0.001).

Operative mortality (3.7% vs. 2.2%, in the SITA and BITA respectively, p=0.003) and occurrence of sternal infection (3% vs 2%, p=0.019) were lower, in the BITA group.

BITA patients also had improved 10 year Kaplan- Meier survival (72.2% vs.56.6% p=0.037) however, after propensity score matching (1213 well matched pairs) BITA was not associated with better adjusted survival (HR 0.964[95%CI 0.874-1.097] p=0.574) (cox model)

Conclusion: This large study does not support routine use of BITA in all patients .Earlier mortality from non-cardiac causes, reduces contribution of BITA and increases the influence of co-morbidities on cox- adjusted survival. Selective use of BITA in lower risk patients might un-mask the benefits of BITA.