Bilateral internal thoracic artery grafting may improve outcome of coronary artery surgery. Risk-adjusted survival.

BACKGROUND

Excellent clinical results of the patients with single left internal thoracic artery (ITA) grafting compared with saphenous vein grafting have prompted surgeons to use both ITAs. However, long-term benefits of the bilateral ITA grafting have not been proven.

METHODS AND RESULTS

We reviewed our experience of 2826 patients (age 62 +/- 9 years [mean +/- 1 SD], 2350 men, mean follow-up 52 months) who underwent surgery with ITAs, supplemented by saphenous vein grafts when required, between 1985 and 1995. Single ITA grafting (n = 1557) was compared with double (n = 1269), by means of the Cox proportional hazards model. Significant predictors of all-cause mortality were as follows: (1) peripheral vascular disease, rate ratio (RR) = 2.4 (1.7 to 3.4 [95% CI]); (2) prior myocardial infarction, RR = 2.1 (1.5 to 3.1); (3) severe left ventricular dysfunction, RR = 3.9 (2.6 to 5.9) and moderate left ventricular dysfunction, RR = 2.0 (1.5 to 2.6); (4) age > or = 70 years, RR = 3.4 (2.4 to 4.8), and age 60 to 69 years, RR = 1.7 (1.3 to 2.4); (5) diabetes mellitus, RR = 1.7 (1.3 to 2.4); (6) carotid disease, RR = 1.7 (1.2 to 2.4); and (7) single ITA (versus bilateral ITA), RR = 1.4 (1.1 to 1.8). Number of vessels diseased, surgical status (i.e., urgent versus elective), hypertension, and sex were not significant predictors. Unadjusted actuarial survival rates at 10 years were 86 +/- 3% (mean +/- 95% CI) for bilateral ITA group and 71 +/- 5% for single ITA. Single ITA was also a predictor of all-cause mortality, late myocardial infarction, or late reoperation (RR = 1.3 [1.1 to 1.6]).

CONCLUSIONS

Bilateral ITA grafting may improve long-term survival and freedom from late myocardial infarction or reoperation after coronary artery surgery. Mathematical modeling may assist in developing a strategy for use of bilateral ITA grafts.