Efficacy of single versus bilateral internal mammary artery grafting in women: A long-term study

Background. Coronary artery bypass grafting carries a higher operative mort ality and less favorable long-term benefit in women than in men. Bilateral internal mammary artery grafting (BIMA) has been shown to yield excellent p erioperative and long-term results in both women and men. However, controve rsy continues to exist as to the benefits of a second internal mammary arte ry graft in women. Methods; A retrospective analysis was performed comparing 261 consecutive w omen from a single surgical practice receiving BIMA and supplemental vein g rafts between January 1972 and October 1994 with a computer-matched cohort of 261 women receiving single internal mammary artery (SIMA) and vein graft s during the same period. Univariate analysis confirmed the homogeneity of the two groups based on nine preoperative variables. Results. Operative mortality was comparable in the two groups, 3.8% (10 of 261 patients) in the SIMA and 3.4% (9 of 261 patients) in the BIMA group, w ith a markedly reduced mortality in both groups since 1990, 2.3% (2 of 86 p atients) in the SIMA and 1.3% (1 of 78 patients) in the BIMA group. The mea n number of distal grafts (2.78, SIMA; 3.14, BIMA), perfusion time (104 min utes, SIMA; 108 minutes, BIMA), and cross-clamp time (58 minutes, SIMA; 66 minutes, BIMA) were all comparable. There was no significant difference in the incidence of postoperative complications, including sternal wound infec tion. Patient follow-up ranged from. 1 month to 27 years, with a mean of 10 .0 years in the SIMA group and 9.1 years in the BIMA group. Clinical result s were excellent, with 100% (136 of 136 patients) of the SIMA and 100% (167 of 167 patients) of the BIMA patients in Canadian Cardiovascular Society c lass I or II at follow-up. Rates of late myocardial infarction, percutaneou s transluminal coronary angioplasty, and reoperation were similarly low in both groups: 3.7% (5 of 136 patients) versus 1.8% (3 of 166 patients), 5.4% (7 of 136 patients) versus 4.8% (8 of 166 patients), and 3.7% (5 of 136 pa tients) versus 1.8% (3 of 166 patients), for SIMA. versus BIMA survivors, r espectively. No significant difference was found in the long-term and event -free survival or in any of the eight subscales of the SF-36 quality of lif e survey for the two groups. Conclusions; Excellent short- and long-term results have been demonstrated with internal mammary artery grafting in women. However, the addition of a second internal mammary artery graft does not appear to confer any addition al clinical benefits in a comparably matched cohort of patients. (C) 2001 b y The Society of Thoracic Surgeons.