End of the millenium - End of the single thoracic artery graft? Two thoracic arteries - Standard for the next millenium? Early clinical results and analysis of risk factors in 1,487 patients with bilateral internal thoracic artery grafts

Purpose: CABG with bilateral IMA grafts (BIMA) can improve long-term result s in cardiac morbidity and mortality. An enhanced incidence of bleeding and wound complications compared to patients with single IMA (SIMA) remains a matter of debate. The aim of the study was to compare the operative outcome s of patients who had undergone CABG with BIMA and SIMA in situ grafts, esp ecially to identify patient-related risk factors, such as obesity, diabetes mellitus and age above 70 years. Methods: Out of a total of 5,144 patients operated on between January 1996 and September 1999, patients with isolate d CABG (n=3,671) with BIMA or SIMA were analyzed retrospectively. In the BI MA group, the patients' (n=1,487) mean age was 64.0 years; mean EF was 62.1 %. In the SIMA group (n=2,184), the mean age was 65.4 years and mean EF 60. 6 % (n. s.). In the BIMA group, the right IMA was anterior of the aorta to the LAD, the left IMA to the lateral wall. In the SIMA group, the LAD was r evascularisized with the left IMA. Additional bypasses were performed with vein grafts. Results: The 30-day lethality was 1.6% in the BIMA group, 1.7% in the SIMA group in patients under 70, and 4.1% (BIMA) and 4.0% (SIMA) in patients over 70 (p=n.s.). A significantly higher blood loss was observed in the BIMA group (BIMA 979 +/- 708 ml, SIMA 790 +/- 575 ml, p<0.05). The r ethoracotomy rate due to bleeding was significantly higher in patients with BIMA (4.1%) compared to those with SIMA (2.5%, p<0.05). In patients with a body mass index (BMI) of less than 27, no significant difference could be found (SIMA 2.8 %, BIMA 3.4 %, p = n. s.). Patients with a BMI >27 showed a significantly higher rethoracotomy rate (SIMA 2.2 %, BIMA 4.9%). A higher incidence of sternal instabilities could be observed in the BIMA group (4.2 %, p<0.05). Diabetes mellitus could not be identified as an independent ri sk factor for sternal complications (SIMA 2.9 %, BIMA 5.0%, p = n. s.). Con clusion: CABG using both IMA's can be performed in nearly all patients as a routine method with good clinical results and low mortality. Bleeding in t he BIMA group within 48 hours was increased. BMI >27 could be identified as a risk factor for sternal complications, but not diabetes mellitus or age over 70 years.