Left Internal Mammary Artery Operative Topography for MIDCAB and TECAB Procedures

The left internal mammary artery (LIMA) is a common arterial graft in minimally invasive coronary surgery (MICS), such as minimally invasive coronary artery bypass grafting (MIDCAB) or totally endoscopic coronary artery bypass (TECAB). The aim of this study was to perform an analysis of the LIMA operative topography during MICS.

A total of 104 computed tomography angiographies were analyzed retrospectively using 3-dimensional reconstruction and visualization software. Measurements were developed in relation to the anatomical midpoint of the sternal body (SBMP). Parameters were evaluated as lengths, distances, diagonals, or categorical descriptions.

A total of 208 internal mammary arteries of each side were analyzed with the following results: (1) LIMA width = 2.7 mm, (2) SBMP-LIMA bifurcation length = 6.2 cm, (3) SBMP-LIMA distance = 3.2 ± 0.5 cm, (4) xiphoid midpoint-LIMA distance = 3.5 ± 0.7 cm, (5) sternal line-LIMA distance = 1.7 ± 0.3 cm, (6) xiphoid end projection-LIMA bifurcation length = 2.2 ± 1.0 cm, (7) midsternal line-LIMA bifurcation distance = 3.3 ± 0.8 cm, (8) xiphoid end-LIMA bifurcation diagonal = 4.1 ± 0.9 cm, (9) LIMA-left coronary artery distance = 7.0 ± 1.4 cm at the proximal and 7.1 ± 1.3 cm at the distal segment, and (10) LIMA-left anterior descending artery distance = 5.5 ± 1.1 cm at proximal, 4.3 cm at middle, and 4.2 ± 1.5 cm at distal segment. The extent of LIMA bifurcation ranged from the level of 5 (1%) to 7 (6%) rib cartilages.

Based on the detailed surgical anatomy of LIMA, it was concluded that the fourth intercostal space should be considered as an appropriate approach for MIDCAB or TECAB in the studied region.