Anatomic assessment of the bifurcation of the left main coronary artery using multidetector computed tomography

Multiple techniques for stenting left main coronary artery (LMCA) bifurcation lesions exist, and an accurate understanding of normal LMCA anatomy is essential for proper diagnosis and therapeutic intervention for these lesions. The purpose of this paper is to identify various anatomic LMCA characteristics at the point of bifurcation and draw relevant clinical lessons from these characteristics.

Two independent observers analyzed 105 cardiac dual-source computed tomography images recording LMCA length, angle of bifurcation, and cross-sectional area of the LMCA, left circumflex artery (LCX), and anterior interventricular artery (AIVA) at the point of LMCA bifurcation. Frequency of left dominance, right dominance, and codominance, as well as LMCA trifurcation was also noted.

Average LMCA length was 9.9 ± 4.15 (range 2-21 mm). Average angle of bifurcation between LCX and AIVA was found to be 69.3° ± 33.3° (range 14°-200°). The most frequent division of the LMCA is a bifurcation into the terminal LCX and AIVA. In 20/105 cases (19.0%) a trifurcation pattern was identified. Average cross-sectional areas at point of LMCA bifurcation were as follows for LMCA, LCX, and AIVA respectively: 12.4 ± 4.4 mm(2) (range 2.3-25.9 mm(2)), 7.4 ± 3.5 mm(2) (range 1.2-23 mm(2)), 8.5 ± 3.5 mm(2) (range 1.3-25.9 mm(2)). Frequency of heart dominance was as follows for right dominant, left dominant, and codominant 85.7, 9.5, and 4.8%, respectively.

Accurate knowledge of the in vivo anatomy of the area of bifurcation of the LMCA is essential for avoiding the misdiagnoses of diseases and for proper stent placement during percutaneous intervention in the area of bifurcation.