The Left Main Bifurcation Angle and Changes Throughout the Cardiac Cycle: Quantitative Implications for Left Main...

The objective of this study was to quantify the left main (LM) bifurcation angles and their changes throughout the cardiac cycle.

LM stenting is an accepted alternative to coronary artery bypass grafting. However, the LM bifurcation has great anatomic variability. Three-dimensional angles and their cyclic changes are important for coronary stenting.

Patients undergoing coronary computed tomography angiography (CCTA) for chest pain were scanned and analyzed in three-dimensional views for left main-left anterior descending (LM-LAD), left main-left circumflex (LM-LCX), and left anterior descending-left circumflex (LAD-LCX) angles and their cyclic changes. Calculations and assessment of angles, angular variability, and how these angles change throughout the cardiac cycle were analyzed.

Forty-four patient scans were analyzed. The median end-diastolic LM-LCX angle was 130° and the LAD-LCX was 74°. Median end-systolic angle for the LM-LCX was 133°, and LAD-LCX was 69°. Large differences were found across all three absolute angles (LM-LCX, LAD-LCX, LM-LAD). Marked variability also occurred in how these angles changed throughout the cardiac cycle.

LM bifurcation geometry in patients shows marked absolute angle variability, as does diastolic-systolic angle movement. LM bifurcation stents should accommodate wide interpatient bifurcation angles at rest for both the LM-LAD and LM-LCX angles.