Anatomical Variations in the Branching Pattern of the Left Coronary Artery: A Cadaveric Study in the Eastern Indian Population

BACKGROUND: Knowledge of the anatomical variations of the left coronary artery (LCA) is essential for accurate interpretation of coronary angiography, interventional planning, and surgical revascularization. Branching pattern variability directly influences myocardial perfusion and the extent of ischemic injury. This study aimed to document the branching pattern of the LCA in adult cadaveric hearts from Eastern India. METHODS: Sixty formalin-fixed adult human cadaveric hearts were dissected in the Department of Anatomy, IMS and SUM Hospital, Siksha 'O' Anusandhan (Deemed to be University), Bhubaneswar, India. The origin of the LCA from the left aortic sinus was identified, and the epicardial fat in the left atrioventricular groove and anterior interventricular sulcus was removed using blunt dissection to expose the main trunk of the LCA and its major branches, like the left anterior descending (LAD) and left circumflex artery (LCx), following them distally. The LCA was thus exposed from its origin to termination, and its branching pattern was classified into bifurcation, trifurcation, tetrafurcation, and any other variations. Of course, branching or termination of major branches of the LCA or branches from such major branches was also noted. All findings were photographed, documented, and quantitatively analyzed. RESULTS: A total of 60 formalin-fixed adult human cadaveric hearts were examined. Bifurcation, in which the LCA divided into the LAD and LCx arteries, was the most common configuration and was observed in 42/60 hearts (70%). In the bifurcation pattern, the branches were separate proximal to the terminal division. Trifurcation, in which the LCA gave rise to the LAD, LCx, and ramus intermedius, was seen in 15/60 hearts (25%). Tetrafurcation, characterized by division into the LAD, LCx, and two rami intermedii, was present in 3/60 hearts (5%). The 95% confidence Interval (CI) for bifurcation was 58.4 to 81.6%, for trifurcation, 95% CI was 14.1% to 35.9 %, and for tetrafurcation, 95% CI was 0% to 10.6 %.In addition, the LCA terminated as the left marginal artery (included in the category of bifurcation of LCA) in two of 60 hearts, while the left marginal artery arose directly from the LCA (included in the category of trifurcation of LCA) in another 2/60 hearts. CONCLUSION: Bifurcation was the most common LCA branching pattern. Some rare variations (not reported in research papers yet from Eastern India) involving the left marginal artery were also noted in the study. Detailed anatomical knowledge of LCA variation assists clinicians in improving diagnostic accuracy and enhancing the safety of interventional and surgical procedures. However, our study has some limitations, such as a relatively small sample size and a single-region cadaveric study. So we propose larger multicentric radiological and interventional studies, which will be of great benefit to the surgical and radiological community.