Microanatomy of Left Internal Thoracic Artery and Left Anterior Descending Artery: A Comparative Study

Abstract

Introduction: The knowledge of the microscopic structure of the left internal thoracic artery (LITA) and left anterior descending (LAD) artery can be correlated to the effectiveness of coronary artery bypass grafting using LITA graft. The objectives of the study were to study the microanatomy of the LITA and LAD artery, to compare the thickness of the wall of both arteries, and to report the elastic and muscular nature of these arteries. Materials and Method: Postmortem specimens of both the arteries from 50 samples of males were collected from the mortuary of Forensic Medicine, Government Medical College, Thiruvananthapuram. The tissues were subjected to hematoxylin and eosin and special staining. A photo micrometer was used for measuring the thickness of the wall, diameter of the lumen, and number of smooth muscles. Results: The mean thickness of tunica intima (TI) of LITA and LAD was 18.8 μ and 129.8 μ, respectively. The lumen diameter of LITA and LAD was 945.25 μm2 and 1653.45 μm2, respectively. The thickness of tunica media (TM) and the diameter of the lumen of LITA were increased with age. The number of smooth muscles in LITA was decreased with age. The thickness of TI, media, adventitia, and the luminal diameter of LAD were increased with age. The number of smooth muscles in LAD was decreased with age. Conclusion: Proximal segments of LITA had more elastic fibers arranged in concentric lamellae, especially in the outer zone. The TM of LAD has a greater number of smooth muscles and a smaller number of elastic fibers.

Keywords

• anterior interventricular artery
• coronary revascularization
• histology
• left internal mammary artery
• photomicroscope