Translational Research in Anatomy (Mar 2023)
Case analysis of a RIII-C single coronary artery with type IV dual LAD and right-dominant triple PDA
Abstract
Introduction: Coronary artery anomalies are rare congenital variations of the arteries that supply the heart. Examples of these anomalies include the development of a single coronary artery (SCA) to supply the entire myocardium, two left anterior descending arteries (LAD) occupying the anterior interventricular sulcus, and three posterior descending arteries (PDA) occupying the posterior interventricular sulcus. Reports of rare, simultaneously occurring coronary artery anomalies serve as valuable references for medical education and clinical practice but are scarce in the literature. The present study describes a human cadaveric heart where a SCA gives rise to distinct dual LADs and three PDAs. The study aims to characterize the anomalies and investigate the anatomy, histology, and clinical considerations of this unique coronary anatomy. Methods: The SCA, dual LAD, and triple PDA were discovered during routine cadaveric dissection in a medical education curriculum. The heart was eviscerated, and the anomalies were cleaned of extraneous tissue and photographed. Color replacement was performed on the images to aid in structure identification. The SCA was characterized using Lipton's classifications, and the dual LAD was classified according to the thirteen variations (“Types”) of dual LAD described in the literature. Length, luminal area, and plaque buildup were recorded for each of the relevant arteries. A constriction on the great cardiac vein and an unknown tissue mass associated with the left main coronary artery (LMCA) were examined via histological staining and light microscopy. Courses of the coronary artery anomalies were superimposed on volume rendered computerized tomographic angiography images depicting typical coronary anatomy for comparison. Results: The SCA arose from a solitary coronary ostium in the right coronary sinus and traveled 0.57 cm from the aortic trunk before branching the right coronary artery (RCA), long LAD, LMCA, and descending septal artery. The RCA maintained typical anatomic course before terminating as a right-dominant triple PDA. The long LAD coursed pre-pulmonic along the anterior interventricular sulcus for 13.89 cm before terminating near the apex of the heart. The LMCA tracked retro-aortic, between the aorta and the atrial wall, for 5.67 cm before bifurcating into the left circumflex artery (LCX) and 10.8 cm short LAD. Multiple anastomoses were noted involving the long LAD, short LAD, second PDA, third PDA, diagonal branches of the short LAD, and left marginal artery. The constriction on the great cardiac vein, caused by an overlaying left diagonal artery, decreased the venous wall thickness and altered its tissue composition. The unknown tissue adhered to LMCA appeared mucinous in origin. Conclusions: The heart presented in this study was supplied by a unique (Lipton's) RIII-C SCA with Type IV dual LAD and right-dominant triple PDA. Unexpected complications can arise during cardiac procedures for patients with coexisting coronary artery anomalies such as these. This report may serve as an important reference for cardiothoracic surgeons, interventional cardiologists, coronary angiographers, and medical educators when presented with a similar case and determining therapeutic design.
