Origin, course and variations of cornary arteries in postmoterm cases at the University Teaching Hospital. Lusaka, Zambia

Abstract

Background: Coronary arteries play an important role in supplying blood to the muscular walls and tissues of the heart. With increase in the rate of cardiovascular diseases, knowledge of the normal and variant anatomy of coronary arteries is indispensable and imperative both in diagnosis, treatment and implementation of interventional measures. An anatomical understanding of the possible coronary artery anomalies is essential for accurate angiographic interpretation and also for cardiologists performing cardiac surgery. The aim of this study was to describe the origin, course and variations of coronary arteries in post-mortem cases at the University Teaching Hospital in Lusaka, Zambia. Materials and methods: The study design used was a descriptive cross-sectional study in which 127 human hearts from post-mortem cases were dissected and examined. The hearts were obtained from cases of ages between 17 and 86 years and of the 127, 96 were males and 31 females. The costochondral joints were cut to remove the sternum and the cartilage part of the ribs. The aortic sinuses of the ascending aorta were all examined for presence coronary ostia and an incision made through the non-coronary aortic sinus to enable visualisation of the coronary ostia which are origins of coronary arteries in the aortic sinuses. Measurements of the width and height of coronary ostia were taken using a digital vernier caliper. The hearts were examined grossly and dissected to follow the coronary arteries in their subepicardial course. Results: The age ranged between 17 and 86 years. Out of the 127 hearts, the left coronary artery (LCA) arose from : the left aortic sinus (LAS) in 90 (70.9 %) hearts, the sinutubular junction (STJ) in 33 (25.9 %) hearts, a common trunk with right coronary artery (RCA) whose ostium was located in the right aortic sinus (RAS) in 1 (0.8 %) heart, a common ostium with the RCA in tubular part of ascending aorta above the RAS in 1 (0.8 %) heart, the RAS in 1 (0.8 %) heart. The left main coronary artery (LMCA) was absent in 1 (0.8 %) heart. The right coronary artery arose from: the RAS in 97 (76.4%) hearts, the STJ in 25 (19.7 %) hearts, the LAS in 2 (1.6 %) hearts, a common ostium with the LCA in tubular part of ascending aorta above the RAS 1(0.8%) heart, a common trunk with LCA whose ostium was located in RAS in 1 (0.8 %) heart and STJ of LAS 1 (0.8%) heart. Six (6) (4.72%) hearts out of the 127 had coronary artery anomaly/variations in origin and course of the main trunk right and left coronary arteries. Of the six (6) hearts with coronary artery anomalies only one (1) was from a female and the five (5) from males. The left coronary ostium width range was 1.6 – 7.9 mm with a mean of 4.62 (± 1.104) mm whilst the left coronary ostium height range was 1.5 – 4.9 mm with a mean of 2.64 (± 0.719) mm. The right coronary ostium width range was 1.6 – 9.6 mm with a mean of 3.66 (± 1.40) mm whilst the right coronary ostium height range was 1.1 – 4.9 mm with a mean of 2.27 (± 0.72) mm. The mean cross sectional areas of the left and right coronary ostia were found to be 9.70 mm2 and 6.99 mm2 respectively and when compared using t-test and the left coronary ostium was found to be significantly larger p-value 0.000000000 (p < 0.05). Conclusion: The location of coronary ostia (origin of coronary arteries) were described and seen that the majority of the coronary ostia were located in their respective aortic sinuses. Coronary ostia dimensions i.e. width, length and cross sectional area were analysed and seen that the left coronary ostium is significantly larger than the right coronary ostium (p-value 0.000). Incidence of coronary artery anomalies/variations of origin and further course was found to be 4.72% (6/127 hearts).