Study of branching pattern of right coronary artery in 50 specimens

Parthiban, K (2008) Study of branching pattern of right coronary artery in 50 specimens. Masters thesis, Madurai Medical College, Madurai.

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Abstract

INTRODUCTION: Coronary artery disease is the commonest cause of heart diseases and the most important cause of death all over the world. According to Parks (2005) it is the cause of 25-30 percent of deaths in most ind ustrialised countries. Coronary artery occlusion may either result in myocardial infarction or lead onto ischemia and angina pectoris. The recent advances in direct coronary artery surgery, the newly invented techniques in bypass surgery and the modern methods of revascularization require a complete knowledge of the coronary circulation. AIM OF THE STUDY: Coronary artery disease, in developing world as compared to the developed world, occurs a decade earlier. In India, it has been the most frequent single cause of death in men under the age of 65. In U.S sudden death is more common in young adults with coronary arterial anomalies (Liberthson RR 1979). The increasing use of diagnostic and therapeutic interventional procedures in bypass surgeries and myocardial revascularization, outlines the necessity for a sound basic knowledge in anatomy of coronary circulation. With this aim, an attempt has been made to study the right coronary artery in detail i.e. its origin, course, branching patterns, termination and the presence of anomalous artery. MATERIALS AND METHODS: From early days, manual dissection of the coronary vessels from their origin in the aortic root to their apparent distal termination – where they attenuate to such a degree that they cannot be followed further by visual inspection. Injection of dyes into the coronary arteries before dissection is an adjunctive method that greatly facilitates the procedure and improves its accuracy. Replacing the dyes with radio-opaque fluids permits postmortem angiography which facilitates careful study of the vessels without disturbing their anatomic integrity. Hildebrand (1900) introduced such a technique to study systemic circulation and Fryett (1905) later extended it, to study the coronary circulation. The most selective technique for the study of vasculature in detail was described by Hyrtl (1873). It involves filling the vasculature with a mass that hardens, to corrode the organ leaving a cast of vaculature (Injection Corrosion Technique). Nussbaum (1912) used metal alloys and later James (1961) used plastics to prepare casts. Of the various methods available for studying the anatomy of coronary arteries, the method followed for the present study is the Manual Dissection method. MATERIALS: The 50 specimens for this present study were obtained from the Forensic medicine department. The specimens were collected without any age, sex, socio-economic status, religion, and pathological bias. The hearts were removed during autopsy by following method: A transverse cut was made through the manubrium of sternum immediately inferior to its junction with the first costal cartilage. An incision was made through the parietal pleura in the first intercostal space extending up to mid- axillary line. From this line, the second and subsequent ribs were divided inferiorly up to the level of xiphisternal joint. The inferior part of the sternum with costal cartilage and anterior parts of ribs were elevated. The parietal pleura extending from back of sternum on to the mediastinum on both sides was divided. The anterior part of sternum was lifted up and hinged on the superior part of the abdominal wall after dividing the sternopericardial ligaments. The fibrous pericardium was separated from the adjoining structures. By dividing the fibrous pericardium the heart was exposed and delivered out of middle mediastinum by cutting branches of arch of aorta, superior and inferior vena cava, pulmonary veins and artery. The collected specimens were preserved in 10% formalin solution and numbered serially from 1 to 50. The specimens were dissected using a pair of scissors, forceps and scalpel. CONCLUSION: The present work was carried out to study the branching pattern of right coronary artery in 50 specimens. The right coronary artery was found to arise from the anterior aortic sinus in all the specimens except one, in which the right coronary artery was found to arise from left posterior aortic sinus. The right coronary ostium was below the sino rubular junction in 90% of the specimens and at sino tubular junction in 10%. The right coronary ostium above the sino tubular junction was not found in any of the specimens studied. A slight variation in the course of the right coronary artery was noticed in 2 specimens. The average distances of the three branches of first segment of right coronary artery from the ostium were found to be 8.62mm, 16.39mm and 40.04mm respectively. These measurements will probably be of use in planning bypass grafting. The incidence of sino atrial nodal artery arising from the right coronary artery was 76%. Third coronary artery was present in 10% of the specimens studied. The atrioventricular nodal artery arose from right coronary artery in 82%, from the left coronary artery in 18%. The posterior interventricular artery arose from the right coronary artery in 82% and from left circumflex artery in 18%. Parallel branches were present in 16% of the specimens. The right coronary artery terminated between crux and left border in 62%, at the right margin in 14%, reached the left border in 12%, at crux in 8%, and between right margin and crux in 4%. The posterior interventricular artery terminated in the distal one third of the posterior interventricular sulcus in 48%, in the middle one third of the posterior interventricular sulcus in 32%, in the proximal one third of the posterior interventricular sulcus in 20%. The right coronary artery was the dominant in 82% and left coronary artery was the dominant in 18%. The presence of anomalous artery-right coronary artery arising from the left posterior aortic sinus was found in only one out of fifty specimens studied. An in depth knowledge of the anatomy of the coronary arteries, ‘crown’ of the heart, is a self evident prerequisite for a complete under standing of the coronary artery disease or for more intelligent planning of surgery. The present study on the right coronary artery, its origin, course, branching patterns, termination and the presence of anomalous arteries was to be of some use to the specialists during cardiac catheterizations and to effectively plan bypass surgeries using normal or anomalous coronary arteries. This study would be of use to interventional radiologists and cardiologists for their invasive or non invasive procedures.

Item Type: Thesis (Masters)
Uncontrolled Keywords: branching pattern, right coronary artery, 50 specimens.
Subjects: MEDICAL > Anatomy
Depositing User: Subramani R
Date Deposited: 05 Oct 2019 08:05
Last Modified: 05 Oct 2019 14:01
URI: http://repository-tnmgrmu.ac.in/id/eprint/11687

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