Original Article

Study of level of termination of right coronary artery and its dominance in human cadaveric specimens

Lakshmiprabha R1, Ramesh P2, Shivaleela C3, Kavyashree A N4, Anupama D5

1Professor and HOD, 2Tutor Cum Research Scholar, 3, 4Associate Professor, Professor, Department of Anatomy, Sri Siddhartha Medical College, SSAHE, Tumkur.

DOI -10.46319/RJMAHS.2020.v03i01.004

Abstract Background: Major arterial supply to the heart is by Right coronary artery and its branches. are also called as vasa vasorum of the heart. According to Gray's anatomy, 70% of the show Right coronary dominance which indicates that Posterior inter ventricular artery arises from RCA in these cases and in such cases usually RCAs terminate beyond the crux of the heart (In Posterior interventricular sulcus - PIVS).The aim of this study was to find out the levels of termination of Right coronary artery and pattern of coronary dominance. Materials and methods: For this study, 55 human formalin fixed cadaveric heart specimens were taken from the department of anatomy of SSMC, Tumakuru. Results: Right coronary artery(RCA) terminated beyond the level of the crux of the heart (PIVS) in 35 heart specimens and 72 .2 % were right coronary dominant. Conclusion: Our study results are helpful for the accurate interpretation of advanced radiological techniques like angiography especially the termination levels of right coronary artery and it acts as a guide to cardiothoracic surgeons for Coronary artery interventional surgeries and management of IHD. Keywords: Right coronary artery, coronary dominance, termination levels

Introduction in the anastomotic branch or in PIVA. And the same was neglected in previous cardiothoracic interventions.[3] The word coronary is derived from Latin and Greek words co-ro-ne and koro ne which means anything RCA supplies whole of the right , variable parts curved or hooked. The word coronary also indicates that of the diaphragmatic surface of the left ventricle, the anything encircling like a crown.[1] Coronary arteries are posterior one third of , right the vasa vasorum of the heart and they arise from aortic , part of the left atrium, and sinuses of ascending . Right coronary artery (RCA) , and part of left and left coronary artery (LCA) arise from anterior aortic bundle branch. The incidence of right coronary artery sinus and left posterior respectively.[2] dominance (RCAD) is 90% and left coronary dominance (LCAD) is 10%.[4] Coronary Artery dominance (CAD) in the humans was described more on the basis of origin of posterior Minor congenital anomalies among coronary arteries interventricular artery (PIVA) which arises from right are revealed frequently during cardiac catheterization coronary artery in 67% of individuals which is called without any adverse prognosis and also these kind of RCAD and from Circumflex branch of left coronary Address for Correspondence: artery (LCA) in 33% of individuals which is described as Ramesh Palanisamy, Tutor Cum Research Scholar, LCAD. Coronary occlusion occurs in posterior part of Department of Anatomy, Sri Siddhartha Medical College, Sri Siddhartha Academy of Higher Institution, the right coronary artery, beyond the level of crux either Tumkur 572107. E-mail: [email protected]

Attribution-NonCommercial-ShareAlike 14 4.0 International Licence Res J Med Allied Health Sci | Jan-June. 2020 | Volume 3 | Issue 1 Ramesh P, et al.: Study of level of termination of right coronary artery DOI -10.46319/RJMAHS.2020.v03i01.004 www.rjmahs.org anomalies revealed gave guidelines for avoiding the sheet and data was analysed using Epi- info software. complications.[5] Descriptive statistics was applied to interpret the data. In order to avoid irreversible complications like Results necrosis of the area supplied by the injured coronary Total 55 heart specimens were utilised for the study. arteries and its branches, it is better to know all the Table 1 shows the level of termination of the right relevant and possible variations in the origin, course, coronary artery. 1 terminated at the level of rt border of branching pattern, distribution and termination of the heart, in 4 specimens before the crux of the heart coronary arteries.[6] (Figure 1), in 5 specimens at the crux of the heart, in 35 Various ethnic and regional studies of coronary artery (71.42%) specimens, right coronary artery continued as dominance stated varied percentages. Myocardial posterior interventricular artery in the posterior Infarction (MI) is commonly noticed in the region interventricular groove beyond the crux of the heart and supplied by left coronary artery and their branches due to in 4 specimens the level of termination was at the left its increased transverse diameter than the RCA. The border of the heart (Figure 2). minor occlusions in the posterior part of the right coronary artery and its branches are neglected most Table 1: Termination levels of right coronary artery commonly by the surgeons.[7, 8, 9] The present study was (RCA) undertaken to study the minimal error area (termination Number of Termination level Percentage levels of the right coronary artery) details for specimens of RCA * (%) interventional procedures and also for better (N=49) At the level of the right understanding of termination of RCA in this region. 1 2.04 This helps the cardiothoracic surgeons for a planned border Before the crux of the approach and better outcome. 4 8.16 heart At the level of the crux of Materials and Methods 5 10.20 A gross anatomical study of 55 specimens of heart by the heart After the crux of the dissection method was conducted in the Department of 35 71.42 heart(PIVS) anatomy, SSMC, Tumakuru for a period of 4 years. At the level left border 4 8.16 Cadaveric heart specimens without any gross pathology TOTAL 49 100 were included for the study & these were obtained following prior permission from Institutional ethical clearance Committee. 10 Heart specimens were taken out after incisions on the fibrous along with vessels related to it without damaging the outer surface. Specimens were thoroughly washed in running water and blood clots were removed from heart chambers without damaging other structures. The heart specimen was dissected underwater by conventional methods and the veins accompanying the arteries were removed for clear visualization of arteries avoiding the confusion. Areas like coronary sulcus, interventricular sulcus dissected meticulously and utmost care was taken at the time of removal of fat from the specimens for the preservation of coronary arteries & their branches along their complete course.[10] The course of the RCA, it's branching pattern and it's levels of termination was noted carefully and Figure 1: Termination of right coronary artery before photographed. Study details were entered in the excel the crux of the heart

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and termination. This study mainly focuses on the levels of termination RCA particularly in the posterior aspect of the heart, ie in the Right coronary sulcus and Posterior interventricular groove. During angiography and other surgical procedures related to coronary arteries, this study helps in better approach particularly on the posteroinferior aspect of the heart. 1) Level of termination of Right coronary artery

Table 2: Level of Termination of Right coronary artery in various studies.

At the right Before At or after border of the crux the crux of Authors the heart of the the heart (%) heart (%) (PIVG) (%) Gray’s anatomy2 10 10 60 Kalpana R et al7 7 3 70 Elururavitheja et 8 13 23 57 al Figure 2: Termination of right coronary artery after Bheemeshpusala 9 15 22.5 55 the crux of the heart and near the left border. et al Present study 2 8 81

In 81% of the specimens studied, the level of termination of RCA was at or after the crux of the heart (PIVG) which was more in comparision with the results of study by Kalpana R et al. (70%), Ravitheja E et al (57%) and Pusala B et al (55%) and also with it's reference in Grey's anatomy (Table 2). In the present study, termination of RCA at the level of right border of the heart was seen in 2% of the specimens which is lesser than the results mentioned by Kalpana et Figure 3: Bar diagram shows the origin of the posterior al (7%), Gray's Anatomy(10%), Ravitheja E et al (13%) interventricular artery (PIVA) in our study / coronary and Pusala B et al (15%). The percentage of termination dominance of RCA before the crux of the heart was 8% and was more than the results obtained by KalpanaR et al (3%) Figure 3 shows the Source of origin of posterior and less than that in the Gray's Anatomy (10%), interventricular artery. Out of 55 specimens studied , Ravitheja E et al (23%) and Pusala B et al (22.5%) (Table PIVA arose from RCA in 39 specimens (72.2%) which 2). indicates the Right coronary artery dominance (RCAD - 72.2% cases) and in 15 specimens (27.3%) PIVA arose 2) Coronary Artery Dominance from LCA which indicates the left coronary artery In the present study, Right Coronary Artery dominance dominance (LCAD- 27.3%) and in 1 case it was arising was found more frequently (72.2%) than the left from both (0.5% - Codominant circulation) . coronary artery dominance (27.3%) similar to that described in Gray's anatomy. This also correlates with Discussion the previous studies done by Sally P et al (70% RCAD, The study of Right coronary artery was done globally by 15 % LCAD), [12] Moore et al ( RCAD -67%), Venkatesh various authors regarding its origin, course, distribution et al ( RCAD- 69%) (Table 3). [2,3,11]

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Table 3: Percentage of Coronary artery dominance Conflict of interest: Nil in different studies. References RCA LCA 1. Co-ro-ne. Dorland's illustrated medical dictionary. 30th Authors dominance Dominance edt., Philadelphia : Saunders, 2000:420. (%) (%) 2. Standring S. Gray's Anatomy:The Anatomical Basis of 2 Gray’s anatomy 70 20 Clinical Practice. 40thed. Edinburgh, London, New York, 3 Moore et al 67 33 Oxford, Philadelphia, St. Louis, Sydney, Toronto, 4 Snell R et al 90 10 Elsevier, Chirchill Livingstone; 2008: 1017-1023. Kalpana R et al7 89 11 3. Moore K L, Dalley A F.Clinically oriented anatomy. Venkatesh K et al 11 68.75 16.66 5thEd. Philadelphia: LWW; 2017: 141-161 Present study 72.2 27.3 4. Snell R. Clinical anatomy by regions. 9thEd.

Philadelphia: Lippincott Williams & Wilkins; 2012: 79- A study by Kalpana R et al shows RCAD of higher 92. percentage (89%) than our study with RCAD (72.2%) 5. Charles E. Wilkins et al “Coronary Artery Anomalies” A and Richard Snell also documented 90% of RCAD Review of More than 10,000 Patients from The Clayton where Rt Coronary arteries continue as PIVA which is Cardiovascular Laboratories” Texas Heart Institute about 20% higher than our study results (Table 3). [4,7] Journal 1988;15:166-173. Regional variations have been documented in Coronary 6. Walmsley R, Watson H, Kirklin JW. Clinical anatomy of the heart. 1stEd. Edinburgh: Churchill Livingstone. artery dominance. So before planning the surgical 1978:199-214. procedures proper evaluation of the coronary artery 7. Kalpana R. A study of principal branches of coronary dominance and their termination levels will be helpful in arteries in human. J AnatSociInd Dec 2003; 52(2):137- avoiding the minimal errors and failures of procedures 40. thus modifying the outcome of treatment. 8. Ravitheja E, Padmavathi M. A study on variation in the Conclusion termination of right and left coronary arteries and their clinical significance. Int J Anat Res. 2018;6(3.2):5531- Detailed knowledge regarding the level of termination 34. of Coronary arteries and preponderance of Coronary 9. Pusala B, Reddy M V. Termination and dominance of dominance will be of great help to Cardiothoracic coronary arteries: On telangana population. Int J Anat surgeons. This helps them to manage the Coronary Res. 2017; 5(2.1):3735-40. artery related diseases with sound knowledge & clarity 10. Romanes G, Cunningham D. Cunningham's manual of of its anatomy which yields better outcome in their practical anatomy. 16thEd.London: Oxford University surgical procedures. This study also aids in better Press; 2019: 49-78 interpretation of angiograms by Intervention 11. Venkateshu KV. Coronary artery dominance. Anat cardiologists regarding narrowing or occlusion of the Karnataka Jun 2005;2(1):18-21. Right coronary artery and its branches and its levels of 12. Allwork SP. The applied anatomy of the arterial blood termination in the posterior aspect of the heart either in supply to the heart in man. AnatSoci Great Britian and Right Atrio Ventricular Sulcus and Posterior Inter Ireland Aug 1987;153:1-16. Ventricular Sulcus.

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