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Prevalence of Coronary and Extracoronary Ostia in Southern Rajasthan: A Cadaveric Study |
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Shiv Kumar Sharma, Pratima Jaiswal, Aarushi Jain, Gulam Rasool 1. Medical Officer, Department of Anatomy, Government Medical College, Kota, Rajasthan, India. 2. Senior Professor and Head, Department of Anatomy, Government Medical College, Kota, Rajasthan, India. 3. Associate Professor, Department of Anatomy, Government Medical College, Kota, Rajasthan, India. 4. Medical Officer, Department of Anatomy, Government Medical College, Kota, Rajasthan, India. |
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Correspondence Address : Pratima Jaiswal, I-Ka-27, Vigyan Nagar, Kota, Rajasthan, India. E-mail: drpratimajaiswal@gmail.com |
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ABSTRACT | |||||||||||||||||||||||||||||||||||||||
: A variable incidence of additional coronary ostia or third coronary ostia is found along right ostium in the Anterior Aortic Sinus (AAS). Extracoronary ostia in AAS provide third coronary artery or right conus artery which supplies pulmonary conus and upper part of right ventricle. Third coronary artery is an important bridge for collateral circulation between right and left coronary system. Aim: To reveal the number, shape, and position of coronary and extracoronary ostia in aortic sinuses in Southern Rajasthan. Materials and Methods: This observational descriptive study was conducted on 100 human hearts extracted from cadavers and preserved in formalin at Department of Anatomy, Medical College, Kota, Rajasthan, India from December 2019 to January 2021. Specimens were observed for numbers, shape and position of Coronary and Extracoronary Ostia. Data was entered in Microsoft Excel Worksheet and analysed in Medcalc software version 20.0.3. Results: A total number of 100 extracted human cadaveric hearts were studied and analysed. In Anterior Aortic Sinus, single coronary ostium was found in 82% specimen, double ostia were observed in 17% specimen and triple ostia were noticed in only 1% specimen in AAS. In extracoronary ostia, 17 specimens were found round while only one specimen was found elliptical in shape and 16 specimen were found below sinu-tubular junction in position while one specimen was found above sinu-tubular junction and one specimen was at level of sinu-tubular junction. Conclusion: The role of extracoronary ostia should always be taken into account during investigative and remedial interventions. Awareness about extracoronary ostia would provide a deeper insight about possible complications arising during various surgical procedures to avoid damage. | |||||||||||||||||||||||||||||||||||||||
Keywords : Anterior aortic sinus, Right conus artery, Sinu-tubular junction, Third coronary artery | |||||||||||||||||||||||||||||||||||||||
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INTRODUCTION | |||||||||||||||||||||||||||||||||||||||
Principal vasa vasorum of the heart are coronary arteries. Word ‘coronary’ (Latin word) signifies a coronet framework of all coronary arteries around the heart. The right and left coronary artery arises from anterior and left posterior aortic sinuses, respectively. Variations are rare but the two may start separately or in common from the same sinus; three or even four coronaries have been noticed. The most common variation concerns a right coronary branch, arteria coni arteriosi or conus artery, which is 64% of its first branch but often arises separately in anterior sinus and 36% as a third coronary artery (1). Shape and location of ostia is important for cardiac catheterisation. Superior origin of coronary arteries augments risk for myocardial ischemia and sudden death due to circuitous passage of coronary artery through aortic wall (2). The upper limit of aortic valve beyond level of free border of cusp forms circumferential sinutubular ridge which is viewed from the aortic aspect (3). The sinutubular junction separates the aortic root and ascending aorta. Occasionally, right or left coronary ostium arises above sinotubular junction. This ostial dislocation has been termed high takeoff coronary artery, high takeoff position, or ectopic coronary ostium (4). In current concept, coronary arteries grow into the aorta from peritruncal ring of coronary arterial vasculature. Recently, it is stated that the union of the small vessels to the developing aorta harbingers the formation of coronary artery orifices in the aortic sinus (5). This study principally focuses on extracoronary ostia shape and position which is one of its kinds in southern Rajasthan and provides insight to the interventionalists here so that they can correctly interpret the angiographic findings. The findings of the study will be beneficial for the population of the Rajasthan. Other prevalence study of extracoronary ostia has been conducted in central India and southern India where the frequency was 32-40% and 10-18%, respectively (12),(13),(14),(15),(16). Thus, the purpose of the research was to know the prevalence of extracoronary ostia as an origin for third coronary artery and number, shape, position of coronary ostia in Southern Rajasthan. | |||||||||||||||||||||||||||||||||||||||
MATERIAL AND METHODS | |||||||||||||||||||||||||||||||||||||||
This observational descriptive study was conducted in Department of Anatomy, Government Medical College, Kota from December 2019 to January 2021, after seeking proper approval from Institutional Review Board and Ethical Committee (approval number PNCGMC/PG/ETH/1804 dated 16/12/2019) of Government Medical College, Kota, Rajasthan, India. At 95% confidence interval and 80% beta error sample size was calculated using OpenEPI software. So this study was conducted on 100 preserved human cadaveric hearts procured from the Department of Anatomy and Department of Forensic medicine, Medical Collage Kota as per the guidelines in Cunningham’s Manual of practical anatomy (6). Inclusion criteria: Both the genders, age group of more than 30 years and Indian ethnicity were taken as eligibility criterion. The age group was above 30 years as the study is mostly on hearts of donated cadavers in the Department. Exclusion criteria: All samples with any pathology or damage were excluded. Microdissection of 10% formalin fixed hearts was done. The parameters of coronary ostia were observed after dividing the ascending aorta transversely, one centimeter above aortic leaflet commissure. Coronary sinuses were observed and finding was noted for number, shape, position, and variation of ostia if any. STATISTICAL ANALYSIS The data was evaluated by Medcalc software version 20.0.3 and frequency was assessed for statistical significance by chi-square test. The p-value <0.05 was considered significant. | |||||||||||||||||||||||||||||||||||||||
RESULTS | |||||||||||||||||||||||||||||||||||||||
Single ostium was found in 82 specimen of hearts for right coronary artery origin. Double ostia were seen in 17 specimens and one triple ostia in AAS as shown (Table/Fig 1),(Table/Fig 2). Third coronary artery commences from a separate opening as an additional coronary ostium in AAS. Then, it passes inferiorly and to the left side of right coronary artery through sub-epicardial adipose tissue of coronary sulcus for a short distance. After leaving coronary sulcus, it runs over the surface of right ventricle anteriorly to reach the pulmonary conus (Table/Fig 3). The current study revealed that 18% specimens had separate origin of right conus artery which form as Third Coronary artery. In left posterior aortic sinus, single ostium was found in all 100 specimens as shown (Table/Fig 4). Shape of right coronary ostia were round in 92% of specimen and 8% were elliptical while in left coronary ostia 75% were round and 25% were horizontally elliptical as shown (Table/Fig 5). Shape of extracoronary ostia was found round in seventeen specimens while one specimen had elliptical extracoronary ostia (Table/Fig 6). The right coronary ostium was found below the sinu-tubular junction in 94% of the specimens, at sinu-tubular junction in 4% while above the sinu-tubular junction were 2% of the specimens studied as depicted (Table/Fig 7) (3). (Table/Fig 8) shows the shape of extracoronary ostia to be round in 94.44% of specimen and horizontally elliptical in 5.56% of specimens while vertically elliptical ostia were not seen at all in any of the specimens. In sixteen specimens of extracoronary ostia were found below sinu-tubular junction, single specimen had above sinu-tubular junction and one at sinu-tubular junction as shown (Table/Fig 9). | |||||||||||||||||||||||||||||||||||||||
DISCUSSION | |||||||||||||||||||||||||||||||||||||||
Variations of coronary ostia are frequent and have medical repercussion. Extracoronary artery arises customarily from right aortic sinus. Literature uses different terms for identifying right conus artery as third coronary artery which has separate origin from extracoronary ostia in anterior coronary sinus (1). (Table/Fig 10) shows the comparison of frequency of extracoronary ostia by different authors (7),(8),(9),(10),(11),(12),(13),(14),(15),(16). In present study, extracoronary ostia in the AAS were found in 18% specimen of heart while Wolloscheck T et al., accounted presence of additional ostia in 65% of subjects in an anatomical and trans-thoracic echocardiographic study (7). Kalpana R et al., ascertained the incidence of third coronary artery in 24% of specimens (8). Stankovic I and Jesic M and Blake established incidence of third coronary artery 34.8% and 23.5% while Joshi SD et al., and Bharambe VK et al., found incidence of third coronary artery to be 29.52% and 22%, respectively (9),(10),(11) . Chhaparwal R et al., Dhobale MR et al., Jyothi SR et al., Dakhaneprafulla S et al., and Saminathan S et al., observed frequency 40%, 32%, 10.2%, 18% and 17%, respectively (12),(13),(14),(15),(16). Additionally, this study revealed shape and position of extracoronary ostia. This data from other authors was not amply available for comparison. Data obtained for location in relation of sinutubular junction of Right Coronary Ostia (RCOS), Left Coronary Ostia (LCOS) in the studies by Kalpana R; and that by Saminathan S; were comparable to the present study as mentioned (Table/Fig 11) [8,16]. In their study, most of 90%, 89% in right and 80%, 92% in left were below STJ and 1% and 5% above STJ in right ostia respectively. In case of left ostia, they had not found above STJ while 2% specimen in present study was above STJ. Comparing the shape of coronary ostia, Mobin N et al., found round shape in 70.9% specimens in right ostia, 52.7% in left ostia while 92% round shape was found in present study in right ostia (17). In horizontally elliptical shape, Mobin N et al found 27.3% in right, 40.9% in left but in present study, 8% and 25% were horizontally elliptical in right and left ostia respectively as shown (Table/Fig 12) (17),(18). This knowledge is important for anatomist, radiologist, interventional cardiologist and cardiothoracic surgery. Panaromic information and dimensional analysis of the of the coronary ostium is essential for numerous interventional cardiovascular procedures such as catheterisation of coronary arteries, percutaneous aortic root valve replacement, aortotomy, incision for aortic valve exposure, aortic root enlargement and surgical ostioplasty (18). Limitation(s) The main limitation of the study was its small sample size and gender differentiation was not considered. The hearts used were not freshly procured which might affect the dimensions of the study. This knowledge is important for anatomist, radiologist, interventional cardiologist and cardiothoracic surgery. | |||||||||||||||||||||||||||||||||||||||
CONCLUSION | |||||||||||||||||||||||||||||||||||||||
Role of extracoronary ostia should always be taken into account during investigative and remedial interventions. Awareness about extracoronary ostia would provide a deeper insight about possible complications arising during various surgical procedures to avoid damage. Present study revealed variation in number and shape of coronary and extracoronary ostia, knowledge of which is also important for cannulation of vessels during procedure like open aortic surgery and coronary arteriography. Present anatomical study also focuses on position of coronary as well as extracoronary ostia. So, it may help the cardiac surgeons to reconstruct aortic root and their satisfactory recovery. The study samples should be more and freshly procured which would yield accurate dimensions. Study would be more valid if done in living subjects using angiography. Individuals with multiple ostia should have regular follow up to watch out for any coronary artery disease related symptoms extracoronary though correlation of multiple ostia and clinical symptoms is not much studied. | |||||||||||||||||||||||||||||||||||||||
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