{"\ufeff\nJournal of Cardiovascular, Neurovascular & Stroke \nhttps://mycvns.com \nA CASE OF RIGHT CORONARY ARTERY ATRESIA WITH DOMINANT LEFT CIRCUMFLEX CORONARY ARTERY \u2013 SINGLE LEFT CORONARY ARTERY OR CORONARY OSTIAL ATRESIA? \nMohammed, N.A1*,Abdul Kadir, R.F1, Yusoff M.R2\n1 Department of Radiology, Faculty of Medicine, Universiti Teknologi MARA, Malaysia 2 Department of Medicine, Faculty of Medicine, Universiti Teknologi MARA, Malaysia \n*Corresponding author: \nNurul Amira Mohamed, Department of Radiology, Faculty of Medicine, Universiti Teknologi MARA, 47000 Sungai Buloh, Selangor, Malaysia \nEmail: namira.mohamed@ymail.com\nDOI: https://doi.org/10.32896/cvns.v8n1.11-18 \nReceived: 02.02.2026 \nRevised: 24.03.2026 \nAccepted: 29.03.2026 \nPublished: 31.03.2026\nABSTRACT \nCoronary artery anomalies are uncommon and are frequently detected incidentally during coronary angiography or computed tomography coronary angiography (CTCA). Coronary ostial atresia and single coronary artery are particularly rare entities and may pose a diagnostic dilemma because of overlapping imaging features. We report a case of a 74-year-old woman who presented with intermittent, non-exertional chest tightness and underwent CTCA for pre-operative cardiac assessment. Imaging demonstrated non-visualization of the right coronary artery (RCA) ostium. The left circumflex artery was dominant and continued along the left atrioventricular groove into the right atrioventricular groove, supplying the right coronary artery territory. Mild non-obstructive atherosclerotic plaques were present in the left anterior descending and left circumflex arteries. No significant myocardial ischemia or structural cardiac abnormality was identified. This case highlights the challenge of differentiating a single coronary artery variant from congenital or acquired right coronary ostial atresia on CTCA. Recognition of key anatomical features is essential, as accurate classification has important implications for prognosis and clinical management. CTCA provides excellent spatial resolution for non-invasive evaluation of coronary artery anomalies, allowing precise anatomical delineation. Given the patient\u2019s mild symptoms and absence of significant coronary obstruction, conservative medical management was adopted. \nKeywords: Coronary Vessel Anomalies": null, " Coronary Artery Atresia": null, " Single Coronary Artery": null, " Coronary Angiography": null, " Tomography, X-Ray Computed\n11 \n\nJournal of Cardiovascular, Neurovascular & Stroke \nhttps://mycvns.com \nINTRODUCTION \nCoronary artery anomalies are rarely identified, with literature reporting an incidence of approximately 0.6\u20131.5% in coronary angiograms (1). Among these anomalies, coronary ostial atresia and single coronary arteries (SCA) are least frequently observed (2). Right coronary ostial atresia without associated congenital anomalies in adults remains particularly uncommon (3). This case reports non-visualization of the right coronary artery (RCA) ostium, with the dominant left circumflex artery (LCx) continuing through intercoronary communication along the right atrioventricular groove (AV groove) to supply RCA territory. This being a case of single coronary artery is considered, as such coronary course has not been previously reported in local literature. \nCASE REPORT \nher cataract surgery to exclude coronary \nartery\ndisease.\nCT\nshowed\nnon-\nvisualization of the RCA ostium with tiny vessel arising from the right coronary sinus (FIGURE 1). The left circumflex (LCx) continued in left atrioventricular (AV) groove to the right AV groove supplying \ndistal\nRCA\nterritory\n(FIGURE\n2).\nOtherwise, the left anterior descending coronary artery (LAD) has calcified and non-calcified plaques from proximal to distal causing mild stenosis. The LCx has calcified and non-calcified plaques at proximal segment causing mild stenosis. The CT essentially revealed a left dominant system with non-visualization of the RCA ostium and non-obstructive coronary artery disease. This rare presentation raises diagnostic consideration of single left coronary artery versus right coronary ostial atresia, which will be discussed based on distinguishing radiological features. \nA 74-year-old female with underlying DISCUSSION \nhypertension, \tdyslipidemia, hypothyroidism and COPD presented with intermittent chest tightness lasting a few minutes per episode, which was infrequent. There were no other associated symptoms, and episodes occurred both at rest and during exertion. She remained functionally active, exercising three times weekly with 30-minute walks. Clinical examination \nrevealed\nno\nsignificant\nfindings.\nElectrocardiogram\nwas\nnormal.\nEchocardiogram demonstrated normal left ventricular size and systolic function, impaired relaxation pattern of diastolic dysfunction with elevated LV filling \npressure,\nno\nregional\nwall\nmotion\nabnormality, and no significant valvular disease. A CT coronary angiography was performed for cardiac assessment prior to \n12 \n\nJournal of Cardiovascular, Neurovascular & Stroke \nhttps://mycvns.com \ncontinuing along the left atrioventricular groove into the right atrioventricular groove to supply the RCA territory. These findings raise the diagnostic consideration of either a single coronary artery (SCA) or coronary ostial atresia as differential diagnosis. Differentiating between SCA and coronary ostial atresia involves assessment of coronary origin, course, and collateral \nthe LCx which corresponds to a left type I (L-I type) variant of SCA. This subtype is rare, approximately about 0.016% (6, 7). Generally, it is regarded as benign and normally treated conservatively. SCA has spectrum of manifestations such as angina, syncope, myocardial infarction, malignant arrhythmia and cardiac failure (8). Higher risk of sudden cardiac death reported in \ncirculation\npatterns\n(2).\nIn\nSCA,\nSCA patients (9).  SCA with origin of RCA\n\nparticularly single left coronary artery variants, typical CT features include absence of a separate RCA ostium, supply of the RCA territory from branches of the \nfrom LCx has been reported to have an incidence of 0\u20130.035% (2). There are cases reported with associated congenital cardiac anomalies specifically valvular anomalies \nleft coronary system, and a continuous (10). \narterial course originating from either left coronary sinus or a common trunk (3). Compensation by collateral vessels such as \nVieussens\u2019\narterial\nring\nor\nother\nintercoronary collateral pathways may also be seen as described by Angelini et al. In our case, CTCA revealed non-visualization of the RCA ostium with collateral supply from the LCx to the RCA territory, which corresponds with features of a single left coronary artery variant. However, coronary \nostial\natresia\nwhether\ncongenital\nor\nacquired can still be considered as \ndifferential\ndiagnoses\nin\nthis\ncase,\nconsidering her late symptoms onset and \npresence\nof\ncoronary\natherosclerotic\ndisease\n(5).\nLipton et\nal described\nclassification of the coronary anomalies, which guides in  recognizing these anomalies and their management. The classification of SCA is based on the origin and its course in relation to the ascending aorta and pulmonary trunk (6). Our case revealed that the LCx supplying the RCA territory through extension of collaterals from LCx in right atrioventricular groove as seen on the CTCA.  Using the Lipton-Yamanaka classification, the present case exhibits an anomalous RCA coming from \n13 \n\nJournal of Cardiovascular, Neurovascular & Stroke \nhttps://mycvns.com \nsymptoms to severe ischemia episodes (11). Right coronary ostial atresia should be considered different from RCA arising from single coronary trunk, even though the LCA supplies circulation in both conditions (2). This is because in the prior condition, RCA circulation is completely dependent \ncontinuation into the right AV groove and supply of RCA territory without an independent RCA. Right coronary ostial atresia remains a close differential due to overlapping collateralization patterns. \non LCA patency (3). In the present case, we CONCLUSION \nstill cannot ascertain if RCA was filling retrogradely almost up to its proximal part \nby\ncollateral\nextension\nfrom\nLCx\ncontinuing in the right AV groove as \ndepicted\nby\nGupta\net\nal\nin\ntheir\nconventional angiogram. Additionally, on our CTCA, ostial stump of the RCA was not visualized. Lipton et al have suggested that in congenital ostial atresia or hypoplasia, a small stump may be detected (6) though this may not always be the case (2). Nevertheless, distinguishing congenital atresia of the ostium from acquired ostial atresia is also important to highlight. Few features are suggestive of congenital coronary ostial atresia most importantly the presence of only 1\u20132 full diameter \nconnecting\ncollateral\nvessels\nwithout\nnarrowing at the junction of the two vessels (3). On the contrary, acquired cases feature a rich network of septal, infundibular, and atrial collaterals that progressively enlarge postnatally, exhibiting collaterals that are smaller than distal recipient vessels. (2). Additionally, absence of typical clinical angina and lack of evidence of myocardial scarring is highly indicative of coronary ostial atresia (2). Several acquired causes which include atherosclerosis, syphilis, Kawasaki, and Takayasu arteritis (3) must be also ruled out in an adult patients when assessing coronary ostial atresia in CTCA. Overall, the CTCA findings are most consistent with a Lipton L-I type single coronary artery based on non-visualization \nof\nRCA\nostium,\ndominant\nLCx\n\n14 \n\nJournal of Cardiovascular, Neurovascular & Stroke \nhttps://mycvns.com \nDATA AVAILABILITY \nFurther information regarding the data \nused for this work can be obtained upon \nreasonable request. \nACKNOWLEDGEMENT \nWe extend our sincere appreciation to our \nesteemed\ncolleagues\nin\nfor\ntheir\nunwavering\nsupport\nand\ninvaluable\nguidance.\n\n\nFUNDING: \nThis work received no external funding. \nCONFLICT OF INTEREST: \nThe authors have no conflicts of interest \nto declare and is in agreement with the \ncontents of the manuscript. \nREFERENCES: \n1. \tYamanaka O, Hobbs RE. Coronary \nartery anomalies in 126,595 patients \nundergoing coronary \tarteriography. \nCatheterization \tand \tCardiovascular \nDiagnosis. 1990": null, "21(1):28-40. \n2. \tGupta MD, Girish MP, Vignesh V, \nNarang P, Trehan V, Tyagi S. Absent right \ncoronary artery: A case of single coronary \nartery or congenital ostial atresia? Indian \nHeart Journal. 2015": null, "67:S11-S3. \n3. \tAngelini P. Congenital coronary \nartery ostial disease: a spectrum of \nanatomic\nvariants\nwith\ndifferent\npathophysiologies and prognoses. Tex \nHeart Inst J. 2012": null, "39(1):55-9. \n4. \tVanhoenacker PK, Heijenbrok-Kal \nMH, Van Heste R, Decramer I, Van Hoe \nLR,\nWijns\nW,\net\nal.\nDiagnostic\nPerformance\nof\nMultidetector\nCT\nAngiography for Assessment of Coronary \nArtery Disease: Meta-analysis. Radiology. \n2007": null, "244(2):419-28. \n15 \n\nJournal of Cardiovascular, Neurovascular & Stroke \nhttps://mycvns.com \n12.\nBigler MR, Kadner A, R\u00e4ber L,\nOpposite Sinus of Valsalva: Current\n\nAshraf A, Windecker S, Siepe M, et al. Therapeutic Management of Anomalous Coronary Arteries Originating From the \n16 \n\nJournal of Cardiovascular, Neurovascular & Stroke \nhttps://mycvns.com \nFIGURE LEGENDS: \n\nFigure 1. Axial CT coronary angiography image demonstrating non-visualization of the right \ncoronary artery ostium (*). \n17 \n\nJournal of Cardiovascular, Neurovascular & Stroke \nhttps://mycvns.com \n\nFigure 2. Volume-rendered CT coronary angiography image showing non-visualization of the \nright coronary artery ostium (yellow arrow). The left circumflex artery (black arrow) \ncontinues along the left atrioventricular groove into the right atrioventricular groove to supply \nthe distal right coronary artery territory (*). \n18": null}