|Year : 2020 | Volume
| Issue : 2 | Page : 63-68
A study on coronary artery anomalies in adult patients undergoing coronary angiography for various indications
Avijit Moulick1, Bhuban Majhi2, Gouranga Sarkar3
1 Department of Medicine, North Bengal Medical College, Darjeeling, West Bengal, India
2 Department of Cardiology, Bankura Sammilani Medical College, Bankura, West Bengal, India
3 Department of Cardiology, IPGMER, Kolkata, West Bengal, India
|Date of Submission||30-May-2020|
|Date of Decision||10-Jun-2020|
|Date of Acceptance||16-Jun-2020|
|Date of Web Publication||4-Aug-2020|
Dr. Avijit Moulick
Flat 2F, Spandan Apartment, 1/14 Extn Chittaranjan Colony, Jadavpur, Kolkata - 700 032, West Bengal
Source of Support: None, Conflict of Interest: None
Introduction: As variations in coronary artery anatomy is very common, the term “coronary artery anomaly” (CAA) applies only to the rarer forms of anatomic aberrations seen in the general population. CAAs are usually detected incidentally during coronary angiography (CAG) or autopsy. Some hemodynamically significant anomalies cause symptoms at young age and can cause sudden death. Knowledge of CAA is necessary to suspect them in appropriate clinical setting for early diagnosis and management that may be lifesaving.
Subjects and Methods: Over a period of 1 year, we studied coronary anatomy of 1000 adult patients attending a tertiary cardiac center for coronary artery disease, valvular heart disease planning valve surgery, etc., where CAG was required. The absolute prevalence of different CAAs was recorded.
Results: In our study, 3.6% of the patients had CAA. Most common of them were “right coronary artery arising from the left sinus” and “separate origin of the left anterior descending artery and left circumflex artery from the left sinus.” A significant coronary artery fistula was the next common.
Conclusion: Some CAAs made coronary intervention technically challenging. There were hemodynamic implications in some, namely myocardial ischemia resulting from significant myocardial bridge and “coronary steal phenomenon” related to large coronary artery fistula. A high index of suspicion is required for early diagnosis, and the management of most serious forms can abort serious consequences. Information regarding CAAs is also helpful to overcome procedural difficulty during coronary and cardiothoracic interventions and avoid complications.
Keywords: Adult patients, coronary angiography, coronary artery anomaly
|How to cite this article:|
Moulick A, Majhi B, Sarkar G. A study on coronary artery anomalies in adult patients undergoing coronary angiography for various indications. Heart India 2020;8:63-8
|How to cite this URL:|
Moulick A, Majhi B, Sarkar G. A study on coronary artery anomalies in adult patients undergoing coronary angiography for various indications. Heart India [serial online] 2020 [cited 2020 Oct 31];8:63-8. Available from: https://www.heartindia.net/text.asp?2020/8/2/63/291356
| Introduction|| |
Because of considerable variability of coronary anatomy, what is considered abnormal, aberrant, anomalous, or ectopic, is often unclear. Usually, the term “anomalous” is used to define any variant form observed in <1% of the general population. Coronary artery anomalies (CAAs), therefore, represent marked deviations from the normal pattern. Anomalies are present at birth, but, few are symptomatic during childhood. Most anomalies are discovered as incidental findings during coronary angiography (CAG), other imaging studies, or at autopsy. However, some anomalies present with symptoms or potentially serious sequelae that require intervention/surgical treatment. CAAs are often recognized in association with structural forms of congenital heart disease. Importantly, CAAs are a cause of sudden death in young athletes in the absence of additional heart abnormalities. The clinician should suspect the presence of a CAA in a young person who experiences exertional syncope, myocardial infarction, exercise-induced arrhythmias, or cardiac arrest. Some anomalies impose “technical/procedural challenges” during the procedure of CAG, coronary intervention, or cardiothoracic surgery itself. The angiographer should be able to identify anomalies in order to perform accurate evaluations and avoid subsequent errors in management. A popular classification of the CAAs considering the anomalies of origin, course, and destination is available in the literature. However, a widely agreed-upon scheme to classify CAAs should consider all possible coronary anatomic variations independently from the clinical and hemodynamic implications. Some authors, therefore, prefer to categorize CAAs as “severe” or “hemodynamically significant” anomalies versus “minor” ones. The literature on CAA is mainly dependent on numerous case reports and few large case series. There is no large case series from the eastern parts of India. Case series of large number of patients undergoing CAG for a valid indication will, therefore, reveal the incidence of different CAAs in our part of the country.
| Subjects and Methods|| |
In this “cross-sectional observational study,” we evaluated 1000 randomly selected adult patients admitted in the departments of cardiology and cardiothoracic surgery who underwent CAG for various indications like acute coronary syndromes and chronic stable coronary artery disease (CAD), preoperative CAG before valve and other cardiothoracic surgery, CAG during peripheral arterial angiography in patients with peripheral arterial disease, during renal or carotid angiography, before device implantation like implantable cardioverter-defibrillator in patients with ventricular tachycardia, etc. over a period from May 2016 to April 2017.
Details of clinical history were obtained and clinical examination performed in all patients. A baseline electrocardiography and echocardiography were obtained in all. Troponin test and quantitative estimation of creatine phosphokinase-MB were done as per indication.
Detail evaluation of coronary anatomy was performed from cine images with regard to origin, number, course, termination of individual coronary arteries, and any other CAAs present. Management of each case was recorded.
Statistical analysis was done and presented as charts and tables. The anomalies those impose “technical/procedural difficulties” during the procedure of CAG, were recorded.
Ethical clearance was approved by the “institutional ethics committee.”
| Results|| |
Among the 1000 studied patients, 770 were male and 230 were female, with age ranging from 19 to 83 years. Among them, 602 were hypertensive and 501 were diabetic.
Vast majority of the patient population underwent CAG for evaluation of suspected obstructive CAD, for example, ST-elevation myocardial infarction (STEMI), unstable angina and non-STEMI, and stable CAD (SCAD). This can be expected in a high-volume cardiac intervention institute. [Table 1] shows the distribution of patients according to indications of CAG.
|Table 1: Distribution of patients according to indication of coronary angiography|
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CAAs were detected in 36 patients with 3.6% prevalence [Table 2]. Among them, thirty-one (86%) had anomaly of origin and course, and five patients (14%) had coronary artery fistulae [Figure 1]. Most common among all the anomalies was origin of the right coronary artery (RCA) from the left coronary sinus [Figure 2] with a relative prevalence of 27.8%.
|Table 2: Prevalence of coronary artery anomaly in total patient population|
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|Figure 1: Coronary artery fistulae arising from the left anterior descending artery and draining into the pulmonary artery|
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|Figure 2: Origin of the right coronary artery from the left coronary sinus|
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CAAs were found in seven patients without any evidence of obstruction in coronary arteries. Two of them presented with clinical features of SCAD; one had a muscle bridge in the left anterior descending artery (LAD) and the other had the origin of the left main coronary artery (LCA) from the right sinus with a septal course [Figure 3]. Another young man presented with features suggestive of inferior wall myocardial infarction and had a fistula of RCA without any obstructive CAD. The remaining four patients were imaged for indications other than suspected obstructive CAD (like presurgical exclusion of CAD in patients planned for valve surgery). All the remaining 29 patients with CAAs had coexistent obstructive CAD.
|Figure 3: Left main coronary artery arising from the right coronary sinus|
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One patient had a single coronary artery (0.1%) originating from the left coronary sinus and giving three separate branches to supply all three vascular territories, namely LAD, left circumflex artery (LCx), and RCA [Figure 4]. This can also be considered as RCA arising from LCA.
|Figure 4: A single coronary artery from the left sinus giving all three coronary arteries/right coronary artery arising from the left main coronary artery|
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Three patients (0.3%) had evidence of myocardial/muscle bridges in LAD course leading to demonstrable obstruction to blood flow, and one of them had symptoms in the absence of obstructive coronary lesions in CAG. Two others had atherosclerotic coronary obstruction in other vessels apart from myocardial bridges in LAD.
Most CAAs were associated with technical difficulties during procedure overcome by changing catheter type and modified techniques.
| Discussion|| |
The study was undertaken to find the prevalence of different CAAs in patients attending this institution, a high-volume cardiac center, in order to get an overall estimate of such anomalous coronary anatomy in this part of the country as this hospital has a large catchment area including most of eastern India.
A total of 36 CAAs were detected with a prevalence of 3.6% in our study population which is higher than found in most studies of large series. Yamanaka and Hobbs found 1.3% CAAs in 126595 patients of Cleveland clinic registry. However, Angelini et al. found an even higher overall incidence of CAAs (5.6%) in 1950 patients studied.
The most common (27.8%) anomaly in our study was anomalous origin of RCA from the left coronary sinus (anomalous coronary artery from the opposite sinus [ACAOS]). This anomaly is suspected when the RCA ostium is unable to be located in the right sinus of Valsalva and collateral vessels are absent.,,, This was one of the most common types of CAAs reported in a large series from western India where Lingaraju et al. found this anomaly in 31% of all anomalies, only closely second to separate the origin of LAD and LCx (33%) which had the highest prevalence in their study. Angelini et al. found this anomaly in 0.92% of their patients, and they found a slightly higher prevalence of two other anomalies, namely split RCA and ectopic origin of RCA from the right sinus. Yildiz et al. from Turkey found this anomaly second most prevalent to the split origin of LCA in 12,457 patients who underwent CAG. This anomaly was a probable cause of sudden cardiac death in large series of sudden cardiac death victims evaluated at autopsy. However, the clinical outcome for these patients is most often benign. Management of the asymptomatic patients with this anomaly, therefore, creates a classic risk–benefit dilemma.
Noteworthy, however, is the opposite and far less common anomaly, i.e., origin of LCA from the right sinus (left ACAOS), for its association with sudden cardiac death in the young, mainly during exertion.,,,, The RCA may arise separately or share a common ostium with the anomalous left coronary artery (single coronary artery from the right sinus). Five anatomical subtypes are possible and are classified according to the relationship of the anomalous coronary artery with the aorta and pulmonary artery, namely “anterior,” “between,” “septal,” “posterior,” and “combined.” The “septal” subtype is the most common, whereas the “between/interarterial” type is rare and most serious. In a study, the left ACAOS was found to be only the second most important precipitating cause (after hypertrophic cardiomyopathy) of sudden cardiac death in young athletes. Eckart et al. studied 277 deaths unrelated to trauma among military recruits in the American Armed Forces Institute, one-third of the cardiac cause of death was due to this anomaly, and none was related to the right ACAOS. In a study analyzing autopsy findings among young athletes with sports-related sudden cardiac death in Switzerland, 7% of the cases had ACAOS. We found two patients having LCA originated from the right sinus with a septal course, and one of them had chest pain on exertion leading to CAG which showed no obstruction. This anomaly must be excluded in appropriate patients (ideally with computed tomography [CT] or magnetic resonance [MR] angiography) while deciding stent placement during percutaneous coronary intervention to avoid complications.
There is an association of slit-like coronary ostia with oblique or angular takeoff in these anomalies instead of round ostia and vertical takeoff and thereby more chance of compromised coronary circulation. On this basis, surgical repair should be considered in all such patients. They should be suspected in a young person with exertional angina and may prevent sudden deaths if corrected timely. They are also an important cause of confusion or ambiguity during coronary bypass surgery, and reports are there when wrong coronary artery was grafted in the presence of such anomaly. Therefore, it is of utmost importance that coronary arteries are named/described according to their area of supply or distal course instead of their origin. These anomalies can be suspected during echocardiography [Figure 5] and should be excluded meticulously in clinical conditions mentioned above.
|Figure 5: Two-dimensional echocardiographic parasternal short-axis view showing the origin of the left main and right coronary arteries from the left sinus|
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Separate origin of LAD and LCx from the left coronary sinus, defined by the absent left main trunk, is a common anomaly, and Yamanaka and Hobbs, Yildiz et al., and Lingaraju et al. found this as the most common type of CAAs in their series.,, They are clinically benign.
LCx arising from RCA or directly from the right coronary sinus is a commonly encountered variant and was the second most common type in Yamanaka's series.,, Apart from technical issues during CAG, coronary intervention, or surgery, they should not produce coronary ischemia.
The absent LCx and the proposed LCx territory being completely supplied by a large RCA (superdominant RCA) is also benign anomaly and diagnosed after corroborating all the cine images carefully.
Several Indian studies involving patients undergoing CAG and CT CAG reported separate origin of LAD and LCx, RCA from the left sinus, and LCx from RCA/right sinus as the most common CAAs.,,,, [Table 3] shows the salient features of these studies.
|Table 3: Salient findings of some important Indian studies on coronary artery anomalies|
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Coronary artery fistulae with large intracardiac shunts are rarely detected in adults since the majority are detected and repaired during childhood. The most common type of fistula is the coronary to pulmonary artery type and usually arises from LAD [Figure 1] or RCA. Fistulae draining into right heart chambers function as left to right shunts and may result in right ventricular volume overload. Large fistulae can cause myocardial ischemia by the mechanism of shunting of blood from the downstream flow into the fistula (coronary steal phenomenon). This is more serious in the presence of any level of coronary obstruction just distal to the fistula resulting in more shunting of blood than can be due to the obstruction alone. Coiling or stenting (with covered stents) of such fistulae is indicated if they cause symptoms. In difficult cases, surgical ligation should be done at the drainage site. They can also predispose to infective endocarditis.
Myocardial/muscle bridge is another anatomic variation whose milder forms are quite common and insignificant, but severe forms (not adequately defined) can cause myocardial ischemia. They can also complicate cardiothoracic surgery as they pass through an intramyocardial course. RCA originating from the posterior sinus and ascending aorta are unusual anomalies., They give rise to technical challenges or complications in coronary intervention and cardiothoracic surgical procedures but do not produce ischemia.
Routine evaluation of coronary artery origin is possible with modern echocardiography (transthoracic and transesophageal) machines and must be undertaken in clinically relevant cases [Figure 5]. Advanced imaging techniques such as multidetector-row CT or MR imaging can further describe in detail the origin and course of the coronary arteries, and they are very helpful, especially in patients with structural congenital heart diseases. Budoff et al. found CT angiographic studies as a very effective, noninvasive method and more informative where CAG findings are suboptimal. A stepwise imaging approach starting with noninvasive modalities is ideal in such clinical setting.
| Conclusion|| |
Anomalous coronary circulation can be a cause of coronary ischemia, heart failure, and myocardial infarction. They can cause sudden cardiac death in athletes. They can be a source of procedural difficulty in coronary as well as cardiothoracic interventions even if not having the above serious effects. Differentiation between the clinically serious and relatively benign anomalies is very important. Clinical suspicion of hemodynamically serious anomalies is key to early diagnosis and management. Our study revealed some common anomalies in the adult population, and therefore, these should be suspected in relevant clinical and procedural circumstances.
Financial support and sponsorship
All the CAG procedures were performed free of cost as per current West Bengal Government health-care practice.
Conflicts of interest
There are no conflicts of interest.
Institutional ethics committee.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2], [Table 3]