Heart India

ORIGINAL ARTICLE
Year
: 2018  |  Volume : 6  |  Issue : 4  |  Page : 133--140

Study of clinical profile, incidence, pattern, and atherosclerotic involvement of congenital coronary artery anomalies in adults undergoing coronary angiography: A study from a tertiary care institute in western part of India


Jaywant M Nawale, Ajay S Chaurasia, Digvijay Deeliprao Nalawade, Piyush Choudalwar, Nikhil Borikar, Dhirendra Tiwari 
 Department of Cardiology, TNMC and BYL Nair Ch. Hospital, Mumbai, Maharashtra, India

Correspondence Address:
Dr. Digvijay Deeliprao Nalawade
Department of Cardiology, 18-ICCU, Ground Floor, OPD Building, Nair Hospital, Mumbai Central, Mumbai - 400 008, Maharashtra
India

Abstract

Objective: Congenital coronary artery anomalies (CCAs) are rare, clinically benign, and majority are diagnosed incidentally during coronary angiography or an autopsy. Identification of CCA is important for management by cardiologists or cardiac surgeons, and also few cases of CCA are potentially serious which may cause sudden cardiac death. We performed a retrospective, single-center study to evaluate the clinical profile, incidence, pattern, and atherosclerotic involvement of CCA in patients undergoing coronary angiography. Methods: Coronary angiographies performed in adult patients during the study period of 2 years were screened for CCA. These patients were retrospectively analyzed in terms of clinical characteristics and angiographic profiles. Results: Of 4481 angiograms screened, 86 patients were found to have CCA with the incidence of 1.91%. Nearly 76.7% were male and 23.3% were female, with a mean age of 53.02 ± 10 years. Anomalies of origin and course were most common (94.18%) followed by anomalies of termination (5.81%), with right coronary artery (RCA) being the most common artery. Anomalous origin of RCA from the left sinus of Valsalva and separate origin of left anterior descending artery and left circumflex artery were both found to be the most common types. The incidence of atherosclerosis in anomalous vessels was 52.32%. Conclusions: CCAs were diagnosed incidentally during coronary angiography and had male predominance with conventional risk factors. The incidence of CCA was slightly higher than that of the previous angiographic studies, but the pattern of anomalies was similar with majority being benign. Anomalous vessels did not predispose to atherosclerotic involvement as compared to normal vessels in the same patients.



How to cite this article:
Nawale JM, Chaurasia AS, Nalawade DD, Choudalwar P, Borikar N, Tiwari D. Study of clinical profile, incidence, pattern, and atherosclerotic involvement of congenital coronary artery anomalies in adults undergoing coronary angiography: A study from a tertiary care institute in western part of India.Heart India 2018;6:133-140


How to cite this URL:
Nawale JM, Chaurasia AS, Nalawade DD, Choudalwar P, Borikar N, Tiwari D. Study of clinical profile, incidence, pattern, and atherosclerotic involvement of congenital coronary artery anomalies in adults undergoing coronary angiography: A study from a tertiary care institute in western part of India. Heart India [serial online] 2018 [cited 2019 Dec 6 ];6:133-140
Available from: http://www.heartindia.net/text.asp?2018/6/4/133/247574


Full Text



 Introduction



Coronary artery anomalies (CCAs) are rare congenital disorders with variable clinical presentation and incidence. Most of the CCAs are clinically benign and majority are diagnosed incidentally during coronary angiography or an autopsy. However, few cases of CCA are potentially serious and may present as angina, syncope, dyspnea, ventricular arrhythmia, heart failure, acute coronary syndrome, and even sudden death, especially in young athletes after extreme exertion. Association of CCA with atherosclerosis is not definite, but few studies have shown anomalous vessels to be more prone to atherosclerosis.[1] Performing catheterization procedures in such anomalies is technically challenging and increases fluoroscopic times.[2] For cardiac surgeons, unawareness of CCA can lead to unwanted ligation of anomalous vessels or accidental compression during valve replacement.[3]

Due to various clinical implications and geographical variability,[3] recognition of CCA is important, and very few studies have been published from India. Hence, we performed a retrospective, single-center study to evaluate the clinical characteristics and angiographic profile of CCA in patients undergoing coronary angiography at a teaching institute in the western part of India.

 Methods



Patient selection

We retrospectively screened 4481 coronary angiograms performed in our institute during a period of 2 years (January 2015–January 2017) and patients with CCA were selected depending on the following criteria:

Inclusion criteria

Adult patients more than 18 years of age with ischemic and valvular heart diseases who underwent coronary angiography for various indications were included in the study.

Exclusion criteria

Patients with congenital heart disease were excluded from the study. Similarly, patients with coronary anomalies such as myocardial bridging, ectasia, and separate origin of the conus artery from the right coronary sinus were also excluded from the study.

All these patients were analyzed in terms of clinical profile which included demographic factors, risk factors, clinical presentation, and coronary angiographic profile which included the incidence, pattern, and atherosclerotic involvement of CCA. The angiographic course of anomalous vessels was defined according to studies by Yamanaka and Hobbs et al.[4] and Serota et al.[5] Patients were diagnosed to have coronary artery disease (CAD) when a significant lesion (>50% luminal narrowing) was present in either one or more vessels or in a major branch.[3] We compared the atherosclerotic involvement in anomalous coronary arteries with the normal coronary arteries in the same patients, which served as the control group. In cases with anomalies of the left main origin, both the left anterior descending artery (LAD) and left circumflex artery (LCX) were considered as anomalous, patients with single coronary artery were considered as one anomalous vessel, while cases with both long and short LAD in case of dual LAD were considered as anomalous.

Statistical analysis

Statistical analysis was done using SPSS software version 16.0 (SPSS Inc., Chicago, IL, USA), and data were presented as mean, standard deviation, and percentages. Chi-square test was used to compare the presence of CAD in anomalous coronaries and normal coronaries. P < 0.05 was accepted as statistically significant.

 Results



Clinical characteristics [Table 1]{Table 1}

During the 2-year study period, 86 patients were found to have CCA, of which 66 (76.7%) were male and 20 (23.3%) were female with a mean age of 53.02 ± 10 years (age range: 30–76 years) [Table 1]. Considering the risk factors, hypertension was present in 45 (52.3%) patients, diabetes mellitus in 32 (37.2%) patients, smoking in 37 (43%) patients, dyslipidemia in 17 (19.76%) patients, and a family history of ischemic heart disease in 5 (5.81%) patients [Table 1]. Of these, 81 (94.2%) patients had undergone angiography for suspected or known ischemic heart disease with clinical presentation as chronic stable angina in 18 (20.9%), unstable angina in 23 (26.7%), non-ST-segment elevation myocardial infraction in 5 (5.8%), and ST-segment elevation myocardial infarction in 35 (40.7%) patients [Table 1]. Five (5.8%) patients had valvular heart disease, with rheumatic heart disease in three (3.5%) and calcific aortic stenosis in two (2.3%) patients [Table 1].

Incidence and pattern of coronary artery anomalies [Table 2] and [Table 3]{Table 2}{Table 3}

The incidence of CCA was found to be 1.91% (86 patients out of 4481). Angiographically, these CCAs were classified as anomalies of origin and course (81 patients [94.18%]) and anomalies of termination (coronary artery fistulae) (5 patients [5.81%]) [Table 2]. From clinical point of view, according to a study by Yamanaka and Hobbs et al.,[1] these CCAs were classified as benign (65 patients [75.58%]) and potentially serious (21 patients [24.42%]) [Table 3].

Anomalous right coronary artery

Anomalies of origin of right coronary artery (RCA) were found to be most common with an angiographic incidence of 0.93% and an anomaly incidence of 48.83% [Table 2]. RCA had anomalous origin from the left sinus of Valsalva (LSV) [Figure 1] in 20 patients (23.25%), posterior sinus of Valsalva (PSV) in 7 patients (8.13%), and ascending aorta above the right sinus of Valsalva (RSV) in 15 patients (17.44%) [Table 3]. The initial course of all cases of RCA arising from LSV was interarterial (between aorta and pulmonary arteries), while for cases arising from PSV, it was retroaortic. Distal course and distribution of RCA as well as the origin and course of left coronaries were normal in all these cases.{Figure 1}

Anomalous left main artery

Anomalies of left main artery were found in 22 patients with an angiographic incidence of 0.49% and an anomaly incidence of 25.58% [Table 2]. Absence of the left main with a separate origin of LAD and LCX in LSV was found in 20 patients (23.25%), with further course of both vessels being normal. In one patient (1.16%), the left main artery had anomalous origin from the ascending aorta above the LSV with normal distal course and distribution. Another patient (1.16%) had anomalous origin of the left main artery from the PSV with initial retroaortic course followed by bifurcation into LAD and LCX with normal distal course and distribution.

Anomalous left circumflex coronary artery

Anomalies of origin of LCX from either RSV or RCA were found in 15 patients (17.44%) with an angiographic incidence of 0.33% [Table 2]. LCX was arising from RSV [Figure 2] in 14 patients and from RCA in one patient. The initial course was retroaortic in all cases followed by normal distal course and distribution. LAD in all these cases was arising from the LSV with separate origin and normal course.{Figure 2}

Anomalous left anterior descending artery

Anomalous LAD was found in the form of dual LAD (Type V) in one patient (1.16%) with an angiographic incidence of 0.02% [Table 2]. Short LAD was arising from the left main artery, with short normal course giving diagonals and few septals. Long LAD was arising from the RSV separately, with proximal intramyocardial course before reaching the interventricular groove and giving predominantly septals with supply till apex.

Single coronary artery

Single coronary artery was found in one patient (1.16%) with an angiographic incidence of 0.02% [Table 2] and [Figure 3]. The left main artery was arising from the ascending aorta just above the LSV and giving RCA just after origin which traversed between the great arteries and later resumed its normal course. LAD and LCX had normal course and distribution.{Figure 3}

Coronary artery fistulae

Coronary artery fistulae were found in 5 patients (5.81%) with an angiographic incidence of 0.11% [Table 2]. Three patients had fistulous connections between proximal LAD and pulmonary artery, while one patient had fistula arising from the proximal LAD and draining into the left atrium. One patient had multiple small fistulae arising from both proximal LAD and LCX and draining into the pulmonary artery.

Atherosclerotic involvement of coronary artery anomalies

Out of 86 patients with CCAs, 59 were found to have atherosclerotic involvement with an incidence of 68.6%, of which 45 patients (52.32%) had atherosclerotic disease in anomalous vessel (with or without involvement of normal vessels), while only 6 patients (6.69%) had disease restricted to anomalous vessel only [Table 4]. The atherosclerotic involvement in different types of anomalies is summarized in [Table 4]. Out of the total 256 vessels of 86 patients, 147 vessels were normal, while 109 vessels were anomalous. CAD was present in 66 of 147 (44.89%) normal vessels and 57 of 109 (52.29%) anomalous vessels. There was no statistically significant association of CAD in anomalous coronary arteries in comparison to normal coronaries (P = 0.24).{Table 4}

 Discussion



Clinical characteristics

In our study, CCAs were found more commonly in males as compared to females [Table 1], which was similar to previous studies [Table 5] and [Table 6] and possibly could be due to more angiograms being performed in male patients. Since patients with congenital heart disease were excluded, the average age of presentation was 53.02 ± 10 years, with ischemic heart disease (94.2%) as the most common indication for coronary angiography and acute coronary syndrome (79.1%) being the common clinical presentation [Table 1]. Patients diagnosed with CCA had conventional risk factors, with hypertension (52.3%) being the most common followed by smoking (43%) and diabetes (37.2%) [Table 1].{Table 5}{Table 6}

Incidence and pattern of coronary artery anomalies

The incidence of CCA reported in literature is variable and depends on various factors such as diagnostic modality used, criteria used to define the anomalies, and characteristics of the study population. The incidences of CCA reported in several large-scale conventional angiographic studies are summarized in [Table 5] and [Table 6]. Overall, the incidence of CCA ranges from 0.32% to 5.64% [Table 5], while the previous Indian studies show it to be ranging from 0.46% to 2.06% [Table 6]. Since there is no clear consensus regarding the criteria and definitions used for defining the anomalies, the methodology used in each study differs. The study with the largest angiographic population (Yamanaka and Hobbs et al.)[4] had an incidence of 1.3%, while the study which was prospective and used strict diagnostic criteria (Angelini et al.)[1] had the highest incidence of 5.64%. In our study, the incidence of CCA was found to be 1.91%, which was slightly higher than majority of earlier studies, but still consistent with few[1],[15],[19] [Table 5] and [Table 6].

In this study, anomalies of origin and course (94.18%) were found to be most common followed by anomalies of termination (coronary artery fistulae) (5.81%) [Table 2]. RCA was the most common artery found to have anomalies with an angiographic incidence of 0.93% and an anomaly incidence of 48.83%, which was similar to few earlier studies[1],[3],[6],[7],[19] [Table 5] and [Table 6]. Two types of anomalies were found to be equally most common: the anomalous origin of RCA from LSV and the separate origin of LAD and LCX in LSV. Each of these anomalies had an angiographic incidence of 0.45% and an anomaly incidence of 23.25% [Table 3]. Previous international studies have also shown either of these anomalies to be most common[4],[6],[7],[8],[10],[11],[12],[14],[16] [Table 5]. Furthermore, these two anomalies were either most common or second most common in all previous Indian studies[3],[17],[18],[19],[20] [Table 6] except in studies by Garg et al.[3] and Somashekhara et al.,[20] wherein separate origin of LAD and LCX were excluded and found to be least common, respectively.

Anomalous origin of LCX from RSV or RCA and anomalous origin of RCA from ascending aorta were found to be the second most common types, each with an angiographic incidence of 0.33% and an anomaly incidence of 17.44% [Table 3]. In few large studies,[9],[13],[15] anomalous origin of LCX from RSV or RCA was found to be the most common type [Table 5]; however, Yamanaka and Hobbs et al.[4] reported its angiographic and anomaly incidences as 0.4% and 30%, respectively, while Indian studies by Garg et al.[3] and Lingaraju et al.[18] reported it as the second and third most common types, respectively. Anomalous origin of RCA from the ascending aorta had angiographic and anomaly incidences as 0.15% and 11.2%, respectively, in the Cleveland series.[4]

Dual LAD is a rare anomaly with an angiographic prevalence ranging from 0.01% to 0.03% in the published studies.[21],[22] It is classified into six different types based on the origin and course of the long LAD.[23] In Types I, II, and III, both the long and the short LADs originate from the proximal LAD. In Types IV, V, and VI, the long LAD originates from the proximal RCA or from the right coronary sinus and takes an epicardial course or an intramyocardial course, or an interarterial course, respectively.[23] In this study, we found one case of Type V LAD with angiographic and anomaly incidences of 0.02% and 1.16%, respectively.

Single coronary artery is also a rare anomaly with an angiographic prevalence ranging from 0.02% to 0.05% in the previous studies and commonly associated with congenital heart disease.[4],[14] According to Lipton classification, these are classified as Type I if there is only one artery with anatomical course of either left or right, Type II if single artery after origin divides into right and left coronary arteries, and Type III for other atypical patterns and designated as “R” or “L” depending on whether the ostium is located in the RSV or LSV, respectively.[4] Yamanaka and Hobbs et al.[4] found 56 such cases, with L-I as the most common followed by R-II and L-II. In our study, it was one case of L-II type with angiographic and anomaly incidences of 0.02% and 1.16%, respectively.

Coronary artery fistulae are considered as anomalies of termination with a frequency of 1/50,000 livebirths and 1/500 patients at cardiac catheterization.[9] More than 50% of these fistulae have a connection with the RCA. Most of them drain into the right ventricle (40%), right atrium (25%), or coronary sinus, while some drain into the pulmonary artery, left atrium, or left ventricle.[4],[11] In some series, fistulae were more common with an anomaly incidence of 21%.[9] In our study, however, its angiographic and anomaly incidences were 0.11% and 5.81%, respectively, with majority arising from the LAD and draining into the pulmonary artery, similar to other large studies.[3],[4]

Benign versus potentially serious

Considering the pathophysiologic relevance, majority of the CCAs were benign (75.58%), with only 24.42% of them being potentially serious. Yamanaka and Hobbs et al.[4] classified certain anomalies as benign since they do not cause any hemodynamic impairment or myocardial perfusion abnormalities in the absence of atherosclerosis, while few anomalies were considered to be potentially serious as they may lead to anginal syndromes, myocardial infarction, arrhythmias, and sudden death, especially in the young.[4] Benign and potentially serious anomalies found in our study are summarized in [Table 3].

Anomalous origin of coronary artery from opposite sinus can have prepulmonic or interarterial or intraseptal or retroaortic proximal course. Of these, only interarterial course (between aorta and pulmonary artery) is considered to be potentially serious, while rest all are benign.[24] This interarterial course could represent up to 30% risk of sudden cardiac death and it is reported as a cause of sudden death in 5%–35% of young individuals in association with extreme exertion, while this risk in the middle aged and the elderly is usually low.[24] The exact pathophysiology causing sudden death in these subsets is not known. The slit-like ostium and narrow angle of origin could create valve-like compression of the artery due to dilatation of the aortic wall during increased cardiac output states, leading to myocardial ischemia. However, recent intravascular ultrasound (IVUS) studies have shown that almost all arteries with interarterial course have variable intramural course (artery within aortic wall), which is responsible for subsequent hemodynamic effects.[25]

Most of the benign anomalies of origin [Table 3] had normal distal course and distribution except for anomalous origin of LCX from RSV or RCA and anomalous origins from PSV, wherein the proximal courses were retroaortic in all, which is consistent with previous studies.[3],[4] While in cases with anomalous origin of RCA from LSV, the proximal course was interarterial, which is also seen in 90% of such cases in literature.[24] The left main artery can also have anomalous origin from RSV, with 75% of these having interarterial course;[24] however, no such patient was found in our study. In patients with a single coronary artery, sudden death has been reported to be associated with a major coronary artery having interarterial course,[14] which in our case was the dominant RCA.

According to Angelini et al., due to lack of clear consensus, symptomatic patients with carriers of such anomalous arteries with interarterial courses may require evaluation in terms of clinical profile, IVUS, computed tomography (CT) coronary angiography, myocardial perfusion scans, etc., to look for high-risk factors such as acute angle of origin, slit-like coronary ostium, intramural course, and inducible ischemia in order to decide whether to manage them conservatively or consider intervention in the form of angioplasty and stenting or surgical repair.[25]

Usually, small coronary artery fistulae do not cause significant shunt and are asymptomatic. However, if the shunt is large, pulmonary hypertension, congestive heart failure, bacterial endocarditis, rupture, and myocardial ischemia may occur.[4] In the present study, all the fistulae were small without significant shunting and so were considered as benign [Table 3].

Atherosclerotic involvement of coronary artery anomalies

The atherosclerotic involvement of CCA is controversial, with few previous studies[3],[6],[7],[10],[13],[15],[17] showing its incidence to be variable ranging from 1.7% to 72.2% [Table 5] and [Table 6]. In our study, the overall incidence of atherosclerosis in anomalous vessels was 52.32% which was higher but similar to the study by Tharwat et al.[15] However, there was no statistically significant association of CAD in anomalous vessels as compared to normal vessels in the same patients (P = 0.24), which was consistent with a majority of previous studies.[3],[6],[7],[13],[17],[26] On the contrary, studies by Tharwat et al. and Somashekhara et al.[20] concluded that CCAs are frequently involved in atherosclerosis. Few studies have shown anomalous vessels arising from the right side with retroaortic course to have increased atherosclerotic involvement,[1],[27] while Sohrabi et al.[14] found anomalous RCA arising from LSV to have an increased incidence of atherosclerosis. However, such vessel-specific predisposition was not found in our study [Table 4].

Study limitations

This was a single-center, retrospective study which included patients undergoing coronary angiography and so had referral bias and may not represent the whole population in general. Other imaging modalities such as CT/magnetic resonance coronary angiography and IVUS were not evaluated. Since atherosclerotic involvement was not compared with patients without anomalous arteries and atherosclerosis being multifactorial, further large-scale prospective studies are required to establish the relation between atherosclerosis and CCA.

 Conclusions



CCAs were diagnosed incidentally during coronary angiography and had male predominance with conventional risk factors. The incidence of CCA was slightly higher than the previous angiographic studies, but the pattern of anomalies was similar. Though most of the CCAs were benign, their angiographic recognition is important for further cardiac interventions in the form of coronary angioplasty or surgery and, also, the rarer potentially serious anomalies warrant further investigations for deciding management and follow-up. The incidence of atherosclerotic involvement in anomalous vessels was slightly higher than that of previous studies but without any statistically significant association as compared to normal vessels in the same patients, which is similar to previous studies.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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