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CASE REPORT
Year : 2023 | Volume
: 9
| Issue : 1 | Page : 76-78
Short Chronic Total Occlusion Stump Creating an Optical Illusion of an Anomalous Coronary Artery: A Pseudo Anomaly
Ankit Kumar Sahu1, Pramod Sagar2, Satyendra Tewari1, Aditya Kapoor1
1 Department of Cardiology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Lucknow, Uttar Pradesh, India
2 Department of Pediatric Cardiology, Madras Medical Mission, Chennai, Tamil Nadu, India
Correspondence Address:
Ankit Kumar Sahu
Department of Cardiology, Sanjay Gandhi Post Graduate Institute of Medical Sciences, Raibareli Road, Lucknow - 226 014, Uttar Pradesh
India
Source of Support: None, Conflict of Interest: None
CheckDOI: 10.4103/jpcs.jpcs_66_22
Coronary artery anomalies are often asymptomatic and detected incidentally during coronary angiography, cardiac surgery, or autopsy. However, sometimes in chronic total occlusion, the distal part of a vessel is well collateralized from the contralateral vessel that it appears almost as an anomalous coronary artery. Here, we discuss a rather interesting angiogram which at first instance, looked like a case of a dual left anterior descending (LAD) artery with anomalous origin of the LAD from the proximal right coronary artery, but after further evaluation appeared to be a case of an occluded LAD filling through Vieussens' arterial ring.
Keywords: Chronic total occlusion, coronary anomaly, Vieussens' arterial ring
Coronary artery anomaly constitutes one of the rare congenital heart diseases. Most of the anomalies are benign, and are incidentally detected during diagnostic coronary angiography. Chronic total occlusions (CTOs) commonly found during the evaluation of angina are usually associated with well-developed collaterals. Sometimes, the collaterals can be as large as the native artery. We present a case where a large abnormal vessel posed a diagnostic dilemma, anomalous artery, or collateral.
Case SummaryWe present a case of a 47-year-old gentleman, with risk factors of diabetes, hypertension, and tobacco chewing with a history of exertional angina for 4 months without any history of rest angina, dyspnea, or syncope. Clinical examination was unremarkable except for the presence of hypertension and periorbital xanthelasma. The electrocardiogram showed ST segment depression (~1 mm) in the inferior leads. Echocardiography revealed normal left ventricular ejection fraction without any regional wall motion abnormality. The left coronary angiogram in the left anterior oblique cranial and right anterior oblique caudal view showed normal left main coronary artery (LMCA) giving rise to a branch, presumably the left anterior descending (LAD) artery running in the anterior interventricular groove terminating well before the apex and giving rise to the septal branches. The later phase of injection shows slow retrograde filling of circumflex running in the left atrioventricular groove and the obtuse marginal branches from ipsilateral collaterals making a case of proximal left circumflex (LCX) artery occlusion [Figure 1]. The right coronary artery (RCA) angiogram showed a codominant RCA artery free of significant disease giving origin to the posterior descending artery. An interesting note was made of a large tortuous conal branch from the proximal RCA ascending in an antero-cranial course continuing in the anterior interventricular groove and extending beyond the apex of the heart [Videos 1-4]. This good-sized artery gave branches similar to the diagonal and septal branches in a fashion similar to the LAD [Figure 2].
Figure 1: Angiogram of the left coronary artery. AP caudal view (a and b) and LAO cranial (c and d) showing a vessel, presumably LAD (black arrow) and retrograde filling LCX artery (white arrow). AP: Antero-posterior, LAO: Left anterior oblique, LAD: Left anterior descending, LCX: Left circumflex
Figure 2: Angiogram of the RCA. LAO view (a-c) and LAO Cr view (d-f) showing large tortuous conal branch from the proximal RCA ascending in an antero-cranial course to fill a large vessel antegradely in the anterior interventricular groove extending beyond the apex and reminiscent of the Vieussens' arterial circle. The origin (black arrow) and continuation as LAD (white arrow) can be made out. RCA: Right coronary artery, LAO: Left anterior oblique, Cr: cranial, LAD: Left anterior descendingThere are certain mirages in this angiogram. (1) The only branch of the LMCA may be assumed to be diagonal with total occlusion of the LAD at the LAD-diagonal junction since it appears to be short and does not reach apex. This can be assorted by noting that this artery runs in the anterior interventricular groove and gives origin to the septal branches. (2) The vessel filling from the proximal RCA collaterals may be considered an anomalous LAD. Many indicators such as contrast filling this artery in an antegrade fashion and the RCA collateral feeding this artery, being large and tortuous without coronary atherosclerosis in this vessel, indicate toward it being an anomalous LAD arising from the proximal RCA making it a case of a dual LAD.
Computed tomography (CT) coronary angiography was done to ascertain the course and origin of this collateral vessel as well as native LAD. Veil was lifted over the suspense in that the LMCA gave origin to the LAD that terminated shortly into CTO stump after giving origin to a small diagonal (D1), an average-sized ramus intermedius, and LCX which was totally occluded from the ostia [Figure 3]a and [Figure 3]b. Distal LAD was filling antegrade exceptionally well from a large RCA collateral (a reminiscent of the Vieussens' arterial circle). The collateral-LAD junction was also so smooth. These factors gave an illusion that this Rentrop grade 3 collateral was a distinct vessel arising from the RCA [Figure 3c and d]. The patient was advised coronary artery bypass grafting.
Figure 3: Multislice CT angiographic images showing the left main giving origin to LAD (white arrow), ramus (black arrowhead), and osteo-proximally occluded LCX (black arrow). There is a short proximal length of the LAD, followed by CTO segment just after giving origin to a small diagonal (a and b). Mid LAD is filling from the large RCA conal branch collateral (c and d) (white arrowhead). CT: Computed tomography, LAD: Left anterior descending, LCX: Left circumflex, RCA: Right coronary artery, CTO: Chronic total occlusion Discussion Vieussens' arterial ring (VAR) refers to the connection between the conus artery and the LAD coronary artery's proximal right ventricular branch.[1] Anatomical studies have estimated VAR to be prevalent in 48% of population as an embryonic conotruncal ring remnant.[2] However, the recent multidetector CT-based studies have demonstrated VAR in 3.19%.[3] One of its variants (Type 2 VAR) is associated with a short LAD branch, which terminates in the anterior descending groove, and the long branch, which originates from the right coronary circulation, passes in front of the pulmonary artery and extends to the distal section of the anterior descending groove resembling type 4 dual LAD, which was seen in our patient.[4] The incidence of type 4 dual LAD, involving LAD arising from the RCA, ranges from 0.01% to 0.03%.[5],[6],[7],[8],[9],[10]
This case demonstrates the lacunae in angiographic interpretation of coronary anomalies, collateral vasculature, and their look-alike. In this scenario, the only vessel arising from the left main may be mistaken for ramus like diagonal as it is short and does not reach the apex in the presence of totally occluded LCX from the ostia. Many indicators such as antegrade contrast filling of the LAD from the proximal RCA collaterals and the absence of atherosclerosis in this vessel indicate toward it being an anomalous LAD arising from the proximal RCA. However, CT coronary angiography helps in delineating CTO stumps with retrogradely filling CTO vessel from VAR, which mimics anomalous coronaries as shown in this case.
ConclusionCoronary artery CTO with well-developed large collaterals can give an illusion of coronary anomaly. Multimodality approach, including CT coronary angiography and systematic evaluation of coronary angiography, can identify the pathology and helps in decision-making.
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The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.
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