Abnormal blood supply to a normal lung: left circumflex artery branch supplying the right lung
- Yamasandi Siddegowda Shrimanth 1,
- Mandava Satya Sahitya 1,
- Muniraju Maralakunte 2 and
- Bhupendra Kumar Sihag 1
- 1 Cardiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
- 2 Radiodiagnosis and Imaging, Post Graduate Institute of Medical Education and Research, Chandigarh, India
- Correspondence to Dr Bhupendra Kumar Sihag; drbhupendrasihag@gmail.com
Abstract
A middle-aged woman with hypertension presented with atypical chest pain of 1 month duration and had a positive exercise stress test. She underwent diagnostic coronary angiography which demonstrated an anomalous branch arising from the proximal part of the left circumflex artery supplying the right lung. She had atherosclerotic plaques in the right coronary artery and left anterior descending artery. Stress myocardial perfusion imaging did not reveal any inducible ischaemia in the left circumflex artery territory. She was started on medical therapy for coronary artery disease and is doing well on follow-up.
Background
Anomalies of the coronary arteries are a rare presentation. They account for 1%–5% of the cases undergoing coronary angiography. Anomalous origin of the coronary artery, congenital absence, hypoplasia and abnormal termination (fistulas) are more commonly described.1 There have been few case reports of systemic blood supply arising from the coronary artery. Majority of these case reports have been of coronary vessels supplying the sequestrated lung segments. We present a case of an anomalous coronary artery branch supplying a normal lung.
Case presentation
A middle-aged woman with hypertension presented with atypical chest pain for the last 1 month. She had no significant medical history. On examination the patient had xanthelasma. The rest of the general and systemic examinations were unremarkable. ECG showed normal sinus rhythm. Echocardiography showed normal left ventricular function with no regional wall motion abnormality. She was subjected to treadmill stress test with Bruce protocol, which was mildly positive for stress-induced ischaemia. The patient was taken up for coronary angiography. Angiogram showed plaque in the proximal left anterior descending artery and midportion of the right coronary artery with right dominant circulation (figure 1D–F). The left circumflex artery was normal except for an anomalous branch arising from the proximal portion. This abnormal branch was crossing the spine and coursed towards the hilum of the right lung on anteroposterior view (figure 1A,B, video 1). CT of the chest and coronary angiography were planned for further characterisation of the vessel and to look for the status of the lungs. A systemic collateral channel of 2.4 mm in diameter was seen arising from the proximal left circumflex artery 3 mm away from the ostium. It showed a tortuous course towards the hilum of the right lung and supplied the upper lobe of the right lung (figure 2). No lung abnormality was noted. To decide on whether to intervene with coiling for this abnormal branch, a stress myocardial perfusion imaging was done and showed no inducible ischaemia in the left circumflex artery territory. She was started on aspirin, statin, beta blockers and lifestyle modification. She was asymptomatic at 4-month follow-up.
Coronary angiogram. (A) AP view showing the artery arising from the proximal portion of the left circumflex artery crossing the spine and reaching the hila of the right lung (arrows). (B) Demagnified AP view showing the course of the abnormal artery from LCX to the right lung upper lobe. (C) AP caudal view showing the origin from the proximal LCX (white arrow). (D) AP caudal view showing an otherwise normal LCX. (E) AP cranial view showing plaque in the proximal left anterior descending artery. (F) Left anterior oblique cranial view showing plaque in the mid-right coronary artery. AP, anteroposterior; LCX, Left circumflex artery.
CT. ECG-gated aortogram, volume-rendered images (A, B) showing the origin (arrowhead) and complete course (arrows) of the systemic arterial collateral channel from the left circumflex coronary artery. Maximum intensity projection coronal (C) and axial (D) reformatted images showing the mediastinal and hilar (right side) course of the systemic collateral arterial twig (red arrows) ultimately supplying the upper lobe of the right lung.
Discussion
Coronary arteries supplying the lung are rare. There have been a few case reports describing an aberrant supply of pulmonary segments from the coronary arteries.2–8 Anastomosis of the coronary and bronchial vessels has also been described.9 The pulmonary sequestrum in these reports received supply from the atrial branches of the right and left circumflex coronary arteries. The venous drainage of the pulmonary segments in these cases was to pulmonary veins. The most common segment to be supplied was the posterior basal segment. The proximity of this lung segment and the coronary vessels explains the possibility of this anomaly. There have been case reports of the left pulmonary sequestrum being supplied by the right coronary atrial branch and vice versa.2 Few cases of pulmonary artery agenesis with collaterals from the coronary arteries supplying the affected lung have been reported in the literature.5–8 In the case reported by Gupta et al,6 the patient had adenocarcinoma of the right lung. In the case reported by Kadi et al,5 the patient had myocardial ischaemia demonstrated on myocardial perfusion scan. In our case, the branch from the left circumflex artery supplied the normal lung tissue of the right lung and both pulmonary arteries were well developed, with no myocardial ischaemia on perfusion scan.
Almost all cases with this anomaly had presented in old age with symptoms of ischaemia. In the absence of significant coronary artery disease, ischaemia can probably be explained by the coronary steal phenomenon. However, no causal relationship between an anomalous coronary branch and ischaemia has been established so far. There are very few case reports of this type of coronary anomalies and hence studies on natural history are lacking. Resection of the pulmonary segment is recommended in case of recurrent infections or haemoptysis due to the sequestrated lung or if coronary steal phenomenon is present.10 Both American heart association (AHA) and European society of Cardiology (ESC) guidelines for adult congenital heart diseases advocate for cardiovascular CT to evaluate for high-risk anatomy features (intramural course, slit-like orifice) and assessment of physical stress-induced ischaemia using advanced imaging modalities such as nuclear study or cardiac magnetic resonance for decision making in coronary anomalies.11 12 A stress myocardial perfusion imaging was performed in our patient which did not show any signs of inducible ischaemia. The patient was medically managed with antiplatelet and antianginal medications.
Symptoms, complications and significant shunt are the main indicators of percutaneous or surgical closure of abnormal branches. Surgical approach if required would be dictated by the coronary vessel and the pulmonary lobe involved. The incision should allow for pulmonary resection, exposure of feeding vessels and arteries to be bypassed, and potential cannulation for cardiopulmonary bypass.10
Systemic blood supply from coronary vessels, although rare, should be considered a differential among coronary artery anomalies as it can lead to coronary steal and ischaemia. Also, these anomalous arteries could be the source of haemoptysis if that particular part of the lung was to get diseased.13 Knowledge about the origin of these anomalous arteries is paramount, if surgical ligation or transcatheter occlusion is planned.10
Learning points
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Coronary artery anomalies can present with ischaemic symptoms due to coronary steal.
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Coronary artery branch supplying the lung is very rare and intervened on only when it is causing significant coronary steal, resulting in myocardial ischaemia or is associated with pulmonary pathology.
Ethics statements
Patient consent for publication
Footnotes
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Contributors YSS and BKS were involved in the management of the patient, and in conceptualising the case report, preparing the manuscript and finalising it. MSS was involved in preparing the manuscript, literature review and proof-reading. MM was involved in preparing the manuscript, proof-reading and preparing the images.
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Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
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Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
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Competing interests None declared.
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Provenance and peer review Not commissioned; externally peer reviewed.
- © BMJ Publishing Group Limited 2022. No commercial re-use. See rights and permissions. Published by BMJ.
References
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