Coronary-intercostal steal syndrome, a rare connection between the left circumflex coronary artery and intercostal arteries: A case report

A 60-year-old female patient presented with typical anginal pain on exertion and relieved by rest for about one month. Percutaneous coronary angiography was done and showed an abnormal left circumfl ex coronary artery connecting to intercostal artery. Embolization of that abnormal connection was done successfully and the patient discharged from hospital after 24 hours. This case shows a new form of coronary steal syndrome. This cause could be missed if not put under the differential diagnosis of typical anginal pain with normal coronary arteries.


Introduction
Congenital anomalies of the coronary arteries are present in about 1% of the general population [1]. The discovery of these anomalies is accidental during work up for angina pectoris. They can be looked up using invasive coronary angiography, or better using multidetector computed tomography coronary angiography [2]. There are many forms of coronary artery anomalies that are asymptomatic, non-signi icant to more complex dangerous forms that can lead to sudden cardiac death [1]. In this case we present a rare anomaly of the left circum lex coronary artery that resulted in myocardial ischemic symptoms on exertion and angiography showed that the left circum lex coronary artery is anastomosed with the intercostal arteries. In our knowledge, this case is the irst time to be found in our country and it is not found in the literature.

Case Report
A 60-year-old female patient complained from retrosternal chest heaviness that increases with exertion and relieved by rest, this pain radiated to left arm and its severity was 8/10. On examination, the patient looked anxious with good general condition, and stable vital signs. Chest examination and cardiovascular examination were normal. ECG was done it was normal, without ischemic changes. Complete blood count, kidney function tests, and lipid pro ile were normal.
A diagnostic invasive angiography for the coronary arteries was done and showed a bizarre anatomy of the left circum lex coronary artery as it not only supplies the heart but also it continues its way to supply the left side of chest wall. Otherwise, the coronary arteries are patent with no stenosis noticed, Figure 1. Embolization of the left circum lex coronary artery after its heart-supplying branching was done using 3 coils, and control angiography showed total occlusion of the abnormal connection, Figure 2. Total procedure time was 45 minutes and the patient discharged from the hospital without complications 24 hours later.

Discussion
Myocardial ischemia occurs when there is decrease in blood supply to heart muscle, there are many causes for the ischemia, ours is imbalance between oxygen supply and demand [3]. Congenital anomalies of the coronary arteries are rare, incidentally discovered during coronary angiography, or autopsies. The incidence of coronary artery anomalies increased from 0.3% in 1956 [4] to 2.33% in 2015 [5], in fact, the prevalence and the real incidence among general population is unknown and it could reach 5.6% [6]. This increase is mainly due to improve in diagnostic methods, from accidental inding in autopsies [4] to multi-detector row computed tomography coronary angiography [5] or percutaneous coronary angiography. Congenital anomalies of the coronary arteries are mainly asymptomatic and have no great impact on the person's life, but sometimes it forms a lifethreatening condition when there is anomalous origin of the left coronary artery from the pulmonary artery, large coronary arteriovenous istulas, and those anomalies associated with a coronary artery coursing between the great vessels [6]. In young athletes, congenital coronary artery anomalies constitutes the second cause of sudden cardiac death, about 12% of deaths [1].
Although there are many forms of coronary artery anomalies reported in literature [1,4,6,7], the anomalies of the left circum lex coronary artery are rare, it constitutes about 0.3% of coronary artery anomalies [8]. In addition to that, no one has reported an anomaly like the case we present in which the left circum lex coronary artery continues to supply the left chest wall. This anomaly presents as myocardial ischemia like the idea of coronary steal syndrome, and coronary subclavian steal syndrome. On exertion, the blood lows through the left circum lex coronary artery to join the intercostal arteries in supplying the muscles of chest wall, resulting in relative myocardial ischemia [9]. Medical intervention mainly is indicated if the symptoms affects patient's life, and it can be performed through the percutaneous coronary intervention and occlude the abnormal connection, using embolizing material like the coils [10].
According to variants of coronary artery, the management plan differs. Some variants mandates surgery to correct the anomaly like when the left coronary artery courses between the great vessels, and some are managed when they are symptomatic, but most of them require observation only [11].

Conclusion
Congenital anomalies of the coronary artery are rare but important to manage it they are symptomatic. They could present as arrhythmias, chest pain, or sadly sudden cardiac arrest. The management is different between the variants of the coronary artery some need open heart surgery, others require endovascular embolization as in this case, and many could be observed without intervention.

Consent
Verbal informed consent was obtained from the patient who was conscious and oriented to publish this case and all related materials.