230 ANOMALOUS ORIGIN OF LEFT CIRCUMFLEX ARTERY FROM RIGHT SINUS OF VALSALVA: A RARE CASE BUT WITH GREAT CLINICAL RELEVANCE
Authors: Poleggi Cristina , Restelli Davide , Luongo Alfredo , La Cognata Olga , Lo Savio Armando , Crea Pasquale , Micari Antonio , Di Bella Gianluca , Dattilo Giuseppe 
Published: December 2022

Abstract

Introduction
The anomalous connection of the left circumflex artery (LCx) to the right coronary artery (RCA) or sinus is the most frequent coronary artery (CA) anomaly. Among them, only those with an interarterial course are regarded as hidden conditions at risk of myocardial ischemia (MI) and sudden cardiac death (SCD). We report an uncommon of anomalous origin of LCx from the right sinus of Valsalva and a retroaortic path causing MI.

Case presentation
A 61-year-old man presented to the emergency department complaining palpitations and chest discomfort for an hour. He only had history of hypertension. Physical examination was unremarkable. The ECG demonstrated atrial flutter with a 2:1 conduction ratio and a ventricular rate of 157 bpm and ST segment depression in leads V4-6. Transthoracic echocardiography did not reveal segmental kinetic anomalies but a five-chamber apical view showed a “RAC sign”, typical of anomalous retroaortic course of the left coronary artery. The patient was treated with intravenous infusion of amiodarone. He restored sinus rhythm and symptoms regressed completely, but the ECG taken after conversion showed flattened T waves in leads V5-6 and negative T waves in I and aVL. Cardiac enzymes had transient increase. After the acute episode ended the patient underwent cardiac computed tomography angiography (CTA) with evidence of anomalous origin of LCx from the right sinus with a retroaortic course. A coronary angiography excluded obstructive atherosclerotic coronary lesions. Nuclear myocardial perfusion imaging revealed reversible small subsegmental perfusion defects in mid inferolateral wall and apical lateral wall. We established a medical treatment with beta-blocker.

Discussion
Our patient had anomalous connection of the LCx branch to the right sinus of Valsalva with a retroaortic course. Although this anomaly is usually considered benign, cases of association with SCD and MI have been reported. The factor responsible for this pathogenicity could be high orifice, ostial stenosis, slit-like/fish-mouth-shaped orifice and acute-angle take-off. As cardiac CTA did not reveal any of these characteristics, we hypothesized that the increased cardiac output and expansion of the great vessels during tachycardia could cause compression of the retroaortic segment or angling at its origin and generate ischemia. Repolarization abnormalities at ECG are well documented during supraventricular tachycardia as a response to pacing-induced stress. These changes are usually diffused and disappear after conversion to sinus rhythm. In this case they appeared hours later, accompanied by cardiac enzyme buildup. As the epicardial coronary arteries did not show any pathology, we suggest that the patient had transient ischemia due to LCx anomaly. We confirmed it by myocardial perfusion imaging. As for the management of this anomaly in adults, surgery is recommended as class IC in patients with typical angina symptoms who present with evidence of stress-induced myocardial ischemia in a matching territory or high-risk anatomy. Our patient has never had clear manifestations of angina. All these elements together with the age of our patient motivated us to use a conservative approach.

Conclusions
We report a case of anomalous origin of LCx from right sinus of Valsalva causing transient myocardial ischemia in a patient that has always been asymptomatic. This anomaly has been and continues to be considered benign, nevertheless we suggest to judge the clinical significance of this kind of CA anomaly on a case-by-case integrated approach.