When the Right and Left Coronary Arteries Join: A Case Report of Intercoronary Communication and Literature Review.

An intercoronary communication is a very rare congenital anomaly characterized by a short connection between two main coronary arteries. A 41-year-old female presented with dyspnea and elevated D-dimer and N-terminal pro brain natriuretic peptide levels. Pulmonary CT angiography demonstrated a pulmonary embolism and significantly enlarged mediastinal lymph nodes. Echocardiography revealed apical akinesia and impaired left ventricular function (ejection fraction of 45%). Coronary angiography showed no evidence of obstructive coronary artery disease but identified an abnormal continuity between the distal right coronary artery and the distal left circumflex artery. Each coronary injection demonstrated retrograde filling of the contralateral artery. The short intercoronary connection did not have the characteristics of an acquired collateral circulation. Cardiac MRI revealed apical akinesia with multifocal areas of subepicardial late gadolinium enhancement raising suspicion for cardiac sarcoidosis. Fewer than 30 cases of intercoronary communication have been reported in the literature to date. This anomaly is often discovered incidentally, as in the present case, and may have a myocardial-protective effect in the presence of coronary artery disease. Conversely, it can also be associated with coronary steal phenomena. However, establishing proof for these mechanisms remains challenging.