Objectives: Congenital absence of the right coronary artery (RCA) is an exceedingly rare coronary anomaly in which the left coronary system supplies the entire myocardium. We report a case of congenital absence of the RCA with a superdominant left circumflex artery (LCX) supplying the entire RCA territory in a patient presenting with stable angina, highlighting the diagnostic and clinical importance of recognizing this unusual coronary anatomy.


Methods: A 57-year-old man with hypertension and type 2 diabetes mellitus presented with a one-month history of typical anginal chest pain. Clinical evaluation included electrocardiography, transthoracic echocardiography, single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI), and coronary angiography to assess myocardial ischemia and coronary anatomy.


Results: SPECT MPI demonstrated a small-to-moderate reversible perfusion defect in the apical region. Coronary angiography revealed no identifiable RCA ostium in the right coronary sinus, confirming congenital absence of the RCA. Selective left coronary angiography demonstrated a markedly enlarged, superdominant LCX that coursed through the left atrioventricular groove, crossed the crux, and extended into the right atrioventricular groove, supplying the territories normally perfused by the RCA. A myocardial bridge was also observed in the mid-left anterior descending artery without significant compression at rest, and no significant obstructive coronary artery disease was identified. Medical treatment with bisoprolol was initiated, and the patient remained asymptomatic during follow-up.


Conclusions: Congenital absence of the RCA with compensatory perfusion by a superdominant LCX is a rare coronary anomaly that may present with angina and evidence of myocardial ischemia. Accurate delineation of coronary anatomy is essential to establish the diagnosis, avoid unnecessary attempts to cannulate a nonexistent RCA ostium, and guide future interventional or surgical management.