ALCAPA: 3D MDCT presents an intuitive perspective

Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is one of the rare congenital anomalies with exceptional presentation till adulthood. The complications include left ventricular dysfunction, severe mitral regurgitation and myocardial infarction. We report a case of a young female with dyspnea and murmur with left to right shunt which was finally diagnosed as ALCAPA by multi-detector cardiac computed tomography (MDCT).

A 45-year-old female presented with dyspnoea on exertion New York Heart Association [(NYHA) II class] and chest heaviness for seven days. Physical examination reveals 2/6 systolic diffuse murmur over the left sided chest with predominance over the pulmonary area. Electrocardiogram (ECG) reveals sinus rhythm with infrequent premature ventricular contractions (PVCs) and echocardiography reveals left to right shunt flow with inconspicuous ends. Cardiac computed tomography (CT) study reveals very interesting and unusual findings. Only one coronary artery was found to originate from the aortic root (Figure 1A and Figure 1B). Right coronary artery (RCA) originates from the right coronary sinus as a large-sized and ecstatic artery with a highly tortuous course and abundant collaterals (Figure 1C). No coronary origin was detected from the left coronary cusp. Surprisingly, the left coronary equivalent artery was revealed, originating from the main pulmonary artery with course toward anterior interventricular groove and branching into left anterior descending and left circumflex coronary arteries with normal courses (Figure 1D and Figure 1E). Finally, cardiac CT unveiled the definitive diagnosis of anomalous left coronary artery from the pulmonary artery (ALCAPA).

Approximately 90% of the infants with ALCAPA die during the first year of their life and very few survive till adulthood [1]. The adult cohort of ALCAPA is increasing due to better advanced cardiac imaging techniques like multidetector computed tomography (MDCT). It is characterized by exuberance in collateral coronary circulation from RCA to left coronary artery (LCA); thus allowing survival up to adulthood, coronary “steal” phenomenon from RCA to LCA and pulmonary “steal” phenomenon as LCA to PA [2]. In the adult type of ALCAPA, re-establishment of dual coronary system by ligation of the LCA from the pulmonary artery with coronary artery bypass grafting and reimplantation of LCA coronary button to aorta with interposition graft are the preferred methods of surgical approach [3].