A Rare Finding – MRI Leads to the Surprising Discovery of Anomalous Left Circumflex Coronary Artery from the Pulmonary Artery (ALXCAPA) in a 42-Year-Old Woman

A 42-year-old woman was referred to our department for an MRI following the identification of posterior wall motion abnormalities on routine echocardiography. Her medical history includes surgical repair of a patent foramen ovale (PFO), ventricular septal defect (VSD), and removal of a supravalvular membrane in the left atrium at age 3. She had a normal childhood post-surgery, with regular pediatric cardiology follow-ups showing no significant findings. Her family history was unremarkable, with no known genetic or congenital disorders.

When specifically questioned, the patient reported lifelong palpitations and reduced endurance, symptoms she had accepted as normal and never associated with a serious condition. She denied any history of syncope or anginal symptoms. Physical examination was unremarkable. An electrocardiogram demonstrated sinus rhythm with T-wave inversions in V1 to V5, and routine blood tests were within normal limits.

The MRI revealed a normally sized left ventricle with preserved systolic function, confirming the hypokinesia observed in echocardiography. After administration of intravenous contrast, late gadolinium enhancement (LGE) imaging showed a subendocardial scar at the inferior and inferolateral basal walls of the left ventricle, consistent with infarction due to chronic ischemia. Flow measurements between the aorta and both pulmonary arteries indicated no significant intracardiac shunt.

 

Subsequently, the patient underwent selective coronary angiography, which revealed a dilated left anterior descending artery (LAD) without stenosis or sclerosis, along with retrograde filling of the anomalous left circumflex coronary artery (LCX) through multiple collateral vessels of varying sizes from both the LAD and the right coronary artery (RCA).

 

Further evaluation with coronary CT angiography confirmed the anomalous origin of the LCX from the proximal right pulmonary artery. No malignant course of the LCX was observed, though dilation of non-anomalous coronary vessels with extensive collateralization from the LAD and RCA to the LCX was evident.

 

The patient was referred to a specialized cardiothoracic center, where conservative management was provisionally recommended due to her mild symptoms, extensive collateral circulation, small myocardium at risk, young age, and preserved cardiac function.

After twelve months of follow-up, the patient remains asymptomatic. Regular six-month follow-ups, including ECG, transthoracic echocardiography, and MRI, are planned to monitor physical activity, functional status, and cardiovascular health.

Discussion:

Anomalous origin of the LCX from the pulmonary artery is extremely rare, first documented in an adult in 1992, with only 53 cases reported since. Common symptoms include exertional angina, shortness of breath, and palpitations. In most documented cases, treatment has involved surgical ligation or coronary bypass surgery. In this patient’s case, however, a conservative approach was deemed appropriate due to her well-developed collateral circulation and mild symptoms.

References:

Talkhatova S. ALCAPA in adult asymptomatic patient: Case report. Int J Surg Case Rep. 2023.
Gupta MD. Anomalous Left Circumflex Coronary Artery from Pulmonary Artery (ALXCAPA): Unusual cause of exertional chest pain in an octogenarian. Eur Heart J Case Rep. 2020.
Guenther TM. Anomalous Origin of Circumflex or Left Anterior Descending Artery From Pulmonary Artery. World J Pediatr Congenit Heart Surg. 2020.