From the Guidelines
An absent left circumflex artery in the presence of scimitar syndrome is a significant concern that requires careful medical evaluation and management, as it may impact myocardial perfusion and exacerbate the effects of abnormal pulmonary blood flow. Scimitar syndrome is a rare congenital heart defect characterized by abnormal pulmonary venous return from the right lung to the inferior vena cava, often associated with other cardiac anomalies 1. When this condition occurs alongside an absent left circumflex artery (a coronary artery variant), it creates a complex cardiovascular situation that may affect heart function and blood supply.
Key Considerations
- Patients with scimitar syndrome and an absent left circumflex artery should undergo comprehensive cardiac imaging, including echocardiography, cardiac CT or MRI, and possibly cardiac catheterization to assess the full extent of the anomalies and their hemodynamic impact 2.
- Management typically involves a multidisciplinary approach with cardiologists and cardiothoracic surgeons, and may range from regular monitoring to surgical intervention depending on symptom severity, degree of pulmonary venous drainage abnormality, and presence of other cardiac defects.
- The concern stems from potential issues with myocardial perfusion due to the coronary anomaly and abnormal pulmonary blood flow from the scimitar syndrome, which together could lead to heart failure, pulmonary hypertension, or exercise intolerance.
Diagnostic Approach
- Cross-sectional imaging with CMR or CTA is ideal for delineating pulmonary venous connections, as it provides detailed information on the anatomy and hemodynamics of the cardiac and pulmonary vascular systems 1.
- CMR has the advantage of not using ionizing radiation and may also quantify the degree of shunting, making it a valuable tool in the evaluation of scimitar syndrome and its associated anomalies 2.
Management
- Surgical repair of scimitar syndrome may involve direct reimplantation of the scimitar vein into the left atrium, conduit placement to the left atrium, or intracaval baffling, and is typically considered in patients with significant symptoms or hemodynamic abnormalities 1.
- The presence of an absent left circumflex artery may impact the surgical approach and requires careful consideration by a multidisciplinary team of cardiologists and cardiothoracic surgeons.
From the Research
Absent Left Circumflex Artery in Scimitar Syndrome
- The absence of the left circumflex artery (LCX) is a rare congenital anomaly of the coronary circulation, considered largely benign, although it may be associated with exertional chest pain and premature atherosclerosis 3, 4.
- In the context of scimitar syndrome, the presence of an anomalous origin of the left circumflex artery from the pulmonary artery has been reported, which may lead to significant complications, including pulmonary hypertension and impaired left ventricle function 5.
- Scimitar syndrome is a rare congenital anomaly, and the presence of an absent LCX in this context may be a concern, as it may be associated with increased risk of pulmonary vein stenosis or death 6.
- The incidence of left circumflex ALCAPA (anomalous origin of the left coronary artery from the pulmonary artery) in scimitar syndrome patients has been reported to be around 5.5%, highlighting the importance of investigating for ALCAPA in patients with scimitar syndrome, especially those with evidence of ischemia 7.
- The management of scimitar syndrome patients with an absent LCX or ALCAPA requires a comprehensive anatomical and functional assessment to determine the best course of treatment, which may include surgical intervention or close monitoring 4, 6.