Quadricuspid aortic valve and its rare association with left main obstruction: case report and literature review.

The quadricuspid aortic valve (QAV) is a rare congenital anomaly. We report a 51-year-old woman with QAV who experienced intermittent chest pain due to fibrotic tissue overgrowth from the small left coronary cusp, obstructing the left main coronary artery (LM). Angiography revealed a large "Vieussens' arterial ring," which acted as a collateral channel from the right coronary artery to the left coronary artery, preserving coronary blood flow and left ventricular function. Surgery successfully removed the tissue, maintaining both aortic valve function and coronary patency. This case highlights the need to consider QAV complications and use various imaging modalities for accurate diagnosis and treatment planning, including evaluating potential issues like aortic regurgitation and coronary anomalies.