Congenitally persistent left superior vena cava: a possible unpleasant problem during invasive procedures.

The persistence of the left superior vena cava is the most common thoracic vein anomaly, but, nevertheless, it continues to be an unpleasant finding during invasive diagnostic cardiovascular procedures and is sometimes a challenge during invasive therapeutic interventions. Persistent left superior vena cava usually occurs in 0.5% of the normal population and 0.47% of patients undergoing pacemaker or implantable cardioverter defibrillator implantation. The incidence in congenital heart disease varies (2-5%), and it is more frequent in stenosis or pulmonary atresia, D-transposition, complete atrioventricular septal defects, and anomalous pulmonary vein drainage. The diagnosis is almost always incidental, during anaesthesiological procedures such as central vein placement, or diagnostic cardiovascular procedures, such as right heart catheterization, but it may sometimes be discovered during therapeutic paediatric cardiac catheterization, such as during patent foramen ovale or atrial septal defect transcatheter closure. Echocardiography is useful to identify patients in whom computed tomography and especially magnetic resonance imaging may pose a definitive diagnosis. In indicated cases, when cyanosis is present and the anomaly is isolated, treatment options include surgical ligation and transcatheter closure using large occluder devices, whereas more challenging surgical repairs are needed when the anomaly is associated with other complex congenital heart diseases. Different specialists at different levels such as anaesthesiologists, invasive cardiologists, electrophysiologists and cardiac surgeons should be aware of the variety of technical problems that may be caused by a persistent LSVC.