Abstract
BACKGROUND: Persistent left superior vena cava (PLSVC) is the most common thoracic venous anomaly and is often associated with complex congenital heart disease (CHD). Venous drainage typically occurs into the right atrium via the coronary sinus (CS). However, in 10-20% of cases, it drains into the left atrium, producing a right-to-left shunt that may result in symptoms and cerebrovascular complications. CASE PRESENTATION: A 23-year-old woman with a history of double-outlet right ventricle corrected at age 13 presented in the postpartum period with dysarthria, left central facial palsy and left hemiparesis. Brain MRI angiography revealed right middle cerebral artery (M2) occlusion, and she underwent thrombolysis and thrombectomy. Suspecting a cardioembolic event, transesophageal echocardiography with left-arm agitated saline injection revealed early left atrial opacification and delayed right-sided filling via a residual ventricular septal defect -suggesting a PLSVC draining into the left atrium. Cardiac CT confirmed CS agenesis and a PLSVC connected to the left atrial roof. She was discharged on enoxaparin. CONCLUSIONS: PLSVC is a vascular anomaly with an estimated prevalence of 0.2-3% in the general population and 1-12% among CHD patients. A dilated CS on transthoracic echocardiography should prompt a bubble test; early opacification of the left chambers after left-arm saline injection suggests drainage to the left atrium. Cardiac CT, MRI or invasive angiography can clarify the anatomy. PLSVC has clinical implications including technical considerations for percutaneous procedures and cardiac surgery, a predisposition for arrhythmias, and -when draining into the left atrium- an increased risk of cerebrovascular events. Closure of a PLSVC draining into the left atrium should be considered in symptomatic patients or those at high risk of paradoxical embolism, following anatomical assessment. In pregnant women with CHD, cardiac risk assessment, multimodal imaging and multidisciplinary follow-up are crucial due to associated hemodynamic changes and hypercoagulable state.