Although percutaneous interventions are integral to the management of congenital heart disease, they carry an inherent risk of major complications that may necessitate emergency cardiac surgery. This chapter reviews the aetiology, recognition and management of such complications in both paediatric and adult congenital populations. Common indications for emergent surgical intervention include vascular injury, cardiac perforation with tamponade, device malposition or embolisation and structural or valvular damage. The chapter discusses the role of established risk stratification tools such as C3PO, CHARM, CRISP, IMPACT and the recently developed PREDIC3T score, in predicting adverse events and facilitating timely rescue. It also highlights the significance of multidisciplinary preparedness, real-time imaging and the availability of surgical and mechanical support, including extracorporeal membrane oxygenation. Particular emphasis is placed on early detection, coordinated response and the collaborative interface between interventional cardiology, surgery, anaesthesia and intensive care. Despite the low incidence of catastrophic events, proactive risk assessment, adherence to procedural protocols and robust institutional preparedness remain essential in ensuring optimal outcomes following congenital cardiac catheterisation.