Mitral valve disease is common in ageing populations, with mitral regurgitation (MR) being the most prevalent lesion. Surgical mitral valve repair or replacement remains the gold standard for most patients with severe symptomatic disease; however, nearly half are considered high-risk surgical candidates due to advanced age or significant comorbidities. Over the past decade, transcatheter interventions—including transcatheter edge-to-edge repair (TEER) and transcatheter mitral valve replacement (TMVR)—have expanded treatment options for patients who are inoperable or at prohibitive surgical risk. Procedural safety has improved markedly, with major complication rates after TEER falling to approximately 3%. Nonetheless, serious complications such as cardiac tamponade, clip embolisation, device detachment, severe residual MR, and persistent iatrogenic atrial septal defects may arise and necessitate urgent surgical intervention. This chapter reviews current evidence and surgical considerations for managing patients who require cardiac surgery following percutaneous mitral valve procedures. Key aspects include strategies for cannulation, choice of sternotomy versus minimally invasive approach, and decision making on repair versus replacement—each tailored to patient suitability and case complexity. Although outcomes remain variable, reflecting the high-risk nature of this population, timely surgical intervention can be life-saving. Careful patient selection, multidisciplinary procedural planning, and readiness for immediate surgical conversion remain critical to optimising results.