Transcatheter Valve-in-Valve Implantation

Surgical valve replacement is frequently required in patients with severe native valve disorders not amenable to valve repair. Until recently, valve replacement invariably required open-heart surgery with cardiopulmonary bypass. This major surgery was associated with morbidity, mortality, long hospital stays, and disability. The surgical prosthetic valves commonly used are less than perfect, and the long-term results are still suboptimal. Most prosthetic valves that are surgically implanted are either mechanical or biological (tissue valves). Although the mechanical valves are durable and can potentially last for a lifetime, they require full, lifelong anticoagulation therapy, which may result in bleeding tendency and limitation of strenuous sports and physical activity. Bioprosthetic valves were introduced with the hope that anticoagulation would not be required. Unfortunately, biological valves degenerate and fail within years after their surgical implantation and become stenotic, insufficient, or both. Valve failure is more rapid in young patients. Therefore, bioprosthetic valves are more frequently recommended in older adult patients (who have higher prevalence of coronary disease and other comorbidities). However, with improved patient care and better survival of cardiac patients, many individuals will require one or more major open-heart surgeries to replace a failed valve. The repeat procedure carries relatively high morbidity and mortality, with long hospitalizations and frequently incomplete recovery.