Management of Vascular Access in Transcatheter Aortic Valve Replacement : Part 1: Basic Anatomy, Imaging, Sheaths, Wires, and Access Routes

Transcatheter aortic valve implantation (TAVI) has emerged as a new therapy for patients with severe aortic stenosis who are inoperable or at very high risk of open heart surgery. Vascular complications are a potential limitation of TAVI and have been associated with bleeding, transfusions, and mortality. Transfemoral TAVI can be considered the least invasive approach and is therefore the most widely used access for TAVI. With the current 18-F to 24-F sheaths, the majority of patients can be treated via the transfemoral route. Initially, open surgical access was routinely used to introduce the large sheaths and catheters. Subsequently, percutaneous techniques have emerged as the new standard, resulting in a less invasive, fully percutaneous procedure. Stiff wires allow insertion of the sheath and delivery of the device without causing trauma to the artery. Given the high burden of vascular disease in TAVI candidates, increasing the effectiveness of pre-procedural screening is key. This often begins with conventional angiography, but computed tomography allows visualization of the artery in 3 dimensions, thereby overcoming some of the limitations of conventional angiography. Approximately one third of patients do not have adequate anatomy to allow safe transfemoral access. In such patients, alternative access routes such as the transapical, transaxillary, or direct aortic access are preferred. These alternative routes all have specific advantages and disadvantages.