Introduction Aortic valve replacement is a class I indication for patients with severe aortic stenosis and symptoms in the ACC/AHA guidelines for the treatment of cardiac valvular disease.1 Since some patients can be judged too high a risk to undergo surgery, they may be denied aortic valve replacement. Transcatheter aortic valve replacement (TAVR) has been developed as a potential option for this patient group. To date, there are two studies that have evaluated two valve devices: The PARTNER Trial

using the Edwards SAPIEN valve, which was approved for use in nonsurgical candidates by the FDA in December 2011,2, 3 and Inhibitors,research,lifescience,medical the CoreValve US Pivotal Trial (using the Medtronic CoreValve) that is currently active and accruing patients. Both of these devices require large bore access for placement. The Edwards SAPIEN valve used in the PARTNER Trial can be inserted using an iliofemoral access or a transapical cardiac access. For the valves used in the PARTNER Trial, the small valve (23 mm) required a 22-Fr sheath and the large valve Inhibitors,research,lifescience,medical (26 mm) required a 24-Fr

sheath Inhibitors,research,lifescience,medical for iliofemoral access. Both valves used a 26-Fr sheath when direct transapical cardiac insertion was used in patients who were not candidates for iliofemoral access. A newer version, the SAPIEN XT, can be inserted using an 18-Fr sheath via the iliofemoral route. The Medtronic CoreValve currently comes in 23 mm, 26 mm, 29 mm, and 31 mm sizes and all are inserted through an 18-Fr sheath. For both valves, the femoral route is the preferred method of insertion whenever possible. When iliofemoral access is not possible with the CoreValve, both subclavian artery and direct aortic approaches have Inhibitors,research,lifescience,medical been used. Planning access for TAVR requires knowledge of the luminal size as well as the degree of vessel calcification and tortuosity. Inhibitors,research,lifescience,medical We consider a high-quality thin-slice

CT scan with contrast that extends from the femoral artery to the subclavian artery the cornerstone of evaluation. Arteriography and intravascular ultrasound (IVUS) can add additional data but are not considered acceptable as standalone imaging modalities. For the non-interventionist, it is important to remember that the size of the catheters to be used is listed as the outer diameter (OD), while the Amisulpride size of the sheaths to be used is listed as the inner diameter (ID). In the French sizing system, 3 Fr equals 1 mm — therefore, the ID of the 18-Fr, 22-Fr, and 24-Fr sheaths are 6 mm, 7 mm, and 8 mm respectively. In general, the outer diameter is about 1 mm larger, which is important in planning access. In noncalcified CYC202 arteries, we can generally insert a sheath through an artery that is about 0.75% of the sheath’s outer diameter; in a heavily or circumferentially calcified artery, we need an artery that is 1.25% of the sheath’s outer diameter.