Cath Lab Digest

Regardless of the merit of a new medical device, it does not take long for patients or relatives to inquire about new technology that could potentially be used to their advantage. However, when asked by an experienced and generally skeptical cardiology colleague who underwent aortic valve replacement with a bioprosthetic valve more than 10 years ago (with excellent results) whether a percutaneous valve may be an option for him in the event of prosthetic failure, two aspects of this new technique become apparent. First, it has already become a real treatment option and, second, specialists who frequently manage patients with aortic valve disease better become well prepared to answer important questions regarding this new technology such as patient suitability and limitations, current periprocedural complication rates and data regarding intermediate and long-term results, as well as potential improvements that are expected with technology currently under development.

Two factors determine patient suitability: 1) the anatomy of the iliofemoral vasculature and the aortic valve and its surroundings; and 2) the patient’s clinical condition which dictates perioperative risk for conventional surgical valve replacement. Akin et al, in the February 2010 issue of Vascular Disease Management, present an excellent review on the clinical and anatomical appropriateness for transcatheter aortic valve replacement emphasizing a multidisciplinary approach to patient selection that not only takes into account the quantitative assessment via conventional surgical risk scores (high risk is typically a projected mortality of > 20% by EuroSCORE and > 10% by STS score), but also the clinical variables that are clearly associated with a high surgical risk but not part of traditional scores (e.g., porcelain aorta, chest radiation, previous aorto-pulmonary bypass). The authors appropriately point out that, currently, given the excellent results with conventional surgery, patients who are not considered to have a high surgical risk should not be offered percutaneous treatment merely due to patient preference. Both del Valle-Fernandez et al and Akin et al review the anatomical requirements for transcatheter valve replacement, particularly with the CoreValve, the most important of which are the maximum width of the ascending aorta, the size of the aortic annulus, the degree of aortic regurgitation, annulus-to-aorta angle, sinus of Valsalva height, the aortic root diameter and the position of the coronary artery ostia. In addition, the iliofemoral circulation needs to be of sufficient diameter and configuration to accommodate the sheath. However, an insufficient iliofemoral circulation does not preclude the use of an alternative vascular access (via the axillary/subclavian route) or the less invasive surgical transapical approach. In the previous January 2010 issue, Gerckens et al described their results with the trans-subclavian approach,¹ and in this issue, Dr. Doss reports on the approach to transapical aortic valve replacement and summarizes the currently available data on more than 1,000 patients. Similar to the transfemoral technique, this approach is rapidly evolving and, though a hybrid operating room with readily available capabilities to establish on-pump support is essential, conversion to on-pump has become uncommon in the hands of experienced multidisciplinary teams.